Effect of fermentation on protein digestibility of soybean and sweet potato blends: aspergillus oryzae vs. Lactobacillus plantarum
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Date
2009
Authors
Tuitoek, P.J.
Mahungu, S.M.
Shalo, P.L.
Kiplamai, F. K.
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta university
Abstract
The improvement of nutritional quality of foods through fermentation has been practiced for long.
Fermentation imparts desirable characteristics to products and makes them more utilizable nutrient
sources than the unfermented products. Sweet potatoes have been under utilized industrially and
are mainly used at household level. Soybeans are rich in proteins but their full utilization has been
hampered by their anti-nutritional properties which are destroyed by heating and fermentation. The
purpose of this study was to produce suitable blends of soybean and sweet potato flours targeted
at alleviating protein related malnutrition. The quality characteristics of the fermented and
unfermented soybean and sweet potato composite flours were compared. The fermentation with
Lactobacillus plantarum was at 370C for 168 hours with sampling every 24 hours. The Aspergillus
oryzae fermentation was performed at 250C for six weeks with samples taken weekly for laboratory
analysis. In-vitro protein digestibility was determined enzymatically. The data obtained was subjected
to General Linear Model (GLM) of the Statistical Analysis System (SAS). Protein digestibility was
improved by an average 4% (p< O.05) in the bacterial fermented composites and by an average of
5.5% (p< O.05) in the composite flours fermented with the mould. The composite containing 50%
soybean and 50% sweet potato reflected higher protein digestibility than the composite with 25%
soybean and 75% sweet potato. Fermentation significantly increased protein digestibility but an
initial drop was observed in the higher (50% soybean and 50% sweet potato) protein composite for
both bacterial and mould fermentations. Optimum protein digestibility improvement was achieved
thus a baseline for development of suitable blends targeting protein malnutrition.
Description
This article was scanned from a hard copy of African Journal of Applied Human Sciences pg.44-49, vol. 1 no. 1 2009
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Citation
African Journal of Applied Human Sciences pg.44-49, vol. 1 no. 1 2009