Production of Glucose Syrup from Local Starch Sources

Abstract

Production of glucose from yam, corn and rice starch using a- amylase and amyloglucosidase involves three processes: gelatinization, liquefaction and saccharification. A 20 g quantity of starch was mixed with 100 ml distilled water, pH adjusted to 6.5 by adding water after which the mixture was heated in a boiling water bath to gelatinize it. Liquefaction of the gelatinized starch was done by adding 0.5ml of α-amylase and the temperature raised to 100°C, for about 15 min. The temperature was reduced to 60°C after cooling to inactivate alpha-amylase and pH was adjusted to 4.8-5.0 using 0.1N HCl. Addition of 0.5ml of amyloglucosidase breaks down maltose to glucose. This was done for 6-8hr at 60° C. Amyloglucosidase was inactivated by heating to 90°C for 5 min. Glucose concentrations were read using glucose oxidase method. Yam was found to give highest glucose concentration of 25.20 mg/dL, followed by corn (15.84 mg/dL) and rice (10.62 mg/dL). It is obvious that hydrolysis of starch from yam, corn and rice will help meet the high demand placed on sugars.

Keywords: glucose syrup, starch, amyloglucosidase, hydrolysis

Nigerian Journal of Pharmaceutical Research, Vol. 9 No 2 pp. 34 - 40 (Sep 2011)