In this study, we analysed Eisei-boros with added mushroom powder (Coprinus comatus, Grifola gargal, and Agaricus blazei) by electron spin resonance (ESR). The ESR spectrum of all Eisei-boros with the mushroom powder showed a singlet at g=2.0 because of organic free radicals. In Eisei-boros with A. blazei powder, a weak singlet signal from Fe³⁺ originating from materials contained in Eisei-boros was detected. Eisei-boros with mushroom powder and those without any powder showed the same singlet signals but different relaxation behaviours. Moreover, the relaxation times (T₁ and T₂) of the singlet signal differed among the samples. The radicals also differed between Eisei-boros with mushroom powder and those without it. We conclude that the new radicals are contained in Eisei-boros with mushroom powder.

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6-Gingerol is the main pungent substance in ginger (Zingiber officinale Roscoe). It is well known that 6-gingerol is converted to 6-shogaol during heating and drying because of dehydration. It is assumed that the degree of pungency and antioxidant effects of ginger will also vary during these processes. However, only a few studies have been performed on the conversion to 6-shogaol in ginger under daily cooking conditions. Therefore, in this study, the conversion of 6-gingerol to 6-shogaol in ginger under different daily cooking conditions, that is, boiling, steaming, stir-frying, baking, and microwaving, was investigated using high-performance liquid chromatograpy (HPLC.). Moreover, the alterations in antioxidant effects were measured using 2,2-diphenyl-1-picrylhydragyl (DPPH) assay and the degree of pungency of ginger was compared using sensory evaluation.
The ratio of 6-gingerol to 6-shogaol concentration in raw ginger was 98:2. After boiling and steaming for 60 minutes, the concentration of 6-shogaol increased by more than 3 times; this difference was statistically significant (p<0.01). However, it was also confirmed that a sufficiently high amount of the 6-gingerol in ginger was retained after boiling (93:7), steaming (92:8) and stir-frying (97:3); thus, the antioxidant effect and pungency were also maintained after steaming and boiling.

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We conducted a survey questionnaire targeting registered dietitians and nutritionists who is working at food service and non-food service facilities to study the type of cooking training in which training facilities for registered dietitians and nutritionists should educate to satisfy their needs. The questionnaire consisted of both closed- and open-ended questions. We analysed the differences between food service and non-food service facilities regarding the extent of cooking training required by each facility. The results showed that knowledge of miso soup and boiled greens recipes are essential at both facilities. However, knowledge of dipping and boiling procedures was required more often by food service facilities than non-food service facilities. The procedure for making broth was a more important skill at non-food service facilities than food service facilities. The results also showed that basic cooking skills and knowledge are important at both facility types, although the types of cooking procedures and meals required differed between facilities. Requirements for basic cutting techniques used in daily cooking were not significantly different between facilities, indicating the importance of these basic skills. From entire questionee we also found that the quantity of seasoning and cooking time differed between mass cooking and small portion cooking.

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In this study, recipes for boiled and seasoned food in the NHK Kyo no Ryori were analyzed. The recipes analyzed were obtained from a total of 42 text books from those published every 15 years from 1960. Of the 3,373 recipes studied, 535 (15.9%) were for boiled and seasoned food. In particular, recipes for boiled and seasoned Japanese food accounted for 74.8% of the total recipes in 1975. The main ingredient of this food was vegetables. In particular, Japanese radish was used in many recipes during the research period. Beef, pork, and chicken were used in many recipes involving boiled and seasoned food. The frequency of use of each type of meat changed every year. The frequent inclusion of recipes for boiled and seasoned food and the changes in the main ingredients of these recipes reflected a change in eating habits and a preference for the simple taste of these healthy foods.

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