Noriaki Saigusa

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.

Effects of rice bran lipids and fermentation temperatures on the characteristics of aromatic red rice wine

Abstract The lipid fraction extracted from the bran layer of aromatic red rice (Oryza sativa var. Indica, Tapol) did not show a direct influence on the characteristic aroma formation in aromatic red rice wine. The optimal temperature for aromatic red rice wine brewing was rather higher (25°C) than that of traditional sake brewing (7–16°C).

The Enzyme Production Control by Sound Waves in the Case of Koji Mold

Abstract In the production of fermented food in the Orient region, microbial starter called rice-koji, which is prepared by culturing koji mold (fungus) conidia on cooked rice, is an important saccharifying agent. In koji-making, temperature, humidity, pH, light, and oxygen are important environmental factors. However, there is no report of koji-making controlled by sound waves. In Japan, sound waves have been used in various processes, including the aging of spirits, particularly shochu (Japanese traditional spirits), cultivation of vegetables and fruit, and even the breeding of cattle. However, there are few reports as paper. The reason for this is that elucidation of scientific mechanism of sound effects is thought to be difficult. In this study, focusing on the enzyme activity of rice-koji, we confirmed the relationship between enzyme activity and frequency of sound waves. Especially, we aimed to prove that sound waves are one of the important environmental factors influencing the enzyme activities of rice-koji. To identify the critical frequencies affecting enzyme activity, rice-koji was produced with the acoustic culture apparatus using various frequencies, and the enzyme activities of the resulting rice-koji were compared. As a result, enzyme activity doesn’t depend at all on the high and low frequency. But, it was confirmed that each feature of rice-koji was made with each frequency. From these result, the possibility was suggested that sound wave irradiation was one of the important environment condition for rice-koji-making.

Control of Microorganism by Sound Wave -- Effects of Sound Wave on Enzyme Balance in Rice Koji

In this study, it was revealed that a specific sound wave affect to the enzyme balance of rice koji. Protease activity was decreased by incubation under a frequency of 1 kHz. Furthermore, glucoamylase activity was decreased by incubation under a frequency of 6.3 kHz. Moreover, by incubate under a frequency of 16 kHz, peptidase activity was decreased and protease activity was increased. So, we investigated an effect of the strength of sound wave against to enzyme balance under a frequency of 6.3 kHz. At the results, it was confirmed that the enzyme ratio (α-amylase/glucoamylase) was about 3.4 in spite of strength. This result indicated that a frequency of sound wave is more important than strength to enzyme balance.