Biosynthesis and Characterization of Glucose Syrup Derived from Manihot Dulcis TMS 4(2) 1423 Starch

Abstract

Glucose syrup was produced from untreated and acid-treated starch obtained from low cyanide cassava species, Manihot dulcis TMS 4(2)1423 (sweet cassava), by enzymatic hydrolysis. The starch for biosynthesis was processed from freshly harvested tubers using the standard traditional method. Acid-treated starch was obtained by treatment of the derived starch with 0.1M HCl. While dextrinization was achieved with the aid of α-amylase, saccharification was achieved with the aid of glycoamylase and fungamyl enzymes. Granular size, moisture content and iodine tests were determined for both the untreated and acid-treated starch samples using standard methods. In order to characterize the prepared glucose syrups, Fehling test, Biuret test, glucose concentration (GC), dextrose equivalent (DE), relative density (RD), pH, viscosity and surface tension (ST) were determined. Granular size range of 7 – 15 μm and moisture content of 12 % were determined for the untreated starch sample. The acid-treated starch had granular size range of 5 – 12 μm and moisture content of 8 %. Both starches had positive iodine test results. Glucose syrup derived from untreated starch afforded GC of 52.6 mmol/litre, DE of 52.30, RD of 1.0736, pH of 2.30, viscosity of 2.70 centipoise, percentage yield of 1.51 and ST of 46.45 dynes/cm. Glucose syrup derived from acidtreated starch had GC of 56.2 mmol/litre, DE of 58.60, RD of 1.1702, pH of 2.50, viscosity of 4.30 centipoise, percentage yield of 1.72 and ST of 48.57 dynes/cm. While the Fehling tests were positive, the Biuret tests were negative for both syrups. Acid-treated Manihot dulcis TMS 4(2)1423 starch was recommended for the commercial production of glucose syrup.

Keywords: Glucose syrup, cassava starch, biosynthesis, Mannihot dulcis

Nigerian Journal of Pharmaceutical Research, Vol. 9 No 1 pp. 23 - 29 (February 2011)