1

EFFECT OF DRYING METHODS ON THE NUTRIENT AND

PHYTOCHEMICAL PROPERTIES OF SOME CULTIVATED AND WILD

LEAFY VEGETABLES.

BY

EME-OKAFOR, EZINWA PERPETUA

PG/M.Sc/08/49418

DEPARTMENT OF HOME SCIENCE, NUTRITION AND DIETETICS

FACULTY OF AGRICULTURE

UNIVERSITY OF NIGERIA, NSUKKA

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EFFECT OF DRYING METHODS ON THE NUTRIENT AND

PHYTOCHEMICAL PROPERTIES OF SOME CULTIVATED AND WILD

LEAFY VEGETABLES.

A RESEARCH PROJECT PRESENTED IN PARTIAL FULFILMENT OF

THE REQUIREMENTS FOR THE AWARD OF MASTERS OF SCIENCE

DEGREE IN NUTRITION AND DIETETICS

IN

DEPARTMENT OF HOME SCIENCE, NUTRITION AND

DIETETICS

FACULTY OF AGRICULTURE

UNIVERSITY OF NIGERIA, NSUKKA

BY

EME-OKAFOR, EZINWA PERPETUA

PG/M.Sc/08/49418

SUPERVISOR

PROFESSOR I.C. OBIZOBA

JULY, 2012.

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CERTIFICATION

This is to certify that this thesis has been approved for the award of

Masters of Science Degree in the Department of Home Science, Nutrition

and Dietetic of University of Nigeria, Nsukka and that the candidate has

effected all the corrections pointed out by the External examiner.

……………… …….... ………..…… ……….. Prof. (Mrs) N.M. Nnam Date Prof. I.C. Obizoba Date

(Head of Department) (Supervisor)

................................... ……………. Prof. (Mrs) E.K. Ngwu Date

(Internal Examiner)

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ACKNOWLEDGMENT

I wish to acknowledge the help of the Almighty God who without his support his

work would not become a reality. I wish to thank my supervisor Prof I.C Obizoba

who painstakingly guided me throughout the course of this work. Prof., I am really

grateful. May God Almighty ever remain merciful to you. To my parents for all their

care and support throughout my course of study. Mum and dad, I am forever indebted

to you. To my siblings for all their love and distractions. I say thanks for being there.

To the special friends in my life, I pray that the you never lack. To all the lecturers,

staff and students of the department of Home Science, Nutrition and Dietetics who

contributed in one way or the other in making this research work what it is, I say

thank you and lastly, to the ever green memory of Late Prof. E.C.Okeke who saw to

the perfection of my synopsis. Madame, I pray that the ever merciful God grants you

eternal rest. Amen.

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DEDICATION

This work is dedicated to God Almighty for his love and mercy towards me, and to

my parents Prof. and Mrs E.E Okafor for all their support, prayers and

encouragement.

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ABSTRACT

The aim of this study was to determine the nutrient and phytochemical composition of

fresh, sun and shade dried okra, bitter, scent, G. latifolium and roselle leaves. The

vegetables were purchased from two markets. Okra, bitter, scent and G.latifolium

leaves were purchased from Nsukka and roselle leaves were bought from Jos market.

All the vegetables were washed, weighed and divided into two equal parts. Each part

was sun, or shade dried, pulverized, packed and stored. The fresh samples for each of

the vegetables served as control. The fresh, sun and shade dried samples of all the

vegetables were separately analyzed for various nutrient and phytochemicals on dry

weight basis using standard assay techniques. Data generated were statistically

analyzed. The means were separated and compared. All the fresh samples had high

moisture values(Okra leaf; 62.22%, bitter leaf; 62.32%, scent leaf; 62.46%,

G.latifolium; 61.44% and roselle leaf; 85.53%) . The moisture content of the sun and

the shade dried samples differed (P<0.05). The exception was that of roselle whose

sun and shade dried values were comparable (6.36 and 6.38%) (P>0.05). Fresh

samples of all the vegetables had lower protein. The processed okra, bitter, scent and

roselle leaves had comparable values (P>0.05). Moisture lost due to drying increased

nutrient density of the vegetables, especially the roselle leaves. The phytochemicals

(Tannins, phytate, saponins and flavonoid) of the fresh samples were higher than

those of the sun and the shade dried samples. This showed that fresh vegetables are

better sources of phytochemicals as against the sun and the shade dried samples. The

shade dried samples had lower tannins except for the bitter leaf and the sundried

samples had lower phytate except the G. latifolium. The sun and the shade dried

samples had comparable saponins and flavonoids content (P<0.05). As judged by the

results, domestic food processing techniques improved the nutrient content of these

vegetables and decreased some of the food toxicants and antinutrients.

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CHAPTER ONE

1.0 INTRODUCTION

Man must eat to survive for the continuity of the human race. The foods for

human consumption are of both plant and animal origin. Cereals, legumes, roots,

tubers, suckers, oils, nuts, fruits and vegetables are plant foods. Meat, milk, eggs and

oils are animal products. Both plant and animal foods contain nutrients. Oxford

Medical Dictionary (2003) defines nutrients as substances that must be consumed as

part of the diet to provide energy, protein for growth or substances that regulate

growth or energy production. Carbohydrate, proteins, fats, vitamins, minerals and

water are the existing six nutrients.

It is known that too much or too little of these nutrients have adverse effects

on health. The source of these nutrients equally determines how healthy one is. A

typical example is in the case of fats. Animal fat contains about 40-60% of fat as

saturated fatty acids. Plant oils contain mostly unsaturated fatty acids ranging from 73

to 94% of total fat (Wardlaw & Kessel, 2002). Plant oil is the most beneficial to

health. Current studies showed that plant nutrients are not inferior to animal nutrients

as it was earlier thought. In addition, plants contain other non-nutritive dietary

components that are beneficial to health. These components are called

phytochemicals. “Phyto” because they are only found in plant based foods

(Pamplona-Roger, 2005). The present study concentrated on nutrient and

phytochemical levels of five cultivated and wild vegetables.

Vegetables are generally herbaceous (non-woody) plants that are cultivated in

farms, collected from forest trees, market and home gardens as well as kitchen

gardens for home use. Usually, all the botanical parts of the plants (leaves, buds or

flowers, calyxes, fruits, stalk, roots are consumed) (Pamplona-Roger, 2005). This

study laid emphasis on green leafy vegetables.

History shows that vegetables were used for a number of purposes. Many in

the past consumed these vegetables without knowing all they contain. Scent leaf was

used and is still being used to stop diarrhoea. How and what stops diarrhoea in scent

leaf is still a puzzle to many. The foods our ancestors consumed consisted of

carbohydrates, starchy vegetables, leafy vegetables and little or no animal products.

There were not much occurrences of various chronic diseases such as morbid obesity,

cancer, heart and renal failure three to four decades ago as they are now. The juvenile

and paediatric cases of these diseases are on the increase. The cause of their increase

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is due to migration/changes in lifestyle and food habits (Ene-Obong, 2008). The very

sharp shift from traditional diets as well as the advent of exotic diseases appears to

suggest a serious warning. These warnings call for urgent increases in consumption of

preventive and curative substances inherent in plant based food, especially vegetables.

Chemically, green leafy vegetables are composed of water; 90 to 95%,

minerals e.g. phosphorus, potassium, calcium, iron, vitamins, fibre, proteins,

chlorophyll and most recently discovered- phytochemicals (Pamplona-Roger, 2005).

Indigenous traditional foods are on the verge of extinction. The younger generation is

ignorant of them as such; consume less of these vegetables (Ene-Obong, 2008). As

most of these traditional foods are on the verge of extinction, so are the vegetables,

condiments and spices used in their preparation. Some of the wild forest vegetables

might have been used by a particular community in the past. Based on these serious

observations associated with less consumption of indigenous foods and increases in

many chronic ailments, it is imperative to study the nutrient and phytochemical

potentials of some cultivated and wild vegetables.

1.1 Statement of problem

The increase in the consumption of western diets and neglect of our traditional

foods has precipitated a corresponding increase in ill-health due to diet related non-

communicable diseases. These diseases are of various forms; cancer, kidney and liver

diseases, diabetes and many more. Prevention of these diseases based on new

incidences of these diseases is imperative. This is because these diseases are of

increasing public health concern. Extensive studies are ongoing to address these

public health threats both for the cure of already existing cases and prevention of new

cases. One hopes that the results of these studies will provide baseline information as

to their causes and treatment.

However, some of the information based on the results of recent studies point

to the type of foods consumed by people. Currently, nutrients from plant based foods

have promising solution (Ene-Obong, 2008). Vegetable based foods are advocated

because of their high content of non-nutritive dietary components that are safer and

more beneficial to man. Some of these vegetables contain antioxidants and

phytochemicals. Sadly, in Nigeria, little attention is paid to fruits and vegetables.

Statistics from World Bank (1991) showed that at the National level, an average

household expenditure on household staples was highest on fish (N140.84) followed

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by meat products (N81.54). The least weekly expenditure was on fruits (N13.12)

followed by weekly expenditure on green leafy vegetables (N20.88).

Vegetables are the most affordable dietary sources of vitamins, trace elements

and other bioactive compounds that offer the only practical and sustainable way to

ensure that micronutrients are supplied through the diet (Odo, 2007). It is imperative

to study more vegetables for their nutrient and photochemical potentials. The

investigation of these vegetables would be of immense benefit to the society.

1.2 Objective of the study

The general objective of the study were to determine the effect of drying

methods on the nutrient and phytochemical properties of some cultivated and wild

leafy vegetables.

The specific objectives of the study are to;

a. determine nutrient, and phytochemical content of these vegetables

b. sun, shade dry and pulverize these vegetables to determine the nutrient content

of their flours.

c. determine the nutrient and phytochemical potentials of these vegetables on dry

weight basis.

1.3 Significance of the study

The results of this study would be a promising and useful tool to home makers

on the increasing need to produce both cultivated and wild forest vegetable and

consume them, especially the children and younger adults. Increase consumption of

these vegetables might be the solution to the cases of micronutrient deficiencies world

wide and some chronic and deadly diseases such as cancers and other diseases and

their complications, particularly in developing countries, Nigeria inclusive.

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CHAPTER TWO

2.0 LITERATURE REVIEW

In 2000, the member states of the United Nations committed themselves, to

creating a “more peaceful, prosperous and just world” to “freeing our follow men,

women and children from the abject and dehumanizing conditions of extreme

poverty” to making “the right to development a reality for every one” and to ridding

“the entire human race from want” (Von Braun, Swaminthan & Harlow, 2004). This

declaration needed an enforcement which was the Millennium Development Goals

(MDGs). The MDGs are specific and should be met by 2015. The MDGs cannot be

achieved without a direct focus on nutrition because each of the eight goals is directly

or indirectly linked to it.

Nutrition as defined by the council of Food and Nutrition of the American

Medical Association is the “Science of food, the nutrients and the substances therein,

their action, interaction and balance in relation to health and diseases, the process by

which the organism ingests, digests, absorbs, transports, utilizes and excretes food

substances (Wardlaw & Kessel, 2002). Nutrients are classified into micro and macro

nutrients. The macro nutrients being proteins, carbohydrates and fats, and the micro

are vitamins and minerals. Malnutrition is a condition of impaired development and

function caused by either long term deficiency or an excess in energy and/or nutrient

intake (Wardlaw & Kessel, 2002). The former, representing the nutritional state in

Nigeria. The focus here was on micronutrient malnutrition which is of global public

health importance.

2.1Micronutrient malnutrition in Nigeria

In 1990, the term hidden hunger was adapted to refer to micronutrient

deficiency due to substances so small that one could not see them. One out of three

people in the world are affected by one or multiple micronutrient deficiencies (WHO,

2006). Micronutrient deficiencies of international interest include vitamin A, iron,

iodine and zinc. Their deficiencies among the Nigerian population have been

documented (Ene-Obong, 2008). The Nigerian Food Consumption and Nutrition data

showed that 29.5% of children had marginal vitamin A deficiency, and 13% of

mothers and 19.2% of pregnant woman were at risk of vitamin A deficiency. The

study also showed that 20% of the children were both iron and zinc deficient while

14.5%, 8% and 4% had mild, moderate and severe iodine deficiency (Maziya-Dixon

et al., 2004). A study by Ene-Obong, Odoh and Ikwuagwu (2003) showed that despite

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adequate intakes of vitamin A, 40% of male and 32% of female adolescents had low

plasma concentration of vitamin A (< 20 ug /dl). The first, fourth, fifth and sixth

MDGs (which are to; Eradicate extreme poverty and hunger, reduce child mortality,

improve maternal health and combat HIV/AIDS, malaria and other diseases) are

directly linked to micronutrient malnutrition. To combat micronutrient deficiency,

food and nutrition security is paramount and this cannot be achieved if agriculture and

nutrition are not given top priority.

Sadly, indigenous food crops are no longer given the top priority they deserve

(Okafor, 1975). They and are at the point of extinction (Okeke, Ene-Obong,

Uzuegbunan, Ozioko & Kuhnlein, 2008). The younger generations do not even know

them, like them, let alone consume them (Ene-Obong, 2008). Some food items such

as African yam bean and pigeon pea are now rarely consumed by urban dwellers. This

is because of the length of time they take to cook and amount of fuel they consume,

despite the fact that they are highly nutritious (Okigbo, 1980). They equally contain

both micro and macro nutrients in appreciable amounts. The above scenario shows

that there is need for advocacy and sensitization on the importance of indigenous food

crops and vegetables. The focus here is on vegetables, nutrients and phytochemicals

content.

2.2 Vegetables

The term vegetable usually refers to the fresh edible portion of a herbaceous

plant -root, stem, leaves, flower or fruits (Encarta, 2008). Vegetable are naturally low

in fat and calories. None have cholesterol and many are good sources of fibre. They

are rich in minerals and vitamins (Iloveindia, 2004). Until most recently, a group of

chemicals known as phytochemicals were discovered. They are found only in plant

based food in very small amount. They perform numerous preventive and healing

functions within the body (Pamplona-Roger, 2005).

Vegetables equally contain carbohydrates, proteins, and fat. They can be

categorized according to their type and taste e.g.

Bulb vegetables e.g. onions, garlic and shallots.

Fruit vegetables e.g. avocadoes, cucumbers, okra, tomatoes, pepper and eggplant.

Inflorescent vegetables e.g. broccolis and artichokes.

Leafy vegetables e.g. bitter leaf, scent leaf, lettuce, spinach and cabbage.

Root vegetables e.g. carrots, beets, radishes and turnips.

Stalk vegetables e.g. asparagus, bamboo and celery.

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Tuber vegetables e.g. cassava, yam, sweet potato, and taro.

Source: Iloveindia (2004).

2.2.1 Roselle (Hibiscus sabdariffa)

Roselle is a native of the old world tropics and a species of hibiscus. It is an

annual, erect, bushy herbaceous subshrub that grows up to 2.4m tall. The leaves are

alternate 7.5-12.5cm long, the flowers borne singly in the leaf axils, are up to 12.5cm

wide yellow or buff with a rose or maroon eye and turn pink as they wither at the end

of the day. The typically red calyx consists of 5 large sepals with a collar (epicarlyx)

of 8 to 12 slim pointed bracts around the base (Morton, 1987). It is known as roselle

in Australia, meshta in the Indian subcontinent, bissap in Senegal, Mali, Burkina

Faso, Benin and Niger, rozelle, sorrel or red sorrel in English speaking regions,

rosella in Indonesia and zobo in Nigeria (Wikipedia-Roselle, 2009).

Uses

Primarily, the plant is cultivated for the production of bast fibre from the stem

of the plant. The fibre may be used as a substitute for jute in making burlap (Hibiscus

sabdariffa, 2007; Morton, 1987). The red carlyx has been extensively used more than

any other part of the plant and was the focus of this study.

Nutrient composition

Nutritionists have found roselle carlyces sold in Central American markets to be high

in calcium, niacin, riboflavin and iron. Food values per 100g of edible portion of fresh

Roselle (Hibiscus sabdariffa) calyces are;

Moisture 9.2g

Protein 1.145g

Fat 2.61g

Fibre 12.0g

Ash 6.20g

Calcium 1,263mg

Phosphorus 273.2mg

Iron 8.98mg

B-Carotene 0.029mg

Thiamin 0.117mg

Riboflavin 0.277mg

Niacin 3.765mg

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Ascorbic acid 6.7mg

Source: Morton (1987).

Medicinal properties

1. Several studies have shown that hibiscus tea has a substantial antihypertensive

effect attributed to the flowers ACE-inhibiting anthocyanin content and

possible to a diuretic effect. One study found that hibiscus conferred an

antihypertensive effect comparable to 50mg/day of the drug Captopril

(Wikipedia-Prehypertension, 2009).

2) In East Africa, the calyx infusion, called “Sudan tea”, is taken to relieve

coughs (Wikipedia- Roselle, 2009).

3) Morton (1987) reported that it has also been used in the treatment of urinary

tract infection.

Phytochemical content

The calyces contains the flavonoids; gossypetin, hibiscetine and sabdaretine.

The major pigment formerly reported as hibiscin, has been identified as

daphniphylline. Small amount of myatillie, cheysanthenin and delphinidin are

also present. Toxicity is slight (Morton, 1987; Wikipedia-Roselle, 2009).

2.2.2 Bitter leaf (Vernonia amygdalina)

Bitter leaf is widely distributed throughout tropical Africa. It is a shrub or

small tree of 2-5m with petiolate leaves of about 6mm in diameter and elliptic in

shape. The leaves are green with a characteristic odour and a bitter taste (Anonymous,

1999). It is known in Edo as oriwo, chusar doki in Hausa, fatetale/mayemage in

Ibibio, ityuna in Tiv, ewuro in Yoruba and onugbu in Igbo (Vernonia amygdalalina,

2010).

Uses

The most extensively used part of the plant is the leaves which when washed can be

used for soup and stew making and also in the preparation of various local dishes.

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Nutrient composition

The proximate composition of bitter leaf in percentages and mineral composition in

part per ml as analysed by Okafor (1995) are as follows;

Moisture 76.67 %

Ash 7.67%

Oil 1.10%

Protein 22.07%

Manganese 0.444mg

Calcium 0.185mg

Iron 0.045mg

Phosphorus 6.136 mg

Medicinal properties

1) Many herbalists and naturopathic doctors recommend aqueous extracts of

bitter leaf for their patients as treatment for nausea, diabetes, dysentery and

other gastrointestinal problems. (Wikipedia-Vernonia amygdalina, 2009).

2) Bitter leaf extracts may also suppress, delay or kill cancerous cells in many

ways such as;

a. Suppression of metastasis of cancerous cells in the body by inhibition

of NFkB, an anti-apoptotic transcription factors as demonstrated in

animal studies (Song et al., 2005).

b. Induction of apoptosis as determined in cell culture and animal studies

(Song et al., 2005)

c. Bitter leaf extracts may render cancerous cell to be more sensitive to

chemotherapy (Izevbigie, Bryant & Walker, 2004).

3) It has been used in fever reduction and recently for non-pharmaceutical

solution to persistent fever, headache, and joint pain associated with AIDS

(Herbal Medicine, 1993).

4) It has been used for ginginvitis and toothache due to its proven antimicrobial

activity (Traditional Medicine Development for Medicinal and Dental Primary

Health Care Delivery System in Africa, 2005).

5) In the wild, Chimpanzees have been observed to instinctively ingest the leaves

when suffering from parasitic infections (Huffman & Seifu, 1989).

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Phytochemical content

The characteristic bitter taste of bitter leaf is due to the presence of phytochemicals

such as alkaloids, saponins, tannins and glycosides (Anonymous, 1999; Bonsi, Osuji

& Tuah, 1995).

2.2.3 Okra (Abelmoschus esculentus)

Okra traces its origin form Ethiopia (formally Abyssinia) spreading right through

Eastern Mediterranean, India, Africa, North America, South America and the Caribbean (Okra,

2009). The species is an annual or perennial, growing to 2 meters tall. The leaves are 10-20cm

long and broad, palmately lobed with 5-7 lobes. The flowers are 4-6cm in diameter, with 5

white to yellow petals, often with a red or purple spot as the base of each petal. The fruit is a

capsule up to 18cm long, containing numerous seeds (Wikipedia –Okra, 2010). It is known as

okra or lady finger in English speaking countries, berdi in Malaysia, bamia, bamya or bamieh

in the Middle East, quiabo in Portugal and Angola, okura in Japan and okwuru in Igbo

(Wikipedia-Okra, 2010; Okra, 2007).

Uses

Okra has many species and they are primarily cultivated for their fruits which come in

pods. The pods are used for vegetables, harvested and ate when tender. The focus is on the

leaves. The products of the plant are mucilaginous and the leaves are not an exception. The

cooked leaves are used as powerful soup thickeners (Wikipedia-Okra, 2010).

Medicinal properties

Okra has several health benefits that include;

1) The superior fibre found in okra stabilizes blood sugar by curbing the rate at which

sugar is absorbed from the intestinal tract.

2) Okra fibre is used for treating ulcers and to keep joints limber.

3) It neutralizes acids, being very alkaline and provides a temporary protective coating for

the digestive tract.

4) Tankano (1999) reported that okra prevents pimples and maintains smooth and beautiful

skin. Its fibre is excellent for feeding the good bacteria (probiotics). This contributes to

the health of the intestinal tract.

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2.2.4 Utazi (Gongronema latifolium)

G. latifolium is a tropical rainforest plant primarily used as spices and vegetable in

traditional folk medicine (Ugochukwu & Babady, 2002). It is a climber from a tuberous base. It

is known as aborade-aborode, akare, kurutu, nsurogya in Ghana, arokeke in Yoruba, gasub in

Senegal, rupe quial in Sierra Leone and utazi in Igbo (Burkill, 1985).

Uses

Different parts of the plant are used for different purposes. However, the most focus in this

work is on the leaves. The leaves are used primarily for culinary and medicinal purposes.

Nutrient composition

The proximate composition of G.latifolium in percentages and mineral composition in part per

ml as analysed by Okafor (1995) are as follows;

Moisture 71.4%

Ash 10.94%

Oil 18.77%

Protein 0.16%

Sodium 58mg

Potassium 336mg

Magnesium 56mg

Calcium 20.75mg

Copper 0.12mg

Iron 8.17mg

Zinc 0.90 mg

Medicinal properties

1) It is a source of iron, promotes pregnancy and treatment of diabetes (Okafor, 1995).

2) Its aqueous and ethanolic extracts have hypoglycemic, hypolipermic and antioxidant

properties (Ugochukwu & Babady, 2003; Ugochukwu, Babady, Cobourne & Gasset,

2008; Ogundipe, Moody, Akinyemi & Raman, 2003).

3) A study by Morebise, Fafunsu, Makinde, Olajide and Awe (2002), showed that it has

anit-inflamatory properties as well as antibacterial uses (Afolabi, 2007).

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Phytochemical properties

Reports by various authors showed that it contains essential oils, saponins and pregnanace

among others (Schneider, Rotscheidt & Breitmaier, 1993; Morebise & Fafunso, 1998).

2.2.5 Scent leaf (Ocimum gratissimum)

Scent leaf is widely distributed in the tropics of Africa and Asia. It is a woody based

perennial plant. It has an average height of 1-3 meters. The leaves are broad and narrowly

ovate, usually 5-13cm long and 3-9cm wide. It is a scented shrub with lime-green fuzzy leaves

(Efirin, 2009). It is known in English as tea bush, in Hawaii as wild basil, efinirin ajase in

Youruba, ufuo-yiba in Urhobo, aci doya tu gida in Hausa (Gills, 1992) and nchuanwu, ahigbo

or ahiji in Igbo.

Uses

The plant is cultivated mostly for the leaves and has been used extensively by

ethnomedicine practitioners for a variety of purposes. In coastal areas of Nigeria, the plant is

used in the treatment of epilepsy (Efirin, 2009) and diarrhoea (Sofowara, 1993). The Igbos of

southern Nigeria uses it in the management of the baby’s cord. It is believed to keep the baby’s

cord and wound surface sterile (Efirin, 2009). Its major culinary function centres on its

usefulness as a seasoning because of its pleasant aromatic flavour.

Medicinal properties

1) Nakamara et al. (1999) reported that the plant has antimicrobial properties and it is used

for the treatment of upper respiratory tract infections, skin diseases and pneumonia.

2) Lemos et al. (1999) showed that it has antifungal activities, antiprotozoal (Holetzl et al.,

2003) and antimalaria activities (Ehiagbonare, 2006).

3) A study on rats also found evidence that the leaf extracts prevented diarrhoea (Offia &

Chikwendu, 1999).

4) Clinical trials on its use in creams formulated against dermatological disease have

yielded favourable results (Edoga & Eriata, 2001).

Phytochemical properties

Phytochemical evaluation of the plant showed that it is rich in alkaloids, tannins, phytates,

flavonoids and oligosaccharides. It has a tolerable cyanogenic content (Ijeh, Njoku & Ekenza,

2004).

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2.3 Origin of phytochemicals

Phytochemicals are of plant origin as the name implies. They are natural

bioactive compounds found in plant foods that work with nutrients and dietary fibre to

protect against diseases (Tantilio, 2009). A wide spectrum of phytochemicals has

been discovered in plant foods, mostly fruits and vegetables. Much more researches

are ongoing, on for details of these important non-nutritve dietary components.

The merits of the preventive and curative potentials of these phytochemicals

would be attained by diversification of our diets (Wardlaw & Kessel, 2002). This is

because; various fruits and vegetables contain varied levels of phytochemicals. Citrus

fruits for example are rich in limonoids that inhibit tumor formation (Lam, Zhang &

Hasegawa, 1994). Cruciferous vegetables, on the other hand, are rich in indoles; a

group of phytochemicals that protect against heart disease, stroke and blindness

(Tantillo, 2009). It is advisable to consume a wide variety of plant foods that contain

different phytochemicals at varied levels to prevent diet related non-communicable

diseases.

2.3.1 Classes of phytochemicals

More than 1,000 different phytochemicals have been identified so far (Be Healthy

Enterprises, 2007). Phytochemicals were classified for easy identification. Some of

the classes include:

1) Carotenoids

a. Alpha-carotene

b. Beta – carotene

c. Beta – cryptoxanthin

d. Lutein

e. Lycopene

f. Zeaxanthin and others

2) Flavonoids/Bioflavonoids/Polyphenols

a. Anthocyanins

b. Catechins

c. Querecetin

d. Tangeritin

e. Resveratrol

f. Hesperidin

g. Coumarins

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h. Isoflavones (Phytoestrogens)

i. Flavanones

j. Flavones

k. Flavanols and others

3) Organosulfides

a. Allicin

b. Glutathione

c. Indole-3-curbinol

d. Isothiocyanates

e. Sulforaphane and others

4) Alkaloids

a. Caffeine

b. Theobromine

c. Theophylline and others

5) Lignans

a. Pinoresinol

b. Caricresinol

c. Secoisolariciresinol

d. Matairesinol and others

6) Saponins

a. Forosterol saponins

b. Spirosterol sriponins

c. Triterpenoid saponins and others

7) Phenolic acids

a. Capsaicin

b. Ellagic acid

c. Gallic acid

d. Rosmaric acid

e. Tannic acid and others

8) Terpenes/ Mono-terpenes

a. Limonene

b. Linolyl acetate

c. Menthol

d. Thymol and others

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9) Inositol phosphates (Phytates)

10) Phenols & cyclic compounds

a. Ginerols

b. Diarylhaptanoids and others

2.3.2 Phytochemicals as pigments and flavours

The myriad of colours and flavours associated with different fruits and vegetables

are not accidents of nature. The pigments and compounds which impact these

characteristic colours to fruits and vegetables are phytochemicals (Tantillo, 2009).

This forms basis for easy identification of phytochemicals contained in a fruit or

vegetable due to their distinct colours and flavours. Different colours suggest different

phytochemicals and different phytochmeicals means different nutritional and health

benefits. Based on these facts, it is important to consume a wide variety of colours of

fruits and vegetables on a daily basis (Be Healthy Enterprises, 2009). Listed below are

a few of the phytochemicals that are responsible for the different colours of various

fruits and vegetables.

1) Carotenoids

These are the pigments responsible for the red, blue, yellow, green and orange

colours of various fruits and vegetables (Tantillo, 2009). The variation in colour

depends on the particular carotenoid in the fruit or vegetable. They are contained in;

red pepper, citrus fruits, water-melon, sweet potatoes, mango and papaya.

2) Flavonoids

These are the pigments responsible for the characteristic blue, dark red and purple

colours of some fruits and vegetables (Sanders, 2004). They can be equally found in

green and orange coloured fruits and vegetables. They are contained in blue berries,

grapes, purple onions, egg plants, purple cabbage, figs, pears, strawberries, cherries,

cranberries, raspberries and red wine.

21

3) Organosulfides

These are found in green vegetables particularly cruciferous vegetables

(Pamplona-Roger, 2005). They are contained in cabbage, turnips and watercresses.

The characteristic flavours of different vegetables and herbs are associated with the

type of phytochemicals they contain. Terpenes are contained in aromatic herbs,

gingerols and diarylhaptanols in ginger, the sulphides in garlic and onions and

diathiolthiones and isothiocyanate in broccoli and other cruciferous vegetables are

examples of various phytochemicals that impact flavours (Craig, 2009).

2.3.3 Health benefits of phytochemicals

It might come as a surprise that compounds such as phytates, saponins,

alkaloids and flavonoids are phytochemicals. The toxic and anti-nutrient properties of

these compounds are now beneficial properties. However, most of these compounds

are detoxified by several processing methods (such as soaking, germination, boiling,

fermentation and other processing methods) (Soetan, 2008). Recent information

showed that they have potent preventive, curative, anti-oxidant and anti-inflammatory

properties some of the health benefits at some of these phytochemicals are well

documented.

1) Saponins

a. Recent reports from Canada showed that dietary sources of saponins offer

preferential chemoprotective strategy in lowering the risk of human cancers.

Saponins can kill or inhibit cancer cells without killing normal cells (Rao,

1996).

b. Saponins have also been reported to lower blood cholesterol. The

hypocholesterolemic activity of dietary saponins may be due to its formation

of some complexes with 3-B-hydroxysteroids. They are known to interact and

form large mixed micelles with acids and cholesterol (Messina, 1999).

c. Besides lowering cholesterol, saponins readily increase the permeability of

small intestine to facilitate the uptake of materials to which the G.I.T. would

not normally be permeable (Johnson, Gee, Price, Curl & Fenwick, 1986).

22

d. Malinow, Marbin and delaCastra (1985) reported that saponins assist in the

prevention of cardiovascular diseases by lowering plasma cholesterol

concentration through the excretion of cholesterol directly or indirectly as bile

acids. Saponins cause a depletion of body cholesterol by preventing its

reabsorption, thus increasing its excretion (Soetan, 2008).

e. Saponins form Vigna radiata, Vigna mungo and Vigna sinensis have diuretic

activities (Chowdhurry, Jahirullah, Tabukder & Khan, 1987). They also have

antidiabetic activities. (Yamaguchi, 1993).

2) Flavonoids

a. Flavonoids act as antioxidants that neutralize or inactivate highly unstable and

extremely reactive molecules (free radicals) that attack our body cells daily

(Tantillo, 2009).

b. Research has shown that flavonoids have anticarcinogenic properties. They

block various hormone activities and metabolic pathways that are associated

with the development of cancers (Caragay, 1992).

c. Flavonoids prevent low density lipolipids cholesterol from oxidation to the

unsafe cholesterol oxides (O-Cholesterol), inhibit platelet aggregation and

have anti-inflammatory and anti-tumor actions (Kanner, Frankel & Granit,

1994).

3) Carotenoids

a. The carotenoids; lutein, zeaxanthin and beta-cryptoxanthin have significant

antioxidant activities. These carotenoids are associated with a lower incidence

of age-related macular degeneration (Seddon, Ajani & Sperduto, 1994).

b. Carotenoids have been linked to decreased risk of both hemorrhagic and

ischemic stroke (United States Department of Agriculture [USDA], 2005).

c. Consumption of tomato products (lycopene) has been linked to decreased risk

of prostate cancer (USDA, 2005).

4) Alkaloids

a. Alkaloids have been shown to be the most potent anti-inflammatory agents

(Soetan, 2008).

23

b. They have been severally reported to have anti-microbial action (Ebana,

Madunagu, Ekpe & Otung, 1991).

c. They are used in the treatment of skin infections (Finar, 1987).

4) Terpenes/Mono-terpenes

Limonene; a terpenoid contained in orange and lemon oil have been shown to posses

anticarcinogenic potentials (Olson, 1988).

5) Lignans (Phytoestrogen)

Due to their oestrogenic and anti-oestrogenic activities, many researchers investigate

their potentials in decreasing the incidence of hormone-associated cancers and

maintenance of bone density (Higdon, 2005).

6) Phytates

Phytates have always been infamous because of the negative effect they have on

absorption of iron, zinc and calcium. However, recent studies showed that they are not

as harmful as was formerly believed. Their health benefits include;

a. As antioxidants they combine with iron which behaves like a free radical of

intense oxidizing action. They prevent an excess of this mineral from harming

the intestinal lining, turning into a factor of cancerous degeneration

(Pamplona-Roger, 2005).

b. Several experiences showed that phytates are anti-carcinogenic in both in-vitro

and in-vivo. This partially explains the cancer preventing activity that whole

grains possess (Pamplona-Roger, 2005).

Apparently, the merits of consuming a diet rich in fruits and vegetables cannot

be over-emphasized. With the wealth of phytochemicals inherent in them, one can be

sure of staying healthy. Of surprising, interest is on the discovery that the so-called

anti-nutrients might not be “anti” after all.

24

CHAPTER THREE

3.0 MATERIALS AND METHODS

3.1 Materials

The wild vegetables used for the study were identified by staff of Botany

Department, University of Nigeria, Nsukka. These vegetables were zobo (Hibiscus

sabdariffa), utazi (Gongronem latifolium), bitter leaf (Vernonia amygdalina), scent

leaf (Ocimum gratissimum) and okra (Abelmoschus esculentus or Hibiscus

esculentus), these were purchased from two different areas. Roselle was purchased

from Jos and bitter leaf, okra, scent leaf and G. latifolium were purchased from Ogige

Market in Nsukka Town, Enugu state, Nigeria.

3.2 Methods

Sample preparation

3.2.1 Processing of roselle

One kilogramme of roselle leaves was washed to remove dust and sand. It was

divided into two equal portions (500g, each). One portion was thinly spread,

sundried and the other was thinly spread and shade dried. Both samples were

pulverized into flour and packaged for use (Fig.1)

Fresh roselle leaves

Washed

Shade dried Sundried

Pulverized

Packaged for use

Pulverized

Packaged for use

25

3.2.2 Processing of bitter leaf

One kilogramme of bitter leaf was washed to remove dust, sand and bitterness.

The sample was divided into two equal portions (500g, each). One portion was thinly

spread and sundried. The other was thinly spread and shade dried. Both samples were

pulverized into flour and packaged for use as that of roselle.

3.2.2 Processing of okra leaves

One kilogramme okra leaves was washed to remove dust, sand and divided

into two equal potions (500g, each). One portion was thinly spread and sundried. The

other was also thinly spread and shade dried. Both samples were pulverized and

packaged for use as in (Fig. 1).

3.2.3 Processing of G. latifolium

One kilogramme of G. latifolium leaves was washed to remove dust sand and

divided into two equal portions (500g, each). One portion was spread and sundried.

The other was thinly spread and shade dried. Both samples were pulverized into flour

and packaged for use (see Fig. 1).

3.2.4 Processing of scent leaf

One kilogramme of scent leaf leaves was washed to remove dust, sand and

divided into two equal portions (500g, each). One portion was thinly spread and

sundried. The other was thinly spread and shade dried. Both samples were pulverized

into flour and packaged for use (see Fig.1).

3.3 Analytical methods

3.3.1 Proximate analysis

The proximate analysis of the food samples was carried out according to

AOAC procedure (2000) for moisture, fat, ash and crude fibre. Protein was

determined by the method described by Pearson (1976).

Moisture: This was determined by the drying method using vacuum oven with

aluminum dish at 78oC for 3h. The dry samples were allowed to cool in a desiccator

prior to re-weighing. The sample was put back in the oven and re-weighed at one-

hour interval until a constant weight was obtained

% Moisture + W2 – W1 x 100

Wt of sample 1

26

Where W2 = initial Wt. of dish and sample.

W1 = Final Wt. of dish and sample.

Fat: Sohxlet extraction method was used to determine the fat content of the samples.

Two grammes of each of the sample were put in a fat extraction thimble and inserted

into the Sohxlet extraction apparatus containing petroleum ether (60% Bp). Heat was

introduced to boil the solvent. The hot solvent was allowed to flow into the thimble

containing the sample to extract fat. At the end of the extraction, the thimble was

removed. The extracted fat and the container were put under fume hood chamber to

dry. The dry container and fat were put in a dessicator to cool. The cooled container

was reweighed. The difference in weight was the weight of fat. The value obtained

was expressed as a percentage of the original weight of the sample.

Ash: This was determined by combusting a known weight of sample in muffle

furnace of 5000C for 5h. The ashed sample was cooled and re-weighed with the

crucible. The percentage ash was calculated using the following steps

Weight of crucible =B

Weight of crucible + ash =A

Weight of crucible + ash – Weight of crucible = Wt. of ash A-B= C

% ash = Wt. + of ash x 100

Wt. + of sample 1

Crude protein: Two hundred milligrammes (200mg) of each sample were weighed

into a micro-Kjeldahl digestion flask. About 2.5g of anhydrous sodium sulphate and

0.5mg of copper sulphate were added as catalysts to each sample and subjected to

heat until a colourless solution (ammonium sulphate) was obtained. The solution was

made up to 100ml in100ml volumetric flask. The micro-Kjeldahl distillation

apparatus was positioned by allowing the tip to be about 2cm inside the digestion

flask. About 5ml of 60% sodium hydroxide solution was added through the funnel

stop cork. On the introduction of stem into the distillation apparatus, NH3 was

liberated, condensed and collected with a receiver flask containing 4% boric acid and

mixtures of methyl red and blue in a ratio of 2:1 as end point indicator. As soon as

NH3 dropped in the beaker containing a mixture of boric acid and methyl red and

blue, the purple colouration of the mixture changed to yellowish-green; a

characteristic of alkaline gas (NH3). Distillation was continued until a reasonable

27

volume was collected for titration. A qualitative analysis of the distillate was attained

by titration to a navy blue colour with 0.01N HCL.

Mg N = Titer × 14.001

Wt. of sample

The percentage of protein was determined by the multiplication of %N with the

conversion factor 6.25(N×6.25).

Crude fibre: Crude fibre content of the sample was determined by the official

method of AOAC (2000). About 2g of the sample were boiled for 30mins and filtered

through a fluted funnel and washed with boiling H2O until the washing was no longer

acidic. The sample was boiled for 30mins with 20ml sodium hydroxide, solar filtered

with hot H2O, using calico cloth, rinsed with 1% HCL and finally methylated spirit.

The residue obtained was collected into a crucible and dried in an oven for 30mins.

The content was cooled in a dessicator, weighed prior to taken to the furnace for

ashing at 350oC for 30mins. The ashed sample was moved from the furnace after the

temperature was cooled to 200oC and put into the dessicator and later weighed. The

loss in weight between the incinerated residue before and after incineration was the

crude fibre content. The percentage fibre was calculated thus;

Total wt of fiber × 100

Wt of the sample

Sugars and starch: Free sugar and starch were determined quantitatively using the

method described by Mcready (1970). Ethanol (95%) was used to first extract sugars

from starch. The residue was then hydrolyses with perchloric acis into

monosaccharides. The sugars were quantified colorimetrically using phenol and

sulphuric acid. Sugars gave an orange colour when treated with phenol and sulphuric

acid. Sugars extracted with the solvent were directly analysed to determine the sugar

content. Sugars obtained after hydrolysis of the residue was converted to starch by

multiplying it by 0.9.

3.3.2 Mineral analysis

Copper, phosphorus, iron and zinc content of the samples were determined after wet

digestion using atomic absorption spectrophotometer (ASS). Phosphorus was

determined using emission spectrophotometer (AOAC, 1995).

28

3.3.3 Phytochemical analysis

Tannins: A modified method described by Price and Butler (1977) was adopted. A

sample of 0.5g of each of the samples was extracted with 10ml of deionized water.

Colour was developed with 3ml of 0.1m ferric chloride in 0.1N HCL followed

immediately by 3ml of 0.008ml potassium ferrocyanate. The absorbance was read at

520nm in a UNICAM SP 400 spectrophotometer. Tannins content was extrapolated

from a previously prepared tannic acid standard curve.

Phytate: A modification of the procedure of Latta and Eskin (1980) was used for the

determination of phytate content of the samples. Five grammes of each of the samples

were passed through an amberlite resin, in-organic phosphorus was eluted with 0.1ml

sodium chloride and 0.7ml sodium chloride. Colour was developed with 1ml of

modified Wade reagent (0.03% FeCl2.6H2O and 0.3% sulphursalicylic acid). The

absorbance was read at 520nm in a CE 2343D digital granting spectrophotometer.

Phytate value was extrapolated from a previously prepared phytic acid standard curve.

Saponins: A spectrophotometric method of AOAC (2000) was developed for the

determination of saponins. Saponins fraction of the samples was prepared by a

column chromatography with porous polymer and hydrolyzed with a 2mol/l mixture

of HCL-Ethanol (1+1) to generate sapogenin. Sapogenin amounts of the sample was

determined by measuring absorbance at 430nm, based on the colour reaction with

anisaldehyde, sulfuric acid and ethyl acetate.

Flavonoids: A High-Performance Liquid Chromatography (HPCL) method was

adopted for the determination and separation of flavonoids. Free flavonoids were

fractionated into neutral and acidic groups by means of solid-phase extraction method,

followed by subsequent HPLC separations

3.3.4 Statistical analysis

The data generated was analyzed using means, standard deviation, standard

error of mean and analysis of variance (ANOVA). Duncan’s New Multiple Range

Test was used to separate and compare means (Steel & Torrie, 1960).

29

CHAPTER FOUR

4.0 RESULTS

Table I shows the chemical composition of fresh, sun and shade dried

okra, bitter, scent, G. latifolium and roselle leaves.

The moisture of the fresh, sun and shade dried okra leaves differed. The fresh

okra leaf had the highest moisture (62.22%). The sun and shade dried sample had

7.66% and 10.27%, each. The difference among the sun and shade dried samples

differed as well as that of the fresh sample (62.22, 10.27 and 7.66%, respectively)

(P<0.05). The protein content of the okra leaf samples differed equally. The range was

from 8.84 to 19.78%. The protein content of the fresh okra leaf differed from those of

the sun and shade dried samples (19.78 and 19.64% vs. 8.84%, respectively) (P<

0.05). Sun and shade drying had equal effect on protein of okra leaf (19.78 vs

19.64%) (P > 0.05). The fat values differed. It ranged from 1.16 to 1.24%. Fresh okra

leaf had higher fat than those of the sun and dried samples (1.24 vs 1.16 and 1.17) (P<

0.05). The sun and shade dried okra leaf had comparable fat (1.16 and 1.17%) (P>

0.05). The ash values differed. The range was from 6.66 to 15.03%. The fresh sample

had the least (6.66%) which differed from those of the sun and the shade dried

samples (6.66 vs 14.69 and 15.05%) (P < 0.05). On the other hand, both the sun and

the shade dried samples had higher and comparable values (14.6 and 15.03%)

The fibre content of okra leaf sample was high. The range was from 9.06 to

19.64%:- There was no difference in fibre between the sun and the shade dried

samples (19.64 vs 9.60%) (P >0.05). The fresh sample had the least (9.06%) (P<0.05).

There were differences in sugar content of okra leaf samples. The fresh okra leaf had

the highest sugar (6.27%). The sun and the shade dried samples had 4.70 and 4.78%,

each. The fresh sample had higher sugar, which was different from those of the sun

and shade dried samples (6.27 vs 4.70 and 4.78%, respectively) (P<0.05). On the

other hand, the sugar content of the sun and the shade dried samples was similar

(4.78vs 4.78%) (P>0.05). The starch values differed. It ranged from 5.69 to 32.46%.

The fresh okra leaf had the least starch (5.69%). The sundried sample had the highest

and the shade dried had the second highest (32.46 and 28.61%, respectively).

Sundrying had an edge over shade drying (32.46 vs 28.61%) (P<0.05). However, both

sun and shade drying had higher starch than that of the fresh sample (32.46 and

28.61vs 5.61%) (P<0.05).

30

Table 1. Chemical composition of fresh, sun and shade dried Okra, Bitter, G. latifolium and

Roselle leaves (%)

MOISTURE PROTEIN FAT ASH FIBRE SUGAR STARCH

FOL 62.22 + 0.02 8.84 + 0.04 1.24 +0.01 6.66+0.01 9.06+0.01 6.27+0.01 5.69 + 0.14

SUOL 7.66 + 0.01 19.64+ 0.04 1.16+0.12 14.67+0.01 19.64+0.01 4.78+0.01 32.46 + 0.02

SHOL 10. 27 + 0.01 19.78+ 0.01 1.17+0.01 15.03+0.01 19.60+0.01 4.70+0.01 28.61 + 0.68

FBL 62.32 + 0.06 7.7+ 0.01 1.25+0.18 7.45+0.15 9.85+0.02 5.79+0.01 3.54 + 0.07

SUBL 6.84 + 0.02 19.88+ 0.01 1.20+0.01 14.86+0.01 19.47+0.02 3.85+0.32 33.89 + 0.03

SHBL 10.35 + 0.01 19.42+0.01 1.19+0.01 14.75+0.01 19.35+0.02 3.36+0.01 31.05 + 0.01

FSL 62.46 + 0.01 9.86 + 0.01 1.39+0.01 6.87+0.01 8.63+0.17 5.36+ 0.01 5.43 + 0.02

SUSL 7.75 + 0.12 13.19 + 0.02 1.25+0.01 13.86+0.01 18.85+0.01 3.46+ 0.01 41.15 + 0.02

SHSL 10.11+ 0.03 13.46 + 0.01 1.16+0.01 13.83+0.01 18.86+0.01 3.41+ 0. 12 39..20 + 0.01

FGL 61.44 + 0..29 9.50 + 0.01 1.34+0.01 7.64+0.01 9.03+0.01 5.59+ 0.01 5.75 + 0.03

SUGL 6.86 + 0.0 17.13 +0 .01 1.17 +0.01 15.03+0.01 19..23+0.01 4.63+ 0.02 36.02 + 0.05

SHGL 10.17 + 0.01 16.85 + 0.02 1.15+0.01 14.97+0.01 19.21+0.01 4.57+ 0.01 33.06 + 0.03

FRL 85..53 + 0.01 3.33 + 0.01 0.226+0.01 1.57+0.01 1.62+0.01 5.37+ 0.01 5.12 + 1.46

SURL 6.36 + 0.01 22.86 +0.01 2.06+0.01 11.2+0.01 11.23+0.01 2.04+ 0.01 66.48 + 46.34

SHRL 6.38 + 0.01 22.39 +.0.01 1.97+0.01 10.96+0.01 11..37+0.01 1.97+ 0.07 64.79 + 10.79

Means + Standard deviation of three determinations

FOL = Fresh Okra leaf FGL = Fresh G. latifolium leaf SUOL = Sundried Okra SUGL = Sundried G.latifolium leaf

SHOL = Shadedried Okra leaf SHGL = Shade dried G latifolium leaf

FBL = Fresh bitter leaf FRL = Fresh roselle leaf

SUBL = Sundried bitter leaf SURL = Sundried roselle leaf

SHBL = Sundried bitter leaf SHRL = Shade dried roselle leaf

FSL = Fresh scent leaf

SUSL = Sundried scent leaf

SHSL=Shadedriedscentleaf

31

The moisture content of the fresh, the sun and the shade dried bitter leaf

samples varied. The sun and the shade dried samples had 6.84% and 10.38%, each.

The fresh sample had the highest moisture (62.32%). There were differences in

moisture among the sun and the shade dried sample as well as that of the fresh (6.84,

10.38 and 62.32%, respectively). (P< 0.05). Its protein content equally differed. The

range was from 9.76 to 19.88%. Both the sundried and the shade dried bitter leaf had

higher protein values than the fresh (19.88 and 19.42 vs 1.76%) (P< 0.05). The

protein values of the sun and the shade dried bitter leaf samples were similar (19.88

and 19.42%, respectively) (P> 0.05). The fat value varied. It ranged from 1.19 to

1.25%. The shade dried bitter leaf had lower fat value as against those of the sundried

and the fresh samples (1.19 vs 1.20 and 1.25%, respectively) (P< 0.05). The sundried

and fresh samples had comparable values (1.20 and 1.2 5%) (P>0.05). The ash

values for bitter leaf samples differed. It ranged from 7.45 to 14 86%. The fresh

sample had the least ash in comparison with the shade and the sundried samples (7.45

vs 14.75 and 14.86%, respectively) (P< 0.05). However, the shade and the sundried

dried samples had similar values (14.75 and 14.86%, respectively) (P> 0.05).

The fibre content was high. It ranged from 9.85 to 19.42 %. The fibre values

for the sun and the shade dried samples were comparable (19.35 and 19.47%,

respectively) (P< 0.05). The fresh sample differed from the rest (P>0.05). The sugar

content of bitter leaf samples differed. Its range was from 3.30 to 5.79%. The fresh

bitter leaf sample had the highest sugar (5.79%) followed by the sundried and the

shade dried samples (5.79 vs 3.85 and 3.36%) (P<0.05) The sun and the shade dried

samples had comparable sugar content (3.85 vs 3.36%) (P>0.05). The starch values

differed. Its range was from 3.54 to 33.89%. The fresh had the least as against those

of the sun and the shade dried samples (3.54 vs 33. 89 and 31.05%) (P<0.05). On the

other hand, the sun and the shade dried samples had similar values (33.89 and

31.05%) (P>0.05).

The moisture values for the scent leaf sample were different. The fresh scent

leaf had the highest moisture (62.46%). The sun and the shade dried samples had

7.75% and 10.11%, each. The difference among the sun and the shade dried samples

as well as that of the fresh differed (7.75, 10.11 and 62.40%, respectively ) (P<0.05).

The protein content of the scent leaf samples varied. Its range was from 9.86 to

13.67%. The sun and the shade dried sample had higher and comparable values.

(P>0.05). The fresh had lower value (9.86%) (P<0.05). The fat values differed. The

range was from 1.16 to 1.39%. Fresh scent leaf had higher fat than the sun and the

32

shade dried samples (1.39 vs 1.25 and 1.16%) (P<0.05). The shade and the sundried

samples had comparable fat values (1.25 and 1.16%) (P>0.05). The ash values for the

scent leaf varied. It ranged from 6.87 to 13.86%. The fresh scent leaf had the least ash

(6.87 vs 13.86 and 13.83%, respectively) (P<0.05). The sun and the shade dried

samples had similar value (13.86 and 13.83%) (P>0.05). The fibre content of the scent

leaf samples was high. The range was from 8.63 to 18 83%. There was no difference

in fibre between the sun and the shade dried samples (P>0.05). The sugar content

differed and ranged from 3.41 to 5.36%. The sun and the shade dried samples had

comparable value as against the fresh sample (3.46 and 3.41 vs 5.36 %, respectively)

(P<0.05). The starch values also differed. The range was from 5.43 to 41. 15% .The

sundried scent leaf had the highest starch (41.15%). The shade dried and the fresh

samples had 39.20% and 5.43%, each. The among between the sun and the shade

dried samples differed as well as that of the fresh sample (41.15, 39.20 and 5.43%)

(P<0.05).

The moisture values for the fresh, the sun and the shade dried G. latifolium

leaf differed. The fresh sample had the highest moisture (61.44%). The sun and the

shade dried samples had 6.86% and 10.17%, each. There was difference among the

sun and the shade dried samples as well as that of the fresh sample (61.44, 10.17 and

6.86%, respectively) (P<0.05). Its protein values differed and ranged from 9.50 to

17.13%. The fresh G. latifolium leaf had the least protein followed by the shade and

the sun dried samples (9.50 vs 16.85 and 17.13%) (P<0.05). The shade dried G.

latifolium had comparable protein with the sundried sample (16.85.vs 17.13%)

(P>0.05). The fat values varied. It ranged from 1.15 to 1.34%.

The fresh G.latifolium leaf had fat value that differed from those of the sun

and the shade dried samples (1.34 vs 1.17 and 1.13%) (P<0.05). On the other hand,

the fat value for the sun and the shade dried samples were similar (P>0.05). The ash

content of the fresh, the sun and the shade dried G. latifolium differed. The range was

from 7.64 to 15.03%. The ash values for the sun and the shade dried samples were

similar (13.03 and 14.97) (P>0.05). However, they differed from that of the fresh

sample (P<0.05). The fibre values were high. The range was from 9.03 to 19.23%.

The sun and the shade dried samples had similar values (19.21 vs 19.23%) (P>0.05).

The sugar content of the samples differed. The range was from 4.57 to 5.59%. The

fresh G. latifolium sample had the highest sugar (5.59%). The sun and the shade dried

samples had higher sugar than that of the fresh sample (5.59 vs 4.60 and 4.57%,

respectively) (P<0.05). However, the sugar content of the sun and the shade dried

33

samples was similar (4.60 and 4.57%) (P>0.05). The starch values ranged from 5.75

to 36.02%. The fresh sample had the least starch (5.75 %). The sundried sample had

the highest starch value (36.02%). The shade dried sample had the second highest

value (36.02 and 33.06%, respectively) (P<0.05). Both the sun and the shade dried

samples had higher starch than the fresh sample (36.02 and 33.06 vs 5.78%) (P<0.05).

The moisture content of the fresh, the sun and the shade dried roselle samples

differed. It ranged from 6.30 to 85.53%. The fresh roselle had the highest moisture

(85.53%). The sun and the shade dried samples had 6.36 and 6.38%, each. The fresh

roselle had higher moisture than the sun and the shade dried samples (85.53 vs 6.36

and 6.338%) (P<0.05). The sun and the shade dried samples had similar moisture

(6.36 and 6.38%) (P>0.05). The protein levels differed. Its range was from 3.33 to

22.86%. The sun and the shade dried roselle had higher protein content that the fresh

sample (22.86 and 22.39 vs 3.33%, respectively) (P<0.05). The protein content of the

sun and the shade dried samples was similar (22.86 and 22.39%) (P>0.05). The fat

values varied. The sundried and the shade dried samples had 0.226 and 1.97%, each.

The difference between the sun and shade dried samples as well as that of the

fresh differed (2.06, 1.97 and 0.226%, respectively) (P<0.05). The ash content of the

fresh, the sun and the shade dried roselle leaf varied. The range was from 1.57 to

11.2%. The ash content of the fresh differed from those of the sun and the shade dried

samples (11.2 and 10.96 vs 1.57%, respectively) (P<0.05). Sundrying did not have an

edge over shade drying (11.20 and 11.96) (P>0.05).The fibre content differed. The

range was from 1.62 to 11.32%. There was no significant difference in fibre between

the sun and the shade dried samples (11.23 vs 11.37) (P>0.05). The values differed

from the fibre value for the fresh sample (11.13 and 11.37 vs 1.62%) (P<0.05). The

sugar content of the roselle sample ranged from 1.97 to 5.37%. The shade dried

sample had the least sugar (1.97%) followed by the sundried sample (2.04%). The

fresh sample had the highest sugar (6.87 vs 2.04 and 1.97%) (P<0.05). The starch

content varied. The sundried roselle had the highest starch (66.48%). The shade dried

and the fresh samples had 64.79 and 5.17%, each. The difference among the sun and

shade dried samples differed as well as that of the fresh sample (66.48, 64.79 and

5.12%, respectively) (P<0.05).

34

Table 2 shows the effects of sun and shade drying on the chemical composition

of fresh, sun and shade dried okra, bitter, scent, G.latifolium and roselle leaves

(dry wt.%).

The protein content of all the fresh, the sun and the shade dried samples

differed. It ranged from 14.30 to 26.27%. Fresh scent leaf had the highest protein

value (26.27%) followed closely by fresh bitter leaf (25.90%). Fresh G. latifolium and

sundried roselle leaves both had comparable protein values (24.63 and 24.41%). Fresh

okra, roselle leaves and shade dried roselle leaf had comparable protein (23.34, 23.01

and 23.91%, respectively). Sun dried bitter leaf, shade dried bitter leaf and sundried

okra leaf had similar protein values (21.53, 21.65 and 21.27%). Sun and shade dried

G. latifolium leaf had similar value 18.40 and 18.10%, each. Shade dried scent leaf

had 14.97% and the sundried scent leaf had the lest protein (14.31%)

Fresh scent leaf had the highest fat content (3.70%) followed by the fresh G.

latifolium (3.47%), the fresh bitter leaf had 3.32% and the fresh okra leaf had 3.28%.

Sun and shade dried roselle had similar fat values (2.20 and 2.10%). The fat values for

the sundried okra leaf and the sundried G. latifolium leaf was comparable (1.26%).

The fat for shade dried okra and bitter leaves and sundried scent leaves was

comparable (1.30, 1.33 and 1.36%)

The ash content of the vegetables differed. It ranged from 10.85 to 19.81%.

Fresh roselle leaf had the least ash (10.85%) followed by the sun and the shade dried

roselle leaves which had similar values (11.96) and 11.71%). Sun and shade dried

scent leaves had similar values (15.02 and 15.38%) and the sun dried okra and bitter

leaves had comparable values (15.89 and 15.94%, each). Fresh G. latifolium had the

highest ash (19.81%) followed closely by the fresh bitter leaf (19.77%).

The fibre levels for the vegetables varied. It ranged from 11.20 to 26.14%. Sun

and shade dried okra leaf and shade dried bitter leaf had similar values (21.27, 21.83

and 21.58%). Sun and shade dried G. latifolium leaves had similar values (20.65 and

20.63%). Fresh bitter leaf had the highest (26.14%) followed by the fresh okra leaf

(23.98%) and fresh G.latifolium (23.41%). Fresh roselle had the least value (11.20%).

Fresh roselle had the highest sugar (37.11%) followed by the fresh okra leaf

(16.60%). Fresh bitter leaf had (15.37%). Fresh scent leaf and G. latifolium leaves had

similar values (14.28 and 14.49%). Shade dried bitter leaf and sundried scent leaf had

equal sugar (3.75%).

35

Table 2. Effects of sun and shade drying on the chemical composition of Okra,

Bitter Scent, G.latifolium and Roselle leaves (Dry wt).

PROTEIN FAT ASH FIBRE SUGAR STARCH

FOL 23.34+0.04 3.28+0.01 17.63+0.01 23.98+0.01 16.60+0.01 15.06+0.14

SUOL 21.27+0.04 1.26+0.12 15.89+0.01 21.27+0.01 5.18+0.01 35.15+0.02

SHOL 22.03+0.01 1.30+0.01 16.74+0.01 21.83+0.01 5.24+0.01 31.87+0.68

FBL 25.90+0.01 3.32+0.18 19.77+0.15 26.14+0.02 15.37+0.01 9.40+0.07

SUBL 21.33+0.01 1.29+0.01 13.94+0.01 20.89+0.02 4.13+0.32 39.36+0.03

SHBL 21.65+0.01 1.33+0.01 16.45+0.01 21.58+0.02 3.75+0.01 34.62+0.01

FSL 26.27+0.01 3.70+0.01 18.30+0.01 22.99+0.17 14.28+0.01 14.47+0.02

SUSL 14.30+0.02 1.36+0.01 15.02+0.01 20.43+0.01 3.75+0.01 44.61+0.02

SHSL 14.97+0.01 1.29+0.01 15.38+0.01 20.97+0.01 3.79+0.12 43.39+0.01

FGL 24.63+0.01 3.47+0.01 19.81+0.01 23.41+0.01 14.49+0.01 14.91+0.03

SUGL 18.40+0.01 1.26+0.01 16.14+0.01 20.65+0.01 4.97+0.02 38.69+0.05

SHGL 18.10+0.02 1.24+0.01 16.08+0.01 20.63+0.01 4.91+0.01 35.51+0.03

FRL 23.01+0.01 1.56+0.01 10.85+0.01 11.20+0.01 37.11+0.01 35.38+1.46

SURL 24.41+0.01 2.20+0.01 11.96+0.01 11.99+0.01 2.18+0.01 71.06+46.34

SHRL 23.91+0.01 2.10+0.01 11.71+0.01 12.14+0.01 2.10+0.07 69.20+10.79

Means + Standard deviation of three determinations

FOL = Fresh okra leaf FGL= Fresh G.latifolium leaf

SUOL = Sundried okra leaf SUGL = Sundried G. latifolium leaf

SHOL = Shade dried okra leaf SHGL= Shade dried G. latifolium leaf

FBL = Fresh bitter leaf FRL = Fresh roselle leaf

SUBL = Sundried bitter leaf SURL = Sundreid roselle leaf

SHBL = Shade dried bitter leaf SHRL = Shade dried roelle leaf

FSH = Fresh scent leaf

SUSL = Sundried scent leaf

SHSL = Shade dried scent leaf

36

Sun and shade dried roselle leaves had comparable sugar (2.18 and 2.10%). The sugar

content of the shade dried roselle was the least (2.10%)

The starch values for the vegetables varied. It ranged from 9.40 to 71.06%.

Sundried roselle had the highest starch (71.06%) followed closely by the shade dried

sample (69.20%). Sundried okra leaf and shade dried G. latifolium leaves as well as

the fresh roselle leaves had comparable values (35.15, 35.51 and 35.38%,

respectively). Fresh scent and G. latifolum leaves had similar starch values (14.47 and

14.91%). Fresh bitter leaf had the least value (9.40%)

37

Table 3 shows the mineral composition of the fresh, the sun and the shade dried

okra, bitter, scent, G. latifolium and roselle leaves (g/100g)

The copper content of the fresh, the sun and the shade dried okra leaves

varied. It ranged from 0.02 to 0.05mg. However, the fresh okra leaf had higher copper

than the sun and the shade dried samples (0.05 vs 0.02 and 0.03 mg) (P<0.05). The

value for the sun and the shade dried samples also were similar (P>0.05). The

phosphorous content of the samples varied. The sundried okra leaf had the highest

value (0.44mg). The fresh and the shade dried okra leaves had 0.39 and 0.42mg, each.

The difference in copper among the sun and shade dried samples as well as the fresh

differed (0.44, 0.42 and 0.39mg, respectively) (P<0.05). The iron content of the okra

leaf samples was different. It ranged from 1.15 to 2.07mg. Fresh okra leaf had the

highest iron (2.07 vs 1.17 and 1.15mg) (P<0.05). However, the iron content of the sun

and the shade dried samples was similar (1.17 and 1.15mg) (P>0.05). The zinc

content of the okra leaf samples varied. The range was from 2.01 to 2.13mg. The zinc

content of the sun and the shade dried samples was similar (2.02 and 2.01mg)

(P>0.05). However, they differed from that of the fresh sample (2.02 and 2.01 vs

2.13mg) (P<0.05).

The copper content of the fresh, the sun and the shade dried bitter leaf samples

varied. It ranged from 0.01 to 0.07mg. The copper values for the fresh, the sun and the

shade dried samples were comparable (0.07, 0.03 and 0.03 and 0.01mg, respectively)

(P>0.05). The phosphorus levels of the samples varied. It ranged from 0.38 to

0.42mg. The phosphorus levels for the fresh, the sun and the shade dried samples

were similar (0.38, 0.41 and 0.42 mg) (P>0.05). The iron content of bitter leaf

samples varied. The fresh bitter leaf sample had the highest iron, followed by the sun

dried sample as well as the shade dried sample (2.04 vs 1.19 and 1.15 mg,

respectively) (P<0.05). The iron content of the bitter leaf samples varied. The fresh

bitter leaf sample had the highest iron, followed by the sun dried as well as the shade

dried samples (2.04 vs 1.19 and 1.15mg, respectively) (P<0.05). The iron content of

the sun and the shade dried samples was similar (1.19 and 1.15 mg) (P>0.05). The

zinc levels differed. It ranged from 1.94 to 2.11mg. The shade dried bitter leaf had the

lowest zinc in comparison with the fresh and the sundried samples (1.94 vs 2.10 and

2.11 mg) (P<0.05). The fresh and the sundried samples had similar zinc (2.10 and

2.11mg) (P>0.05).

38

Table 3: Mineral composition of fresh,the sun and the shade dried okra, bitter,

scent, G. latifolium and roselle leaves (mg/100g)

COPPER PHOSPHORUS IRON ZINC

FOL 0.05 + 0.01 0.39 + 0.00 2.07 + 0.01 2.13 + 0.01

SUOL 0.02 + 0.00 0.44 + 0.03 1.17 + 0.01 2.02 + 0.02

SHOL 0.03 + 0.00 0.42 + 0.00 1.15 + 0.01 2.01 + 0.01

FBL 0.07 + 0.01 0.38 + 0.00 2.04 + 0. 51 2.10 + 0.01

SUBL 0.03 + 0.01 0.42 + 0.04 1.19 + 0.01 2.11 + 0.01

SHBL 0.01 + 0.00 0.41 + 0.00 1.15 + 0.20 1.94 + 0.01

FSL 0.05 + 0.00 0.37 + 0.00 1.96 + 0.01 2.13 + 0.03

SUSL 0.02 + 0.00 0.41 + 0.00 1.25 + 0.01 2.04 + 0.01

SHSL 0.02 + 0.00 0.43 + 0.00 1.17 + 0.01 1.95+ 0.01

FGL 0.05 + 0.01 0.37 + 0.00 1.86 + 0.01 2.08 + 0.01

SUGL 0.02 + 0.01 0.42 + 0.00 1.23 + 0.01 2.01 + 0.01

SHGL 0.03 + 0.00 0.43 + 0.00 1.16 + 0.01 1.81 + 0.01

FRL 0.05 + 0.01 0.39 + 0.00 2.00 + 0.01 2.18 + 0.01

SURL 0.07 + 0.01 0.44 + 0.00 1.74 + 0.01 1.68 + 0.01

SHRL 0.08 + 0.01 0.44 + 0.00 1.86 + 0.01 1.79 + 0.01

Means + Standard deviation of three determinations

FOL = Fresh okra leaf FGL= Fresh G. latifolium leaf

SUOL = Sundried okra leaf SUGL = Sundried G. latifolium leaf

SHOL = Shade dried okra leaf SHGL= Shade dried G. latifolium leaf

FBL = Fresh bitter leaf FRL = Fresh roselle leaf

SUBL = Sundried bitter leaf SURL = Sundried roselle leaf

SHBL = Shade dried bitter leaf SHRL = Shade dried roselle leaf

FSL = Fresh scent leaf

SUSL = Sundried leaf

SHSL = Shade dried scent leaf

39

The copper content of the scent leaf samples was different. It ranged from 0.02

to 0.05mg. The copper values for the sun and the shade dried samples were equal

(0.02mg) (P>0.05). However, they were lower than that for the fresh sample (0.02 vs

0.05mg) (P<0.05). The phosphorus content of the scent leaf samples differed. Its

range was from 0.37 to 0.43mg. The sun and the shade dried samples had similar

value (0.41 and 0.43mg) (P>0.05). However, they had higher values than the fresh

sample (0.41 and 0.43 vs 0.37 mg, respectively) (P<0.05). The iron levels varied. It

ranged from 1.17 to 1.96 mg. The fresh scent leaf had the highest iron (1.96mg). The

sun and the shade dried sample had 1.25 and 1.17mg, each. The difference in iron

among the sun and the shade dried samples as well as that of the fresh sample differed

(P<0.05). The zinc values were different. The range was from 1.95 to 2.13mg. The

shade dried scent leaf sample had lower zinc in comparison with the sun and the

shade dried samples (1.95 vs 2.04 and 2.13mg, respectively) (P<0.05). The sun and

the shade dried samples had comparable zinc (P<0.05).

The copper content of the G. latifolium leaf varied. It ranged from 0.02 to

0.05mg. The fresh sample had the highest value (0.05mg) followed by the shade and

the sundried samples 0.03 and 0.02mg, each. The sun and the shade dried samples had

similar values as well as the fresh samples (P>0.05). The phosphorus content of the

scent leaves differed. It ranged from 0.37 to 0.43 mg. The sun and the shade dried

samples had comparable values (0.42 and 0.43mg) (P>0.05). However, they had

higher values than the fresh sample which had the least value (0.42 and 0.43 vs

0.37mg) (P<0.05). The iron levels equally differed. Fresh G. latifolium leaf had

highest iron (1.86mg). The sun and the shade dried samples had 1.23 mg and 1.16mg,

each. The difference among the sun and the shade dried samples as well as that of the

fresh sample differed (1.23, 1.16 and 1.86mg, respectively) (P<0.05). The zinc levels

varied and ranged from 1.86 to 2.08mg. The shade dried G. latifolium leaf had the

least zinc 1.86mg when compared with those of the sundried and the fresh samples

(1.86 vs 2.01 and 2.08mg) (P<0.05). The sundried and the fresh samples had similar

copper (2.01 and 2.08mg) (P>0.05).

The copper levels for the fresh and the processed roselle leaves varied and

ranged from 0.05 to 0.08mg. The fresh sample had the least copper 0.05mg. The sun

and the shade dried samples had 0.07mg and 0.08mg, each. The phosphorus content

of the processed roselle samples ranged from 0.39 to 0.44mg. Both the sun and the

shade dried samples had equal values (0.44mg) (P>0.05). The fresh sample equally

had comparable phosphorus level with the sun and the shade dried samples (0.39 and

40

0.44mg) (P>0.05). The iron (Fe) levels ranged from 1.74 to 2.0mg). The fresh roselle

had the highest Fe which was comparable with those of the sun and the shade dried

samples (2.0 vs 1.74 and 1.86mg) (P>0.05). The zinc values differed. It ranged from

1.68 to 2.18mg. The fresh roselle leaf had the highest value (2.18mg) and differed

from those of the sun and the shade dried samples (2.18 vs 1.68 and 1.79 mg)

(P<0.05). On the other hand, the sun and the shade dried samples had similar Fe (1.68

and 1.79mg) (P<0.05).

41

Table 4 shows the effects of sun and shade drying on the mineral composition of

fresh, sun and shade dried okra, bitter, scent, G. latifolium and roselle leaves.

The copper (Cu) levels for all the fresh, the sun and the shade dried samples

varied. It ranged from 0.02 to 0.35mg. Fresh roselle lesf had the highest Cu (0.35mg)

followed by the fresh bitter leaf (0.19mg) as well as fresh okra, scent and G. latifolium

leaves. These had comparable Cu (0.13mg). Sun and shade dried roselle leaves had

0.07 and 0.09mg, each. Shade dried okra and G.latifolium and the sundried bitter leaf

had comparable Cu (0.03mg). The least Cu (0.02mg) was those of the sundried okra,

scent and G. latifolium leaves as well as the shade dried scent leaf.

The phosphrus levels varied. Sundried bitter and G.latifolium leaves had the

least phosphorous (P) (0.45mg) followed by the shade dried bitter and G.latifolium

leaves (0.46mg). Shade dried okra and roselle leaves as well as sundried roselle leaf

had 0.47mg. Fresh roselle leaf had the highest (2.70mg). Fresh okra and bitter leaves

had similar P 1.03 and 1.01mg each. Fresh scent and G. latifolium leaves also had

similar P (0.99 and 0.96mg, each).

Fresh roselle leaf had the highest Fe (13.82mg). Fresh okra, bitter and scent

leaves had similar Fe (5.48 5.44 and 5.22mg). Fresh G. latifolium leaf had 4.87mg Fe.

Shade dried bitter and okra leaves as well as sundried bitter leaves had equal Fe

(1.28mg). Sun and shade dried roselle leaves had comparable Fe (1.86 and 1.99mg).

The shade dried G. latifolium leaf had the least Fe (1.25mg) followed by the sundried

scent and G. latifolium leaves. The shade dried scent leaf also had similar Fe (1.36,

1.32 and 1.30 mg). Fresh roselle leaf had the highest zinc (Zn) (15.07mg). Fresh okra,

bitter scent and G. latifolium leaves had similar Zn (5.64, 5.57, 5.67 and 5.39mg).

Shade dried bitter leaf and sundried G. latifolium leaf had comparable Zn (2.16mg).

The value was similar to that of the sun dried okra and the shade dried scent leaves

(2.19and 2.17mg). Shade dried G. latifolium leaf had the least Zn (2.00mg)

42

Table 4: Effects of sun and shade drying on the mineral composition of the fresh,

the sun and shade dried okra, bitter, scent, G. latifolium and roselle leaves (mg

/100g)

COPPER PHOSPHORUS IRON ZINC

FOL 0.13+0.01 1.03+0.00 5.48+0.01 5.64+0.01

SUOL 0.02+0.00 0.48+0.03 1.27+0.01 2.19+0.02

SHOL 0.03+0.00 0.47+0.00 1.28+0.01 2.24+0.01

FBL 0.19+0.01 1.01+0.00 5.41+0.51 5.57+0.01

SUBL 0.03+0.01 0.45+0.04 1.28+0.01 2.26+0.01

SHBL 0.11+0.00 0.46+0.00 1.28+0.20 2.16+0.01

FSL 0.13+0.00 0.99+0.00 5.22+0.01 5.67+0.03

SUSL 0.02+0.00 0.44+0.00 1.36+0.01 2.21+0.01

SHSL 0.02+0.00 0.48+0.00 1.30+0.01 2.17+0.01

FGL 0.13+0.01 0.96+0.00 4.82+0.01 5.39+0.01

SUGL 0.02+0.01 0.45+0.00 1.32+0.01 2.16+0.01

SHGL 0.03+0.00 0.46+0.00 1.25+0.01 2.00+0.01

FRL 0.35+0.01 2.70+0.00 13.82+0.01 15.07+0.01

SURL 0.07+0.01 0.47+0.00 1.86+0.01 1.79+0.01

SHRL 0.09+0.01 0.47+0.00 1.99+0.01 2.91+0.01

Mean + Standard deviation of three determinations

FOL = Fresh okra leaf FGL= Fresh G. latifolium leaf

SUOL = Sundried okra leaf SUGL = Sundried G. latifolium leaf

SHOL = Shade dried okra leaf SHGL =Shade dried G. latifolium leaf

FBL = Fresh bitter leaf FRL = Fresh roselle leaf

SUBL = Sundried bitter leaf SURL = Sundreid roselle leaf

SHBL = Shade dried bitter leaf SHRL=Shadedriedroselleleaf

FSH = Fresh scent leaf

SUSL = Sundried scent leaf

SHSL = Shade dried scent leaf

43

Table 5 shows the phytochemical composition of the fresh, the sun and the shade dried

okra, bitter, scent, G. latifolium and roselle leaves (mg/100g)

The tannins content of the fresh, the sun and the shade dried samples varied. It ranged

from 0.07 to 0.13mg. The fresh sample had the lowest tannins which differed from the shade

and the sundried samples (0.07 vs 0.10 and 0.13mg, respectively) (P<0.05). The sun and the

shade dried samples had comparable tannins (0.10 and 0.13mg) (P>0.05). The phytate content

of the sample differed. Its range was from65.86 to 122.37mg. However, the sun and the shade

dried samples had higher phytate than the fresh sample (123.22 and 122.37 vs 63.86mg,

respectively) (P<0.05). The phytate content of the sun and the shade dried samples was

similar (123.22 and 122.37mg) (P>0.05). The saponins content of the okra leaves varied. It

ranged from 0.03 to 0.11mg. The fresh okra leaf had varied saponins that varied from those of

the sun and the shade samples (0.11 vs 0.03 and 0.03mg) (P<0.05). However, the saponins

values for the sun and the shade dried samples was the same (0.03mg) (P>0.05). The

flavonoid content of okra leaf ranged from 1.69 to 2.54mg. The fresh okra leaf had the highest

flavonoid (2.25 vs 1.69 and 1.76mg) (P<0.05). The shade dried okra leaf had the second

highest and the sun dried sample had the least (1.76 vs 1.69mg, respectively) (P<0.05)

The tannins content of the fresh, the sun and the shade dried bitter leaf samples was

different. It ranged from 0.07 to 0.13mg. The fresh and the shade dried samples had equal

value (0.13mg) (P>0.05). However, they were higher than that of the fresh bitter leaf samples

(0.13 vs 0.07mg) (P<0.05). The phytate content ranged from 57.31 to 125.60mg. However,

the sun and the shade dried samples had higher phytate values than that of the fresh sample

(125. 60 and 124. 38 vs 57.31mg, respectively) (P<0.05). The phytate content of the sun and

the shade dried samples was comparable (125.60 and 124.38mg) (P>0.05). The saponins

levels ranged from 0.03 to 0.13mg. The sun and the shade dried samples had a similar value

(0.03mg) (P>0.05). However, they had higher value than that of the fresh bitter leaf sample

(0.03 and 0.13mg) (P<0.05). The flavonoid content varied. It ranged from 1.44 to 1.98mg.

The fresh bitter leaf had the highest flavonoid (1.98mg) which differed from that of the sun

and the shade dried samples that had 1.33 and 1.44mg, each (P<0.05). The sun and the shade

dried samples had similar value (P>0.05).

Tannins content of the fresh, the sun and the shade dried scent leaves varied. It

ranged from 0.10 to 0.12mg. The sundried scent leaf had the highest tannins (0.12mg). The

fresh

44

Table 5: Phytochemical composition of the fresh, the sun and the shade dried

okra, bitter, scent G. latifolium and roselle leaves (mg/100g)

TANNINS PHYTATE SAPONINS FLAVONOIDS

FOL 0.07 + 0.12 65.86 + 0.02 0.11 + 0.01 2.54 + 0.01

SUOL 0.13 + 0.01 123.22 + 0.01 0.03 + 0.00 1.69 + 0.01

SHOL 0.10 + 0.01 122.37 + 0.02 0.03 + 0.01 1.76 + 0.02

FBL 0.07 + 0.01 57.31 + 0.01 0.13 + 0. 01 1.98 + 0.01

SUBL 0.13 + 0.01 125.60 + 0.07 0.03 + 0.01 1.53 + 0.01

SHBL 0.13 + 0.00 124.38 + 0.07 0.03 + 0.00 1.44 + 0.02

FSL 0.10 + 0.01 60.12 + 0.01 0.11 + 0.01 2.24 + 0.01

SUSL 0.12 + 0.01 123.52 + 0.01 0.03 + 0.01 1.64 + 0.01

SHSL 0.11 + 0.01 122.63 + 0.01 0.01+ 0.00 1.45+ 0.01

FGL 0.07 + 0.00 55.55 + 0.07 0.11+ 0.01 2.12 + 0.08

SUGL 0.11 + 0.01 127.82 + 0.01 0.02 + 0.00 1.85 + 0.02

SHGL 0.08 + 0.01 125.69 + 0.04 0.03 + 0.01 1.40 + 0.02

FRL 0.10 + 0.00 63.24 + 0.01 0.10+ 0.01 1.55 + 0.01

SURL 0.13 + 0.01 121.13 + 0.01 0.04 + 0.01 2.49 + 0.01

SHRL 0.12 + 0.00 122.67 + 0.01 0.03 + 0.01 2.45 + 0.01

Means + Standard deviation of three determinations

FOL = Fresh okra leaf FGL= Fresh G latifolium leaf

SUOL = Sundried okra leaf SUGL = Sundried G. latifolium leaf

SHOL= Shade dried okra leaf SHGL= Shade dried G. latifolium leaf

FBL = Fresh bitter leaf FRL = Fresh roselle leaf

SUBL = Sundried bitter leaf SURL = Sundreid roselle leaf

SHBL = Shade dried bitter leaf SHRL = Shade dried roselle leaf

FSH = Fresh scent leaf

SUSL = Sundried scent leaf

SHSL = Shade dried scent leaf

45

and the shade dried samples had 0.10 and 0.11mg, each. The difference in tannins

among the fresh and the shade dried samples as well as that of the sun dried sample

was similar (P>0.05). The phytate levels ranged from 60.12 to 123.50mg. The fresh

scent leaf had phytate that differed from those of the shade and the sundried samples

(60.12 vs 122.63 and 123.52mg) (P<0.05). On the other hand, the phytate content of

the shade and the sundried samples was similar (P>0.05). The saponins content

deferred. The range was from 0.01 to 0.11mg. The fresh samples had the highest

value in comparism with the shade and the sun dried samples (0.11 vs 0.03 and

0.01mg) (P<0.05). The shade and the sundried scent leaves had similar values. It

ranged from 1.45 to 2.24 mg. The fresh scent sample had the higher flavonoid than

those of the sun and the shade dried samples (2.24 vs 1.64 and 1.45mg) (P<0.05).

The tannins content of the fresh, the sun and the shade dried G. latifolium

leaves varied. It ranged from 0.07 to 0.11mg. The sun dried sample had highest value

followed by the shade dried and the fresh (0.11vs 0.08 and 0.07mg, respectively)

(P<0.05). The shade dried and the fresh samples had similar value (P>0.05). The

phytate values ranged from 55.55 to 127.82mg. The sun dried G. latifolium leaves had

the highest phytate. The shade dried samples had the second highest (127.83 vs

125.67mg, respectively). Sundrying had an edge over the shade drying (127.83 and

125. 67mg) (P<0.05). However, both the sun and shade drying had higher phytate

than that of the fresh sample (127.83 and 125.67 vs 55.55mg) (P<0.05). The saponins

level G.latifolium leaves ranged from 0.02 to 0.11mg. The sun and the shade dried

samples had comparable saponins (0.02 and 0.03mg) (P>0.05). However, the fresh

sample had the highest which differed from those of the sun and the shade dried

samples (0.11 vs 0.02 and 0.03mg) (P<0.05). The flavonoid levels for the fresh and

the processed G. latifolium leaves varied. The range was from 1.40 to 2.12mg. The

fresh sample had the highest value (2.12mg) and the sun and the shade dried samples

had 1.85 and 1.40mg, each. The sun and the shade dried samples had similar value

(1.85 and 1.40 mg) (P>0.05). However, their values were different from that of the

fresh sample (1.85 and 1.40 vs 2.12mg) (P<0.05).

The tannins levels for the fresh, the sun and the shade dried roselle differed.

The sundried sample had the highest tannins (0.13mg). The sun dried and the fresh

samples had 0.12mg and 0.10mg, each. All three samples had similar values (0.13,

0.12 and 0.10mg) (P>0.05). The phytate content varied and ranged from 63.24 to 122.

67mg. Shade dried roselle had the highest phytate (122.67mg). The sundried and the

fresh samples had 121.13 and 63.224mg, each. The difference in phytate among the

46

sundried and the shade dried samples as well as that of the fresh differed (122.07,

121.13 and 63.24mg) (P<0.05). The saponins levels ranged from 0.04mg to 0.11mg.

The sundried sample had the least saponins (0.04mg). The shade dried sample had the

highest followed closely by the fresh sample (0.11 and 0.10mg) (P>0.05). Both had

different values from that of the fresh sample (0.11 and 0.10 vs 0.04mg) (P<0.05).

The flavonoid levels for the roselle samples ranged from 1.55 to 2.49mg. The shade

dried sample had the highest flavonoid (2.49mg) which was similar to that of the fresh

sample (2.45mg) (P>0.05). However, both values differed from that of the sun dried

sample (2.45 and 2.49 vs 1.55mg) (P<0.05).

47

Table 6 shows the effects of sun and shade drying on the phytochemical

composition of the fresh, the sun and the shade dried okra, bitter, scent, G.

latifolium and roselle leaves (mg/100g).

The tannins content for all the fresh, the sun and the shade dried samples

varied. The range was from 0.11 to 0.69mg. Shade dried okra leaf had the least

tannins (0.11mg) and the fresh roselle leaf had the highest (0.69mg). Fresh scent leaf

had the second highest value (0.22mg) followed by the fresh okra and bitter leaves

(0.19mg). Sundried okra, bitter and roselle leaves as well as the shade dried bitter leaf

had comparable value (0.14mg). The value was comparable to those of the shade

dried scent leaf, the sundried G. latifolium leaf and the shade dried roselle leaf

(0.13mg).

Fresh roselle leaf had the highest phytate (457.05mg). The sundried roselle

had the least values (129.37mg). The sun and the shade dried okra leaves, the sun and

the shade dried bitter leaf, the sun and the shade dried scent leaves and the sun and the

shade dried G. latifolium leaves had comparable values (133.45,136.32, 134.77,

138.68, 133.90, 136.36, 137.28 and 134.99mg, respectively). Fresh okra, bitter and

scent leaves had 174.33mg, 152.10mg and 160. 16mg, each.

The saponins levels for the samples differed. It ranged from 0.02 to 0.69mg.

Sundried G. latifolium leaf had the least saponins (0.02mg). The fresh roselle had the

highest saponins (0.69mg). The fresh bitter leaf had the second highest value

(0.35mg). The sun and the shade dried okra leaf, the sun and the shade dried bitter

leaf, the sundried scent leaf and the shade dried G. latifolium leaves had comparable

values (0.03mg). Shade dried scent and the roselle leaves had similar values (0.11mg

and 0.12mg, each). Fresh okra, scent and G. latifolium leaves had similar values

(0.2mg)

Fresh roselle had the highest flavonoid (10.71mg). The fresh okra leaf had the

second highest value (6.72mg). Fresh bitter, scent and G. latifolium leaves had similar

values (5.25, 5.97, and 5.50mg). Sun and shade dried roselle leaves had similar

flavonoid content (2.66 and 2.67mg). Shade dried okra and the sun dried G. latifolium

leaves had similar values (1.96 and 1.99mg). However, the shade dried bitter and the

scent leaves had comparable value (1.61mg).

48

Table 6: Effects of sun and shade drying on the phytochemical composition of

the fresh, the sun and the shade dried okra, bitter, scent, G. latifolium and roselle

leaves (mg/100g).

TANNINS PHYTATE SAPONINS FLAVONOIDS

FOL 0.19+0.12 174.33+0.02 0.29+0.01 6.72+0.01

SUOL 0.14+0.01 133.45+0.01 0.03+0.00 1.83+0.01

SHOL 0.11+0.01 136.32+0.02 0.03+0.01 1.96+0.02

FBL 0.19+0.01 152.10+0.01 0.35+0.01 5.25+0.01

SUBL 0.14+0.01 134.77+0.07 0.03+0.01 1.64+0.01

SHBL 0.14+0.00 138.68+0.07 0.03+0.00 1.61+0.02

FSL 0.27+0.01 160.16+0.01 0.29+0.01 5.97+0.01

SUSL 0.13+0.01 133 .90+0.01 0.03+0.01 1.78+0.01

SHSL 0.12+0.01 136.36+0.01 0.11+0.00 1.61+0.01

FGL 0.18+0.00 144.04+0.07 0.29+0.01 5.50+0.08

SUGL 0.12+0.01 137.28+0.01 0.02+0.00 1.99+0.02

SHGL 0.09+0.01 134.99+0.04 0.03+0.01 1.50+0.02

FRL 0.69+0.00 437.03+0.01 0.69+0.01 10.71+0.01

SURL 0.14+0.01 129.37+0.01 0.04+0.01 2.66+0.01

SHRL 0.13+0.00 131.01+0.01 0.12+0.01 2.67+0.01

Mean + Standard deviation of three determinations

FOL = Fresh okra leaf FGL= Fresh G latifolium leaf

SUOL = Sundried okra leaf SUGL = Sundried G. latifolium leaf

SHOL = Shade dried okra leaf SHGL =Shade dried G. latifolium leaf

FBL = Fresh bitter leaf FRL = Fresh roselle leaf

SUBL = Sundried bitter leaf SURL = Sundreid roselle leaf

SHBL = Shade dried bitter leaf SHRL= Shade dried roselle leaf

FSL = Fresh scent leaf

SUSL = Sundried scent leaf

SHSL = Shade dried scent leaf

49

DISCISSION, CONCLUSION AND RECOMMENDATION

Chemical analysis.

The high moisture for fresh samples as well as the decreased moisture of the

sun and shade dried samples is an expected phenomenon (Table 1). It is common

knowledge that foods including fruits and vegetables exposed to either sun or shade

drying lose moisture along with volatile materials (Ezeife, 2003). The lower moisture

for okra, bitter, scent, G. latifolium and roselle leaves had some nutrition implications.

It is known that the lower the moisture content of a food, the higher the nutrient as

well as the shelf life (Odo, 2007). This indicates that sun drying had an edge over

shade drying. However, sundrying might have adverse effect on volatile nutrients e.g.

vitamin A content of fresh foods. This phenomenon is in line with the findings of

Ogbu (2007).

The lower protein for all fresh samples was due to their higher moisture values

(Table 1). The comparable protein for the sun and the shade dried samples for okra

(19.64 and 19.78%) , bitter leaf (19.88 and 19.42%), scent leaf (13.19 and 13.40%)

and roselle leaf (22.86 and 22.39%) showed that either of the methods was as good as

the other to preserve and increase the nutrient (protein). Sundried G. latifolium had an

edge over the shade dried sample. This indicates the superiority of sun drying to

conserve protein (Aletor and Adeogun, 1995). The lower protein for fresh roselle

leaves was due to its high moisture. It is known that the higher the moisture a food

contains, the lower are the dry matter of which protein is one. This is in agreement

with research carried out by many scholars Odo (2007), FAO (1997), Oguntona

(1998), Udofia (2005) in some seasonal vegetables.

The lower fat for all the sun and the shade dried samples except for the

sundried roselle leaf (2.06%) might be due to varietal differences. The lower fat for

treated sample is good. Lower fat of a food prevents chances of rancidity. The lower

fat for all samples regardless of treatment is expected. Vegetables contain low fat in

general to maintain cell wall integrity (Pampona- Roger, 2005).

The lower ash for all fresh vegetable is normal due to high moisture. The

higher ash for the sun and the shade dried vegetables was due to loss of vegetative

part of the vegetables which released the ash (dry matter) to increase free minerals for

their bioavailability (Ezeife, 2003). The comparable values for the sun and the shade

dried vegetables (Table1) showed that none had an edge over the other to increase ash

in these vegetables. However, the slight differences in these values are ascribed to

varietal differences and individual specificity (Oguntona, 1998: Wachap, 2003).

50

The lower fibre levels for all fresh vegetables are a function of moisture and

soil content. The high level for fibre in the processed samples was not a surprise.

Vegetables are good sources of fibre (Wardlaw and Kessel, 2002). However, the

higher levels for the sun and the shade dried samples were due to; (a) loss of moisture

that precipitated increased dry matter and (b) drying and milling, which led to release

of fibre from its complex carbohydrate compounds due to vegetative losses this is a

comparable phenomenon (Okoh, 1984: FAO, 1997).

The higher sugar for all fresh vegetable as against their processed samples

confirms that fresh vegetables are better sources of sugar. The lower sugar for the sun

and the shade dried samples might be due to loss along with moisture (Wachap,

2003). It is known that volatile nutrients’ including sugar is lost at any increase in

temperature (Ogbu, 2007).

The lower starch for the fresh samples as well as the processed samples is not

difficult to explain. Naturally, vegetables are not good sources of carbohydrate

(starch). However, if total carbohydrate was estimated, the value might have been

different. Total carbohydrate is comprised of fibre and sugar. This might have led to

the low starch. The higher starch for the sundried samples except for that of roselle

appeared to suggest the superiority of sun to shade drying of these vegetables.

Effects of sun and shade drying on the chemical composition

The higher protein for the sun and the shade dried vegetables (Table 2) was

because they contained high moisture that ranged from 61.44 to 85. 53%. When high

moisture was lost due to drying, the dry matter increased including protein (Tables 1

and 2). The higher protein for all treated samples was because they had lower

moisture than the fresh ones. As such, when the protein value was based on residual

moisture, the sun and the shade dried samples were advantaged. The lower fat for the

processed samples was an asset as regards risk of rancidity. Shelf life is enhanced in

foods that have low fat values.

51

Mineral composition

The low copper in all treated vegetables except for that of roselle might: (a) be

that the nutrient was low in the vegetables and (b) the anti-nutrient content in the

samples might have formed complex organic salt that made copper unavailable

(Wardlaw and Kessel, 2002).

The higher phosphorus levels for all the vegetables (treated samples) as

against their controls (Table 3) were associated with sun and shade drying. These

processes decreased moisture to increased dry matter of which phosphorus is one of

them.

The higher iron (Fe) for all fresh samples is not a surprise. Udofia (2005) and

Wachap (2006) observed the same phenomenon in various vegetables they studied.

The sun and the shade dried samples of all the vegetables had low iron. This is

contrary to the study of Kendal, DiPerso and Sefos (2008). They reported that iron is

not lost in vegetables due to drying. However, at higher temperature, the loss could be

possible.

The low zinc levels for the treated samples were expected and the higher

levels for fresh samples were also normal expectation. Zinc might exist as a volatile

substance in its complex salt as such; heat from sun and shade drying caused its

evaporation along with moisture.

Effects of sun and shade drying on mineral composition

The decreased values for copper, phosphorus, zinc and iron (Table 4) for the

sun and the shade dried samples was normal. Many had reported the same observation

(Udofia, 2005; Umoh, 2006; Mefoh, 2008; Okoye, 2006) in various vegetables.

Phytochemical composition

The increases in tannins and phytate are in line with the findings of Udofia

(2005) & Umoh (2006). It equally has some nutrition implications. Decades ago,

these two food none-nutritive components were regarded as anti-nutrients that chelate

nutrients and made them unavailable. Calcium, copper and zinc are good examples of

nutrients chelated by tannins and phytate. Recently, these anti-nutrients were found to

have antioxidant effects. Both are known to reduce serum cholesterol and might also

reduce the risk of cancer (Soetan, 2008: Bender, 2002). The increases in phytate were

much more in the sundried samples (Table 5).

52

The saponins levels for all the samples were low except for roselle (fresh

sample, 0.10mg, the sun and the shade dried samples (0.11mg). The higher saponins

for fresh samples have some health implications. Recent studies revealed that

saponins attacked and destroyed cancer cells. This is because saponins have affinity

for cholesterol in cancer virus cell membrane, leaving non cancer cells intact (Rao,

1996; Messina, 1979). The higher saponins in fresh vegetables means that fresh

vegetable is better source of saponins as well as flavonoids.

Effect of sun and shade drying on phytochemical composition of the vegetables

Lower levels for tannins for all shade dried samples except for that of bitter

leaf suggested that it was much more drastic to reduce tannins with shade drying than

with sundrying (Table 6). On the other hand, the lower phytate for all the sundried

samples except for G. latifolium sample appeared to suggest specificity of sundrying

on photochemical – a commonly observed fact. The comparable saponins for all the

vegetables except for those of the shade dried scent leaf and the shade dried roselle

leaf suggested that none of the food processing methods had an edge over the other.

53

CONCLUSION

The nutrient, mineral and phytochemical composition of the five cultivated

and wild forest vegetables were influenced by sun and shade drying. Both processes

decreased moisture, fat and sugar levels of the samples. They increased protein, ash,

fibre and starch of all the vegetables. When the values were based on residual

moisture, protein decreased except for that of roselle . Fat, ash and fibre increased

only in roselle samples. Both sun and shade drying lowered copper, iron and zinc and

increased phosphorus only. Fresh samples had lower protein. When based on residual

moisture, there were increases in protein of the shade dried samples except for scent

leaf. Fat deceased except for the shade dried scent leaf and the sundried G. latifolium

samples. Ash and fibre deceased due to residual moisture. Tannins and phytate

increased due to residual moisture. Saponins and flavonoids decreased in processed

samples because residual moisture reduced all the phytochemicals. The advantages of

sun and shade drying outweighed their disadvantages as domestic food processing

techniques.

RECOMMENDATIONS

1) Increase in vegetable consumption is imperative for all in both

rural and urban settings.

2) Sun and shade drying are cheap methods to preserve vegetables as

well as other foods to maintain food security all year round.

3) Vegetables should be pulverized and added to children’s foods who

often do not consume vegetables as adults.

54

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