The increasing world population requires a sufficient production of crops and animals for food use, and the production needs to be environmentally and socially sustainable. Meat analogues made from plant, fungal, and insect proteins are expected to serve as a substitute for animal meats. Plant-derived proteins (plant proteins), which are attracting great attention, are focused on in this review as meat and dairy substitutes, since plant proteins may help mankind as a substitute for animal proteins to achieve a secure supply of proteins worldwide while also responding to the demand for plant-derived products by vegetarians and vegans. Aspects discussed in this review also include the role of soybeans as one of the key plant protein sources; its recent production in the world has been increasing due to the extended harvest area of genetically modified soybean varieties. Plant proteins can be processed by extrusion to give meat-like textures. In addition, plant proteins from soybean, wheat, and other plants have traditionally been utilized via fermentation in Japan and other Asian countries. It is expected that the fermentation methods used for those traditional plant protein foods as well as other processing technologies could be applied to produce novel foods based on plant proteins.

Leaf mustard (Brassica juncea) is a kind of cruciferous vegetable that is commonly consumed in Okinawa prefecture. Cruciferous vegetables are known to contain glucosinolate, which is hydrolyzed to isothiocyanate by the enzyme myrosinase; this enzyme derives from the plants themselves or from human intestinal microorganisms. Furthermore, leaf mustard is expected to have some useful functions on human health due to its ingredients, such as sinigrin (a characteristic glucosinolate in leaf mustard), allyl isothiocyanate (AITC), and γ-aminobutyric acid (GABA). The purpose of this study is to clarify the effects of moist heat cooking methods on functional components (sinigrin, AITC, and GABA) contained in leaf mustard. Leaf mustards (grown at the Okinawa Prefectural Agricultural Research Center) were cooked by steaming or boiling with different heating times. Quantitative measurements of sinigrin, AITC, and GABA were carried out by reversed-phase high-performance liquid chromatography. The sinigrin content was not affected by steaming, regardless of heating time. Moreover, myrosinase was deactivated by steaming for 90 seconds or more. During the boiling of leaf mustard, dissolution into the water was deduced to be the main causal factor of the loss of water-soluble components, such as sinigrin, and the effect of decomposition by heat was relatively small. The GABA content was significantly decreased by both moist heat cooking methods. Steaming retained more of the GABA content than boiling for 60 seconds. We concluded that steaming for a sufficient amount of time for deactivating myrosinase is necessary to retain the sinigrin content. Furthermore, over a short heating time, steaming is a better cooking method than boiling to retain the GABA content.

To estimate the behavior of radioactive strontium (⁹⁰Sr) from Japanese green teas (Camellia sinensis) in infusions, the natural stable Sr contained in the infusions was determined by ICP-AES. Ca and other inorganic elements that can be determined simultaneously were also measured for comparison to the behavior of Sr. Seven types of green teas were examined, and the infusions were brewed under the normal conditions for each type. The food processing retention factor (Fr, ratio of the amount of the element in the infusion to the amount in green tea) was generally K, Ni＞Zn＞Mg＞P＞Mn＞Al＞Ba, Sr, Cu, Ca＞Fe. The Fr value for Sr for the first infusions was from less than 0.01 up to 0.07 depending on the type of green tea and its brewing conditions. Sr was found at a low level among the inorganic elements determined in this study; therefore, even in the case of ⁹⁰Sr, the Fr was estimated to be as low as that of natural stable Sr. The similarity in the behaviors of Sr and Ca in many green teas, except for "Hojicha", indicated that Ca could be used as a substitute to determine the behavior of ⁹⁰Sr.

“Geographical Indication (GI) Hokkaido” has been operating since 2018 with the aim of ensuring the quality and branding of wine produced in Hokkaido. The amount of volatile acid, mostly acetic acid, should be regulated for GI certification since excessive amounts contribute to objectionable off-flavors of wine. In this study, a new application of gas chromatography (GC) followed by ethyl acetate extraction was examined as a simple and reliable method of measuring acetic acid in wine. Higher reproducibility (RSD: 2.1 % to 4.4 %) was observed in three types of wine samples with different acetic acid concentrations (254 to 756 µg/mL), accompanied by satisfactory recoveries (98 % to 102 %). The determination range was 254 to 1 236 µg/mL, well covering the required criterion (＜1 000 µg/mL). Significant correlations were recognized between the GC method and high-performance liquid chromatography (HPLC), which has been approved as a screening method for measuring volatile acid in GI wine (r＝0.993, p＜0.0001, n＝22), and also the distilled-titration method (r＝0.974, p＜0.0001, n＝19). Thus, the proposed GC method for the determination of acetic acid in wine samples is simple and reliable; furthermore, it will be useful as an alternative reference based on a different principle to the traditional titration method or the prevalent HPLC method.

Few studies have comprehensively screened for ionic small molecules with high water-solubility in the traditional Japanese mandarin orange Citrus unshiu Marc. Here, we performed metabolomic analysis with capillary electrophoresis-mass spectrometry (CE-MS) to comprehensively identify and accumulate gross quantitative data for water-soluble components in the different varieties of ‘Aoshima’ and ‘Okitsu/Miyagawa Wase’, according to grade and processing method. In this analysis, we focused on 151 components and showed the characteristic components related to each different variety and processing method, e.g., Met, Gly, and Asp in var. Wase; ornithine, putrescine, synephrine, and Gln in var. Aoshima; and pyroglutamate, GABA (γ-aminobutyric acid), and malonate in the juice of var. Aoshima. Furthermore, we conducted processing tests and identified components that were affected by squeezing or heating. These data represent basic data for further investigation of the metabolism of C. unshiu Marc. or chemical changes in their components due to external factors such as processing.

When flour and a 10 % saline medium was cultivated at 30 °Cfor 4 days, salt-tolerant yeast became the main species present (9×10⁸ cfu/mL). A total of 147 yeast strains were isolated from the 10 % saline culture, and 24 strains were identified to be Hyphopichia burtonii (corresponding to 16 % of the isolated strains). Adding the 10 % saline culture to dough produced a softer dough that expanded better. Bread was made by the straight dough method using the 10 % saline culture and dry yeast. The specific volume of the bread (4.43 cm³/g) prepared by this method was 27 % larger than that of bread without the 10 % saline culture (3.47 cm³/g), and the bread crumb hardness was reduced. Similar results were obtained when H. burtonii M2 was used to make bread instead of the 10 % salt culture; however, the specific volume was slightly lower (4.11 cm³/g). The 10 % saline culture, an enrichment culture of salt-tolerant yeast, can be used as a novel liquid seed.