Sourdough and Cereal Beverages - Sourdough Biotechnology - page 267

are antinutritive polyphenols equipped with astringent sensory properties and therefore
generally regarded as highly unfavourable compounds. Bvochora et al. [ 22 ] showed
that the fermentation reduced the levels of tannins (specifically proanthocyanidins)
by more than 50% during 36 h mahewu preparation. According to Oyewole [ 23 ] the
pathogenic Campylobacter , Escherichia coli and Shigella bacteria could not sur-
vive in fermented mahewu products.

11.5 Bushera

Bushera is a fermented beverage traditionally consumed in Uganda; low-alcoholic
bushera is produced using a fermentation period of 1 day whereas longer fermenta-
tion results in an alcoholic beverage that is not suitable for children [ 24 ] . Bushera is
prepared from sorghum malt or millet malt. Its manufacture begins with the addi-
tion of malt flours of sorghum or millet to boiling water. During this boiling stage
the starch gelatinises, with saccharification also likely taking place. After the boil-
ing stage, the gruel is cooled down and fermentation is initiated by adding malt flour
to the system. After 1 day of fermentation a beverage with low alcohol content is
obtained.

11.6 Pozol

Pozol is a maize-based non-alcoholic beverage that originates from the Maya
regions of South-Eastern Mexico and Guatemala (citations in [ 25 ] ). The beverage is
consumed by all family members, including infants, and it is a staple food of
Mayans. The pozol beverage is made by suspending spontaneously fermented maize
dough in water. Prior to fermentation, maize kernels are nixtamalised, i.e. cooked in
lime (1%) water and the hulls are removed. After this stage a second boiling stage
may be used or the nixtamalised dehulled kernels are directly washed and wet-
milled [ 26 ]. The milled mass (called masa or nixtamal ) is moulded into oval-shaped
dough pieces, wrapped in banana leaves and left to stand at ambient temperature for
one to several days. During this period of time, spontaneous fermentation takes
place. At the start of incubation the pH of the dough is ~7 and during the first day it
declines to below pH 5, while after 6 days the pH is below 4 [ 25, 27 ] .
Lactic acid bacteria (mainly from the genera Lactococcus, Lactobacillus,
Leuconostoc and Weissella ) are numerically the dominant microbes (~10 9 cfu/g
FW) whereas yeasts and fungi are also present in substantial numbers [ 26- 28 ] . As
in many other cereal fermentations amylolytic strains of LAB and yeasts as well as
dextran-producing strains apparently have adapted and, thus, are significantly pres-
ent in pozol [ 27 ] . Olivares-Illana et al. [ 29 ] characterised an inulosucrase active
strain of Leuconostoc citreum isolated from pozol that synthesised inulin-type poly-
mers. Of the fungus, all Geotrichum strains and nearly half of the yeast strains were