Effect of substrate and enzyme concentration on isomerization process in fructose syrup production from sago starch

Abstract

Substrate and enzyme concentrations are crucial factors in production of fructose syrup. Optimizing these concentrations during the isomerization process can enhance efficiency, reduce production costs, and shorten production time of sago starch-based fructose syrup. Therefore, this study aimed to determine the optimal substrate concentration using parameters such as fructose content, degree of conversion, and viscosity. It also included determining the appropriate enzyme concentration based on fructose content and degree of conversion. The process involved liquefaction with α-amylase, saccharification with amyloglucosidase, and isomerization with glucoisomerase. Two treatments were applied during the isomerization stage: varying substrate concentrations (50%, 60%, 70%, and 80% w/v) and varying enzyme concentrations (0.04%, 0.07%, and 0.1%). The results showed that for substrate concentrations of 50-80%(w/v), fructose content ranged from 22.96% to 29.00%, the degree of conversion was between 34.11% and 45.91%, as well as viscosity varied from 10.20 to 3819.67 mPa.s. In enzyme concentration trials of 0.04-0.1%, fructose content ranged from 20.67% to 23.33% while the degree of conversion was between 41.33% and 46.67%. The optimal conditions were 50%(w/v) substrate and 0.07% enzyme concentrations, providing the highest conversion efficiency. These results suggested that lower substrate and enzyme concentrations could be efficiently used to improve the overall production process.