Food Biochemistry and Food Processing

27 Bakery and Cereal Products 631

Indigenous fermented cereals can be classified ac-
cording to raw material, type of fermentation, tech-
nology used, product usage, or geographical loca-
tion. They can range from quite solid products such
as baked flat breads to sour, sometimes mildly alco-
holic, refreshing beverages.
Many factors have an influence on the character-
istics of an indigenous product (Fig. 27.6). The
choice of raw material may be primarily influenced
by price and availability rather than by preference.
For instance Togwa, a Tanzanian fermented bev-
erage, may be made from maize in the inland areas
of Morogoro and Iringa, but from sorghum in the
coastal areas of Dar es Salaam and Zanzibar
(Mugula 2001). Similarly, the Ethiopian product
borde may be made from several different grains
according to availability—sorghum, maize, millet,
barley and also the Ethiopian cereal tef (Abegaz et
al. 2002). The use of different grains obviously
affects the sensory characteristics of a product, and
yet it may have the same name throughout the coun-
try. Some fermented cereal products also contain
other ingredients. Idli is a leavened steamed cake
made primarily from rice to which black gram dahl
is added. This not only improves the nutritional
quality, but in addition, the black gram imparts a vis-
cosity, apparently specific for this legume, which
may aid air entrapment during fermentation and
thereby lighten the texture of the product (Soni and
Sandu 1990). However, on a broader basis, the addi-

tion of legumes such as soya bean flour to fermented

cereals has been suggested as an economically feasi-

ble way to generally improve the nutritional quality

of cereal foods.

Some fermented cereal products are made using

unmalted grain, with no extra addition of amylase,

but they tend to either be very thick or of low nutri-

tional density. Malted flour is added to many indige-

nous fermented cereals, a traditional technology that

has far-reaching effects on several product character-

istics. The addition of malt provides amylases (in par-

ticular-amylase) that hydrolyze the starch, sweeten

the product, and also cause a considerable decrease in

viscosity of the product after heat treatment. The

malting process, the germination of grain following

steeping in water, is associated with colossal micro-

biological proliferation, and the organisms that de-

velop during malting are a source of fermenting or-

ganisms. Many Asian products, for example koji, a

Japanese fermented cereal or soya bean product, are

first inoculated with a fungus, as a source of amylase,

in order to liberate fermentable sugars from the cere-

al starch (Lotong 1998).

Many fermented cereals are multipurpose. A sin-

gle product may be prepared in varying thicknesses

and used as a fermented gruel for both adults and

children, or it may be watered down and used as a

fermented thirst-quenching beverage. As Wood (1994)

remarked, the latter type of product makes a mean-

ingful contribution to nutrition; the potential of their

Figure 27.6.Important factors determining the characteristics of spontaneously fermented cereal products.