Optimization of glucose syrup extraction from Colocasia esculenta starch using enzymatic hydrolysis

Abstract

This study aimed to produce, characterize, and optimize glucose syrup from Colocasia esculenta starch through enzymatic hydrolysis, an area that remains insufficiently explored and studied in the existing literature. The process involved starch extraction from Colocasia esculenta and three sequential steps were followed for the extraction of glucose syrup. These stages include gelatinization, liquefaction, and saccharification. The physicochemical properties of Colocasia esculenta-derived starch were analyzed, revealing a moisture content of 12 %, water-holding capacity of 70 %, ash content of 0.66 %, particle size distribution of 7 μm, amylose content of 23.57 %, bulk density of 0.87 g/cm³, and a pH of 7.2. The study investigated the effects of pH, mixing time, and enzyme concentration on glucose syrup yield. The experiments were conducted at a constant temperature of 62.5 °C, with enzyme concentrations of 0.3, 0.35, and 0.4 mg/L, hydrolysis times of 240, 480, and 720 min, and pH levels of 4.5, 4.75, and 5. The results showed that optimal conditions of pH 4.75, enzyme concentration of 0.40 mg/L, and hydrolysis time of 720 min yielded the highest reducing sugar content (46 %), degree Brix (44.2 %), and maximum glucose yield (76 %). Overall, this study demonstrated that locally available Colocasia esculenta is a viable source for producing glucose syrup with desirable characteristics.