In recent years, interest in ‘Japan Wine’, made exclusively from domestic grapes cultivated in Japan, has been growing. Notably, sparkling wine made using In-bottle secondary fermentation, a traditional and authentic method, has garnered significant attention. At the inception of our research in Japan, there was little technical knowledge about the In-bottle secondary fermentation method, and many wine makers struggled to produce sparkling wine using this method. Therefore, we conducted research into stabilizing and improving the production process for In-bottle secondary fermentation, particularly by developing methods that take advantage of the characteristics of Japanese grapes. First, we conducted a field survey in the Champagne region of France to clarify the details of the authentic and traditional method of producing Champagne. Subsequently, based on the acquired technical knowledge, we started trial production research in Japan. Initially, we verified the basic production methods for stabilizing the secondary fermentation process, including preparing yeast starter culture and condition for secondary fermentation. Next, in the wine-making process, we established technology to consistently achieve malolactic fermentation, which is difficult to achieve with white wine. Additionally, we demonstrated the effectiveness of technologies and additives that contribute to stabilizing tartar, a common issue following secondary fermentation in Japanese production. Furthermore, it was shown that adjusting the sugar content in the final process can balance the flavor and enhance sensory characteristics. In this study, the main focus was on examining production methods when using domestic grapes, which have characteristics distinct from those of European grapes. Production tests were conducted using Koshu and Muscat Bailey A varieties. Sparkling wine was produced using Koshu grapes over a period of several years, and production tests were conducted on such factors as the harvest time of the grapes, the selection of dry yeasts, the vinification methods, the blend ratio of the wines, and the effects of the aging period. When making wine using Koshu grapes, the “first pressing juice” (called cuvée in Champagne production)" and “second pressing juice” (called taille) have different compositions than those obtained from European grapes. It was found that the acidity of the cuvée is lower than the acidity of the taille when using Koshu grapes. Consequently, we proposed the method for preparing base wine when producing sparkling wine by fractionating the cuvée and the taille, and blending the wines produced from each. It was also revealed that when making rosé sparkling wine from Muscat Bailey A, it is possible to omit the color extraction processes that are the standard methods for making rosé wine, such as the “semi-maceration fermentation method” and the “saignée method” and make the wine using the simple “direct pressing method” used to make white wine. In addition, regarding the pressing process for Muscat Bailey A, the change in the juice components was revealed to be similar to that for Koshu, and it was confirmed that the taille had a higher acidity than the cuvée, just as in the case of Koshu. This revealed the possibility of effectively using the taille to produce a high-quality product, similar to Koshu. In the future, it will be important to evaluate products after long-term aging, which is crucial for the production of sparkling wines that undergo secondary fermented in the bottle.

Olive, which have been cultivated in Kagawa Prefecture since 1908, have a strong brand name both inside and outside of the prefecture, and brewing sake with yeast isolated from olive will enable the development of a new sake product that highlight the uniqueness of Kagawa. This study was conducted with the aim of commercializing a highly original sake using yeast isolated from olive. Yeasts (OY-4 and -5) were isolated from olive flowers, fruits, and two strains of Saccharomyces cerevisiae with the ability to produce ethanol at 15 ºC were obtained. However, their ethanol production were lower than that of Kyokai-kobo No. 9. To solve this, we attempted to obtain a strain with higher ethanol productivity by selecting alcohol-resistant strains from OY−4 or −5. Yeast were cultured on agar medium containing ethanol, and 5 strains that could be grown on 17 % ethanol were obtained. Among them, OY-04-2 was selected for its high alcohol productivity and good sensory characteristics. OY-04-2 was named “Sanuki Olive Yeast”, and 4 sake products made with the yeast have been on the market since April 2020. These sake products have been highly praised for their fruity aroma and refreshing acidity.

Whey protein concentrate (WPC) has been used in the manufacturing of yogurt to improve its physical properties. However, the addition of WPC alone does not provide sufficient water-holding capacity in yogurt. In this study, an olive leaf water extract (OLEx), which improves the gelling properties of egg white protein and gelatin, was applied to WPC-fortified yogurt, and the effects of WPC added with OLEx (OLEx-WPC) on the physical properties of yogurt were investigated. First, we investigated the physical properties of heat-induced WPC gel containing OLEx. The breaking stress for OLEx-WPC gel increased, and the syneresis ratio for OLEx-WPC decreased compared to WPC without OLEx. SDS-PAGE analysis showed that OLEx polymerizes protein components in WPC. The breaking stress for WPC-formulated yogurt with OLEx increased compared to that without OLEx (control group). The syneresis ratio for yogurt was much lower in the treatment group than in the control group. These results indicate that OLEx is useful for improving the mechanical properties and water-holding capacity of WPC-formulated yogurt.

When food products and solutions are vacuum packaged together using a chamber vacuum packaging machine, the pressure differential created during the process can drive the solutions into the pores of the foods. This study investigated the potential of vacuum packaging as a novel seasoning method for raw vegetables. Four kinds of vegetables were immersed in NaCl solutions isotonic to their intracellular fluids and then vacuum packaged. The results suggest that vacuum packaging facilitates seasoning by promoting the influx of NaCl solution into vegetable pores, including the intercellular spaces, without compromising cell-membrane integrity. Additionally, the effectiveness of this method was found to be influenced by the porosity and structural conditions of the vegetable pores.