Physico-chemical, textural and consumers’ acceptability of biscuits made from composite flour of wheat, fermented soybean-hull and date-pulp

Abstract

Soybean hull consist of complex polysaccharides that cannot be digested by human’s alimentary canal and is usually discarded during processing. These complexes can be broken down by fermentation into simpler and more available forms. This research used solid state fermentation process with some microbes to ferment soybean hull for flour production and investigated the proximate, textural, physical and sensory properties of biscuits produced from composite flour of wheat and fermented soybean hull with date-pulp flour as a sugar replacement in the biscuit production. The proximate composition of the biscuit showed increasing protein (10.15 to 12.25 %), lipids (20.14 to 22.95 %), ash (2.07 to 2.16 %), fibre (1.23 to 1.38 %) and moisture contents (4.65 to 6.03 %) while the carbohydrate content (60.1 to 56.1%) decreased with increasing soybean hull flour. The weight (12.03 to 15.30 g), thickness (6.24 to 7.38 mm), density (5.08 to 5.18 g/cm3), and spread ratio (7.32 to 8.76) of the biscuit increased while its diameter (54.11 to 54.94 mm), decreased, and its volume (5.08 to 5.18 cm3) exhibited no particular trend. No significant difference (p≤0.05) was observed in the textural properties of the biscuit but those produced from 16% soybean hull flour fermented with B. subtilis for 72hrs, and 4% soybean hull flour, fermented with A. oryzae for 72hrs were the most preferred. Therefore, supplementing wheat flour with soybean hull flour fermented with A. oryzea at 72hrs and B. subtilis at 72hrs significantly improved the nutritional quality of biscuit without adverse effects on its physical, textural and sensory properties.