Thirty-three rice vinegar production methods were obtained from 16 books dating back to the Edo period and earlier. The rice vinegar production methods of the Edo period were characterised by a remarkably lower water: materials ratio (volume percentage of water relative to rice and koji) than that employed in the modern times. Furthermore, vinegar production was restricted to summer season, and required a short preparation period of approximately one week to one month. The reproduction test of rice vinegar was conducted at a vinegar manufacturing company that had been producing traditional rice vinegar since the Edo period; the procedures followed were that described in the books from the Edo period. Currently, the water: materials ratio used is approximately 300%. However, when the water: materials ratio was 100-250% as described in the Edo period books, lactic acid fermentation occurred and the ethanol content increased to as high as 9-13 g/ 100 ml during the initial stage of preparation, but acetic acid fermentation was not observed. This suggests that throughout the Edo period, the fermented lactic acid products containing 1-2 g/100 ml lactic acid were obtained via rice vinegar production method and used as vinegar.

We examined rupture, sensory and rheological properties of beef shank patties with low added salt concentrations (0.5% to 1.0%) to reveal the effects of salt reduction on properties of minced meat foods. Scanning electron microscopy showed that the beef patty with 1.0% salt had a smooth surface, and sensory evaluations revealed that it was preferable to that with 0.5% salt. Dynamic viscoelasticity measurements showed that salt addition decreased the temperatures at which G' and G'' started to increase, while frequency dependence excluding the low-frequency region at 30°C and 40°C remained almost the same in all samples. Regardless of salt concentration, no significant difference was observed in the internal structure, composed of soluble myosin with fragmented myofibrils, of beef patties before and after heating. These results indicated that rupture and sensory properties of beef patties with any salt concentrations were determined by internal structures with a little variation.

Owing to recent poor catches of squid, Aomori Prefecture has made efforts to commercialize canned (chub mackerel and fat greenling) and retort (true sardine) fish products. Therefore, we aim to study the effects of various parameters of the manufacturing process on the residual ratio of omega-3 (ω-3) fatty acids (EPA and DHA) in canned and retort products. This study followed an orthogonal experimental design, and analysis of variance (ANOVA) was used for data analysis. We studied both the canned and retort products, based on four parameters of their manufacturing process. We analysed the canned products based on fish species, heating temperature, heating time, and seasoning solution, whereas we analysed the retort products based on container, heating temperature, seasoning solution, and storage time. The results revealed that the fish species and the heating time in canned products, and the seasoning solution in retort products, are the most important parameters affecting the residual ratio of ω-3 fatty acids in the edible part during the manufacturing process.

In this study, we used four types of Sencha green tea leaves to extract the infusion liquid up to the third infusion. We analysed the taste components of the extracts after conducting a taste preference survey among female college students. The taste components (e.g., tannin, caffeine, and glutamic acid) differed significantly between the types of Sencha green tea leaves and the number of infusions. Regardless of the type of leaves, the second Sencha infusions received the highest taste preference among the students. In the second infusions, the average ratio of tannin and caffeine (imparting bitter taste) to glutamic acid (imparting umami taste) was approximately 4:1. Furthermore, we found that the students who consumed green tea daily and whose family members too preferred having it, had a higher inclination for bitter and umami flavours, which are the essential characteristics of green tea. This suggests that the habit of drinking green tea as well as taste preference can be passed on to younger generations by creating an environment where people drink tea brewed with green tea leaves.