Enzymatic hydrolysis of pink lotus seed starch from Dong Thap (Nelumbo nucifera Gaertn.) using amylase

Lotus seeds (Nelumbo nucifera Gaertn.) are a valuable starch source; however, their potential for producing functional glucose syrup has not been fully exploited in Vietnam. Pink lotus seeds from Dong Thap, characterized by high carbohydrate content, are identified as a promising raw material for enzymatic hydrolysis. This study aimed to determine the most suitable amylase enzyme (α-amylase, β-amylase, glucoamylase) for starch hydrolysis, and to evaluate the effects of technological factors including temperature, pH, enzyme concentration, and hydrolysis time. The results indicate that α-amylase is the most appropriate enzyme, with optimal conditions of 90°C, pH 6.5, enzyme concentration of 0.075% (v/w), and hydrolysis time of 30 minutes. Under these conditions, the hydrolysate achieved 9.83 °Bx, reducing sugar content of 14.41%, total sugar content of 36.75%, residual starch of 3.72%, and a Dextrose Equivalent (DE) of 48.12%. The study successfully established a hydrolysis process for lotus seed starch, providing a basis for producing high-quality glucose syrup from local raw materials.