Physicochemical change and sensory quality profile of koji fermented-sorghum during the fermentation process using Aspergillus oryzae culture.

Abstract

Abstract Sorghum although rich in nutrients is known to have a low digestibility rate which hinders their usage. In this research, sorghum was subjected to koji fermentation to increase its digestibility rate. Koji fermentation, which utilizes the Aspergillus oryzae mold, is known for its ability to hydrolyze carbohydrates and protein in food products. Three different boiling times (5 minutes, 10 minutes, and 20 minutes) and three different fermentation times (2 days, 4 days, and 8 days) fermentation were done and the digestibility rate will be expressed as the reduced sugar content, total soluble protein content, and degree of hydrolysis. The result showed that sorghum boiled for 20 minutes and fermented for 8 days, produced the highest reducing sugar content and the highest degree of hydrolysis which were 45.6 mg/g and 77.3%, respectively. While sorghum that had been boiled for 20 minutes and fermented for 2 days showed the highest soluble protein, 21.8 mg/g. Sorghum boiled for 20 minutes was then chosen as the best treatment along with different fermentation times to ferment sorghum before being applied to the sorbet formulation. Throughout the sensory evaluation, the highest acceptance was from koji sorbet made from 4 days of fermentation and 20 minutes of boiling time was the most preferred in sensory with moderate likeness. The sorbet also can be considered as a high protein and light fat food based on its nutritional value with >13% protein content and <5% fat content per serving.