Sourdough and Cereal Beverages - Sourdough Biotechnology - page 266

Table 11.2 Dominant microbes isolated from togwa
Organism Relevant enzyme activities Reference

LAB Weissella confusa [ 14 ]

Lactobacillus fermentum [ 14 ]

Pediococcus pentosaceus [ 14 ]

Lactobacillus plantarum Amylolytic [ 14 ]

Lactobacillus brevis [ 14 ]

Yeasts Saccharomyces cerevisiae [ 14, 16 ]

Issatchenkia orientalis (Candida
krusei)

Phytase [ 16 ]

Pichia guilliermondii [ 16 ]

Kluyveromyces marxianus [ 16 ]

Hanseniaspora guilliermondii Phytase [ 16 ]

Candida glabrata [ 16 ]

Pichia norvegensis [ 16 ]

Pichia burtonii [ 16 ]

Candida tropicalis [ 14, 16 ]

Candida pelliculosa (Pichia
anomala)

[ 14, 16 ]

increased in a yeast-fermented maize base whereas the levels of tetrahydrofolate
remained unchanged. The increase of total folate was highest with a strain of
Candida glabrata , which resulted in a togwa with 23-fold folate content compared
to the control incubation without yeast; the final folate concentration in the
C. glabrata ferment was 700 ng per g dry matter [ 18 ] .
Mugula et al. [ 19 ] investigated the proteolytic activity in togwa and verified that
the added malt was the main source of proteolytic activity. The amino acids leucine,
isoleucine, valine, ornithine, glutamic acid accumulated during togwa fermenta-
tions [ 19 ]. These amino acids are well known to influence flavour formation directly
or indirectly as, for instance, Leu, Val, Ile serve as precursors for Strecker aldehydes
that are typical amino-acid-derived flavour compounds in sourdoughs [ 20 ] .

11.4 Mahewu

Mahewu is a traditional non-alcoholic spontaneously fermented beverage consumed
by the Bantu people of Southern Africa, for example in Zimbabwe. Gruel prepared
from maize or sorghum is cooled down and inoculated with sorghum malt (or wheat
flour) and left to stand for 1-2 days. During the incubation period, saccharification
and spontaneous fermentation take place. The dominant microflora of mahewu con-
sists of lactic acid bacteria, mainly Lactococcus lactis subsp. lactis [ 21 ] as well as
yeasts, although grain-associated fungi were also detected [ 22 ] . A major goal of
using malt combined with fermentation is to reduce the amount of tannins, which