We compared the quality parameters of the large red-fleshed watermelon cultivar 'Matsuribayashi 777'; sugar content and composition, Brix, sweetness, carotenoid content, and amino acid content. Immature and mature fruits were harvested 30 days after pollination (accumulative temperature about 750℃) and 42 days after pollination (accumulative temperature about 1,150℃), respectively. Immature fruits were allowed to ripen in a cool, dark place for 17 days, with the same accumulative temperature of mature fruits (after-ripening fruits). Brix, sucrose content, and total sugar content of the after-ripening fruits were significantly lower than those of the mature fruits, but fructose content was significantly higher, and there was no difference in sweetness. β-carotene content of the after-ripening fruits were not higher than the mature fruits, but total lycopene content had same levels. In general, citrulline (Cit), glutamine (Gln), and arginine (Arg) content accounted for about 70% of the total amino acid content. Gln content was the highest in the mature fruits and tended to decrease in after-ripening fruits. Cit and Arg contents were not significantly different among any of the fruits. These results suggest that ripening technology could be applied to watermelons if the harvest time and ripening conditions for immature fruits are optimized. The establishment of this technology is expected to reduce the occurrence of overripe fruits. In addition, it would shorten the cultivation period and lead to a reduction in field management efforts.

　In radical scavenging reactions under conditions where polyphenols and thiols coexist, not only does each demonstrate an antioxidant reaction, but the synergistic effect between both is exhibited as thiols regenerate polyphenols. This study combined polyphenols and cysteine (Cys) or glutathione (GSH) in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging reaction system and analyzed the combined effect by median effect analysis. In combination with Cys, it showed a strong synergistic effect with flavanols having galloyl groups, such as epicatechin gallate (ECg) and epigallocatechin gallate, and flavonols having pyrogallol structures, such as myricetin, at high concentration ranges. Meanwhile, in combination with GSH, a strong synergistic effect was shown with polyphenols having catechol structures, such as catechin, epicatechin, ECg and quercetin. In both cases, it was suggested that thiols strongly exhibit synergistic effects when combined with polyphenols with catechols, pyrogallols, or galloyl groups having a high radical scavenging capacity and low redox potential. Therefore, it was suggested that the nucleophilic reaction of Cys and GSH with polyphenols having these properties and the regeneration of phenolic hydroxy groups exert the synergistic effect of radical scavenging activity.

　Bacteriocins produced by lactic acid bacteria are natural antimicrobials that have long been consumed via fermented foods. Because of their safety and excellent properties, it has been the focus of renewed efforts to identify novel bacteriocins, and their producing microorganisms as an effective natural food preservative. In this study, we report the first isolation of a bacteriocin-producing lactic acid bacterium, named Lactococcus lactis subsp. lactis NFH-NM9, from Mackerel Nare-zushi in Wakasa, Japan. The analysis of the estimated molecular weight and structural gene sequence revealed that the bacteriocin produced by the strain is nisin F. For the first time, the culture supernatant of this strain was found to exhibit antibacterial activity against Listeria monocytogenes, albeit against some strains. In the future, the precise antimicrobial activity and antimicrobial spectrum obtained by isolation and purification of nisin F are expected to expand the range of applications of this bacteriocin.

　Periodontal disease is a major public health problem that affects over half of the adult population worldwide. Lipopolysaccharides (LPS), produced by the periodontopathic bacterium Porphyromonas gingivalis, induces the expression of inflammatory cytokines that promote inflammatory bone destruction. Buckwheat bran (BB), a traditional pseudocereal crop, belongs to a group of grains having high nutritional value and has been reported to be an effective agent. However, the anti-inflammatory effects of BB on Porphyromonas gingivalis-lipopolysaccharide (P.g.-LPS) -stimulated human gingival fibroblasts (HGFs) have not been completely elucidated yet. This study determined that the buckwheat bran flour hydrolysate powder (BBFHP) significantly inhibited the P.g.-LPS-induced production of inflammation-associated genes, including interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α) and Toll-like receptor 4 (TLR4). Moreover, BBFHP suppressed P.g.-LPS-induced NF-κB signaling. The results suggest that the BBFHP attenuates the production of inflammation-associated molecules and suppresses the activation of NF-κB in P.g.-LPS treated HGFs.