Improvement of the quality of aromatic red rice wine

Abstract

The aromatic red rice wine produced economically by uncooked ethanol fermentation of aromatic red rice ( Oryza sativa var. Indica, Tapol) using a glucoamylase preparation AN-2 (produced by Aspergillus niger) contained a larger amount of aromatic components such as isobutyl alcohol and ethyl acetate than rice wine made from a mixture of glucose and aromatic red rice without glucoamylase AN-2. The red color of rice wine made from aromatic red rice using glucoamylase AN-2, however, was not as brilliant as that of rice wine produced without glucoamylase AN-2. Spectrophotometric analysis revealed that the specific absorbance at 530 nm of the aromatic red rice pigment was drastically decreased in the rice wine produced with glucoamylase AN-2. The red pigment of the aromatic red rice wine was partially decolorized enzymatically with the liberation of glucose by the action of β-glucosidase contained in the glucoamylase AN-2. Sumizyme (a glucoamylase produced by Rhizopus sp.) containing a lower amount of β-glucosidase, however, did not decolorize the characteristic red color of aromatic red rice wine. The aromatic red rice wine made with Kyokai no. 9 yeast was judged to have an excellent quality by organoleptic testing and was found to contain a 1.6 times higher amount of ethyl acetate by gas chromatographic analysis. Here, the brilliant red-colored, aroma fortified, wine-like alcoholic beverage was newly developed with aromatic red rice, Sumizyme glucoamylase, and Kyokai no. 9 yeast.