TITLE:
Application of Wild Yeast (Saccharomyces cerevisiae) Isolates from Palm Wine and Honey in Baking of Cassava/Wheat Composite Bread
AUTHORS:
James Bitrus, Onyetugo C. Amadi, Tochukwu N. Nwagu, Chukwudi I. Nnamchi, Anene N. Moneke
KEYWORDS:
Saccharomyces cerevisiae, Cassava, Wheat, Aroma, Flavour
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.11 No.7,
July
17,
2020
ABSTRACT: Saccharomyces cerevisiae (baker’s yeast) and wheat flour are the
conventional raw materials used in baking of
bread. Wheat flour is preferred due to gluten proteins providing bread
elasticity. Interest is shown in using flours from cassava mainly due to
economic and health reasons. Cassava does not have gluten protein required for
bread elasticity. A different type of yeast would be required to bake bread
using cassava flour. We investigated the use of composite
(cassava/wheat) flour technology for bread baking. We also isolated yeast
strains from palm wine (SPW) and honey (SH) using enriched media and evaluated their ability to produce
acceptable cassava/wheat composite flour bread. Total of six yeast (3 each for
palm wine and honey) strains identified as Saccharomyces cerevisiae were isolated. Two strains
designated SPW and SH were selected and used for bread production. A commercial
yeast strain (CY) was used as control. The major interest in this study
included aroma, colour, taste, crust/texture, pore size, loaf weight and
volume. Yeast concentration—1% - 3%, and flour composite
combinations of 90% wheat/10% cassava, 80% wheat/20% cassava, and 70% wheat/30%
cassava were studied. The control was 100% wheat flour. Bread made from 90W:10C
and 80W:20C compared favourably with bread made from 100% wheat flour. Loaf
volumes were: SPW (850 cm3), CY (760 cm3) and SH (570 cm3),
whilst loaf weights were: 243 g for SPW, 260 g for CY and 298 for SH. Pore size estimations were:
SPW loaf porosity (0.765), CY (0.740) and SH (0.655). Yeast concentrations of
2.5% performed best when SPW was used to produce bread from 70W:30C composite
loaf. SPW also displayed combined role of
gas production, aroma and flavor development in wheat/cassava composite bread. Mean performance of CY, SH and SPW on sensory parameters of bread
produced, varied significantly (p CY
> SH.