In soy sauce production, histamine, which causes allergy-like food poisoning, has become a problem. As a countermeasure against the proliferation of wild lactic acid bacteria responsible for histamine formation, a new lactic acid bacterial strain, Tetragenococcus halophilus MS0204, was isolated from soy sauce moromi in Miyazaki prefecture. The efficacy of adding MS0204, which does not produce histamine, as a starter culture was investigated, and it was confirmed that its use suppressed histamine production. Furthermore, sensory evaluations indicated that the quality of soy sauce produced with MS0204 was comparable to or superior to that of additive-free soy sauce. These findings confirm the suitability of this novel lactic acid bacterium as a starter for soy sauce production.

In this study, lactic acid bacteria were primarily collected from plant sources, and a bacterial library was constructed. To avoid duplicate isolates, the collected bacteria were classified by restriction enzyme cleavage polymorphism analysis of 16S rDNA. Most of the strains grew poorly in milk, with the exception of Lactococcus lactis, which showed good fermentability in milk, leading to the selection of L. lactis SIY8. Strain SIY8 exhibited a pronounced ability to induce interleukin 12. Furthermore, when strain SIY8 was cocultured with L. delbrueckii ssp. bulgaricus, the growth of the latter was promoted in the fermentation of milk. The resultant fermented milk had a higher free amino acid content than regular yogurt, potentially influencing its taste.

Various types of rice flour are available in Japan, but the quality is inconsistent. Therefore, in order to produce high-quality rice flour consistently, it is necessary to establish guidelines for rice flour production. The author has identified the characteristics of rice flour that are conducive to making high-quality bread, sponge cake, and noodles. There guidelines indicate four indices: particles size under 75 μm, degree of damaged starch, amylose content, and water content. Among these, particles size under 75 μm, degree of damaged starch, and water content are recommended as common indicators across all applications when manufacturing products. The amylose content can vary based on the specific application of the rice flour. Aiming to produce rice flour that meets specific criteria, our institute analyzed rice flour samples from millers in Niigata Prefecture and provided feedback on the results. As a result, flour milling companies in Niigata Prefecture are able to supply rice flour with stable quality.

With the objective of shipping squash fruit during the winter season, which constitutes the off-season for domestically grown squash fruit, we aimed to develop storage techniques that mitigate the softening of squash fruit mesocarp that typically occurs during prolonged storage. Utilizing near-infrared spectroscopic analysis to sort squash fruit based on dry matter immediately after harvest proved to be efficacious in limiting mesocarp softening. Through this approach, fruits with a dry matter ratio of 30 % (w/w) or higher, when stored at 10 °C, demonstrated the ability to maintain their mealy texture even after a 2-month storage period. Furthermore, employing a highly mealy cultivar and storing it at a temperature of approximately 10 °C enabled the preservation of the mealy texture for over 2 months, eliminating the necessity for screening based on dry matter.

The sake yeast strain “KODO” was isolated from the soil of Kumano Kodō, a world heritage site, and has been used in sake fermentation. In this study, we bred the strain to enhance the productivity of ethyl caproate, which is one of the important flavor compounds of ginjo-shu. The concentrations of ethyl caproate of test brewing sake fermented by bred yeasts were 8–10 fold higher than that of the parental KODO strain. Furthermore, the concentrations of acetic acid of test brewing sake fermented by bred yeasts were 1/3–1/5 fold lower than that of the parental KODO strain. “KODO.ec 162”, one of the bred yeasts, has been used for sake fermentation since 2021.

Lipases play an important role in the initial hydrolysis and absorption of lipids in organisms. It is generally known that lipases specifically hydrolyze fatty acids bound to the primary hydroxyl groups of the glycerol backbone. The reaction, however, is not entirely specific due to the fatty acyl transfer from the secondary position to the primary one. Our study revealed that the substrate specificity of a lipase can be controlled by simple factors such as water, alcohol concentration, and temperature in the reaction system, and that the selective synthesis of target products can be achieved using lipases. Enzymatic methods were developed to efficiently obtain biodiesel (fatty acid methyl esters) and to selectively synthesize 1-MAG or 2-MAG. This led us to also develop a novel method for determining the fatty acid composition at the sn-2 position of triacylglycerols. This analytical method has the advantage of including fats and oils containing short-chain fatty acids and polyunsaturated fatty acids in the scope, which are not covered by the scope of conventional methods.

We established several study groups with members such as private companies and government agencies. The activities of these study groups are collaboration for the exchange of information, development of new technologies and products, and sales promotions at related events. Herein, I will introduce the study group activities for research support for Akamoku (called Gibasa in Akita Prefecture) and Jerusalem artichokes. Specifically, we researched the differences in characteristics of these local products made in Akita Prefecture. In the Akamoku study group of Akita Prefecture, a salient feature was that the relative viscosity varied depending on the manufacturing region. In addition, the relative viscosity and fucoxanthin content—reported to have an antiobesity effect—were found to differ according to cultivation area, crop time, and sex. In the Jerusalem artichoke study group of Akita Prefecture, a salient feature was that the inulin sugar degree of polymerization was low in the domestic Jerusalem artichoke and it was the chief ingredient in the Akita Prefecture product. The free sugar and fructooligosaccharide content were found to vary according to cultivation area, cultivation technique, and cultivation year. These tendencies were also recognized for free amino acids, particularly Arg.

Through the use of vacuum packaging and high-pressure thermal processing, we have developed REAFRU, a processed fruit product that can be stored at room temperature, has no additives, retains the taste and aroma of fresh fruit, and has an excellent appearance. REAFRU production consists of peeling, cutting, vacuum packaging and high-pressure thermal processing with a retort sterilizer. Setting the degree of vacuum packaging as 99 % or higher is necessary. A heating temperature of 100 ℃ for 10 minutes is appropriate. To prevent discoloration after processing, the gas barrier performance of the pouch is important and a very low oxygen transmission rate is required. The technology for production of REAFRU has been shared with five companies in Hokkaido, and the products are sold for general and business use, and the production volume is steadily increasing.

There has been growing interest in inside-outside beauty products. Companies in Fukuoka Prefecture were not able to develop such products as expected because of the lack of collaboration with skin health research experts. The diverse and complex needs of the companies did not closely match the specific materials or technologies developed by public research or other institutions. In this work, we describe the support system we have established for the development of functional food and cosmetic products. The system consists of a series of technologies such as the extraction, analysis, isolation, identification, concentration and enrichment of bioactive compounds; the functional analysis of food materials, with special focus on skin care function; and drying and powdering. Thirty-eight products have been successfully released by the companies through the application of this system. In conclusion, the support system we established was considered useful to promote the development of functional food and cosmetic products in Fukuoka.

A byproduct of sake production is sake-kasu, which contains abundant nutrients. However, since consumption of sake-kasu is decreasing, we attempted to develop a high-value sake-kasu. We steamed the sake-kasu to remove alcohol (nAS) and then inoculated the nAS with lactic acid bacteria or acetic acid bacteria and incubated the samples at 30°C for 2 days. The sugars, organic acids, amino acids, trace elements, and ferulic acid were measured in the fermented sake-kasu. Lactic acid was produced in the sake-kasu fermented with lactic acid bacteria, while gluconic acid was produced in the sake-kasu fermented with acetic acid bacteria. In the sake-kasu fermented with Gluconobacter oxydans NBRC 3189, seven times as much ferulic acid was produced compared to the non-fermented sake-kasu. Thus, we were able to produce a high value sake-kasu by bacterial fermentation.

The value-added improvement of prefectural farm products is important for the development of Ibaraki agriculture as a growth industry, and investigation of the impact of storage during long-term shipment and the development of high-quality products are needed. Japanese chestnuts, which are a specialty product of Ibaraki Prefecture, were wrapped without sealing in polyethylene film during storage (packaging that was folded the mouth of the bag). Results showed that the packaging treatment could decrease desiccation of the chestnuts (floating chestnuts), and combined with storage at -1 °C, could delay browning of the fleshy interior compared to conventional storage (2 °C) for around one month. It was further clarified that fungal growth could be suppressed. In addition, by using a retort sterilizer for the purpose of cooking and sterilization concurrently, stewed sweet chestnuts characterized by a bright color and softness were produced, and the original flavor and nutritional components of the Japanese chestnuts were retained.

Yukishita kyabetsu, cabbage (Brassica oleracea L. var. capitata L) that is cultivated or stored under snow cover for several months, was analyzed before and after snowfall; the sugar content, which imparts sweetness, was mostly retained. Meanwhile, the nitrate nitrogen (nitrate ion) concentration, which causes astringency, was decreased. In the analysis using a taste sensing system, the astringency and bitterness decreased because of the decrease in nitrate ions; thus, it was speculated that the sweetness increased in comparison. For cabbage stored in the snow room, we conducted a 5-day distribution test using three temperature groups (1, 10, and 20 °C) to clarify the effect of distribution temperature following shipment. The results showed that the sugar content was unchanged for almost 5 days in the 1 and 10 °C temperature groups, while it decreased in one day in the 20 °C temperature group. In the 20 °C temperature group, the nitrate ion concentration, which is responsible for bitterness, more than doubled in one day of distribution storage.

A few novel strains of lactic acid bacteria were isolated from local foods, such as traditional Japanese pickles, in Niigata. We attempted to apply these strains to food fermentation to create new plant-based foods.Latilactobacillus sakei UONUMA strains (UONUMA-1, UONUMA-2, and UONUMA-3) isolated from Japanese pickles in snow caverns in the Uonuma region of Niigata have potential for use in biopreservation. Additionally, these strains were able to reform the flavor of koji amazake. Lactiplantibacillus paraplantarum YAMAKOSHI strain, which is isolated from traditional non-salt "Izekomina" pickles from the Yamakoshi region of Niigata, has the characteristics of yielding a viscous and sticky fermented food.These characteristics were exploited to produce foods such as lactic acid fermented koji amazake, rice bran pickles, vegetable paste, yogurt, and gelato for commercial use. Furthermore, a yogurt-like beverage, solely made from rice, was successfully produced and commercialized.

Dried Japanese noodles are one of the most favored foods in Japan and are supplied as a preserved food due to its long shelf life. In the production of dried noodles, the drying process governs product quality and is known to be challenging, as the strips of fresh noodles are relatively thick and have limited strength to withstand the internal stress caused by rapid drying. Therefore, controlled humidity drying is necessary to maintain balance between the rates of evaporation and internal moisture diffusion. However, optimal drying conditions are difficult to achieve due to the complexity of operating variables, such as temperature, humidity, and velocity. In the present study, we regarded the drying of fresh noodles as a moisture diffusion phenomenon within a solid material. The moisture diffusivity, the effect of the drying condition on drying kinetics, and the stress induced by drying were investigated to obtain technical information about the optimal drying operation. It is expected that this information will be useful in establishing optimal drying protocols for Japanese noodles.

Flavor is one of the important factors for udon, white salted Japanese noodles. Using gas chromatography/mass spectrometry, we analyzed the volatile compounds from the flour, dough, and boiled noodles to clarify the mechanism of udon flavor formation. Hydrocarbons were the main compounds from the flour, while aldehydes and ketones were the main compounds from the dough and noodles. These aldehydes and ketones are presumed to be generated from the enzymatic oxidation of unsaturated fatty acids by lipoxygenase (LOX) upon the addition of water. LOX activity was significantly higher in the cultivar Norin61 than in Satonosora. In conclusion, the characteristic volatile compound profiles of Norin61 are due to differences in LOX activity. These results have been applied to the development of new value-added noodle products by various companies.

Shijimi, the brackish-water bivalve Corbicula japonica, is one of the most important fishery resources in Aomori Prefecture. We worked on developing a new product using Shimiji extract to promote the prefecture’s industry. In the course of researching the stabilization of the quality of Shimiji extract, we found that the ornithine content of the extract increased when the bivalve was frozen. It was not influenced by the period of freezing. This phenomenon was not apparent in the scallop, little-neck clam, or hard clam. We applied various low-temperature conditions for processing the bivalve from 4°Cto －10°Cand measured the ornithine content of each extract. The ornithine content was maximized by processing at －4°C. The increase in the ornithine content was reduced when the bivalve was stored at 5°Cor 15°Cafter processing at －4°C, and this decrease was reversed when the bivalve was again processed at －4°Cafter warming. Based on these experimental results, it was thought that freeze processing the bivalve increased the ornithine content of the extract. Furthermore, a novel ornithine-containing tripeptide, named acorbine, was found in the bivalve and is believed to be the source of increased free ornithine.

In this study, processing conditions for hydrolyzing isoflavone glycoside derived from soybean were examined for miso production. The result showed that the amount of isoflavone aglycones in Miso was related to β-glucosidase activity in Koji measured with isoflavone glycosides (genistin) as the substrate, but it was not related to the enzyme activity determined using a synthetic substrate, p-nitrophenyl-β-D-glucopyranoside. In a large-scale production test at four brewing companies, the amount of isoflavone aglycones in miso increased when using Koji made from Tane-koji (Koji mold spore), which was bred and selected specifically to produce β-glucosidease. For further improvement, it is necessary to investigate factors other than β-glucosidase and to determine optimal conditions.

Large amounts of purple-colored liquid waste containing nasunin are generated by plants manufacturing lightly salted eggplant products (Asa-zuke). A combination method using HP-20 and 5mol/l acetic acid as an elution liquid can be used to prepare nasunin-containing pigment powder from liquid waste of brined eggplant. The ORAC value for the powder was estimated to be about 10432µmol trolox equivalent/g, which was 69% that of chlorogenic acid. However, the nasunin-containing pigment powder exhibited low water-solubility and a strong acetic acid odor. Here, treatment with β-cyclodextrin and γ-cyclodextrin was investigated in order to address these undesirable characteristics. The optimal conditions for improving the characteristics of the powder were obtained by mixing γ-cyclodextrin and the powder in a 1:1 molar ratio (γ-cyclodextrin: nasunin/chlorogenic acid), and stirring for more than 10 minutes. This treatment increased the water-solubility of the powder from 32% to 81% and decreased the odor of acetic acid by 81%. The contribution of nasunin to the ORAC value of the antioxidant powder was estimated to be approximately 26%. In addition, it was found that nasunin exerts an anti-inflammatory effect and that this effect is mediated by its antioxidant activity.

Sudachi, Citrus sudachi, is a major local food in Tokushima Prefecture, and over 98% of this fruit is produced in Tokushima Prefecture. After juice is extracted from sudachi, sudachi peer is not used effectively. Sudachitin, a polymethoxylated flavone is isolated from sudachi peer, and its structure is similar to nobiletin, which possesses anti-inflammatory and anti-obesity actions. First, we evaluated the effect of sudachitin on lipid and energy metabolism in mice fed a high-fat diet. C57BL/6J mice were fed a high-fat diet treated with 5mg/kg/day sudachitin orally for 12 weeks. The mice treated with sudachitin showed significantly decreased body weight gain, body fat and viscera fat compared to that of mice fed a high-fat diet. Moreover, sudachitin improved glucose intolerance and insulin resistance in these mice. We concluded that sudachitin may improve metabolic syndrome by enhancing energy metabolism. Purified sudachitin cannot be used as a food ingredient because of the possibility of side effects and it is too expensive for clinical use at present. Therefore, we tried to produce a sudachi powder which contained sudachitin at high concentration from the dried sudachi peer containing a low amount of sudachitin. It is possible to adjust the content step-by-step from 1% to 80%. We also evaluated the function of sudachi peer extract powder using an animal model of obesity. The mice treated with sudachi peer extract powder showed significantly decreased body weight gain compared to that of mice fed a high-fat diet.

The production of miso has been decreasing due to changes in eating habits and social environments. In addition, there has been a recent move towards reduced salt intake to diminish lifestyle-related diseases. To maintain the demand for miso, it is important to develop salt-free miso manufacturing technology. Thus, collaborative research involving industry, academia, and the government was conducted to develop salt-free miso. The production of salt-free miso requires the control of lactic acid bacteria, spore-forming bacteria, and hygiene-related bacteria. In addition, it is necessary to propagate specific fermentation microorganisms such as yeast and lactic acid bacteria to improve the taste of miso soup. Here, miso production was divided into two steps. In the high-temperature digestion step, miso was heated to 55°Cand the temperature was maintained for 1 to 5 days. In the second, low-temperature addition and multistage fermentation step, a fermentation microorganism corresponding to the desired product quality was added at a temperature of approximately 10°Cand the fermentation temperature was then raised in multiple steps. The microflora produced in each manufacturing step was analyzed by PCR-DGGE to identify hygiene-related bacteria and lactic acid bacteria. Processing conditions during the high-temperature digestion step were set as the critical control point in manufacturing.