Changes in pH, titratable acidity, total soluble solids and protein of rice during natural fermentation at 37 °C 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 content fluctuated during the first 24 h of fermentation but started to increase thereafter. Non-protein nitrogen was unchanged during the first 12 h of fermentation but increased sharply with progressive fermentation. The in vitro protein digestibility markedly increased as a result of fermentation. The increase in the globulin + albumin fractions constituted the most remarkable increase and were the major proteins in the 36 h fermented rice; the increase was up to 2.7 fold. The prolamin fraction, which was the minor fraction, the G1-glutelin and G2-glutelin fractions increased with progressive fermentation time. The G3-glutelin, which was the major protein fraction of unfermented rice, markedly decreased as a result of fermentation, while insoluble protein fluctuated during the fermentation process.
Fermentation In vitro protein digestibility Protein fraction Rice Solubility