A Study of Optimal Conditions for Reducing Sugars Production from Cassava Peels by Diluted Acid and Enzymes

Abstract

Cassava peels were dried and milled into small pieces. 1.5%(w/v)Cassava peel was hydrolysed by 0.1 M sulfuric acid at 135^oC under pressure 15 lb/inch² for 90 min producing 66.28%yield of reducing sugars while 0.025 M hydrochloric acid produced 63.29% yield of reducing sugars under the same conditions. Hydrolysis by 0.25 M acetic acid could produce 30.36% yield of reducing sugars under the same conditions. Enzymatic hydrolysis of 1.5% cassava peels by a-amylase at pH 6.0, 90^oC for 2 hr produced 40.79% yield of reducing sugars. After that, the reaction mixture was continuously hydrolysed by amyloglucosidase at pH 4.0, 50^oC for 24 hr, which produced 70.11% yield of reducing sugars. Hydrolysis of 1.5% cassava peel by cellulase under optimal condition at pH 5.0, 50^oC for 24 hr produced 43.39% yield of reducing sugars. Hydrolysis of 1.5% cassava peels by xylanase under optimal conditions at pH 4.0, 50^oC for 9 hr produced 2.64% yield of reducing sugars while hydrolysis by pectinase under optimal condition at pH 5.0, 40^oC for 3 hr produced 9.01% yield of reducing sugars. From this study, it was shown that cassava peels could produce reducing sugars by dilute acid hydrolysis and that several enzymes digestion.