Laboratory scale production of glucose syrup by the enzymatic hydrolysis of starch made from maize, millet and sorghum

Abstract

Glucose syrup production from maize, millet and sorghum starch was investigated. The starch extracted from yellow maize after steeping for 72hrs and purified by sedimentation method had the greatest yield of 86.71% (4.34 ± 0.37g) followed by the starch made from millet and sorghum with a yield of 65.94% (3.30 ± 0.25g) and 64.71% (3.23 ± 0.09g), respectively. The lowest gelatinization onset temperature of 59.25 ± 0.90oC was observed with sorghum starch. The glucose recovered with pure amyloglucosidase from Rhizopus mold produced 17.15 ± 0.10 mg/ml reducing sugar from yellow maize starch after 10 minutes. Millet and sorghum starch followed with a yield of 15.79 ± 0.20mg/ml and 11.32 ± 0.26mg/ml in 10 minutes, respectively. Liquid glucose produced with the pure amyloglucosidase revealed a dextrose equivalent of 78.28 ± 0.57%, 73.50 ± 0.66% and 65.66 ± 0.61% for sorghum, yellow maize and millet, respectively. Sorghum and yellow maize starch exhibited good potential as substrates for glucose syrup production.