Effect of fermentation on sorghum protein fractions and in vitro protein digestibility

Changes in pH, titratable acidity, total soluble solids and proteins of Dabar sorghum (Sorghum bicolor (Linn) Moench.) during natural fermentation at 37 degreesC for up to 36 h were monitored. The pH of the fermenting material decreased sharply with a concomitant increase in the titratable acidity. Total soluble solids increased with progressive fermentation time. The crude protein and non-protein nitrogen slightly increased during the last stages of fermentation. The in vitro protein digestibility markedly increased as a result of fermentation. The globulin plus albumin fractions increased significantly (p < or = 0.05) during the first 8 h of fermentation. Kaffirin fraction decreased during the first 8 h of fermentation but increased sharply as fermentation progressed. Cross-linked kaffirins fluctuated during the fermentation process. Glutelin like protein, which was the minor fraction, true glutelins, the second most abundant fraction, together with non-extractable proteins fluctuated during the fermentation process.