PROTEIN ENRICHMENT OF SWEET-POTATO RESIDUE WITH AMYLOLYTIC YEASTS BY SOLID-STATE FERMENTATION

Starchy agricultural wastes were inoculated with amylolytic yeasts for protein enrichment by solid-state fermentation. The moisture content of substrate was 65-69 percent, and water activity was equivalent to 0.98-0.99. The optimum conditions for protein enrichment were initial moisture content 65 percent, initial pH 4.5, a 1:1 mixture of ammonium sulfate and urea was incrementally added to the ferment with 1 percent added at zero time, 1 percent added at 24 h, and 0.5 percent added at 48 h, and incubation with amylolytic yeasts (1.0×1010/100 g substrate) at 30°C for 2-3 days. The final product contained 16. 11-20.82 percent protein.