1. rad - Aidoo et al-2006-FEMS Yeast Research

M I N I R E V I E W

Occurrenceand functionofyeasts inAsian indigenousfermentedfoodsKofi E. Aidoo1, M. J. Rob Nout2 & Prabir K. Sarkar3

1Food Research Laboratories, Caledonian University, Glasgow, Scotland; 2Laboratory of Food Microbiology, Wageningen University, Wageningen,

The Netherlands; and 3Microbiology Laboratory, University of North Bengal, Siliguri, India

Correspondence: M. J. Rob Nout,

Laboratory of Food Microbiology, Bomenweg

2, 6703 HD Wageningen, The Netherlands.

Tel.: 131 317 482834; fax: 131 317 484978;

e-mail: [email protected]

Received 10 March 2005; revised 31 August

2005; accepted 31 August 2005.

First published online 15 November 2005.

doi:10.1111/j.1567-1364.2005.00015.x

Editor: Teun Boekhout

Keywords

pancakes; bread; amylolytic starters; snacks;

beverages; condiments.

Abstract

In the Asian region, indigenous fermented foods are important in daily life. In

many of these foods, yeasts are predominant and functional during the fermenta-

tion. The diversity of foods in which yeasts predominate ranges from leavened

bread-like products such as nan and idli, to alcoholic beverages such as rice and

palm wines, and condiments such as papads and soy sauce. Although several

products are obtained by natural fermentation, the use of traditional starter

cultures is widespread. This minireview focuses on the diversity and functionality

of yeasts in these products, and on opportunities for research and development.

IntroductionIndigenous, also referred to as traditional, fermented foods

are those popular products that since early history have

formed an integral part of the diet and that can be prepared

in the household or in cottage industry using relatively

simple techniques and equipment. Some of these products

have undergone industrial development and are also now

manufactured on a large scale (Wood, 1998; Boekhout &

Robert, 2003; Hui et al., 2004). Yeasts occur in a wide range

of fermented foods, made from ingredients of plant as well

as animal origin. This minireview illustrates a selection of

fermented products of particular interest because of the

predominant yeasts that contribute to their attractive char-

acteristics. When yeasts are abundant, alone or in stable

mixed populations with mycelial fungi or with (usually

lactic acid) bacteria, they have a significant impact on food

quality parameters such as taste, texture, odour and nutri-

tive value. Among the Asian indigenous fermented food

products, we examined pancakes and bread, amylolytic

fermentation starters, alcoholic snacks and beverages, and

condiments. Table 1 illustrates the diversity of ingredients

used. Whereas fermentation plays an important role in the

home kitchen, several products are presently manufactured

on medium or large industrial scale (Steinkraus, 1989). Up-

scaling of processes requires control of the operations and of

the quality and safety of ingredients and products. In

addition, new aspects of functionality are becoming more

important for exploitation. Future prospects for research

and development will be discussed at the end of this review.

Pancakesandbreads

Pancakes

Idli, dosa and appam, consumed in India and Sri Lanka, are

cereal–legume mixture foods which, from a nutritional

point of view, are advantageous because of an improved

balance of carbohydrates and proteins. To prepare idli, rice

(Oryza sativa) and blackgram (Phaseolus mungo) dal (de-

husked split seeds) are soaked separately in water. The

soaked rice is then coarsely ground, whereas dal is ground

to a smooth mucilaginous paste. The two slurries (2 : 1) are

mixed with salt, put in a closed container and left overnight

to allow a definite leavening (a two- to three-fold increase in

the original volume) and to develop a pleasant acid flavour.

The fermented batter is poured in cups of an idli pan, and

FEMS Yeast Res 6 (2006) 30–39c� 2005 Federation of European Microbiological SocietiesPublished by Blackwell Publishing Ltd. All rights reserved

Tab

le1.

Yea

st-b

ased

trad

itio

nal

ferm

ente

dfo

ods

and

bev

erag

esof

Asi

a

Nam

eof

the

food

Countr

yM

ajor

Ingre

die

nts

Funct

ional

Mic

roflora

Ferm

enta

tion

contr

ibute

sto

:Ref

eren

ces

Panca

kes

and

leav

ened

low

-sal

tbre

ad

Idli

India

,Sr

iLan

kaRic

ean

dbla

ckgra

m

dal

LAB,Sa

cchar

om

yces

cere

visi

aeFl

avour,

text

ure

,nutr

itio

nal

valu

eSo

ni&

Sandhu

(1991)

Dhokl

aIn

dia

Ric

ean

dBen

gal

gra

mLA

B,Pi

chia

silv

icola

Flav

our,

text

ure

,nutr

itio

nal

valu

eK

anek

ar&

Josh

i(1993)

Nan

,ku

lcha

and

bhat

ura

India

,Pa

kist

an,

Afg

han

ista

n,Iran

Whea

tflour

LAB,Sa

cchar

om

yces

cere

visi

aean

doth

erye

asts

Text

ure

,flav

our

Sandhu

etal

.

(1986)

Am

yloly

tic

ferm

enta

tion

star

ters

Rag

iIn

dones

iaRic

eA

myl

om

yces

rouxi

i,H

anse

nula

spp.,

Sacc

har

om

ycopsi

s

fibulig

era

Star

chdeg

radat

ion,al

coholic

ferm

enta

tion

Hes

seltin

e

etal

.(1

988);

Saono

etal

.

(1996)

Murc

ha/

mar

cha

India

,N

epal

Ric

eM

uco

rsp

p.,

Rhiz

opus

spp.,

Pich

iaburt

onii,

Sacc

har

om

yces

cere

visi

ae

Star

chdeg

radat

ion,al

coholic

ferm

enta

tion

Shre

stha

etal

.

(2002);

Tsuyo

shie

tal

.

(2005)

Loog-p

ang

Thai

land

Ric

eSa

cchar

om

ycopsi

sfibulig

era,

Pich

iaan

om

ala

and

oth

er

yeas

ts

Star

chdeg

radat

ion,al

coholic

ferm

enta

tion

Lim

tong

etal

.

(2002)

Tane

koji

Japan

Ric

eA

sper

gill

us

ory

zae,A

sper

gill

us

usa

mii

Star

chan

dpro

tein

deg

radin

g

enzy

mes

for

rice

win

em

akin

g

Men

Vie

tnam

Ric

eA

myl

om

yces

rouxi

i,Sa

cchar

om

yces

cere

visi

aeSt

arch

deg

radat

ion,al

coholic

ferm

enta

tion

Dung

etal

.

(2005)

Swee

t–

low

alco

holic

snac

ksfe

rmen

ted

with

amyl

oly

tic

star

ters

Tape

keta

n,Ta

pe

kete

lla/p

euje

um

Indones

iaRic

e,ca

ssav

atu

ber

sA

myl

om

yces

rouxi

i,M

uco

rsp

p.,

Rhiz

opus

spp.,

Sacc

har

om

ycopsi

sfibulig

era,

Pich

iaburt

onii,

Pich

iaan

om

ala

Star

chdeg

radat

ion,glu

cose

form

atio

n,al

coholic

ferm

enta

tion,flav

our

Ko

(1986)

Boon-L

ong

(1986)

Kao

-mar

kTh

aila

nd

Ric

e

Win

esbre

wed

with

amyl

oly

tic

star

ters

Sake

Japan

Ric

eA

sper

gill

us

ory

zae,

Sacc

har

om

yces

sake

,H

anse

nula

anom

ala

Sacc

har

ifica

tion,al

cohol,

flav

our

Yak

juan

dta

kju

Kore

aRic

e,w

hea

t,bar

ley,

mai

ze,m

illet

Asp

ergill

us

ory

zae,A

sper

gill

us

soja

e,Rhiz

opus

spp.,

Sacc

har

om

yces

cere

visi

ae,H

anse

nula

anom

ala,

Han

senula

subpel

liculo

sa,C

andid

asa

ke,To

rula

spora

inco

nsp

icua,Pi

chia

poly

morp

ha

Sacc

har

ifica

tion,al

cohol,

flav

our

Rhee

etal

.

(2003)

Tapuy

The

Phili

ppin

esRic

eSa

cchar

om

ycopsi

sfibulig

era,

Rhodoto

rula

glu

tinis

,

Deb

aryo

myc

eshan

senii,

Can

did

apar

apsi

losi

s,Tr

ichosp

oro

n

fennic

um

Sacc

har

ifica

tion,al

cohol,

flav

our

Koza

ki&

Uch

imura

(1990)

Ruou

nep

than

Vie

tnam

Purp

leglu

tinous

rice

Am

ylom

yces

rouxi

i,Sa

cchar

om

yces

cere

visi

aeSa

cchar

ifica

tion,al

cohol,

flav

our

Dung

(2004)

Jnar

d/ja

anr/

thum

ba

Nep

al,In

dia

,

Bhuta

n

Finger

mill

et/r

ice/

mai

ze/w

hea

t

Muco

rsp

p.,

Rhiz

opus

spp.,

Sacc

har

om

ycopsi

sfibulig

era,

Pich

iaan

om

ala,

Sacc

har

om

yces

cere

visi

ae,LA

B

Sacc

har

ifica

tion,al

cohol,

flav

our

Tam

ang

etal

.

(1988)

Continued

FEMS Yeast Res 6 (2006) 30–39 c� 2005 Federation of European Microbiological SocietiesPublished by Blackwell Publishing Ltd. All rights reserved

31Yeasts in Asian indigenous fermented foods

steamed until the idli cakes (Fig. 1a) are soft and spongy

with a honeycomb structure inside. A slightly modified

version of this batter, where the proportion of rice is

increased and both the ingredients are finely ground, is used

to prepare two additional foods: dosa (highly seasoned

griddled pancake) and appam (poached egg-like pancake).

Idli is a natural fermented food. Both bacteria and yeasts

are generally introduced by the two main ingredients and

participate in the fermentation. A bit of freshly fermented

batter (‘backslop’) is often added to the newly ground batter.

As the fermentation progresses, both bacterial and yeast cell

numbers increase significantly with a concomitant decrease

in pH, and an increased volume of batter, amylase and

protease activity. Leuconostoc mesenteroides is the most

commonly encountered bacterium (Nout & Sarkar, 1999).

During fermentation, along with L. mesenteroides, Sacchar-

omyces cerevisiae, Debaryomyces hansenii, Pichia anomala

and Guehomyces pullulans are predominant among the yeasts

appearing first, and Trichosporon cutaneum develops subse-

quently. Eventually, only S. cerevisiae persists (Soni & Sandhu,

1991).

The role of yeasts in idli batter fermentation is contro-

versial. Although the fermentation was reported (Ramak-

rishnan, 1979) to be entirely due to heterofermentative L.

mesenteroides, later work has shown yeast involvement in the

fermentation (Venkatasubbaiah et al., 1984). The major

functions of the fermentation include the leavening of the

batter and the improvement of taste and nutritional value of

idli. The role of lactic acid bacteria is to reduce the pH of the

batter to an optimum level (pH 4.1–4.5) for yeast activity.

Yeasts help in the degradation of starch (which cannot be

carried out by L. mesenteroides) into maltose and glucose by

producing extracellular amylolytic enzymes. They also pro-

duce carbon dioxide and play a significant role in leavening.

The sources of the yeast strains are the surface of stone

grinders used for preparation of batter, and the rice used in

batter preparations. Not only the load but also the diversity

of yeasts in fermenting batter is greater in winter than in

summer. Fermentation of batter by inoculating the ingredi-

ents with individual yeasts and in combination with L.

mesenteroides reveals that yeasts contribute not only to gas

production, resulting in good texture, but also towards

sensory qualities. The higher activity of amylases, levels of

B vitamins and free amino acids attained in yeast-enriched

fermentations suggest the positive contribution of yeasts to

these constituents (Venkatasubbaiah et al., 1984, 1985). It

can be said that even if the yeasts are not essential for the

leavening of idli batter, they are certainly important for the

desirable organoleptic qualities and on nutritional grounds.

The possible synergism between bacteria and yeasts remains

to be determined.

Dhokla, popular all over India, is similar to idli except

that the dal used is of Bengalgram (Cicer arietinum). DuringTab

le1.

Continued

.

Nam

eof

the

food

Countr

yM

ajor

Ingre

die

nts

Funct

ional

Mic

roflora

Ferm

enta

tion

contr

ibute

sto

:Ref

eren

ces

Bev

erag

esfe

rmen

ted

from

sugar

yju

ices

Palm

win

es(T

oddy/

tari,Tu

ack,

Tuba)

India

,Ban

gla

des

h,

SriL

anka

,

Thai

land,

Mal

aysi

a,

Indones

ia,th

e

Phili

ppin

es

Sap

of

coco

nut,

dat

e

or

pal

myr

apal

m

LAB,A

AB,Sa

cchar

om

yces

cere

visi

ae,Sc

hiz

osa

cchar

om

yces

pom

be,

Kodam

aea

ohm

eria

nd

oth

erye

asts

Alc

ohola

nd

flav

our

pro

duct

ion

Bat

ra&

Mill

ner

(1974);

Josh

i

etal

.(1

999)

Kom

buch

a/te

a-

fungus

Japan

,In

dones

ia,

Chin

a,Russ

ia

Tea

liquor

and

sugar

AA

B,Bre

ttan

om

yces

spp.,

Zygosa

cchar

om

yces

kom

buch

aensi

s,Sa

cchar

om

yces

spp.

Org

anic

acid

s,vi

tam

ins,

hea

lth

bev

erag

e

May

ser

etal

.

(1995)

Condim

ents

Wad

iIn

dia

,Pa

kist

anBla

ckgra

mdal

Can

did

akr

use

i,LA

BA

cidifi

cation,le

aven

ing,

nutr

itio

nal

valu

e

Sandhu

&So

ni

(1989)

Papad

/pap

adam

India

Bla

ckgra

mdal

Can

did

akr

use

i,Sa

cchar

om

yces

cere

visi

aeTe

xture

,flav

our

Shurp

alek

ar

(1986)

Soy

sauce

sJa

pan

,C

hin

aSo

ybea

ns

and

whea

tA

sper

gill

us

ory

zae,A

sper

gill

us

soja

e,Zy

gosa

cchar

om

yces

rouxi

i,C

andid

asp

p.

Enzy

mic

deg

radat

ion

of

star

ch

and

pro

tein

s,fo

rmat

ion

of

flav

our

Aid

oo

etal

.

(1994)

Mis

oJa

pan

Ric

ean

dso

ybea

ns

Asp

ergill

us

ory

zae,Zy

gosa

cchar

om

yces

rouxi

i,LA

BFl

avour

Ebin

e(1

989)

AA

B,ac

etic

acid

bac

teria;

LAB,la

ctic

acid

bac

teria.


32 K. E. Aidoo et al.

fermentation, there is an almost two-fold rise in the batter

volume and a drop of pH from 5.2 to 4.5. The microorgan-

isms involved in the fermentation are Lactobacillus fermen-

tum, L. mesenteroides and Pichia silvicola (up to 107 g�1)

(Joshi et al., 1989). The lactic acid bacteria contribute lactic

acid and acetoin, imparting a sour taste and a pleasant

flavour. The yeast produces folic acid and raises the volume

of the batter, imparting sponginess to the product (Kanekar

& Joshi, 1993).

Breads

Nan (naan) is generally consumed as a staple food by the

people of Afghanistan, Iran, India and Pakistan. It is a flat

leavened bread, made by mixing white wheat flour with

sugar, salt, backslop and water. The dough is left for 12–24 h,

formed into balls and flattened. Smoothly flattened dough is

slapped onto the inner wall of the clay-clad brick oven,

called ‘tandoor’, where it sticks while baking until the dough

is puffed-up and light brown.

From a new dough (pH 5.9) for making nan, 105 yeast

cfu g�1 and 102 lactic acid bacteria cfu g�1 were obtained, as

compared with respective counts of 108 and 109 from ripe,

fermented dough (pH 4.8). Saccharomyces cerevisiae is the

predominant yeast (Sandhu et al., 1986).

Bhaturas (pathuras) and kulchas of northern India and

Pakistan are prepared from similar leavened doughs; they

are respectively deep-fried in oil or prepared on a griddle.

Kulcha dough contains yeasts and lactic acid bacteria. The

yeasts belong mainly to the genera Saccharomyces, Candida,

Hansenula, Saccharomycopsis, Kluyveromyces, Rhodotorula,

Pichia, Torulopsis, Trichosporon and Debaryomyces (Sandhu

et al., 1986).

Amylolytic fermentation starters

Amylolytic starters are used in the form of starchy tablets

containing mixed cultures of starch-degrading moulds and

fermenting yeasts. They are used for the manufacture of

beers, wines and pasty snacks from various kinds of cereals

and starchy crops, such as rice, sorghum, millet and cassava.

Table 1 shows some of the starters that have been described

and analyzed. The major principle of their manufacture is to

prepare an uncooked dough of rice or wheat flour (some-

times mixed with cassava meal), water and a variety of herbs

and spices. This dough is inoculated with a backslop and

shaped into small balls or flattened tablets (cakes), which are

incubated at around 30 1C for about a week. During this

period the niche microfloras develop and, simultaneously,

the tablets dehydrate. These tablets can be stored at ambient

temperatures without significant loss of viability for at least

6 months.

Studies on the microflora of starters such as Indonesian

ragi (Fig. 1b) and Chinese chiu-chu have been reported as

early as the end of the 19th century. The principal amylolytic

moulds are Amylomyces rouxii, Rhizopus spp., Mucor spp.

and Aspergillus spp. Common yeasts in many starter tablets

are Hansenula spp., Saccharomycopsis fibuligera, Candida

spp. and Sm. cerevisiae (Saono et al., 1996). The exact

mycoflora of ragi varies with location and the particular

fermentation for which the starter is to be used. A study on

nearly 100 amylolytic yeast strains isolated from ragi and

other starters revealed that the predominant amylolytic

yeasts are Sm. fibuligera and, to a lesser extent, Saccharomy-

copsis malanga (Hesseltine & Kurtzman, 1990).

Selected strains of Aspergillus oryzae are used in the

preparation of tane-koji in the manufacture of sake. The

Fig. 1. (a) Idli (centre) served hot, with sambar (left) and chutney (right). (b) Amylolytic fermentation starters: Men (left) and Ragi (right). (c)

Condiments: wadis of Punjab (left) and Bengal (top right), showing cavities in some inverted wadis. Middle-sized wadis (bottom right) are made of lentil.

(d) Condiments: Papads (top) as marketed, (bottom) baked.



mould produces a-amylase and amyloglucosidase, which

hydrolyze starches to dextrin, maltotriose, maltose and

glucose, and acid and alkaline proteases, which hydrolyze

proteins to peptides and amino acids. Other essential

moulds in the production of rice wine include Aspergillus

usamii and A. rouxii.

Moulds belonging to the genera Mucor and Rhizopus are

usually the main enzyme producers for the production of

rice wines in India and Nepal (Shrestha et al., 2002). The

main yeasts which ferment saccharified rice starch to alcohol

are Pichia burtonii, Sm. fibuligera, S. cerevisiae, Candida

glabrata and Candida lactosa, while Sm. fibuligera produces

amylolytic enzymes as well (Tsuyoshi et al., 2005). In

murcha from India, Saccharomycopsis capsularis and P.

burtonii also contribute to the degradation of starch

(Tsuyoshi et al., 2005). Other yeast species, namely Hanse-

nula spp., Pichia spp. and Torulopsis spp., have also been

isolated from rice wine. The role of Sm. fibuligera is two-

fold: it is an important amylolytic species (Dansakul et al.,

2004) and it also produces alcohol, albeit at relatively low

levels (Limtong et al., 2002).

In a study of yeast diversity in Thai traditional alcohol

starters, 43 yeasts from 38 samples of loog-pangkao-mag

(starters for alcoholic sweetened rice) and 49 from 19

samples of loog-pang-lao (starters for rice wine) were

investigated (Limtong et al., 2002). Saccharomycopsis fibuli-

gera predominated (31 isolates) in both types of loog-pang;

the organism showed strong amylolytic activity but was a

poor alcohol producer. Other species identified include P.

anomala (8), Issatchenkia orientalis (6), P. burtonii (6),

Pichia fabianii (4), Candida rhagii (4), C. glabrata (3),

Torulaspora globosa (3), Pichia mexicana (2) and single

isolates of Pichia heimii, Rhodotorula philyla, S. cerevisiae,

Torulaspora delbrueckii and Trichosporon faecale. These have

low amylolytic activity but possess high or moderately high

alcoholic fermentation.

An interesting functional aspect of these fungi is their

formation of functional enzymes to release assimilable

carbon sources. These enzymes are valuable in brewing and

flavour development. For example, glucoamylase (glucan

1,4-a-glucosidase) [EC 3.2.1.3] is a key enzyme in rice wine

fermentation, converting starch directly into glucose. Glu-

coamylase is inducible by glucose, starch, maltose and

glycerol and can degrade a variety of polysaccharides. This

enables the yeast to mobilize assimilable carbon sources. On

the other hand, glucosidase activity can also contribute to

flavour development as a number of flavour precursors in

fruits are glycosides. Esters, fusel alcohols, acids and other

compounds which contribute to flavour are also produced.

Based on abilities to produce high amylolytic activities

(mainly due to a-amylase and/or amyloglucosidase), a

number of strains of A. rouxii, Rhizopus spp. and Sacchar-

omycopsis spp. have been selected. For instance, a combina-

tion of A. rouxii and Sm. fibuligera produces a good quality

tape. Similarly, defined granulated starters containing

A. rouxii and Sm. cerevisiae make high-quality Vietnamese

rice wine (Dung et al., 2005).

Snacks andbeverages

Sweet, lowalcoholic snacks

A popular type of indigenous fermented snack can be

encountered in a large part of East Asia, e.g. tape ketan,

kao-mark (from glutinous rice), and tape ketella or peujeum

(from cassava roots) (see Table 1). Common features are the

semi-solid consistency, the distinct sweet, mild-sour taste

and the fruity flavour of alcoholic fermentation that has just

started. They can be consumed as such or used as an

ingredient in homecooking and baking. The principle of

their manufacture involves the preparation of the substrate

(glutinous rice or peeled, chopped cassava) by washing,

soaking and steaming until soft; followed by cooling,

inoculating with powdered starter and fermenting under

cover for 1–3 days. In Indonesia, ragi tape would be used

(Ko, 1986) and in Thailand, loog-pang starter is used to

prepare kao-mark (Boon-Long, 1986). The major modifica-

tions of the substrate, i.e. release of glucose from cooked

starch by fungal glucoamylase, and alcoholic-organic acids

fermentation and flavour formation are ascribed to a limited

selection of fungi. These include A. rouxii, Rhizopus spp.,

Mucor spp., Sm. fibuligera, P. burtonii, P. anomala and S.

cerevisiae (Boon-Long, 1986; Ko, 1986). Pichia anomala is

required to develop a rich aroma and the typical flavour of

tape (Ko, 1986) by formation, for example, of isobutanol,

isoamyl alcohol and their esters. The ethanol (up to 10%

v/v) serves as a source of calories and helps prevent growth

of disease- or toxin-producing microorganisms in the

products. Although bacteria, particularly Bacillus spp. and

Acetobacter spp., are present in relatively low numbers

(o 105 cfu g�1), they nevertheless are considered to contri-

bute to the quality and flavour of tape ketan (Ardhana &

Fleet, 1989). In particular, the ability of Bacillus spp. to

produce amylolytic and proteolytic enzymes would make a

significant contribution to the degradation of macromole-

cular substrates, leading to its desired moist appearance and

soft texture (Ardhana & Fleet, 1989).

Ricewines

Rice wines are produced from the hydrolytic breakdown

products of cereal starches and other polysaccharides. They

range from simple Thai rice wine to highly sophisticated

Japanese sake. The moulds involved in alcohol production

of Asian rice wines include A. rouxii, and the yeasts

S. cerevisiae, Saccharomycopsis burtonii, Sm. fibuligera,



Cm. lactosa and related yeasts. Rice and/or cereal wines are

produced on both a cottage and a commercial scale in most

Asian countries, especially Japan, China, Korea, Thailand,

the Philippines and Vietnam (Nout & Aidoo, 2002).

Wines may be distilled to obtain a liquor or spirit, for

instance the famous Indonesian brem bali, an alcoholic

liquor produced in Bali from the liquid portions of tape

ketan. These liquors can also be used to fortify rice wine.

Sake is a pale yellow rice wine of Japanese origin with an

alcohol content of 15–16% (weight in volume, w/v) or

higher. Steamed rice is mixed with tane-koji (A. oryzae )

and allowed to ferment for 5–6 days, after which it is mixed

with yeast moto or ragi starter and water to form the main

mash, or moromi. Moto dominates the moromi fermenta-

tion. Wild yeasts tend to die off at the early stages of moromi

fermentation due to nitrite produced by nitrate-reducing

bacteria.

Malaysian rice wine or tapai is lighter in colour, ranging

from red to pink. It is made from cooked gelatinized rice

and red pulverized ragi (yeast cake, or jui-piang).

Yakju and takju are Korean alcoholic beverages originally

made from rice, but which are now made from wheat,

barley, corn or millet. In the traditional yakju process,

steamed, cooled rice is mixed with nuruk amylolytic starter,

and yeast inoculum is added. Takju is made by diluting fresh

yakju liquor prior to filtration. In comparing the traditional

and industrial rice wine brewing processes in Korea, it was

noted (Rhee et al., 2003) that nuruk is used in the traditional

method, normally carried out at low temperatures

(5–10oC). The industrial brewing follows the Japanese sake

brewing method and undergoes relatively high temperature

fermentation (25oC). The alcohol content in the industrial

rice wine tends to be higher but the wine is lower in esters

than the traditional brew.

In the Philippines, tapuy (Kozaki & Uchimura, 1990)

(Igorot ethnic group) is an acidic but sweet alcoholic

rice wine and is known by other names such as binubudan

(Ifugao), binuburan (Ilocano) or purad (Tagalog). The Thai

rice wines such as sato and krachae are cloudy yellow liquids

made from glutinous rice (Vachanavinich et al., 1994).

In Vietnam, ruou nep and ruou nep than are made by

steaming white or purple glutinous rice, respectively,

and inoculation with men, an amylolytic starter (Table 1,

Fig. 1b). Fermentation is carried out in a two-stage

process of which the first stage is aerobic mould fermenta-

tion in a solid-state condition (Dung, 2004). The main

alcoholic fermentation occurs during the second stage after

water has been added and lasts for approximately 5 days.

At the final stage, the wine is a turbid suspension of pink

red colour, containing 8–14% (w/v) alcohol and some

residual sugars. The wine may be clarified and/or strength-

ened by blending with distilled alcohol, depending on local

demand.

Jnard

Jnard, or jaanr (Tamang et al., 1988), is a common name for

some traditional alcoholic fermented beverages in the east-

ern Himalayas in India, generally produced by using murcha

as a starter. Seeds of finger millet (Eleusine coracana)

are boiled, drained, cooled, mixed with powdered murcha

(Tamang & Sarkar, 1995) (1–2%, w/w), packed in a bamboo

basket, covered and left for 2–4 days. At the

end of saccharification, a sweet aroma is emitted when

the mass is transferred into an earthen pot and covered

to make it airtight. After fermentation, the seeds are

kneaded to remove seed coats, put into a bamboo/wooden

vessel and lukewarm water is added. After about 10 min,

the beverage is ready to drink. Good quality jnard has a

pleasant sweet aroma blended with mild alcohol (Tamang

et al., 1988).

The mixed population of moulds, yeasts and lactic acid

bacteria in murcha starter (Tamang et al., 1988) soon

becomes active, bringing about changes in the substrate,

increasing the temperature of the fermenting mass by 4 1C

over the ambient (20–25 1C) within 2 days of fermentation.

Amylase activity reaches its peak on the second day of

fermentation; mucoraceous fungi have an active role in

saccharification and liquefaction of starch. The moulds

Mucor circinelloides and Rhizopus chinensis, and the yeast

Sm. fibuligera, which are dominant at the start, disappear

within 12 h of fermentation. Mature jnard contains P.

anomala, S. cerevisiae and C. glabrata yeasts and lactic acid

bacteria (105–106 cfu g�1), which include Pediococcus pento-

saceus and Lactobacillus bifermentans. These three yeast

species increase from 105 to 107 cfu g�1 within 2 days, and

the population then remains the same till the end of

fermentation. The titratable acidity and alcohol content of

the fermenting mass increase significantly during the fer-

mentation.

Palmwines

In almost all tropical places in Asia where palm trees grow,

the sap obtained from the decapitated inflorescence of

various species of palms is fermented to produce an

alcoholic beverage called palm wine, or toddy. In India there

are three types of toddy: ‘sendi’, obtained from wild date

palm (Phoenix sylvestris); ‘tari’, from palmyra palm (Borassus

flabellifer) and date palm (Phoenix dactylifera); and ‘nareli

(nira)’, from coconut palm (Cocos nucifera) (Batra & Mill-

ner, 1974). The toddy from coconut flower juice is known as

‘ra’ and ‘panam culloo’ in Sri Lanka, ‘nuoudua’ in Vietnam,

‘tuak (tuack)’ in Malaysia and Indonesia, and ‘tuba’ in the

Philippines.

There is an art in binding the flower spathes, pounding

them to cause the sap to flow properly by cutting the spathe



tip and collecting the sap into the earthen pitchers which

contain yeasts and bacteria in the left-over toddy from the

previous lots. The fermentation starts as soon as the sap

flows into the pitcher. Palm wine is either consumed fresh as

it is brought down from the tree or fermented for up to 24 h.

The freshly cut sap is generally a dirty brown sweet liquid

having 10–18% w/w sugar, which after fermentation results

in the formation of a product containing as much as 9%

(volume in volume, v/v) ethanol (Steinkraus, 1996; Joshi

et al., 1999).

The palm wine fermentation is always an alcoholic–lacti-

c–acetic acid fermentation, involving mainly yeasts and

lactic acid bacteria. In the fermenting sap, S. cerevisiae is

invariably present but lactic acid bacteria such as Lactoba-

cillus plantarum, L. mesenteroides or other species of bacteria

like Zymomonas mobilis and Acetobacter spp. vary. The other

yeast types include Schizosaccharomyces pombe, Saccharo-

myces chevalieri, Saccharomyces exiguus, Candida spp. and

Saccharomycodes ludwigii in the samples of coconut palm

wine (toddy). Saccharomyces cerevisiae, Sch. pombe, Koda-

maea ohmeri and Hanseniaspora occidentalis are character-

ized as maximum ethanol producers in toddy (Joshi et al.,

1999). The yeasts, especially Saccharomyces spp., are largely

responsible for the characteristic aroma of palm wine

(Uzochukwu et al., 1999). During fermentation, there is

continuous effervescence as a result of the production of

carbon dioxide. A yeasty odour develops, and after a couple

of hours yeasts form a sediment at the bottom of the

container. The main ingredient of the fresh sap (pH �7.2)

is sucrose (12–15%, w/w). During the first 24 h, more than

half of the total sugars are fermented. Palm wine is a good

source of B vitamins.

Kombucha

Kombucha from Central and East Asia is a beverage

obtained by fermentation of sweetened boiled tea with a

mixed culture of yeasts and acetic acid bacteria (Campbell-

Platt, 1987). Other names for kombucha, or ‘tea fungus’,

include ‘fungus japonicus’, ‘tee kwass’, ‘tea kvass’, ‘cham-

pignon de longue vie’, ‘Indo-Japanese tea fungus’ and

‘Manchurian mushroom’. Kombucha is a symbiosis of

Acetobacter spp. – mainly Acetobacter xylinum – and various

yeasts. The mixed yeast-bacterial culture growing on sugary

tea extract accumulates lactic (0.1%), acetic (traces) and

gluconic (0.01–0.3%) acids, and some ethanol (0.3%). The

pH decreases steadily to about 2.5. The resulting beverage

also contains vitamins and minerals and is considered to be

a healthy product.

The yeast flora of commercial tea fungus includes the

genera Brettanomyces (56%), Zygosaccharomyces (29%) and

Saccharomyces (26%) (Mayser et al., 1995). Saccharomycodes

ludwigii and Candida kefyr (anamorph of Kluyveromyces

marxianus) in isolated cases, as well as a pellicle-forming

yeast, C. krusei and apiculate yeasts, Kloeckera spp. and

Hanseniaspora spp. have also been reported. However,

Zygosaccharomyces kombuchaensis is the dominant yeast

species now known to be commonly associated with kom-

bucha tea (Kurtzman et al., 2001). In another study of four

commercial kombucha products (Teoh et al., 2004), the

yeasts found included Brettanomyces bruxellensis (anamorph

of Dekkera bruxellensis), Candida stellata, Sch. pombe,

T. delbrueckii and Zygosaccharomyces bailii. Comparing

these findings, it appears that the fermentation is initiated

by osmotolerant yeasts and is then succeeded and ultimately

dominated by acid-tolerant species.

Condiments

Wadis

Wadis, traditionally consumed in Punjab and Bengal of

India, are now popular in many places of India, Pakistan

and Bangladesh. These dried, hollow, brittle cones or balls

(3–8 cm diameter, 15–40 g in weight) (Fig. 1c) are used as a

spicy condiment or an adjunct for cooking vegetables, grain

legumes or rice.

To prepare wadi, dals, generally of blackgram, are soaked,

drained, ground into a smooth soft dough, left to ferment

for 1–3 days, moulded into cones or balls, deposited on

bamboo or palm mats smeared with oil, and sun-dried for

4–8 h. The surface of the cones or balls becomes covered

with a mucilaginous coating which helps to retain the gas

formed during their fermentation. The wadis look hollow,

with many air pockets and yeast spherules in the interior and

a characteristic surface crust.

Initially the microflora is diverse and contains lactic acid

bacteria, bacilli, flavobacteria and yeasts. Gradually,

L. mesenteroides, L. fermentum, S. cerevisiae and Tr. cuta-

neum become dominant. Candida vartiovaarae and K.

marxianus are also often found. The development and

prevalence of microflora are affected by the seasons, summer

being more favourable for bacteria and winter for yeasts.

The production of acid and gas results in a fall of pH from

5.6 to 3.2 and two-fold rise in the volume of the dough. The

lactic acid bacteria are mainly responsible for the acidifica-

tion of dough, favourable conditions for the yeasts to grow

and become active for leavening. The fermentation brings

about a significant increase in soluble solids, non-protein

nitrogen, soluble nitrogen, free amino acids, proteolytic

activity and B vitamins including thiamine, riboflavin and

cyanocobalamine. On the other hand, the levels of reducing

sugars and soluble protein decrease. Amylase activity in-

creases initially, but declines thereafter (Batra & Millner,

1974; Sandhu et al., 1986; Sandhu & Soni, 1989). Wadis

prepared by inoculating sterilized ingredients with a mixed



culture of C. krusei (anamorph of Issatchenkia orientalis)

and L. mesenteroides resemble the marketed ones. In con-

trast, the uninoculated controls were hard and compact and,

when broken, had a glistening surface (Batra & Millner,

1974).

Papads

Papad (papadam) is another important condiment or

savoury food in India, Pakistan and Bangladesh. This thin,

usually circular, wafer-like product (Fig. 1d) is used to

prepare curry or is eaten by itself as a crackly snack or

appetizer with meals after roasting or deep-frying in oil.

Papad-making under controlled conditions has already

developed into a cottage or small-scale industry.

Blackgram flour or a blend of blackgram with Bengal-

gram, lentil (Lens culinaris), redgram or greengram (Vigna

radiata) flour is hand-kneaded with a small quantity of

peanut oil, common salt (about 8%, w/w), ‘papad khar’

(saltworts produced by burning a variety of plant species, or

from very alkaline deposits in the soil) and water, and then

pounded into a stiff paste. The dough (sometimes with a

backslop and spices added) is left to ferment for 1-6 h. The

fermented dough is shaped into small balls which are rolled

into thin, circular flat sheets (10–24 cm diameter,

0.2–1.2 mm thick) and generally dried in the shade to

12–17% (w/w) moisture content. Candida krusei and

S. cerevisiae are involved in the preparation of papad

(Shurpalekar, 1986).

Soysauces

Soy sauces are light to dark brown liquids with a meat-like

salty flavour used in cooking and as a table condiment.

Traditionally made in China, Japan, Korea, Thailand, the

Philippines, Indonesia and Malaysia, soy sauce is now also

produced in Europe and the Americas. There are two

specific fermentation stages involved in soy sauce produc-

tion: aerobic koji fermentation, which involves the use of A.

oryzae or Aspergillus sojae, and an anaerobic moromi or salt

mash, which undergoes lactic acid bacteria and yeast (Zygo-

saccharomyces rouxii) fermentations.

The two main groups of enzymes produced by A. oryzae

during koji fermentation are carbohydrases (a-amylases,

amyloglucosidase, maltase, sucrase, pectinase, b-galactosi-

dase, cellulase, hemicellulase and pentosan-degrading en-

zymes) and proteinases. Lipase activity has also been

reported. These major enzymes hydrolyze carbohydrates

and proteins to sugars and amino acids and low molecular

weight peptides, respectively. These soluble products are

essential for yeast and bacterial activities during moromi

fermentation (Aidoo et al., 1994; Chou & Rwan, 1995).

In this fermentation Tetragenococcus halophila initially

proliferates and produces lactic acid, which lowers the pH

to 5.5 or less. Acid-tolerant dominant yeasts, notably Z.

rouxii, grow and produce about 3% (w/v) alcohol and

several compounds which add characteristic aroma to soy

sauce.

Although Z. rouxii is the dominant moromi yeast which

produces alcohol and several compounds that add charac-

teristic aromas to soy sauce, other yeasts such as Candida

versatilis and Candida etchellsii also produce phenolic com-

pounds, i.e. 4-ethylguaiacol and 4-ethylphenol, which con-

tribute to soy sauce aroma. Nearly 300 types of flavour

compounds have been identified in Japanese soy sauce

(Nunomura & Sasaki, 1992). Zygosaccharomyces rouxii pro-

duces flavour compounds including alcohols, glycerol,

esters, 4-hydroxy-5-methyl-3(3 H)-furanone (HMMF),

4-hydroxy-2 (or 5)-ethyl-5(or 2) -methyl-3(2 H)-furanone

(HEMF) and 4-hydroxy-2,5-dimethyl-3(2 H)-furanone

(HDMF). Of the furanones, HEMF produced by Z. rouxii

and Candida spp. gives Japanese-type soy sauce its

characteristic flavour (Hanya & Nakadai, 2003). This com-

pound is also reported to have antitumour and antioxidative

properties (Nagahara et al., 1992; Koga et al., 1998). Higher

alcohols such as isobutyl alcohol, isoamyl alcohol and

2-phenyl ethanol, produced by C. versatilis, are also impor-

tant flavour constituents of soy sauce. Certain strains

of yeasts have deleterious effects on soy sauce. Film-

forming yeasts, mainly belonging to the genera Zygosacchar-

omyces, Hansenula and Pichia, cause spoilage in moromi

fermentation.

Miso

Miso is a salty paste with a meat-like flavour made by

fermenting soybean, with or without the addition of rice or

barley, using A. oryzae and a yeast, Z. rouxii. Sometimes,

Tetragenococcus halophila and Enterococcus faecalis are also

involved in the fermentation. Miso is a seasoning agent and

is also used in the preparation of miso soup. Heat-treated

rice and/or soybeans are used to prepare ‘shinshu’ or rice-

soybean miso. After the initial solid-substrate fermentation

dominated by A. oryzae, salt (38% of the original weight of

dry soybeans) is added to the koji and mixed thoroughly.

The mixture is backslopped or inoculated with Z. rouxii and

allowed to ferment for up to 15 days for sweet miso and

2–12 months for salty miso. Although other halophilic

yeasts such as Torulopsis versatilis may be present, only Z.

rouxii produces the desired metabolites for an acceptable

product (Ebine, 1989). Flavour components in miso are

similar to those of soy sauce. Furanones, HEMF and HDMF,

produced by Z. rouxii, have been identified as important

flavour components in miso. Miso also contains B vitamins

(riboflavin and cyanocobalamine) as a result of yeast

fermentation.



Futureperspectives

Upgrading of traditional home-scale processes is needed so

that they can continue to maintain and strengthen the

cultural heritage and can compete successfully with im-

ported products. Whereas small-scale manufacture has the

advantages of short distribution lines, income generation for

families, etc., urbanization and the resulting growing de-

mand for ready-to-consume high-quality foods requires

larger-scale controlled industrial production. Examples of

industrialized traditional fermented foods (Steinkraus,

1989) are:

i alcoholic snacks such as tapai, which are now produced at

a small cottage scale in Malaysia using commercially

available pure culture starters of the starch-degrading

mould A. rouxii and the yeast Sm. fibuligera;

ii rice wines such as Japanese sake, using A. oryzae for rice

saccharification and sake yeasts (S. cerevisiae strains

selected for reduced foam production, or killer properties

if required);

iii condiments such as soy sauce inoculated with Z. rouxii

and Candida spp. and miso in which similar halotolerant

yeasts are used for flavour development.

Yeast products such as enzymes, B vitamins, trace ele-

ments (selenium, chromium), glycans, flavour components

and carotenoid pigments occur in traditional foods, but

could be exploited more effectively as purified substances

and food ingredients. Yeasts have a relatively high content of

protein, lipids and micronutrients. In view of the wide-

spread micronutrient deficiencies in regions that depend

predominantly on plant-based diets, the addition of yeast-

derived food products could contribute to improved nutri-

tional status (Mai et al., 2002).

In conclusion, a wide variety of yeasts are involved in

traditional fermented foods. Although the occurrence of

various yeasts has been reported, knowledge and under-

standing of their ecology including aspects such as microbial

successions and competitiveness, and of their genetic and

physiological properties remain to be acquired. In particu-

lar, yeasts that contribute to desirable product properties

require more precise characterization, using genomics,

proteomics and physiological approaches for more efficient

identification and exploitation, while developing consumer-

friendly strategies to control fermentations and safeguard

hygiene.

References

Aidoo KE, Smith JE & Wood BJB (1994) Industrial aspects of soy

sauce fermentations using Aspergillus. In: The Genus

Aspergillus: From Taxonomy and Genetics to Industrial

Application (Powell KA, Renwick A & Peberdy JF, eds), pp.

155–169. Plenum Press, New York, NY.

Ardhana MM & Fleet GH (1989) The microbial ecology of tape

ketan fermentation. Int J Food Microbiol 9: 157–165.

Batra LR & Millner PD (1974) Some Asian fermented foods and

beverages and associated fungi. Mycologia 66: 942–950.

Boekhout T & Robert V (2003) Yeasts in Food: Beneficial and

Detrimental Aspects. B. Behr’s Verlag GmbH & Co. KG,

Hamburg, Germany.

Boon-Long N (1986) Traditional technologies of Thailand:

traditional fermented food products. In: Traditional Foods:

Some Products and Technologies (Potty VH, Shankar JV,

Ranganath KA, Chandrasekhara N, Prakash V, Sri Hari BR &

Dastur S, eds), pp. 114–133. Central Food Technology

Research Institute, Mysore, India.

Campbell-Platt G. (1987) Fermented Foods of the World. A

Dictionary and Guide. Butterworth Scientific Ltd, Guildford,

Surrey, UK.

Chou C-C & Rwan J-H (1995) Mycelial propagation and enzyme

production in koji prepared with Aspergillus oryzae on various

rice extrudates and steamed rice. J Ferment Bioeng 79:

509–512.

Dansakul S, Charoenchai C, Urairong H & Leelawatcharamas V

(2004) Identification of yeasts isolated from Thai fermented

foods by sequence analysis of rDNA. Poster 11-12, p. 263.

FoodMicro 2004: the 19th international ICFMH Symposium.

New tools for improving microbial food safety and quality.

Portoroz, Slovenia.

Dung NTP (2004) Defined fungal starter granules for purple

glutinous rice wine, Ph.D. Thesis. Wageningen University,

Wageningen, The Netherlands, pp 110.

Dung NTP, Rombouts FM & Nout MJR (2005) Development of

defined mixed-culture fungal fermentation starter granulate

for controlled production of rice wine. Innov Food Sci Em

Technol 6: 429–441.

Ebine H (1989) Industrialization of Japanese miso fermentation.

In: Industrialization of Indigenous Fermented Foods (Steinkraus

KH, ed), pp. 89–126. Marcel Dekker, New York, NY.

Hanya Y & Nakadai T (2003) Yeasts and soy products. In: Yeasts in

Food: Beneficial and Detrimental Aspects (Boekhout T & Robert

V, eds), pp. 413–428. B. Behr’s Verlag GmbH & Co, KG,

Hamburg, Germany.

Hesseltine CW & Kurtzman CP (1990) Yeasts in amylolytic food

starters. An Inst Biol Univ Nac Auton Mexico, Ser Bot 60: 1–7.

Hesseltine CW, Rogers R & Winarno FG (1988) Microbiological

studies on amylolytic Oriental fermentation starters.

Mycopathologia 101: 141–155.

Hui YH, Meunier-Goddik L, Hansen AS, Josephsen J, Nip W-K,

Stanfield PS & Toldra F (2004) Handbook of Food and Beverage

Fermentation Technology. Marcel Dekker, New York, NY.

Joshi N, Godbole SH & Kanekar P (1989) Microbial and

biochemical changes during dhokla fermentation with special

reference to flavour compounds. J Food Sci Technol 26:

113–115.



Joshi VK, Sandhu DK & Thakur NS (1999) Fruit based alcoholic

beverages. In: Biotechnology: Food Fermentation (Joshi VK &

Pandey A, eds), pp. 647–744. Educational Publishers,

Ernakulam, India.

Kanekar P & Joshi N (1993) Lactobacillus fermentum, Leuconostoc

mesenteroides and Hansenula silvicola contributing to acetoin

and folic acid during ‘dhokla’ fermentation. Indian J Microbiol

33: 111–117.

Ko SD (1986) Indonesian fermented foods not based on

soybeans. In: Indigenous Fermented Food of Non-Western

Origin, Mycologia Memoir No.11. (Hesseltine CW & Wang

HL, eds), pp. 67–84. J. Cramer, Berlin, Germany.

Koga T, Moro K & Matsudo T (1998) Antioxidative behaviors of

4-hydroxy-2,5-dimethyl-3(2 H)-furanone and 4-hydroxy-2(or

5)-ethyl-5(or 2)-methyl-3(2 H)-furanone against lipid

peroxidation. J Agric Food Chem 46: 946–951.

Kozaki M & Uchimura T (1990) Micro-organisms in Chinese

starter ‘bubod’ and rice wine ‘tapuy’ in the Philippines. J Brew

Soc Jpn 85: 818–824.

Kurtzman CP, Robnett CJ & Basehoar-Powers E (2001)

Zygosaccharomyces kombuchaenensis, a new ascosporogenous

yeast from ‘Kombucha tea’. FEMS Yeast Research 1: 133–138.

Limtong S, Sintara S, Suwannarit P & Lotong N (2002) Yeast

diversity in Thai traditional alcoholic starter. Kasetsart J (Nat

Sci) 36: 149–158.

Mai TTT, Takasaki S, Yasue M, Kitabatake K & Chuyen NV (2002)

Comparison of ingestive effects of brewer’s yeast, casein, and

soy protein on bioavailability of dietary iron. J Nutr Sci

Vitaminol (Tokyo) 48: 298–304.

Mayser P, Fromme S, Leitzmann C & Grunder K (1995) The yeast

spectrum of the ‘tea fungus kombucha’. Mycoses 38: 289–295.

Nagahara A, Benjamin H, Storkson J, Krewson J, Sheng K, Liu W

& Pariza MW (1992) Inhibition of benzo(a)pyrene-induced

mouse forestomach neoplasia by a principal flavour

component of Japanese-style fermented soy sauce. Cancer Res

52: 1754–1756.

Nout MJR & Aidoo KE (2002) Asian fungal fermented food. In:

The Mycota, vol. 10: Industrial Applications (Osiewacz HD, ed),

pp. 23–47. Springer-Verlag, New York, NY.

Nout MJR & Sarkar PK (1999) Lactic acid food fermentation in

tropical climates. Antonie van Leeuwenhoek 76: 395–401.

Nunomura N & Sasaki M (1992) Japanese soy sauce flavour with

emphasis on off-flavours. In: Off-flavours in Foods and

Beverages (Charalambous G, ed), pp. 287–312. Elsevier,

Amsterdam, The Netherlands.

Ramakrishnan CV (1979) Studies on Indian fermented foods.

Baroda J Nutr 6: 1–54.

Rhee SJ, Lee CYJ, Kim KK & Lee CH (2003) Comparison of the

traditional (samhaeju) and industrial (chongju) rice wine

brewing in Korea. Food Sci Biotechnol 12: 242–247.

Sandhu DK & Soni SK (1989) Microflora associated with Indian

Punjabi warri fermentation. J Food Sci Technol 26: 21–25.

Sandhu DK, Soni SK & Vilkhu KS (1986) Distribution and role of

yeasts in Indian fermented foods. In: Yeast Biotechnology

(Vashishat RK & Tauro P, eds), pp. 142–148. Haryana

Agricultural University, Hisar, India.

Saono S, Gandjar I & Basuki T (1996) Indigenous fermented

foods in which ethanol is a major product. In: Handbook of

Indigenous Fermented Foods (Steinkraus KH, ed), pp. 363–508.

Marcel Dekker, New York, NY.

Shrestha H, Nand K & Rati ER (2002) Microbiological profile of

murcha starters and physico-chemical characteristics of poko,

a rice based traditional fermented food product of Nepal. Food

Biotechnol 16: 1–15.

Shurpalekar SR (1986) Papads. In: Legume-based Fermented

Foods (Reddy NR, Pierson MD & Salunkhe DK, eds), pp.

191–217. CRC Press, Boca Raton, FL.

Soni SK & Sandhu DK (1991) Role of yeast domination in Indian

idli batter fermentation. World J Microbiol Biotechnol 7:

505–507.

Steinkraus KH (1989) Industrialization of Indigenous Fermented

Foods. Marcel Dekker, New York, NY.

Steinkraus KH (1996) Handbook of Indigenous Fermented Foods.

2nd edn. Marcel Dekker, New York, NY.

Tamang JP & Sarkar PK (1995) Microflora of murcha: an

amylolytic fermentation starter. Microbios 81: 115–122.

Tamang JP, Sarkar PK & Hesseltine CW (1988) Traditional

fermented foods and beverages of Darjeeling and Sikkim – a

review. J Sci Food Agric 44: 375–385.

Teoh AL, Heard G & Cox J (2004) Yeast ecology of kombucha

fermentation. Int J Food Microbiol 95: 119–126.

Tsuyoshi N, Fudou R, Yamanaka S, Kozaki M, Tamang N, Thapa

S & Tamang JP (2005) Identification of yeast strains isolated

from marcha in Sikkim, a microbial starter for amylolytic

fermentation. Int J Food Microbiol 99: 135–146.

Uzochukwu S, Balogh E, Tucknot OG, Lewis MJ & Ngoddy PO

(1999) Role of palm wine yeasts and bacteria in palm wine

aroma. J Food Sci Technol 36: 301–304.

Vachanavinich K, Kom WJ & Park YI (1994) Microbial study

on krachae, Thai rice wine. In: Lactic Acid Fermentation

of Non-Dairy Food and Beverages (Lee C-H, Adler-Nissen

J & Barwald G, eds), pp. 233–246. Harn Lim Won, Seoul,

Korea.

Venkatasubbaiah P, Dwarakanath CT & Murthy VS (1984)

Microbiological and physico-chemical changes in idli batter

during fermentation. J Food Sci Technol 21: 59–62.

Venkatasubbaiah P, Dwarakanath CT & Murthy VS (1985)

Involvement of yeast flora in idli batter fermentation. J Food

Sci Technol 22: 88–90.

Wood BJB (1998) Microbiology of Fermented Foods. 2nd edn.

Blackie Academic and Professional, London, UK.



1. rad - Aidoo et al-2006-FEMS Yeast Research

Documents

Transcript of 1. rad - Aidoo et al-2006-FEMS Yeast Research