It has been reported that folate (a vitamin) is involved in a variety of physiological functions and is an essential component for normal fetal development during pregnancy. The Ministry of Health, Labor, and Welfare has provided regarding the ingestion of folate supplements (recommended to reduce the risk of prophylaxis) to women planning a pregnancy. However, these supplements are taken by women at a later stage of their pregnancy. Therefore, awareness about the importance of folate and how it can be obtained from foods on a daily basis are required. In this context, focusing on toasted nori, which has a high folate content, we conducted a study on the differences in the folate content among samples of toasted nori and the relationship between its taste and color, which is an important factor when purchasing nori. Upon measuring the folate levels from 10 samples of different regions and grades, it was revealed that the differences in their maximum and minimum levels were more than twice. A color difference analysis revealed that the brighter the yellow and green colors of the samples, the lower the folate levels, whereas the darker the sample colors, the higher the folate levels. To analyze the taste of nori, the levels of four types of free amino acids, known as taste-active amino acids, present in the nori were measured. The result showed the strongest correlation between the free aspartic acid and folate levels. Hence, our study suggests that consumers must observe the color of the toasted nori during purchase as it is correlated with the folate levels.

　Age-related decline in appetite may lead to a decrease in dietary diversity; however, the associations of appetite and its related factors with dietary diversity remains unclear. With the aim to cross-sectionally investigate these associations in middle-aged and older Japanese community dwellers, this study included 1,287 subjects aged 49-95 years participating in the 9th wave (2018-2022) of the National Institute for Longevity Sciences-Longitudinal Study of Aging. The three appetite-related factors (appetite, hunger sensation, and meal taste) were assessed using the Japanese version of the Appetite Questionnaire (CNAQ-J). Dietary diversity score (DDS) was calculated based on the frequency of consumption of 12 food groups (range: 0-12 points). General linear models were used to examine the associations between each appetite-related factor and the DDS, both for all participants and when stratified by age (<65 years and ≥65 years). Adjustment variables included sex, age, body mass index, alcohol intake, smoking habits, exercise habits, annual household income, depressive symptoms, eating alone, medical histories, and remaining two appetite-related factors. The mean (SD) age of all subjects was 65.7 (10.4) years. The DDS in older adults (8.03 ± 1.89 points) was higher than that in the middle-aged adults (7.24 ± 1.89 points). The DDS showed a positive association with appetite and hunger sensation in all subjects. In older adults, those who reported that their meals were tasty had the highest DDS, even after adjusting for the other two appetite-related factors. While overall appetite ,intensity was positively associated with dietary diversity, the associated factors varied with age. Particularly, meal taste may have an association with dietary diversity in older adults.

　We investigated gluten-free trends by conducting quantitative text analysis of purchase motivation, number of products, and changes over time from 2010 to 2022 in the number of word-of-mouth instances for each product category found in reviews for foods sold on internet sales sites using 'gluten-free' as a keyword. The number of word-of-mouth instances for products sold with 'gluten-free' as a keyword increased from around 2015. This coincided with the release of books in Japan claiming that a gluten-free diet, which had been popular in the United States since around 2013, would help with weight loss and general well-being. Around the same time, there was an increase in word-of-mouth for foods sold as allergy substitutes, motivating people to adopt a gluten-free lifestyle. The number of products sold with 'gluten-free' as a keyword has increased since around 2013, but only about 40% of products include words related solely to 'gluten-free' in their product names from 2018. The products are not marketed solely as 'gluten-free', but also use other words such as those associated with rice. Our findings suggest that the gluten-free trend that started around 2015 expanded in Japan in response to the gluten-free boom overseas. Sellers should have sufficient knowledge of gluten-free standards and labeling rules for specific raw materials.

　The government recommends that each household should maintain a seven-day food supply in preparation for disasters. However, to facilitate this, several challenges must be addressed, such as securing storage space, cost, and renewal of stockpiles. Rolling stock is recommended as a viable solution. This study investigates the safety of frozen foods to determine their suitability for inclusion in rolling stock food.

　The temperature of the frozen food (gyoza) was monitored over time, following the power supply was stopped. We also examined hygiene indicator bacteria, including general bacteria, coliform group, and Staphylococcus aureus, to assess safety. Then, we examined if it was possible to heat the food to a temperature range that effectively sterilizes bacteria causing food poisoning, by cooking it in a plastic bag.

　Our findings show that when the freezer was fully loaded with frozen gyoza, the temperature reached 0 °C after 77 h after the power supply was stopped. When the freezer was opened and almost half of the frozen gyoza was removed, the temperature reached 0 °C within 56 h. The count of viable hygiene indicator bacteria conformed to the standards for frozen foods, ensuring that the food was ready for consumption 72 h after the power supply was stopped. Moreover, when heated in a plastic bag, the food reached a temperature of 75 °C, which can sterilize bacteria causing food poisoning, after 35 min.

　In conclusion, our study demonstrated that frozen food can be safely consumed for up to 72 h, following the power supply was stopped, and it can be used as a rolling stock food in the disaster events.