COMPARATIVE STUDY OF MANGO LEATHER - Sher-e ...

COMPARATIVE STUDY OF MANGO LEATHER

A Thesis

By

SREEDAM CHANDRA PAUL Examination Roll No. 10 AEFT JD-19 M

Registration No. 32486 Session: 2005-06

Semester: July-December, 2011

MASTER OF SCIENCE IN

FOOD ENGINEERING

DEPARTMENT OF FOOD TECHNOLOGY AND RURAL INDUSTRIES

BANGLADESH AGRICULTURAL UNIVERSITY MYMENSINGH

NOVEMBER, 2011


A Thesis By

SREEDAM CHANDRA PAUL

Examination Roll No. 10 AEFT JD-19 M Registration No. 32486

Session: 2005-06 Semester: July-December, 2011

Submitted to the Department of Food Technology and Rural Industries Bangladesh Agricultural University, Mymensingh

in partial fulfilment of the requirements for the degree of

MASTER OF SCIENCE IN

FOOD ENGINEERING

DEPARTMENT OF FOOD TECHNOLOGY AND RURAL INDUSTRIES BANGLADESH AGRICULTURAL UNIVERSITY

MYMENSINGH

NOVEMBER, 2011


A Thesis

By

SREEDAM CHANDRA PAUL Examination Roll No. 10 AEFT JD-19 M

Registration No. 32486 Session: 2005-06

Semester: July-December, 2011

Approved as to style and content by

__________________________ Prof. Dr. M. Burhan Uddin

Supervisor

___________________________ Prof. Dr. Md. Nazrul Islam

Co-Supervisor

______________________ (Dr. Md. Abdul Alim)

Chairman Examination Committee

and Head, Department of Food Technology and Rural Industries

Bangladesh Agricultural University Mymensingh

NOVEMBER, 2011

I

ACKNOWLEDGEMENT

All praises and appreciation are for the almighty creators enabled the author to bring this thesis

in success. I express proud gratitude and respect to my teacher and research supervisor Dr. M.

Burhan Uddin, Professor, Department of Food Technology and Rural Industries, Faculty of

Agricultural Engineering and Technology, Bangladesh Agricultural University, Mymensingh

for his guidance, encourage, suggestions and timely instruction throughout the period of

research work and preparation of this thesis.

I also express proud gratitude and respect to co-supervisor Dr. Md. Nazrul Islam, Professor,

Department of Food Technology and Rural Industries, Faculty of Agricultural Engineering

and Technology, BAU, Mymensingh for his sincere co-operation to carry this research and

preparation of this thesis.

The author also humbly desire to acknowledge heartiest appreciation and cordial thanks to Dr.

Abdul Alim, Head of the Department of Food Technology and Rural Industries, Professor Dr.

Md. Shams-Ud-Din and all other respected teachers of Department of Food Technology and

Rural Industries, Faculty of Agricultural Engineering and Technology, BAU, Mymensingh

for their cordial co-operation to carry this research and preparation of this thesis.

The author received logistic and financial support from the project entitled “Technology

Dissemination for Value Addition to Horticultural Produces by Poor Farmers to Improve their

Livelihood”, funded by ASPS-II Adoptive Research Program (DANIDA) and acknowledges

with thanks.

I also like to express gratitude to Mrs. Roushan Ara Akhter, Deputy Chief Demonstrator and

Mr. Md. Azizul Haque, Deputy Chief Technical Officer and all the staff members of the Food

Technology and Rural Industries, BAU, Mymensingh for their help during the experiment.

The Author

II

ABSTRACT

The present study was concerned with the comparative study of mango leather and

development of product the purpose of this study was to analyze the composition

of mango leather and observation of shelf life of the product. Processed mango

leather contained moisture 21-23%, ash 1.36-1.81%, Protein 8.0-8.4%, total sugar

and protein 8.40-8.47%, whereas mango pulp contain moisture 85%, Ash 0.47%,

TSS 15.1%, acidity 0.16%, vitamin C 43mg/100gm and total sugar 12.02%.

Among the eight formulated products of F1 (mango pulp 100%), F2 (mango pulp

95% + sugar 5%), F3(mango pulp 100%), F4(mango pulp 95% + milk powder 5%)

F5(mango pulp 95% + sugar 5%), F6 (mango pulp 100% ), F7(mango pulp 95% +

milk powder 5%), F8 (mango pulp 95% + sugar 5%), the formulation F7 secured

highest score for overall acceptability and ranked as “like very much” by a taste

testing panel. The formulation F7 contains mango pulp 95% and milk powder 5%.

The chemical analysis showed that the quality of mango leather was satisfactory

but vitamin C was highly reduced. However the developed products contain high

amount of nutrients and were rich in energy. Developed intermediate products

were tested of their acceptability by a taste panel consisting of 10 panelists. The

consumer’s preference was measured by statistical analysis of the score obtained

from the response of the taste panel. The statistical analysis of the score showed

that all the developed products were equally acceptable and sample F7 secured the

highest score and was ranked as “like very much”. The other products were also

liked moderately as far as overall acceptability are concerned. The mango leather

was stored in high density polyethylene packaged coated with aluminum foil and

best quality of mango leather achieved during the 90th

day.

III

CONTENTS

CHAPTER PAGE NO.

ACKNOWLEDGEMENT I

ABASTRACT II

CONTENTS III

LIST OF TABLES V

LIST OF FIGURES VI

LIST OF APPENDICES VII

1. INTRODUCTION 01

2. REVIEW OF LITERATURE 03

2.1 Mango and its nutrient content 03

3. MATERIALS AND METHODS 09

3.1 Materials required 09

3.2 Apparatus required 09

3.3 Methods 09

3.3.1 Extraction of mango pulp 10

3.3.2 Processing mango pulp 11

3.3.3 Preparation of mango leather 11

3.4 Basic formulation for preparation of mango leather 13

3.5 Chemical Analysis

3.5.1

14

3.5.2 Ash content 14

Moisture content 14

3.5.3 Acidity 15

IV

3.5.4 Reducing sugar 16

3.5.5

3.5.6

Non-reducing sugar 17

3.5.7

Estimation of total sugar 18

3.5.8

Total soluble solids (TSS) 18

PH

3.5.9

18

3.5.10

Vitamin-C content (Ascorbic acid) 19

3.5.11 Protein 23

Crude fibre 20

3.6 Sensory Evaluation 25

4. RESULTS AND DISCUSSION 26

4.1 Composition of fresh mango pulp 26

4.2 Composition of mango leather prepared from mango pulp 27

4.3 Effect of storage time and temperature on the chemical

composition of mango leather 29

5. SUMMARY AND CONCLUSION 34

REFERENCES 36

APPENDICES 42

V

LIST OF TABLES

TABLE TITLE PAGE NO.

3.1 The basic formulation for preparation of mango leather

4.1 Composition of mango pulp

4.2 Composition of processed mango leather prepared from

mango pulp

4.3 Shelf life of mango leather with packaging material at

room temperature

4.4 Mean score for color flavor texture and overall

acceptability for various types of mango leather

13

26

27

30

32

VI

LIST OF FIGURES

Figure Title Page No.

3.1Schematic diagram for preparation of mango pulp 10

3.2Schematic diagrams for preparation of mango leather 12

VII

LIST OF APPENDICS

APPENDIX TITLE PAGE NO.

1.

1.1 Rating score for color of mango leather 42

1.2 Analysis of variance (ANOVA) for color mango leather 42 1.3 Duncan’s Multiple Range Test (DMRT) for color 43

2. 2.1 Rating score for flavor of mango leather 43

2.2 Analysis of variance (ANOVA) for flavor of mango leather 44

2.3 Duncan’s Multiple Range Test (DMRT) for flavor 44

3. 3.1 Rating score for texture of mango leather 45

3.2 Analysis of variance (ANOVA) for texture of mango leather 45

3.3 Duncan’s Multiple Range Test (DMRT) for texture 46

4. 4.1 Rating score for overall acceptability of mango leather 46

4.2 Analysis of variance (ANOVA) for overall acceptability

of mango leather 47

4.3 Duncan’s Multiple Range Test (DMRT) for overall

acceptability of mango 47

5. Taste testing of mango leather 48

1

CHAPTER I

INTRODUCTION

Mango (Mangifera Indica) is called the king of fruits. It is also a delicious fruit. It

is most ancient and popular fruit in our country. There are many varieties of

mango are cultivated in our country.

The statistical data shows that in Bangladesh about 71899 acreage of land is under

mango cultivation within an annual production of 766930 metric tons (BBS,

2007). Due to the lack of post-harvest facilities losses as high as 18% (Srinivas,

et.al.1977). Mango leather is a traditional product prepared from ripe mango.

Traditionally sun drying is employed for preparing mango leather from ripe fruit

pulp. But sun dried leather is discolored and the process is unhygienic and lengthy.

Cabinet drying has been carried out for making mango leather (Heikal, et al, 1972;

Mir and Nath. 1995) resulting with better color and flavor. The main constituents

of mango are water 75- 82%; sugar 4 8.7-20%; protein 0.51%;citric acid 0.14-

0.71%; vitamin –C 8.5-50 mg per 100g and ash 0.38-0.635 ( Singh, 1968). Thus

mango is a good source of energy and nutrient.

Mango leather has very low protein content ranged from (1-2%) (Pramanik and

Segupta,1978). Protein content can be increased by adding shrimp flavor and rice

flavor when protein is isolate and 50% protein isolate (Exoma and Noriel,1989;

Payvmo et al,1981; Chauhan and Joshi 1998). Sometime additional sugar, color or

milk powder is added to the mango pulp during preparation of mango leather.

Mango is seasonal in nature and available in large quantity during the peak season.

But this fruit is perishable item and not be fresh for longer time often harvesting.

2

So adequate preservation facilities are responsible for removal of damage/spoilage

of a large quantity of its valuable fruits.

If post-harvest losses could be prevented thus farmer would get proper price of

their products.

The specific objectives of proposed study are:

• Prepare the mango leather by using mango pulp, sugar and milk

powder.

• To study the proximate composition of product.

• To study the keeping quality and shelf life of the processed mango

leather.

3

CHAPTER II REVIEW OF LITERATURE

2.1 Mango and its nutrient content

Jain (1961) has reviewed the chemical composition of mango. It is rich of

carbohydrate as well as vitamin A and C. The following is the chemical

constituent present in mango (25 varieties). Sugar constitutes main bulk of the

carbohydrates and most of the soluble solids in ripe mango.

Chemical Constituent Quantity

1. Moisture 73.9-86.75%

2. Carbohydrate 11.6-24.31%

3. Protein 0.3-1.0%

4. Fat 0.1-0.8%

5. Minerals 0.3-0.7%

6. Vitamin A 650-25940 I.U.

7.Vitamin-C 3.0-83 mg/100 g

Singh (1986) reported that the main constituents of mango were -

Chemical Constituent Quantity 1. Water 75 to 82%

2. Sugar 8.7 to 25%

3. Protein 0.51%

4. Citric acid 0.14 to 0.7%

5. Vitamin-C 8.5 to 50 mg per 100 g

6. Ash 0.38 to 0.63%

4

According to Jacob (1959) beverages are characterized by two principal charters.

Firstly they are liquid or are consumed in a liquid state. Secondly, they are

generally used to quench the thirst. One of the groups of beverages is the still

beverage such as fruit drinks and fruit juices.

Hulme (1971) stated that all juices are inherently unstable microorganisms already

present on the fruit or gaining access to the product during processing. Rapidly

attack them; they are also subject to enzymatic and non-enzymatic chances. It is

thus essential to destroy the micro-organisms at an early stage or to prevent their

development and to restrict chemical change by heat treatments to inactivate

enzymes or by refrigeration.

In food industry fruit juice is defined as the liquid expressed by manual or

mechanical means (pressure) from the edible portion of the fruit. Frequently the

juice may be turbid, contain cellular components in colloidal suspension width

variable amounts of finely divided tissue. It sometimes may contain oily or waxy

material and carotenoid pigments (Hulme, 1971).

Roy et al, (1997) observed that homogenization affects the viscosity, acceptability

and storage properties of mango pulp and mango juice beverages such as squash,

nectar etc. He showed that storage at 4± 1°C ensured maximum retention of

chemical and sensory properties.

Joslyn et al,(1961) investigated that the effects of length and temperature of

storage and the relationship of oxygen, light, sugar, pH and ascorbic acid to

deteriorative changes in color or these factors. Storage temperature and oxygen

content were the most specific for color injury of both juices and isolated

pigments. Adjustment of acidity within the range of pH 2 to 4.5 or sugar addition

had little effect on color retention in fruit juices during storage.

5

Yuan Tayshyu et al, (1996) studied the processing parameters of mango juice

quality. He showed that among the parameters desecration decreased the dissolved

oxygen and thus minimizes the loss of vitamin C during pasteurization. He found

that storage temperature (25-30°C) affects the quality of mango juice Vitamin C,

color and viscosity declined but TSS, pH, acidity etc. did not change significantly.

Ahmed et al,(1988) studied organic and mango beverage prepared with different

sugar acid combinations and evaluated their physiochemical and organoleptic

characteristics during storage at room temperature (10-330C). Different sugar and

acid concentration used had no significant effect on ascorbic acid content and

variations observed in acidity, total soluble solids TSS) and their ratio during

storage was mainly due to difference in initial sugar and acid content. Ascorbic

acid and acidity decreased whereas TSS and TSS/acid ratio increased during

storage.

Flaumenbaum and Shengeliya (1974) reported that the taste of sweetened fruit

juice depends upon the sugar/juice acid ratio. Minimum sugar content should be

18%, acidity 0.8-1.5% and the sugar/acid ratio 20-29.

Cruess(1958) observed that preservation the flavor, aroma, color and vitamin

content of the fresh juice was dependent on the degree of destruction off enzymes

or inhibition of their activity. Enzymes could be destroyed and activity could be

inhibited by pasteurization.

Ahmed (1982) reported that mangoes are one of the richest sources of vitamin-A.

They contain a good amount of Niacin and Riboflavin and a fair quantity of

vitamin C. Unripe mangoes are rich source of vitamin C and iron.

6

Miller et al, (1982) reported that mango juice have a high sugar content but is a

poor source of calcium, phosphorus and iron. Mango has sufficient yellow

pigment provide pro-vitamin A. Mango have been found to be poor source of all

three B vitamins, Thiamine, Riboflavin and Niacin. In green stage ascorbic acid

content is high than half ripe and ripe stage.

BCSIR laboratories in Rajshahi (Anonymous, 1975) investigated the compatibility

of ripe mango juice is mixture with other fruit juice such as pineapple, lemon,

guava etc. It has been observed that the mixed fruit juice had great consumer

appeal. The Central Food Technological Research Institute (CFTRI) proposed a

recipe for the preparation of a mango squash as follows; mango pulp 1 kg; water 1

kg; sugar 1 kg; citric acid 30 g; edible mange yellow color and potassium meta-

bisulphate (KMS) at the rate of 610 mg per kg of finished product (Anonymous,

1975).

EI-Nernr et al, (1989) reported that the freshly prepared and bottled juice was

analyzed for various volatile aroma compounds including esters, carboxyl

compounds, alcohols and lactose. The bottling process resulted in a sharp decrease

in the content of all volatile fractions, especially esters. During subsequent storage,

the contents of these fractions, especially alcohols and lactoses, increased to levels

higher than those in freshly prepared juice.

EI-Sarnaly et al, (1983) studied concentrated mango juice which was stored at –

12°C or 4.5°C for 11 months. Samples were analyzed at storage onset day 0), after

1 month and at 2 months intervals, for chemical composition f acidity as citric acid

%, contents of ascorbic acid, free amino-N carotenoids and pulp; color index and

% reducing sugars and non- reducing sugar) and for flavor substances (esters,

limonene, oxygenated terpenes and carboxyl compounds). He found that there

7

were marked decreases in ascorbic acid content and color index and a marked

increase in pulp content with changes being more marked for the higher storage

temperature, with changes also being greater for storage at 40°F.

FAO and WHO Jointly defined "food additive" as non-nutritive substances added

intentionally to food, generally in small quantities, to improve its appearance,

flavor, texture or storage properties. Some chemicals added to food to impart a

desired quality or for some other functional purpose may be of nutritive value.

Rangana and Bajaj (1990) reported that S02 is widely used throughout the world

principally for treating food of plant origin. It is used in the preservation of fruit

juices, pulps, beverages and concentrates; concentration used may vary from 350

to 2000 ppm. Soluble sulphite salts (e.g. K. M. S) are usually used in treating fruits

products. The activity is higher at pH below 4.0.

Ahmed (1982) reported that mangoes are one of the richest source of vitamin-A.

They contain a good amount of niacin and riboflavin and a fair quantity of

vitamin- C. Unripe mangoes are reach source of vitamin C and iron.

The mangoes can be separated into three parts skin, flesh on pulp and store,

Philippine mangoes have been found to contain 11 to 18% skin, 14-22% seed and

60-73% pulp (Prott and Del Rosorio,1973) whereas mangoes in Hawaii contains

an average of 63-77% of edible matter (Pope 1992). The flesh content of mango,

as reported from various mango growing zones, varies from 58-75% (Winton and

Winton,1935). From the result of analysis of twenty one varieties of mango

growing in Florida, it appears that the seed varies from 6.8 to 17.9 percent, the

skin 9.3 to 16.5 percent and the pulp 69.1 to 93.3 percent (Mustard and Lynch,

1954).

8

Ajila et al,(2007) reported that polyphenol contents in mango peel ranged from 45

to 78% of peel and was found at a higher level in ripe peels. Similarly, coronoid

content was higher in ripe fruit peels. Vitamin C and E contents ranged from 188

to 392 and 205 to 509 micro g/g dry peel and these were found at a higher level in

ripe peels. Both raw and ripe mango peels exhibited significant amount of

protease, peroxide, polyphenol oxidase, xylenes and amylase activities.

Vasquez at al, (2007) observed the effects of thermal mango processing on beta-

carotene stability and inactivation of peroxidase (POD) and polyphenol oxidase

(PPO) which were systematically evaluated on a laboratory scale, mimicking

typical operations in continuous and small-size batch production of mango puree.

Maximum vitamin A loss during pasteurization of mango puree did not exceed

15.4 owning to a total beta-carotene retention of 93% PPO was readily inactivated

after 1 min, whereas residual POD activities of 4.0-6.3% were defected, ever after

16 min at all pasteurization temperatures.

Rebeiro et al,(2007) reported the pulp composition of four mango cultivators

(Haden.Tommy Atkins and Uba) of the opening stage of relation to three

components with antioxidant potential (total phenolic, carotenoid and ascorbic

acid).Differences were found among the four mango cultivators in all the

components analyzed. The content of phenolic compounds ranged from 48.40

(Haden) to 2/63 mg/100g(palmer)beta-carotene from 661.27 (palmer) ; (Uba) and

total ascorbic acid ranged from 9.79 (Tommy Atkins) to 77.71 mg /100g(Uba).

These results corroborated previous information that mangoes are good source of

antioxidants in human diet.

9

CHAPTER III

MATERIALS AND METHOD

The study was conducted in the laboratory of the department of Food Technology

and Rural Industries, Faculty of Agricultural Engineering and Technology

Bangladesh Agricultural University, Mymensingh.

Materials and Apparatus required

3.1.1Materials required

i. Mango

ii. Sugar

iii. Milk Powder

3.1.2 Apparatus required

i. Electric balance

ii. Petridis

iii. Crucible

iv. Desiccator

v. Stainless steel knives

vi. Measuring Flash

vii. High density polyethylene bag with aluminum foil

Methods

a) Extraction of mango pulp

b) Processing mango pulp

c) Preparation of mango leather

10

a) Extraction of mango pulp Fresh fully ripe sound Ashwani mangoes were used for extraction of pulp. Firstly

ripe mangoes were washed within clean water then fruits were peeled by knife.

Pulp was collected by squeezing the flesh of mangos. The pulp was blended in an

electric blender. The mango pulp contains 15.1% total solid. It was stored in a

deep freeze at a temperature of -180C for future use.

Fig:3.1 Schematic diagram for preparation of mango pulp

11

b) Processing mango pulp

Fresh mango pulp contains 15.1% of total solid. So pulp TSS percentage should be

increase for quality mango leather processing. First all fresh mango pulp poured

into a bowl. Then the bowl was heated at 80-900

c) Preparation of mango leather

C until Total Soluble Solid (TSS)

percentage become 30.

At first processed mango pulp were taken and weighted by a balance. Then total

mango pulps were separated into three parts in order to processing of three kinds

of sample. After that mango pulps were mixed with weighted sugar and milk

powder according to the described formulation. Mixed pulp were heated at 80-

900C for 10 minutes and cooled. Then mixture was placed on a steel tray and

smeared with very thin layer of polyethylene to preserve sticking of mango leather

after drying. The mixture was dried by using cabinet dryer with constant

temperature 600C a maximum period of 18 hours. After drying sheet was cut into

(4"×1"×various thickness) bar form. The mango leathers were packed with high

density polyethylene bag and stored at room temperature.

Schematic flow diagram for mango leather is given in following figure:

12

Fig: 3.2 Schematic diagrams for preparation of mango leather

13

3.3 Basic formulation for preparation of mango leather

Basic formulation for preparation of mango leather is presented in the table 3.1the

formulation F1 contained mango pulp 100%. Any kinds of other ingredients are

not used in formulation F1, Formulation F2 contained mango pulp 95% and sugar

5%, Formulation F3 contained only mango pulp100%, Formulation F4 contained

mango pulp 95% and milk powder 5%, Formulation F5 contained mango pulp

95% and milk powder 5%, Formulation F6 contained only mango pulp 100%,

Formulation F7 contained mango pulp 95% and sugar 5%, Formulation F8

contained 95% mango pulp and milk powder 5% and traditional formulation Ft

Sample

contain 100% mango pulp.

Table: 3.1The basic formulation for preparation of mango leather

Formulation Ingredient (%)

Mango Pulp Sugar Milk powder

Single layer

(3mm)

F 100 1 - -

F 95 2 5 -

Two layers

(5mm)

F 100 3 - -

F 95 4 5 -

F 95 5 - 5

Three layers

(7mm)

F 100 6 - -

F 95 7 5 -

F 95 8 - 5

Traditional

(4mm)

F 100 t - -

14

3.5 Chemical Analysis

The ripe mango pulp, pineapple juice and papaya pulp and stored mixed fruit

bar were analyzed for their moisture, ash, titrable acidity, pH, total soluble solids,

total sugar, fibre content and vitamin C. All the determinations were done in

triplicate and the results were expressed as average value.

3.5.1 Moisture content

Moisture content was determined adopting AOAC (2005) method.

Procedure:

At first weight of empty previously dried (1 hr. at 100°C) crucible with cover

was taken and 5gof sample was placed on it. Then the crucible was placed in an

air oven (thermostatically controlled) and dried at temperature of 100 to 105°C

for 24 hrs. After drying, the crucible was removed from the oven and cooled in

desiccator. It was then weighed with cover glass. The crucible was again

placed in the oven, dried for 30 minutes, took out of the dryer, cooled in

desiccator and weighed. Drying, cooling, and weighing were repeated until

the two consecutive weights were the same. From these weights the percentage

of moisture in food samples was calculated as follows:

Moisture ×100

3.5.2 Ash content

Ash content of a foodstuff represents inorganic residue remaining after

destruction of organic matter. The oven-dried sample was taken in a muffle

furnace at 600' C for 4 hrs. After charring over an electric heater.

15

The difference between oven dried matter and final weight represented the ash,

which was expressed in percentage. It was calculated using the following formula:

Ash content =

Where, F= Weight of ash

I=Initial weight of dry matter

3.5.3 Acidity

Acidity was determined following the methods of Jacob (1959) and Rangana

(1990). Known volume of the, fruit pulp was measured in graduated cylinders and

then they were transferred to beakers and sufficiently. The juices were then cooled

and poured back to the same graduated measuring cylinder and made up to the lost

volume with distilled water.

Titration

10m1 pulp/juice was taken in a100ml conical flask. A few drops of 1%

phenolphthalein solution (indicator) was added to the flask and titrated with 0.1N

NaOH solution from a burette until a light pink color appeared and persist for 15

seconds. The titration was done for several times for accuracy. Percent

titrable acidity was calculated using the following formula:

Titrable acidity =

Where,

T= Titre

N= Normality

V1=Volume made up

E= Equivalent weight of acid

16

V2=Volume of sample taken for estimation

W= Weight of sample

3.5.4 Reducing sugar

The reagents used for the estimation of reducing, non-reducing and total

sugar were follows:

i) Fehling's solution (A)

ii) Feeling's solution (B)

iii) Methylene blue indicator

iv) 45% Neutral lead acetate solution

v) 22% Potassium oxalate solution

Standardization of Fehling's solution

10 ml of both Fehling's solution A and Feeling's solution B were mixed together

in a beaker. 10 ml of mixed solution was pipetted into a 250 ml conical flask

and 25 nil distilled water was added to it. Standard sugar solution was taken in

a burette. The conical flask containing mixed solution was heated on a hot plate.

When the solution began to boil, three drops of methylene blue indicator

solution was added to it. Mixed solution was titrated by standard sugar

solution. The end point was indicated by decolorization of the indicator.

Fehling's factor was calculated by using the following formula:

Fehling’s factor=

17

Preparation of the sample 10 g of filtered juice and 100 ml of distilled water were mixed in homogenizer

and transferred to 250 ml volumetric flask. The mixture was neutralized with 0.1N

NaOH and 2 ml of lead acetate solution was added and followed to stand for

10 minutes. 5 ml potassium oxalate solution was added and made to a volume

of 250 ml. Then the mixture was filtered and made the dilution.

Titration for reducing sugar

10 ml of mixed Fehling's solution was taken in a conical flask and 25 ml

of distilled water was added to it. Purified juice was taken in a burette. Conical

flask containing mixed Feeling's solution was added to the flask when boiling

started and titrated with solution taken in the burette at the same time the end

point was indicated by decolorization of indicator. Percent reducing sugar was

calculated by using the following formula:

Reducing sugar =

Where, I = mg of invert sugar required to reduce known volume of

Fehling's solution

D = dilution factor

T = titration

W = weight of sample

50 ml purified solution was taken in a conical flask.5 ml distilled water and 5 g

of citric acid were added to it. Then the conical flask was heated for 10 minutes

3.5.5 Non-reducing sugar

18

for addition of sucrose and finally cooled. The sample was then neutralized by 0.1

N NaOH solution using phenolphthalein as indicator. The volume was made

up to 100 ml with distilled water. The mixed Fehling's solution was titrated using

similar procedure followed as that for reducing sugar. The percent invert sugar

was then calculated by the similar procedure as for reducing sugar from which the

percent non-reducing sugar is calculated as follows:

% Non-reducing sugar =% Invert sugar - %Reducing sugar

3.5.6 Estimation of total sugar

Total sugar can be calculated as follows:

% Total sugar = %Reducing sugar +%Non-reducing sugar.

3.5.7 Total soluble solids (TSS)

Two drops prepared pulp was taken in a refractometer (Model no. 8987

PujiKuki Ltd. Tokyo, Japan) plate and the total soluble solids of the juice was

read directly from the refractometer.

3.5.8 pH

An electrolytic cell composed of two electrodes (caramel and glass electrode) was

standardized with buffer solution of pH = 4.0. Then the electrodes were

dipped into the test sample. A voltage corresponding to the PH of the

solution was developed and directly one can read the PH of the solution

indicated by the instrument (potentiometer).

19

3.5.9 Vitamin-C content (Ascorbic acid)

Ascorbic acid was determined following the method of Rangana (1990).

The equation used for the estimation of vitamin-C were follows:

Mg of vitamin-C per 100g sample= ×100

Where,

T = Titre

D = Dye factor

VI = Volume made up

V2 = Aliquot of extract taken for estimation

W = Weight of sample taken for estimation

3% Meta phosphoric acid (HPO3): Prepared by dissolving the stick or pellets

of HPO3 in glass-distilled water.

Ascorbic acid standard: Weigh accurately 100 mg of L ascorbic acid and

make up to 100 ml with 3% HP03. Dilute 10 ml to 100 ml with 3% HP030

mg =0.3 mg of ascorbic acid)

Dye solution: Dissolve 50mg of the sodium salt of 2, 6dichlorophenol-

indophenol in approximately 150 ml of hot glass distilled water containing

42 mg of sodium bicarbonate. Cool and dilute with glass-distilled water to

200 ml. Store in a refrigerator and standardize every day. The dye 2, 6-

Dichlorophenol Indophenol is blue in alkaline solution and is reduced to light

red color by an ascorbic acid at pH range of 1-3.5

20

Standardization of Dye

Take 5 ml of standard ascorbic acid solution and add 5 ml of HP03. Fill a

micro burette with the dye. Titrate with the dye solution to a pink color,

which should persist for 15 seconds. Determine the dye factor i.e. mg of

ascorbic acid per ml of the dye, using the following formula:

Preparation of the samples

10 ml of the pulp/juice was taken and made up to 100 ml with 3% HP03 and

then filtered. Now 10 ml of the aliquot was taken in a 150 ml conical flask. 1 ml

of 40% formaldehyde and 0.1 ml of HCI were added to it and kept for 10

minutes. This was titrated with standard dye to a light pink color (end

point), which persisted for 15 seconds. Calculation:

Mg of ascorbic acid per 100 ml ×100

3.5.10 Crude fibre

Crude fibre content was determined using AOAC (2005). Method the

accepted methods are as follows:

Reagents

1) 0.255 N sulphuric acid solution (1.25 g H2SO4

2) 0.313 N sodium hydroxide solutions: 1.25 g NaOH/100m1, free or nearly so

sodium carbonate.

/100 ml)

21

Check the concentration of the solution 1 and 2 by titration and adjust

(if necessary) accurately to the stated concentration.

3) Asbestos: Gooch grade, medium fibre, acid-washed and ignited.

4) 10% Potassium sulphate (K2S04) Solution: Dissolve 10 g in water make

up to 100 ml.

1) Liebig condenser.

Apparatus

2) Filtering cloth: Use filtering cloth of such character that no solid

material passes through when filtering. (Retention may be tested by

passing the filtrate through Gooch.) Bucher's lilen or dressed lilen with

approximately 45 Threads per inch may be used.

Determination

Extract 2g of dry material with either or use the residue from crude fat

determination. Transfer the residue and approximately 0.5 g of asbestos, to the

digestion flask. Add 200 ml of the boiling sulphuric acid solution,

immediately connect the digestion flask with condenser, and heat. (Contents of

the flask must come to boiling within 1 min and boiling must continue briskly

for exactly 30 min.) Rotate the flask frequently until the sample is

thoroughly wetted. During digestion take care to keep the material from

remaining on the side of the digestion flask without contact with the solution.

After 30 minutes remove the flask and filter through filtering cloth in a

fluted funnel. Wash with boiling water until the washing are no longer acid. Heat

22

sodium hydroxide solution to boil under reflux condenser. Wash the residue from

acid digestion back.

Into the flask with 200 ml of boiling sodium hydroxide solution connect the

flask with reflask condenser and boil for exactly 30 min.

After 30 min of boiling remove the flask and immediately filter through

filtering cloth in a fluted funnel. Wash with water. For materials, difficult to

filter, filter through filtering cloth in a fluted funnel using vacuum and

wash with 10% potassium sulphate solution. The potassium sulphate solution

may be added during filtration, whenever it becomes difficult. Return the residue

to the digestion flask thorough washing all residues from cloth with hot

water. Filter into the Gooch crucible prepare with thin but a packed layer of

ignited asbestos. After thorough washing of the residue in the Gooch

crucible with holing water, wash with approximately 15 ml of alcohol. Dry

the crucible and the contents at 1100C to constant weight. Cool in a desiccator

and weight. Ignite the contents of crucible in anelectric muffle furnace or over a

burner at dull red heat until carbonaceous matter is destroyed (approximately 20

min). Cool in a desiccator and weight. The loss in weight represents crude fibre.

Calculation

Crude fibre ×100

23

3.5.11 Protein

The accepted methods are as follows. The reagents used for the estimation of

protein were as follows:

1) Concentrated H2S0

2)

4

Potassium, Sulphate = 100g

Copper Sulphate-10 g

Selenium dioxide=2.5 g

Digestion mixture:

3) Boric Acid Solution

4) Alkali solution

5) Mixed indicator solution

6) Standard HCI (0. 1N)

For estimation of protein, the steps were followed:

Digestion: 2g sample, 5 g digestion mixture and 25 ml H2S04

Distillation: After digestion 100ml. water , 100 ml 40% NaOH and glass

blitz were added in the kjeldahl flask which containing about 10 ml 2% boric

acid and 2-3 drops mixed indicator. About 100m1 distillate was collected just

before the distillation was stopped the receiving flask was moved. So that

were taken

in a kjeldahl digestion flask. It was heated for 4 hours in a kjeldahl digestion

and distillation apparatus) If the color of the substance is pale yellow the

digestion is complete.

24

the tip of the distilling tube was out the distillate. Some distilled was collected

in this way to make sure the condenser tube was free from traces of ammonia.

Titration: The calculation of the percent of protein in the sample using

protein factor 6.25.

Nitrogen = ×100

Where,

T= Titre value of the sample (ml)

TB=Titre value of the Bank (ml)

meq. of N2

=0.014

% Protein =% Nitrogen× Protein factor

25

3.6 Sensory Evaluation

Sensory evaluations of all the formulated mango leather were done by taste testing

panel. The taste testing panel was made up with of 10 test panelists. They were

asked to evaluate color, flavor, texture and overall acceptability by a scoring rate

on a 9 point hedonic scale. 9 Like extremely, 8 = Like very much, 7 = Like

moderately, 6 = Like slightly, 5=neither like nor dislike, 4 = Dislike slightly, 3 =

Dislike moderately, 2= Dislike very much and 1 = Dislike extremely. The

preference differences were evaluated by statistical analysis of the data for

variance and consequently Duncan's Multiple Range Test (DMRT). Procedures of

the Statistical Analysis System (SAS, 1985) were used for statistical analysis.

A panel of 10 judges tested the color, flavor, texture and overall acceptability of

mango leather in various ration. The mean scores for color, flavor, texture and

overall acceptability of different types of mango leather such as F1, F2, F3, F4 , F5,

F6 , F7 , F8 and Ft are presented in table 4.4

26

CHAPTER IV

RESULTS AND DISCUSSION

4.1 Composition of fresh mango pulp

The mango pulp was prepared as per the method described in section 3.2. The

mango pulp analyzed for moisture, ash, acidity and sugar. The results are shown in

table 4.1. The mango pulp contained moisture 85%, ash 0.47%, acidity 0.16%,

vitamin-C 43 mg per 100 g. TSS 15.01 and total sugar 12.02%.

Table 4.1 Composition of mango pulp

Chemical Constituents of mango Quantity

1. Moisture 85%

2. Ash 0.47%

3. Total soluble solid(TSS) 15.1%

4. Acidity 0.16%

5. Vitamin-C(mg/100g) 43

6. Total sugar 12.02

4.2 Composition of mango leather prepared from mango pulp

The composition of mango leather prepared from mango pulp were analyzed for

moisture, ash, acidity, vitamin-C, total sugar protein and fibre. The results are

presented in that formulation F1 contains moisture 22%, vitamin-C 13 mg/100 g,

ash 1.81%, acidity 0.09% total sugar 58.98% protein 1.0% and fibre 1.15%.

Formulation F2 contains moisture 20%, vitamin-C 13 mg/100 g, ash 1.76%, acidity

0.09%, total sugar 58.80% protein 1.0% and fibre 1.18%. Formulation F3 contains

27

moisture contain 20%, ash 1.38%, acidity 0.09. Formulation F4 contains moisture

content 21%,ash 1.48%,acidity 0.07%.Formulation F5 contains moisture content

20%, ash 1.49% , acidity 0.07% .Formulation F6 contains moisture content 23%,

acidity 0.09%,total sugar 58.85%. Formulation F7 contains moisture content 22%,

ash 1.48%, acidity 0.08% and Formulation F8 contains moisture content 21%, ash

1.44% and acidity 0.09% and traditional formulation Ft

Chemical Composition

contain moisture content

25.7%, acidity 0.09%, fibre 1.20%, ash 1.45% and protein 1.0%.

Table: 4.2 Composition of processed mango leather prepared from mango pulp

Formulation

F F1 F2 F3 F4 F5 F6 F7 F8 t

Moisture (%) 22 20 20 21 20 23 22 21 25.75

Vitamin-C (mg/100g)

13 13 14 14 11 13.90 13 13 11.35

Acidity (%) 0.09 0.08 0.09 0.07 0.07 0.09 0.08 0.09 0.09

Ash (%) 1.81 1.76 1.36 1.48 1.49 1.43 1.48 1.44 1.45

Total sugar (%) 58.98 58.8 58.95 58.00 58.90 58.85 58.80 58.95 56.5

Protein 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

Crude fibre 1.15 1.18 1.18 1.19 1.15 1.16 1.15 1.16 1.20

28

The color development of laboratory processed mango leather

29

4.3 Effect of storage time at room temperature on the composition of mango leather

This study was conducted to assess the storage time of 150 days, temperature (22-

250C) and packaging materials of high density polyethylene coated with

aluminium foil. Each of the samples was studied after 15 days interval. Studied

shelf life of mango leathers are given in the table 4.2. From table 4.2 we can see

that each of the sample were fresh before the observation of 120th day. There are

no changes in color, flavor and texture of product during these times.

After the observation of 90 days Ft shows light brown colour and partially off

flavour but after the observation of 120 day formulation F1, F3, F6 and F7 show

light brown color, off flavor. There is no fungal growth found during 120th day

observation. At the observation of 150th day formulation F1, F6 show light brown

color, off flavor and formulation F2, F3, F4, F5, F7 and F8 show brown color, off

flavor. Fungal growth was found during the observation of 150th day.

30

Table 4.3 Shelf life of mango leather with packaging material at room temperature

Storage period (day)

Formulation

Color Flavor Texture Fungal growth

Remarks

0

F Deep Orange 1 Pleasant Soft Not visible

Acceptable

F Light orange 2 Pleasant Soft Not visible F Deep Orange 3 Pleasant Soft Not visible F Deep Orange 4 Pleasant Soft Not visible F Light orange 5 Pleasant Soft Not visible F Deep Orange 6 Pleasant Soft Not visible F Deep Orange 7 Pleasant Soft Not visible F Light orange 8 Pleasant Soft Not visible F Light orange t Pleasant Soft Not visible

15

F Deep Orange 1 Pleasant Soft Not visible F Light orange 2 Pleasant Soft Not visible F Deep Orange 3 Pleasant Soft Not visible F Deep Orange 4 Pleasant Soft Not visible F Light orange 5 Pleasant Soft Not visible F Deep Orange 6 Pleasant Soft Not visible F Deep Orange 7 Pleasant Soft Not visible F Light orange 8 Pleasant Soft Not visible F Light orange t Pleasant Soft Not visible

30


45


31

60

F Deep Orange 1 Pleasant Soft Not visible

Acceptable

F Light orange 2 Pleasant Soft Not visible F Deep Orange 3 Pleasant Soft Not visible F Deep Orange 4 Pleasant Soft Not visible F Light orange 5 Pleasant Soft Not visible F Deep Orange 6 Pleasant Soft Not visible F Deep Orange 7 Pleasant Soft Not visible F Light orange 8 Pleasant Soft Not visible F Light orange t Pleasant Soft Not visible

90

F Deep Orange 1 Pleasant Soft Not visible F Light orange 2 Pleasant Soft Not visible F Deep Orange 3 Pleasant Soft Not visible F Deep Orange 4 Pleasant Soft Not visible F Light orange 5 Pleasant Soft Not visible F Deep Orange 6 Pleasant Soft Not visible F Deep Orange 7 Pleasant Soft Not visible F Light orange 8 Pleasant Soft Not visible F Light brown t Partially off flavor Soft Not visible

120

F Light brown 1 Partially off flavor Soft Not visible F Brown 2 Off flavor Hard Not visible F Light brown 3 Partially off flavor Soft Not visible F Brown 4 Off flavor Hard Not visible F Brown 5 Off flavor Hard Not visible F Light brown 6 Partially off flavor Soft Not visible F Light brown 7 Partially off flavor Soft Not visible F Brown 8 Off flavor Hard Not visible F Light brown t Partially off flavor Soft visible

150

F Light brown 1 Partially off flavor Soft Visible Fermentation F Brown 2 Off flavor Hard Visible F Brown 3 Off flavor Hard Visible F Brown 4 Off flavor Hard Visible F Brown 5 Off flavor Hard Visible F Light brown 6 Partially off flavor Soft Visible

F Brown 7 Off flavor Hard Visible

F Brown 8 Off flavor Hard Visible

F Brown t Off flavor Hard Visible

32

Sensory evaluation

For all samples ANOVA (analysis of variance) and DMRT (Duncan’s Multiple

Range Test) was done ANOVA was carried for color flavor texture and overall

acceptability at 5% significant difference.

Table: 4.4 Mean score for color flavor texture and overall acceptability for various

types of mango leather

Sample code Sensory attributes

Color Flavor Texture Overall

acceptability

F 7.31 7.3c 7.6d 7.6bc bc

F 7.42 7.3c 7.4d 7.5c bc

F 8.03 8.0b 8.1bc 7.9ab bc

F 7.84 7.5bc 7.7d 7.5abc bc

F 7.45 7.4c 7.5d 7.3bc c

F 8.66 8.1a 8.1b 8.0ab ab

F 8.67 8.6a 8.3a 8.5a a

F 7.78 7.4bc 7.5d 7.5bc bc

F 7.6t 7.5bc 7.5cd 7.6bc bc

LSD

(P<0.01) 0.4667 0.4809 0.5994 0.5510

A two way analysis of variance (ANOVA) (appendix-I) was carried out for color

preference and results revealed that there was no significant difference in color

acceptability among mango leather.

33

From table 1.3 color of the mango leather sample F7 (mango pulp 95% + milk

powder 5%) secured the highest score and can be ranked as “like very much” and

was closely followed by the other samples. While sample F1 (mango pulp 100%)

secured the lowest score (7.30) where traditional formulation secured score 7.30

but there was no significant difference among the above samples.

In case of flavor among the samples a two way analysis of variance (Appendix-II,

table 2.3) showed that there was no significant difference in flavor preference

among the mango leather. From table 4.4 it is seen that sample F7 secured the

highest score (8.60) for flavor preference and was ranked as “like very much”.

Traditional Formulation Ft also ranked as “like very much”.

In case of texture preference among the samples (Appendix-III, table 3.1, 3.2)

showed that there was no significant difference in texture. From table 3.3 It is seen

that the sample F7 (mango pulp 95% + milk powder 5%) secured the highest score

(8.30) for texture and was ranked as “like very much” and was closely followed by

other samples. Whereas sample Ft secured 7.50 and ranked as “like very much”.

It is apparent from the results of the ANOVA (Appendix-ΙV, table 4.2, 4.3) that

there was no significant difference in overall acceptability of the sample tasted.

Sample F7 (mango pulp 95% + milk powder 5%) secured the highest score (8.50)

for overall acceptability and was ranked as “like very much”. Sample F5 (mango

pulp 95% + sugar 5%) secured the lowest score (7.30) but also was ranked as “like

very much” and sample Ft (mango pulp 100%) secured score 7.60 and ranked as

“like very much”. Thus all the samples were equally acceptable and ranked as

“like very much” while F7 secured the highest scored for all attributes.

34

CHAPTER V

SUMMARY AND CONCLUSION

The fresh “Ashini” variety mango was used in research work. Mango was

collected from Kansat upzilla of Chapainobabgonj district. After collecting

mango was stored at refrigerated temperature. Fresh mango pulp contained

moisture content 85%, ash 0.47%, acidity 0.16%, TSS 15.15, vitamin-C

43mg/100g and total sugar 12.02%. There were eight different samples prepared

by using mango pulp, sugar and milk powder on the basis of thickness.

FormulationF1 contains mango pulp 100%, F2 contains mango pulp 95% and sugar

5%, F3 contains mango pulp 100%, F4 contains mango pulp 95% and milk powder

5%, F5 contains mango pulp 95% and sugar 5%, F6 mango pulp 100%, F7 contains

mango pulp 95% and milk powder 5%, F8 contains mango pulp 95% and sugar

5% and traditional formulation Ft

Mango leather were prepared as per as standard procedure and were analyzed for

proximate composition. The processed formulation F

contained mango pulp 100%.

1, F2, F3, F4, F5, F6, F7, F8and

Ft were development of mango leather with pretreatment was organoleptically

evaluated by a taste testing panel. A statistical analysis of the score given by the

panelist on the sensory properties of various sample showed that color, flavor,

texture and overall acceptability were equally acceptable at 5% level of

significance. The statistical analysis showed that color, flavor, texture and overall

acceptability of mango leather sample F7 (mango pulp 95% + milk powder) was

more acceptable than the formulation F1, F2, F3, F4, F5, F6, F8and Ft. whereas

traditional formulation Ft secured 4th position. However there was no significant

difference among the samples. It indicates that higher properties of mango pulp

with lower level of milk powder render the most acceptable mango leather. In case

35

of texture the panelist were not able to find any significant difference among the

samples and all samples were ranked as like as moderately.

All samples were stored in room temperature (25-300C) by using high density

polyethylene coated with aluminum foil. Every sample was observed after 15days

interval for 8 observations (150 days). During the 6th observation (90 days)

traditional formulation Ft shows light brown color and partially off flavor but all

other samples show good keeping quality. During the 7th observation (120days)

fungal attack was found almost every sample.

From statistical analysis it is observed that color, flavor, texture and overall

acceptability of laboratory prepared sample F7 secured highest score and obtained

as first position where traditional sample Ft

is in fourth position. After observation

of every sample it is found that laboratory prepared samples normal shelf life 90

days, where traditional samples normal shelf life 60 days.

36

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42

APPENDICES

Appendix-I Sensory evaluation of various mango leather

Table 1.1 Rating score for color of mango leather Panelist No.

Sample No. Total F F1 F2 F3 F4 F5 F6 F7 F8 t

1 7 7 8 7 7 8 9 8 8 69 2 7 8 7 8 8 9 9 8 7 71 3 7 7 7 8 7 8 8 8 7 67 4 8 7 9 8 8 9 9 8 8 74 5 7 8 8 9 8 9 8 8 7 72 6 8 8 9 8 8 9 9 8 9 76 7 7 7 9 7 7 8 8 8 8 69 8 8 7 7 8 7 8 9 7 7 68 9 7 7 8 8 7 9 9 7 7 69 10 7 8 8 7 7 9 8 7 8 69 Total 73 74 80 78 74 86 86 77 76 Mean 7.3 7.4 8.0 7.8 7.4 8.6 8.6 7.7 7.6

Table 1.2 Analysis of variance (ANOVA) for color of mango leather Source Degree

of freedom

Sum of squares

Mean squares

F-value Probability Calculated Tabulated

Replication 9 8.04 0.894 3.26 0.0023 Factor A 8 19.36 2.419 8.82 0.0000 Error 72 19.76 0.274 Total 89

Coefficient of variation: 6.70%

43

Table 1.3 Duncan’s Multiple Range Test (DMRT) for color of mango leather LSD value = 0.4667

Sample code Original order of means

Sample code Ranked order of means

F 7.301 Fc 8.606 a F 7.402 Fc 8.607 a F 8.003 Fb 8.003 b F 7.804 Fbc 7.804 bc F 7.405 Fc 7.708 bc F 8.606 Fa 7.609

bc F 8.607 Fa 7.402 c F 7.708 Fbc 7.405 c F 7.60t Fbc 7.301

c Table 2.1 Rating score for flavor of mango leather Panelist No.


1 7 7 8 8 7 8 9 8 8 70 2 8 8 9 8 8 9 8 8 7 73 3 7 7 9 8 8 7 9 7 8 70 4 7 8 8 7 8 9 9 7 7 70 5 7 7 8 7 7 8 8 8 7 67 6 8 7 8 8 7 9 9 7 7 70 7 7 8 7 7 8 7 8 7 8 67 8 7 7 8 8 7 8 9 8 8 70 9 8 7 8 7 7 8 9 7 7 68 10 7 7 7 7 7 8 8 7 8 66 Total 73 73 80 75 74 81 86 74 75 Mean 7.3 7.3 8.0 7.5 7.4 8.1 8.6 7.4 7.5

44

Table 2.2 Analysis of variance (ANOVA) for flavor of mango leather Source Degree

of freedom

Sum of squares

Mean squares



Coefficient of variation: 7.03% Table 2.3 Duncan’s Multiple Range Test (DMRT) for flavor of mango leather LSD value = 0.4809



F 7.301 Fd 8.607 a F 7.302 Fd 8.106 b F 8.003 Fbc 8.003 bc F 7.504 Fd 7.504 d F 7.405 Fd 7.50t cd F 8.106 Fb 7.408 d F 8.607 Fa 7.405 d F 7.408 Fd 7.301

d F 7.50t Fcd 7.302 d

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Table 3.1 Rating score for texture of mango leather Panelist No.


1 7 7 8 7 7 8 8 7 8 67 2 7 8 8 8 7 8 9 8 7 70 3 8 7 9 7 8 8 9 7 8 71 4 8 7 7 7 7 9 8 8 7 68 5 7 7 8 8 7 9 8 7 7 68 6 8 7 9 7 7 8 9 7 8 70 7 9 8 8 8 9 8 8 9 7 74 8 7 7 9 8 8 8 9 7 7 70 9 7 9 8 9 7 7 8 7 8 70 10 8 7 7 8 8 8 7 8 8 69 Total 76 74 81 77 75 81 83 75 75 Mean 7.6 7.4 8.1 7.7 7.5 8.1 8.3 7.5 7.5

Table 3.2 Analysis of variance (ANOVA) for texture of mango leather Source Degree

of freedom

Sum of squares

Mean squares



Coefficient of variation: 8.68%

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Table 3.3 Duncan’s Multiple Range Test (DMRT) for texture of mango leather LSD value = 0.5994



F 7.601 Fbc 8.307 a F 7.402 Fc 8.103 ab F 8.103 Fab 8.106 ab F 7.704 Fabc 7.704 abc F 7.505 Fbc 7.601

bc F 8.106 Fab 7.508 bc F 8.307 Fa 7.50t bc F 7.508 Fbc 7.505 bc F 7.50t Fbc 7.402 c

Table 4.1 Rating score for overall of mango leather Panelist No.


1 8 7 8 8 7 8 9 7 8 70 2 8 8 9 7 8 8 8 8 8 72 3 7 7 8 7 7 9 9 8 7 69 4 7 8 8 7 7 8 8 7 7 67 5 9 8 7 8 7 7 8 7 7 68 6 7 8 7 7 8 8 9 8 8 70 7 8 7 7 8 7 7 9 8 7 68 8 7 7 8 8 7 9 8 7 9 70 9 8 7 8 8 7 8 8 7 8 69 10 7 8 9 7 8 8 9 8 7 71 Total 76 75 79 75 73 80 85 75 76 Mean 7.6 7.5 7.9 7.5 7.3 8.0 8.5 7.5 7.6

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Table 4.2 Analysis of variance (ANOVA) for overall acceptability of mango leather Source Degree

of freedom

Sum of squares

Mean squares



Coefficient of variation: 8.02% Table 4.3 Duncan’s Multiple Range Test (DMRT) for overall acceptability of mango leather LSD value = 0.5510



F 7.601 Fbc 8.507 a F 7.502 Fbc 8.006 ab F 7.903 Fbc 7.903 bc F 7.504 Fbc 7.601

bc F 7.305 Fc 7.60t bc F 8.006 Fab 7.502 bc F 8.507 Fa 7.508 bc F 7.508 Fbc 7.504 bc F 7.60t Fbc 7.305 c

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APPENDIX-V

Taste testing of mango leather Name of the Tester: ………………………… Date: ……………………..

Sco

re Color Flavor Texture Acceptability

Like extremely

9 F F1

F2

F3

F4

F5

F6

F7

F8

Ft

F1

F2

F3

F4

F5

F6

F7

F8

Ft

F1

F2

F3

F4

F5

F6

F7

F8

Ft

F1

F2

F3

F4

F5

F6

F7

F8 t

Like very much

8

Like moderately

7

Like slightly

6

Neither like nor dislike

5

Dislike slightly

4

Dislike moderately

3

Dislike very much

2

Dislike extremely

1

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F1, F2, F3, F4, F5, F6, F7 & F8

Signature

are different in their formulation .………………….

COMPARATIVE STUDY OF MANGO LEATHER - Sher-e ...

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