Biochemical Changes During Controlled Fermentation of Cottonseed (Gossypium hirsutum L.) for Owoh Production

Abstract

This study investigated changes in the carbohydrate, protein and fat contents during controlled fermentation of cottonseeds. Four bacterial isolates, Bacillus subtilis, Bacillus pumulis, Bacillus licheniformis and Staphylococcus spp. were used separately for controlled fermentation of cottonseeds for 72 h, and residual composition of sugars, gossypol and amino acids were estimated every 24 h, while fatty acid profile was done at the end of fermentation. Cottonseed fermented spontaneously served as control. Fermentation of cottonseed with Bacillus spp. and Staphylococcus spp. resulted in cottonseed oil with high concentration of linolenic, linoleic and arachidonic acids. Percentage sucrose content varied significantly (p<0.05), and Bacillus subtilis fermented cottonseed had the highest (6.17%) while the spontaneously fermented cottonseed had the lowest (4.31%) after 24 h of fermentation. Glucose increased from 1.62 to 2.26%, 1.90%, 1.84%, 1.78% and 1.90% in cottonseed fermented with Bacillus subtilis, Bacillus pumulis, Bacillus licheniformis, Staphylococcus spp. and spontaneously fermented cottonseed, respectively. Residual galactose was found to be highest in Bacillus subtilis fermented cottonseeds at 48 h (1.37%) and 72h (1.29%). Bacillus pumulis and Staphylococcus spp. showed highest degree of gossypol degradation after 24 h of fermentation, while spontaneous fermentation recorded the least. There was a general reduction in free amino acids after 24 h of fermentation. Amino acids reduced in all the samples after 72 h of fermentation with the exception of alanine and phenylalanine, which increased slightly in Bacillus subtilis and spontaneously fermented cottonseeds. This study showed that degradation of nutrients in cottonseeds varied with type of bacteria isolate used for fermentation.

Keywords: Bacillus spp., condiment, controlled fermentation, cottonseed, Staphyloccus spp.