Download CHAPTER - II REVIEW OF LITERATURE 2.1. CEREALS AND

CHAPTER - II
REVIEW OF LITERATURE
2.1. CEREALS AND MILLETS – SUBSTRATE FOR FERMENTATION
Cereal and millets form the basic diet for millions of people throughout the
world. They are major sources of inexpensive dietary energy and nutrients worldwide. When compared to other fermentable substrates, cereals and millets are
superior in nutritional quality as these abundant resources contain some of the
essential minerals, vitamins, sterols, growth factors and dietary fibres thus satisfying
essential nutrient needs of mankind. However, presence of some of the anti-nutrient
factors such as phytic acid affects the availability of minerals. Also, the absence of
certain essential aminoacids in cereals makes them inferior to other substrates. The
sensorial properties of products from cereal and millet based are affected due to the
presence of tannin and polyphenols and coarse nature of grains (Chavan and Kadam,
1989).
Though various ways were adopted to overcome these limitations,
fermentation seems to be the best and inexpensive way to improve the nutritional and
sensorial quality of cereals. Fermenting cereals and millets offer several advantages
such as reduction in the level of anti-nutrients (Oyewole, 1997, Mugula et al., 2003,
Hamad and Fields, 1979, Sanni et al., 1999) and improvement in mineral availability
of the cereals (Khetaurpaul and Chauhan, 1991). Generally, fermented cereal and
millet products have enhanced aroma and texture which improve the palatability of
the products. For some of the cereal and millet substrates, fermentation forms the
only option as it eliminates toxins and makes the substrate fit for consumption (Vasconcelos et al., 1990).
Along with the essential nutrients, cereals and millets also contain appreciable
amounts of phytochemicals such as phenols, tannins and flavonoids. Earlier they were
considered as anti-nutrients but in recent years phenolic acids are reported to act as
antioxidants by donating electrons (Chandrasekara and Shahidi, 2010). Several
reports stated the anti-mutagenic, antimicrobial effects of phenolic acids present in
cereals and millets (Jones and Engleson, 2010). These bioactive compounds were
mainly concentrated in the seed coat of the grains and their levels vary among cereals
and millets. These compounds may act either as inhibitor or as enhancer based on
6
their bioavailability and processing methods. The composition of cereal and millets
are presented in Table 2.1.
Table 2.1
Composition of cereal and millet grains
Constituent
Dehulled cereal
Dehulled millet
content
content
(% dry weight basis)
(% dry weight basis)
45-77
16 - 45
Polysaccharides
Starch
Dietary fibre (as non starch 9 - 15
3.6 – 9.8
polysaccharides and lignin
Sugars
Fructose
0.1-0.4
0.12 – 0.23
Glucose
0.1-0.5
0.10 - 0.25
Sucrose
0.5-0.2
0.22 - 1.68
Raffinose
0.2-0.7
0.04 - 0.71
Stachyose
-
0.06 - 0.13
Proteins
8-15
7.3 - 12.5
Lipids
2-6
0.7 - 1.7
Ash (minerals)
1.5 – 3
0.6 - 2.8
Source: FAO, 2008, Salovara et al., (2003)
Other than these nutritional advantages, cereals and millets contain prebiotic
components which support the survival of functional microbes in gastric transit. Short
oligosaccharides, resistant starch, polysaccharides and dietary fibres are recognised as
prebiotics (Macfarlane et al., 2006). Any cereal substrates naturally contain at least
two of the oligosaccharides (Henry and Saini, 1989) which possess different
physiological functions. Also the presence of resistant starch and dietary fibres in
cereals serve as encapsulation materials for probiotic microbes.
Cereals and millets form very good substrates for various groups of
microorganisms. Generally indigenous cereal and millet fermentation is spontaneous
microbiological process hence involves complex microbiota. However due to
7
molecular development in molecular biology techniques biodiversity of various
fermented foods are revealed which lead to the better understanding of the
fermentation process and controlled fermentation process was developed for some of
the indigenous fermented foods.
The review discusses the role of microflora in cereal and millet fermentation
and the benefits offered by them in the substrates due to their metabolic activities.
2.2. MICROBIOLOGY OF CEREAL AND MILLET FERMENTATION
Microbial diversity of cereal and millet based fermented foods range from
LAB to endopsore-forming bacteria, amylolytic and alcoholic producing yeasts and
filamentous moulds. Raw cereals and millets contain surface microflora which are
activated when water is added to the substrates. Microflora also derived from various
sources such as raw materials, utensils/ equipments and food matrix (Jespersen et al.,
2003). The establishment of particular microflora in the substrate depends on water
activity, pH, food matrix composition, salt concentration and method of preparation.
During spontaneous fermentation microbes either occur in succession or co-exist with
other microbial groups in synergistic effect. For example, yeasts multiplication is
favoured by acidic environment developed due to metabolic activities of LAB while
bacteria growth is favoured by the yeast activities as it provides several growth factors such as vitamins, minerals and nitrogen compounds during fermentation (Nout,
1989). However dominance of particular strain during fermentation results due to
competitive abilities of the strain in the substrate. The predominant organisms
reported in all cereal and millet fermentation are LAB and yeasts.
2.2.1. LAB IN CEREAL AND MILLET FERMENTATION
LAB occupies most important part in all cereal and millet fermentation. LAB
strains are given the status of GRAS (Generally Regarded as Safe) because of long
history of use in food industry (Wood and Holzapfel, 1995). They are one of the most
important groups of microorganisms in food fermentations (Abriueol et al., 2011).
LAB strains are capable of lowering the pH to below 4 in cereal based food products
thus preventing spoilage of foods and contributes largely for aroma formation in
cereal products. Due to this property, other non acid producing organisms were
eliminated making LAB as predominant organism in most of the fermentation process
8
(Nout et al., 1989, Brauman et al., 1996). Cereal fermentations are mainly dominated
by four different genera of LAB such as Lactobacillus, Lactococcus, Leuconostoc and
Pediococcus (Salovaara, 1996). Keeping in view of the vast biodiversity of LAB in
various food products and to understand the roles of LAB in fermentation processes,
physiology, genetics and applications of LAB were studied extensively. As
fermentative nature of LAB is diverse and has significant impact on foods to develop
a better controlled process some of LAB genomes have already been published.
Earlier identification of LAB species was based on biochemical characteristics
such as morphology, growth characteristics and mode of glucose fermentation which
enabled identifying LAB isolates at genera level. These characters were still
considered essential in classifying LAB isolates. Recent years have seen an explosion
in the development and application of molecular tools for identifying microbes and
analyzing their activity. These tools are increasingly applied to strains of LAB at
species level including those used in fermentation as well as those marketed as
probiotics. 16S rRNA sequence analysis emerged as a powerful and reliable
technique for identifying and determining the phylogenetic relationships of LAB
strains (Schleifer et al., 1995, Morelli et al., 2004). Another widespread molecular
technique used for LAB identification is Random amplified polymorphic DNA
(RAPD) (Hamza et al., 2009, Mora et al., 2000). RAPD sequencing was used for
monitoring progress of LAB starters during fermentation and for determining
similarity among the LAB isolates (Corsetti et al., 2001, Antonsson et al., 2003).
With new developments of molecular biology and to overcome limitations of
culture dependant techniques, Denaturing Gradient Gel Electrophoresis (DGGE), a
culture independent technique were successfully applied on fermented cereal foods
(Meroth et al., 2003). DGGE presents a clear picture of microbial diversity in fermented foods. However identification of predominant strain during fermentation is
difficult with this technique. Another culture independent technique, Pulsed field gel
electrophoresis (PFGE) allows the separation of large DNA fragments PFGE
protocols were well established for LAB strains but due to labor intensive technique it
is not feasible for large scale typing of isolates. Rep PCR technique is being recently
used widely for identification of LAB to sub species level (Ab) (Towner and
cockayne, 1993).
9
Though several identification methodologies were proposed for LAB the
choice of identification methods depends on the fermentation medium and purpose of
identification. In practice for identification of large number of isolates, a combination
of phenotypic, biochemical and molecular methods was found to be effective
(Kunene et al., 2000).
2.2.2. YEAST IN CEREAL AND MILLET FERMENTATION
Yeast was found along with LAB in almost all cereal and millet fermentations
(Oyewole and Odunfa, 1990, Halm et al., 1993, Hounhouigan et al., 1993).
Significance of Yeast was well reported in Ogi and Kenkey by Jespersen et al.,
(2003). In many of the Asian fermented foods, yeasts were reported to be
predominant and functional during fermentation (Aidoo et al., 2006). Yeast
contributes significantly for structural quality and organoleptic characters of the
product. The sugars formed during fermentation were utilized and converted to main
end product, ethanol. Yeast strains reported to exhibit wide range of enzymatic
activities and also produce flavour compounds such as alcohols, acids, esters,
terpenes and lactones during cereal fermentation (Jansens, 1992). Also yeasts strains
contain high content of protein, lipids and micronutrients which greatly help in
reducing prevailing micronutrient deficiencies in rural set up (Mai et al., 2002). The
predominant strains reported from fermented cereals were Saccharomyces cerevisiae,
Geotrichum candidum, Candida grusei and Candida tropicalis.
Identification of yeast colonies in fermented foods were done by biochemical
methods as described by Kreger van (1984) and Barnett et al., (1990). The tests
include colony and cell morphology, sporulation, fermentation tests and
pseudomycelium formation (Dalmau spot-plate technique). Depending on the
carbohydrate assimilation pattern some of the yeasts organisms were identified and
for this purpose ID32C kits were widely used. Recently molecular based methods
such as rRNA sequencing, PCR-DGGE, Rep PCR analysis were also adopted for
yeast identification (Botes et al., 2007).
2.2.3. FOOD BORNE PATHOGENS
Other than these predominant microbial groups various enteropathogens were
found to be associated with cereal and millet fermentation. As they occur as seed
10
microflora pathogenic groups were inevitable during cereal and millet fermentation.
But reports stated the reduction in pathogenic groups due to LAB and Yeast
dominance. The review further presents the nutritional and functional role played by
predominant microbes in cereal and millet fermentation.
2.2.4. ROLE OF MICROBES IN IMPROVING NUTRITIONAL QUALITY OF
FERMENTED FOODS
As already stated, though cereals and millets are high in nutritional quality the
presence of antinutrient factors hinders their utilization. Various reports stated the
role of LAB and yeast strains in improving mineral availability of fermented millet
and cereal based products. Khetaurpaul and Chauhan (1990) reported increased
mineral availability during pearl millet fermentation effected by pure cultures of LAB
and yeasts.
LAB and yeasts were also reported to exhibit various enzymatic activities
during fermentation. The level of carbohydrates and polysaccharides gets reduced due
to amylolytic activities of LAB (Oyewole, 1997). Proteolytic activities of microbes
during fermentation led to the availability of peptides and amino acids and improves
protein digestibility of the substrates (Mugula et al., 2003). Some of the LAB strains
were reported to improve riboflavin, thiamine, niacin and lysine contents during
millet fermentation (Hamad and Fields, 1979, Sanni et al., 1999).
The duration of the fermentation, method of indigenous processing and
microbial activities were reported to significantly alter bioactive components of the
substrate. During natural pearl millet fermentation, decrease in polyphenolic content
was reported by Elyas et al. (2002) whereas during finger millet fermentation increase
in polyphenolic content was reported by Sripriya et al., (1996). Banu et al., (2010)
stated that type of fermentation and the metabolic activities of LAB were responsible
for the increase in levels of bioactive compounds and antioxidant capacity of rye
bread and rye sourdough. Some of the cereal fermentation utilising LAB as starters
have shown improved antioxidant property (Dajanta et al., 2011). Also the processing
methodologies, such as decortications of sorghum, drastically reduced antioxidant
property of the grain and its health properties. Thus the antioxidant property of
cereals and millets were altered in either way during fermentation by several intrinsic
factors.
11
2.2.5. FUNCTIONAL ROLE OF PREDOMINANT MICROBES IN CEREAL
AND MILLET FERMENTATION
Definition for functional foods given by Hugett and Schliter (1996) says
“foods or food ingredients that exert beneficial effect on host health or reduce risk of
chronic disease beyond basic nutritional functions”. Probiotic foods are regarded as
functional foods as they include functional microbes which provide beneficial effects
to consumers by improving microbial balance in intestinal tract (Fuller, 1989). Today
many specific strains of Lactobacillus, Bifidobacteria, Bacillus and yeast are regarded
as commercial probiotics. However, lactobacilli still remain the most commonly used
probiotic microorganism (Holzapfel and Schillinger, 2002, Saxelin et al., 2005).
Due to increased awareness on probiotics, many proven and approved
probiotic strains are available in market as supplements in dehydrated form. But
fermented foods serve as common carriers of probiotic microbes since they support
growth of these organisms. For many years, there was much emphasis of
incorporating probiotic LAB cultures on dairy products such as milk (Antunes et al.,
2009) yogurt (Aryana et al., 2007) and cheese (Burns et al., 2008). Many dairy
products are optimized for survival of probiotic organisms and marketed successfully.
Probiotic strains were successfully used as starter cultures in dairy foods which lead
to the production of novel types of fermented milks and cheeses (Gomes and Malcata,
1999). Recently owing to increased awareness in probiotics, inclusion of probiotic
strains in cereal and millet fermented substrates was actively investigated. Previous
reports of indigenous cereal and millet fermentation have mentioned anti-diarrhoeal
functions of some of the product (Mensah et al., 1988, 1990, 1991, Nout et al., 1989,
Odugbemi et al., 1991, Kingamkono et al., 1998, Kimmons et al., 1999, Tetteh et al.,
2004). The microbe involved during fermentation process could be probiotic as
ability to decrease the incidence or duration of certain diarrhoeal illnesses is
considered as the most substantiated probiotic health effects.
The fermented Mahewu showed reduction in level of pathogens such as
Salmonella, Shigella, Campylobacter, Aeromonas and pathogenic E. coli which
indicated the presence of LAB strains with potential probiotic properties in traditional
fermented preparations (Simango, 1997). The reports of Kingamkono et al. (1998)
suggested that the traditional cereal fermented foods are good carriers of probiotic
microbes. He reported that Togwa, maize and finger millet based East African
12
traditional food inhibited growth of enterotoxin producing bacteria. Significant
reduction of enteropathogen population was noticed in rectal swabs of children under
five years old when they fed with togwa. Lei and Jakobsen (2004) isolated LAB
strains such as Weisella confusa and Lactobacillus from koko sour water which
exhibited antimicrobial activity against the pathogen Listeria. Part of fermented
portion of koko sour water was used to treat patients with upset stomach which was
also used as refreshing drink instead of water. According to Vogel et al., (1993) some
of LAB strains in sourdough and in fermented cereal foods were identical to species
found in animal and human intestinal tract. The report open up another possibility of
introducing human derived probiotic strains into cereal based traditional food. Cereals
and millets naturally possess prebiotic fibres thus readily support the growth and
survival of probiotic microbes in gastrointestinal tract (Charalampopoulos et al.,
2002). Hence cereal and millet based products with probiotic microbes can be called
as synbiotics. As cereals and millets support growth of functional LAB strains,
development of non-dairy probiotic products will helps in better utilisation of these
abundant resources.
With this view one of the popular traditional cereal based fermented food, ogi
has been modified with functional properties by introduction of probiotic starters with
antidiarrheal properties (Okagabue, 1995). Also a newly developed oat based
fermented product, Yosa which is familiar in Finland regions contain probiotic lactic
acid bacteria which was reported to improve the intestinal environment (Toufeili et
al., 1997). Thus fermented cereal and millet foods form very good alternative to dairy
probiotic foods and infact superior to dairy foods as it is encompasses prebiotic
benefits. This property proves that the potential for using cereal and millet based
indigenous fermented product for probiotic treatments is huge.
2.2.6. LAB AND YEAST – IMPROVING SAFETY OF FERMENTED FOODS
Traditional fermentation process is generally considered as an inexpensive
way to improve the safety of foods. As most of cereal and millet fermentation was
carried out in rural households basic hygienic practices are not generally observed.
However, safety of the fermented foods was ensured by metabolic activities of
microbes in the substrate. Fermentation forms the affordable way of improving safety
of the traditional fermented foods. The preservative properties of fermented foods is
13
attributed to microbial activities such as organic acid production (Ali et al., 2003,
Mugula et al., 2002, Lei and Jakobsen, 2004), alcohol production, hydrogen peroxide
formation (Kullisaar et al., 2002), carbon dioxide production (Adams and Nicolaides,
1997, Caplice and Fitzgerald, 1999), bactericidal compounds production and
competition among the microbes which leads to nutrient depletion.
Acid production of LAB was reported to be more effective towards gram
negative pathogens compared to gram positive organisms (Mensah et al., 1991).
Carbondioxide production by heterofermentative LAB organisms during fermentation
creates an anaerobic environment thus indirectly inhibits aerobic spore forming
organisms during fermentation (Devlieghere, 2000). Under natural conditions,
production of hydrogen peroxide creates structural damages and changes in bacterial
membranes thus inhibit microbial activity.
Another preservative mechanism of cereal fermentation which is very well
studied is the production of bactericidal compounds (Omar et al., 2000, Riley and
Wertz, 2002). Almost all gram positive strains were reported to produce bacteriocins.
However, bacteriocins produced by LAB isolates are very well studied and
understood. Bacteriocins appear to have narrow spectrum activity which acts as a
protective mechanism of fermented foods in household conditions.
Cereals support growth of mould and thereby mycotoxins are produced by
naturally occurring fungi that grow on a wide variety of grains. Mycotoxins cause
harmful effects to human when they are metabolically active in foods. According to
reports of Teniola et al. (2005) and Alberts et al. (2006) lactic fermentation was
effective in reducing mould growth and LAB strains has the capacity to inactivate
mycotoxins during fermentation. Thus lactic fermentation forms the only way to
improve the safety of cereal and millet based foods in rural set up.
On the other side as stated by Bhalla et al. (2008), microbial safety of
fermented foods observed in vitro is not always apparent because a lot of intrinsic
factors are involved during processing at the household level especially with
porridges, where large quantities of water are added during preparation. Hence,
individual field trials are necessary to ensure the safety of fermented foods.
The review further summarises popular cereal and millet based fermented
foods produced in Africa and India and microbiology involved.
14
2.3. CEREAL AND MILLET BASED FERMENTED FOODS
All around the world, cereal based fermented foods and beverages form part of
the human diet. Different varieties of cereal and millet based fermented foods are
prepared in different parts of the world. Some are utilized as colorants, spices,
beverages and breakfast or light meal foods while a few of them are used as main
foods in the diet. The production technologies and substrates vary according to
geographical locations and some of the preparations utilises several fortifying
substances to enhance taste and nutrition. In western countries cereals like wheat and
rye are preferred for consumption whereas in African and Asian countries cereals like
rice, wheat and maize and Sorghum were used for breakfast or light meal preparations
and millets were used for preparation of sour porridges and dumplings. As per the
documented information (Blandino et al., 2003) cereal and millet fermentations were
carried out in African and Asian countries in daily basis.
2.3.1. CEREAL AND MILLET BASED FERMENTED FOOD FROM AFRICA
Some of the popular cereal based fermented food which are widely studied and
documented from African countries includes Ogi, Koko, Kenkey, Uji, Mawe,Tting,
Koko sour and Mahewu. Table 2.2 lists some of the reported indigenous cereal and
millet based preparation of African countries and the microflora involved in the
fermentation process. The fermented preparations of Africa largely include sorghum
and Maize in food preparation and occasionally rice and wheat.
Natural fermentation is commonly practiced for preparation which utilises
microbes occurring naturally in the substrate and in environment (Oyewole, 1997). In
some places, backslopping is done to speed up the fermentation process which utilises
residue from the previous batch (Holzapfel, 2002). Using fermented foods as weaning
products is widespread in Africa (Lorri and Svanberg, 1995). The probiotic and
antimicrobial potential of some of the African traditional foods like koko sour
porridge and Ogi was reported. Ethnic foods also form a source of revenue for many
rural African people to sustain their livelihood. In recent years, starter culture
technologies have been developed for some of the processes such as Togwa, Ting and
Ogi.
15
Fermented product
Substrate
Mahewu/Zulu/
Maize and Sorghum,
Amahewu
Millet and wheat flour
Ogi/ Adifi/Akamu
Maize
Microorganisms involved in process
Process
Reference
Spontaneous
Chavan and Kadam (1989)
fermentation
Odunfa et al., (2001)
L. plantarum, Saccharomyces cere-
Spontaneous
Calderon et al., (2003)
visiae, Candida mycoderma
fermentation/
Lactococcs lactis
Backslopping
Uji
Kenkey
Maize and Sorghum
L. plantarum, L. cellobiosis, L
Spontaneous
Mbuga (1984)
Cassava and millet flour
buchneri
Maize
L. palntarum, L. confusus, L brevis,
Processing
Jespersen et al., (2003)
Pediococcus pentosaceus, Sacchro-
involves fer-
myces cerevisiase, Candida
mentation and
heating and
steaming cycles
Busa
Maize and finger millet
L. helveticus, P. damonsus, S. cere-
Spontaneous
visiae, C. krusei,
fermentation
Nout, 1991
process
Togwa
Sorghum, Maize
L. brevis, L. cellobiosus, L. fermen-
Spontaneous
Mugula et al., (2002)
tum,
L. plantarum, Ped. Pentosaceus,
Candida
pelliculosa, C. tropicalis,
16
Umqombothi
Maize and Sorghum
Candida haemuloni, C. sorbophila,
Spontaneous
Joseph, 2008
Debaryomyces hansenii, S. capsularis, S. Cerevisiae
Ben saalga
Pearl millet
LAB and yeast
Spontaneous
Tou et al., 2006
Dolo/Pito
Sorghum
Saccharomyes cerevisiae, L. fermen-
Spontanous/
Sawadogo et al., 2008
tum
backslopping
Lactococcus lactis, Lactobacillus
Spontaneous
fermentum, Lactobacillus plantarum,
fermentation
Ting
Sorghum
Evelyn et al., 2011
Lactobacillus rhamnosus, Weissella
cibaria,
Enterococcus faecalis
Kunun-zaki
Millet
L. fermentum, L. leichmanni, S. Cer-
Backslopping/
evisia
Spontaneous
Adeyemi & Umar, 1994
fermentation
Mawe
Maize
L. fermentum, L. reuteri, L. brevis,
Spontaneous
L. carvatus, L.buchneri,
fermentation
Hounhouigan et al., 1993
P.acidilactici, Strep. lactis,
L. salivarius, Weissella confuse,
yeasts
Kisra
Sorghum
P. pentosaceus, L. brevis, Yeasts
Spontaneous
(D. hansenii, C. intermedia),
fermentation/
L.fermentum,
Backslopping
Mohammed et al., (1991)
17
2.3.2. CEREAL AND MILLET BASED FERMENTED FOODS FROM INDIA
India is a land of diverse culture and tradition. Traditional preparatory
processes utilises a wide range of raw materials and production processes, leading to
the production of diverse products. Indian fermented foods mainly involve rice and
wheat as fermenting substrates. Some of the fermented preparations also utilises
combinations of legumes and millets. The review presents the range of popular
indigenous cereal and millet based fermented food consumed in north and southern
parts of India.
North east region of Indian subcontinent can be complimented for treasure of
traditional knowledge as it forms home for more than 166 separate tribes speaking a
wide range of languages (Tamang, 2012). This range of communities and its
geographical and ecological diversity makes North East India significantly different
from the other parts of Indian subcontinent. The tribal groups traditionally produce a
variety of fermented foods and beverages and also market them locally. The
sub-tropical climate of North Eastern India is extremely favourable for the cultivation
of many crops. The seasonal crops are preserved by the local women either by sun
drying or made into fermented pickles. There are various ethnic fermented foods that
are prepared and processed by different tribes of North East India that describe their
socio-cultural, ecological, and spiritual life. The processing and preparation of ethnic
foods demonstrate the creativity and treasure of food heritage (Anamika et al., 2007).
The Himalayan dietary culture has both rice and wheat or barley or maize as
staple food along with varieties of ethnic fermented and non-fermented foods
prepared from soybean, vegetable, bamboo, milk, meat, fish, alcoholic beverages,
and wild edible plants (Tamang, 2010a). More than 250 different types of ethnic
fermented foods and alcoholic beverages are prepared and consumed by the ethnic
people of Himalayan region (Tamang et al., 2012). Different types of substrates and
fermenting organisms are being employed for the production of these ethnic food
products. In the Himalayas, ailing persons and post-natal women consume the extract
of ethnic fermented rice product bhaati jaanr due to high calorie content, to regain the
strength (Tamang and Thapa, 2006).
In South India, more than 10 varieties of cereal and millet based fermented
foods and beverages have been prepared and consumed regularly. Most of the South
Indian fermented foods were based on rice and some of the preparations were
fortified with legumes, thus forming wholesome combination of carbohydrates and
protein. One of the popular south Indian traditional food is Idli a fermented rice based
preparation has received much scientific attention. Microflora of idli fermentation has
been explored extensively and the household batter preparation has been converted to
small scale industry to meet the demand for traditional product by urban population.
Recent studies on replacement of rice with other millet such as finger millet were
acceptable by consumer’s and flavour was reported to be improved (Teniola and
Odunfa, 2001). The process for the production of idli using fermented dehydrated
batter was also developed and marketed successfully in South India.
Other than these fermented foods south Indian millet based fermented
preparations such as Koozh, Fermented rice and Kanjika has received only little
scientific attention. These foods have been in use for long time but in recent years
consumption and preparation of South Indian traditional foods were confined to rural
people which may slowly lead to loss of traditional knowledge. The traditional home
scale processes have to be upgraded which will preserve Indian cultural heritage and
also improve the livelihood of local families producing these foods.
19
Table 2.3
Some Common Ethnic Fermented Products of Indian Subcontinent
Fermented product
Substrate
Microorganisms in-
Reference
volved in process
Gulgule
Wheat
Pediococcus sp.
Tamang et al.,
(2012)
Jilebi
Wheat and curd
Lactobacillus sp.
Kodo ka Jaanr
Millet
Pediococcus pentosaceus,
Tamang et al.,
(2012)
Thapa and Tamang
Lactobacillus sp.
(2010)
Rice/ Wheat and Bengal
Leuconostoc mesen-
Aliya and Geervani
gram
torides,
(1981)
Dhokla
Strepotococcus faecalis
Dosa/Idli
Rice and black gram
Leuconostoc mesenter-
Sands and Hankin,
oides,
(1974), Rama-
Streptococcus faecalis,
krishnan, (1993)
Torulopsis. Pullulans
Kanji
Rice with vegetables
Hansenula anomala
Satishkumar et al.,
(2010)
Kishk
Wheat
Streptococcus theromo-
(Economidou and
philus, Lactobacillus bul-
Steinkraus, 1993)
garicus
Nan
Bhatura
Maida/Wheat
Wheat + starting material
Fermented choru
Rice
Saccharomyces cerevisiae, Haard et
LAB
al., (1999).
S. cerevisiae,
D. hansenii
S. fermentati
L. plantarum
L. acidophilus
L. mesenteroides
L. lactis
Streptococcus faecalis,
Sekar and Mariap-
Sekar and Mariap-
Pediococcus acidilacti,
pan (2005)
pan (2005)
Bacillus sp. and Microbacterium flavum.
Koozh/Ambali
Finger millet, pearl mil-
Pediococcus, Leu-
Antony et al.,
let, sorghum
conostoc, heterofermenta-
(1996)
tive LAB
20
2.4. CONCLUSION
The presented informations prove the wide traditional knowledge systems of
India. The traditional beverages prepared by Indian folks are much competent in
satisfying nutrient and health needs. Also microbiological research showed that the
production processes of these fermented foods include diverse microbial groups. The
benefits offered by fermentation can be well utilised and altered by understanding the
microflora involved in the process. Due to intervention of biotechnology some of the
indigenous fermented foods have received good marketability. Identification of
predominant microbes of fermentation led to the introduction of starter culture in
some fermented preparations which improved the safety and marketability of the
indigenous foods. But still many more fermented foods were confined to rural
population due to laborious processing techniques. Only very little is known about
these foods and their microbial content. It is therefore important to analyse
microbiology of these products and technologies for improvement of processing has
to studied and documented for future generations.
21