INVESTIGADORES
MENDOZA Lucia Margarita
congresos y reuniones científicas
Título:
Evolution of yeast population throughout the fermentation of corn flour to produce chicha
Autor/es:
LUCÍA M. MENDOZA; BEATRIZ PADILLA; FERNANDA MOZZI; PIER COCCONCELLI; GRACIELA VIGNOLO; CARMELA BELLOCH
Lugar:
Estambul
Reunión:
Simposio; 23rd International ICFMH Symposium, FoodMicro2012; 2012
Resumen:
Chicha production started with soaking of maize flour with hot water (aprox. 1:1,
w/v). After thoroughly mixed and cooled, flat buns were hand shaped and cooked
on a tray in a rudimentary clay oven during 1.30 h. After baking was completed,
buns were left to cool and grounded by hand, mixed with cane sugar, maize flour
and warm water (aprox. 1:1:5:1) and allowed to ferment at ambient temperature
(18-20º C) during 7-8 days. The fermented mass was then added to fresh maize
flour and warm water (aprox. 1:1:10), mixed thoroughly and allowed to decant
and cool for 2-3 h. Three layers, top liquid (supernatant), middle jelly-like
and bottom solid were separated. The middle layer was subsequently pressed,
filtered and concentrated to constitute the molasses which were mixed with the previous
liquid supernatant, supplemented with water (1:10 v/v) and allowed to further fermentation
for 2 days. After fermentation, chicha
was transferred to a narrow-mouth potsand ready for consumption.
Yeast counts from different stages along the process showed an increase in
colony counts from 102 in the initial stages to 106 in
the first fermentative stage to decrease again in the following steps (102
cfu/ml) to the final increase after the second fermentation step (106
cfu/ml).
A total of 523 colonies were
isolated, identified and classified into thirteen yeast species belonging to
nine genera. The distribution of yeast species showed Saccharomyces cerevisiae as the dominant species (73%) followed by Pichia sp. new. (8%), Candida parapsilosis (5.5%), Pichia membranaefaciens (4.4%) and Cryptococcus flavescens (3.8%).
Yeasts are known to be involved in a
range of functions in fermentations such as degradation of carbohydrates,
production of aromatic compounds and oligosaccharides, stimulation of lactic
acid bacteria, inhibition of mycotoxigenic moulds, degradation of
cyanogenic glucosides and mycotoxins as well as probiotics. The high numbers of
yeasts present along the fermentative process are likely to influence the nutritional
and organoleptic characteristics of chicha.