Effects of Anaerobic Germination and Enzymatic Saccharification on Chemical Compositions of Functional Drink from Riceberry Rice

Abstract

Anaerobic germination and enzymatic saccharification significantly affected the chemical compositions of riceberry rice-based functional drink. Anaerobic germination significantly affected the moisture and carbohydrate contents in germinated riceberry rice (GRR), whereas the contents of crude protein, crude fat, ash and crude fiber were not changed significantly. During anaerobic germination, production of ATP was limited; therefore, the enzyme activity in the seed could be delayed in order to conserve the nutrients. With increasing germination time, gamma-aminobutyric acid (GABA) increased, reaching a maximum percentage of 58.6% in 96-hour GRR but total phenolics and total anthocyanins significantly decreased with a loss percentage of 26.5% and 44.4%, respectively. Enzymatic saccharification using a-amylase and a-glucoamylase significantly increased sugar (total sugar, reducing sugar and glucose) contents in GRR extract, depending on incubation duration of both enzymes. The 0.5 hour-incubation with a-amylase in combination with the 12 hours-incubation with a-glucoamylase was the condition under which the extract contained the highest amount of reducing sugar (22.5 g/L), glucose (11.1 g/L) and total phenolics (22.5 g gallic acid equivalent/L). As the result, anaerobic germination in combination with enzymatic saccharification might be applied as a green process for the production of a functional drink from riceberry rice.