Effect of Fermentation on Proximate Composition and Microbiological Changes of Sorghum and Pumpkin Blend

Abstract

Aim: The aim of this study was to investigate the effect of fermentation on proximate composition, titratable acidity and microbiological changes of sorghum and pumpkin blend. The raw materials used were sorghum and pumpkin flour blend which had three combinations: SpA = 100:0, SpB = 70:30, SpC = 60:40.  Methodology: The blends were subjected to natural fermentation for a period of 72 h. The following microorganisms were isolated from the fermentation process; Staphylococcus aureus, Staphylococcus saprophyticus, Saccharomyces cerevisiae, Lactobacillus casei, Bacillus subtilis, Mucor sp., Aspergillus niger. Among the microorganisms isolated, Aspergillus fumigatus and Lactobacillus plantarum were found to be the most dominant organisms during the fermentation process. The pH value decreased while titratable acidity (TTA) increased in total in all of the samples analyzed. Results from the proximate analysis shows that there was a marginal increase in crude protein content for each sample and the increase are as follows: 10.820±0.042 to 14.520±0.042, 19.610±0.014 to 24.010±0.014 and 22.255±0.035 to 27.335±0.021%. Conclusion: Possible means of getting nutritional benefit components in sorghum is by utilizing fermentation method. Fermentation as investigated in this study revealed that protein and fat content increased, while anti-nutrient content decreased. The content of fat and ash increased while that of carbohydrate and crude fibre decreased after fermentation. There was also a significant decrease in anti-nutritional content of flavonoid, phytate and tannin after 72 h of fermentation.