Dried fish is consumed in many regions of the world. Conventional dried fish is dried or salted for preservation, although dried fish with a low salt concentration has recently been produced because of increased health consciousness by consumers (Hamada-Sato et al., 2012). In addition, the use of new technologies, such as microwave vacuum drying and essential oils, and antioxidants, such as vitamin C and tea polyphenols, has been studied for the production of dried fish (Fu et al., 2015;Viji et al., 2019), and there are nutritionally important components such as polyunsaturated fatty acid (docosahexaenoic acid and eicosapentaenoic acid), taurine, and peptides in fish (Ebizuka et al., 2016). However, the consumption of marine products containing dried fish has decreased recently in Japan (Ministry of Agriculture, Forestry, & Fisheries, 2018). Therefore, the development of new dried fish products is needed to activate the fishery industry (Takiguchi &

Demand for aseptically steamed rice products has been increasing rapidly in Japan over the past 10 years. In our previous study, we showed that proteolytic Clostridium botulinum produce toxins in steamed rice products packaged under a modified atmosphere of < or =0.3% oxygen. In the present study, we examined the effect of pH to control botulism risk in steamed rice products packaged under modified atmosphere (5% CO2 and 95% N2 as the balance) with the inclusion of a deoxidant pack to produce an oxygen concentration of < or =0.3%. A mixture of 10 strains of proteolytic C. botulinum (5 type A strains and 5 type B strains) was inoculated into steamed rice products at pH values between 4.6 and 6.8 prior to packaging. All samples were stored at 30 degrees C for 24 weeks. Samples at higher pH showed earlier starts of neurotoxin production. Neurotoxin was detected after 2 weeks of incubation in samples at pH 5.4 or above, whereas it took 4 weeks for the toxin to be detected in samples at pH 5.2 to 5.3 and 12 weeks in samples at pH 5.0 to 5.1. In samples at pH 4.9 or below, no toxin was detected during the experimental period. Apparent sample spoilage did not occur before C. botulinum produced neurotoxin in most of the samples. Based on these results, we conclude that aseptically steamed rice products must be packaged at pH 4.9 or below under modified atmosphere containing < or =0.3% oxygen, with the inclusion of a deoxidant pack.

Asparagus (Asparagus officinalis L.) has a characteristic flavor and useful components, although the lower stem is not suitable for eating because it has a fibrous skin like wood, being normally discarded. Therefore, to propose drying and roasting as methods for using the hard lower stem of asparagus, usually discarded, useful components in the asparagus stem after drying and roasting were analyzed. The rutin content was decreased significantly by drying and roasting. The ascorbic and folic acids contents were almost unchanged by drying but decreased by roasting. The fructose content was increased by drying, although glucose was almost unchanged. Both were decreased significantly by roasting. The sucrose content was increased by drying but unchanged by roasting. The increase or decrease in some free amino acids were caused after drying, and most of free amino acids disappeared after roasting. Furthermore, characteristic volatile compounds derived from the Maillard reaction were caused by drying and roasting. Most of the useful components in the hard lower stem of asparagus can be concentrated by drying, and characteristic volatile compounds be added by drying and roasting. Therefore, it is promising that the asparagus stem, an unused resource, is able to be utilized as a useful food material by drying and roasting