Effect of fermentation on tannin content and in-vitro protein and starch digestibilities of two sorghum cultivars

Two sorghum cultivars — Safra (intermediate in tannin, 0.65%) and Cross 35:18 (high in tannin, 1.36%) — obtained from Wad Medani Research Station were used in this study. Investigations showed that in-vitro protein digestibility (IVPD) of untreated seeds were 73.6% and 70.7%, respectively, and in-vitro starch digestibilities (IVSD) were 32.3% and 33.8% for Safra and Cross 35:18 cultivars, respectively. The two cultivars were fermented for 14 h and the tannin content, IVPD and IVSD were determined at 2-h intervals. The tannin content decreased from 0.65% to 0.24% and from 1.35% to 0.52% for Safra and Cross 35:18 cultivars, respectively. The IVPD increased from 73.6% to 84.9% and from 70.7% to 80.1% for the two cultivars, respectively. The IVSD increased from 32.3% to 45.2% and from 33.8% to 47.0% for the two cultivars, respectively.