Open AccessProduction of freeze‐dried yeast culture for the brewing of traditional sorghum beer, tchapalo
Author(s) -
N'Guessan Florent K.,
Coulibaly Hermann W.,
AlloueBoraud Mireille W. A.,
Cot Marlène,
Djè Koffi Marcellin
Publication year - 2016
Publication title -
food science and nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 27
ISSN - 2048-7177
DOI - 10.1002/fsn3.256
Subject(s) - sorghum , brewing , sucrose , food science , yeast , glycerol , starter , chemistry , freeze drying , fermentation , biology , biochemistry , agronomy , chromatography
Freeze‐drying is a well‐known dehydration method widely used to preserve microorganisms. In order to produce freeze‐dried yeast starter culture for the brewing purpose of African sorghum beer, we tested protective agents (sucrose, glucose, glycerol) in combination with support materials (millet, maize, sorghum, and cassava flours) at 1:1 ratio (v/v). The yeast strains S accharomyces cerevisiae F 12–7 and C andida tropicalis C 0–7 previously isolated from sorghum beer were used in a mixed culture at a ratio of 2:1 ( C . tropicalis / S . cerevisiae ). After the freeze‐drying, the residual water contents were between 0.78 –2.27%, 0.55 –4.09%, and 0.40–2.61%, respectively, with sucrose, glucose and glycerol. The dried yeasts viabilities were between 4.0% and 10.6%. Among the protective agents used, sucrose was found to be the best protectant giving cell viabilities of 8.4–10.6%. Considering the support materials, millet flour was the best support after drying. When the freeze‐dried yeast powders were stored at 4°C and room temperature (25–28°C) for up to 3 months, the survival rates were the highest with cassava flour as the support material.