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Summary: In this study, the effects of superfine grinding on the structural and physicochemical properties of bitter melon polysaccharides (BPS) were investigated, and Caenorhabditis elegans model was used to evaluate fat‐lowering bioactivities of BPS. Results illustrated that superfine grinding resulted in high extraction of BPSs yielding with altered microstructure, different monosaccharide compositions and molecular weights. In addition, improved water/oil‐holding capacity, solubility and swelling capacity of polysaccharides were observed following superfine grinding. Furthermore, C. elegans study revealed that BPSs exhibited strong inhibitory effects on lipid accumulation, especially BPS‐25 (extracted from bitter melon treated with superfine grinding) reducing the triglyceride content from 9.49 to 1.85 mg g−1.prot. Mechanistic study showed that the lipid‐lowering effects of BPSs largely dependent on the insulin signalling pathway, fatty acid oxidation or lipolysis pathways. In all, our study underscore that superfine grinding can effectively improve the lipid‐lowing effects of bitter melon polysaccharides. [ABSTRACT FROM AUTHOR]

Red rice is a kind of whole grain with health benefits. Probiotic fermentation is widely applied to promote nutrient release from cereals and improve bioactivity. The study aims to investigate the impact of Lactiplantibacillus plantarum (L. plantarum) dy‐1 fermentation on the bioactivities, bioaccessibility, and lipid‐lowering activities of red rice. Results indicated that fermentation significantly increased the protein and total phenolic content by 1.7 and 1.4 times of red rice, as well as the content of essential and nonessential amino acids. Fermentation remarkably increased the bioaccessibility of phenolics and the antioxidant capacity of red rice during in vitro digestion. Additionally, Caenorhabditis elegans study revealed that fermented red rice extract reduced the triglyceride content, alleviated fat deposition, and regulated lipid metabolism by altering the genes in the fatty acid oxidation and synthesis, such as daf‐16, mdt‐15, nhr‐49, fat‐5, fat‐7, and hosl‐1. Therefore, L. plantarum dy‐1 fermentation was beneficial for improving bioaccessibility and lipid‐lowering activities of red rice, which will provide a reference for utilization of red rice as a functional food. [ABSTRACT FROM AUTHOR]

A phosphine‐catalyzed intermolecular annulation reaction of functionalized ortho‐aminoacetophenones with alkynones has been disclosed in this paper. A variety of 2‐alkynylquinolines and benzo‐fused indolizine were selectively afforded in moderate to good yields at different reaction temperatures and with different phosphine catalysts via the in situ generated zwitterionic intermediate derived from alkynone and phosphine. [ABSTRACT FROM AUTHOR]

BACKGROUND Texture softening is always a problem during chilling of grass carp fillets. To solve this problem and provide for better quality of flesh, understanding the mechanism of softening is necessary. Gelatinolytic proteinases are suspected to play an essential role in the disintegration of collagen in softening of fish flesh. In the present study, the types and contribution of gelatinolytic proteinases in chilled fillets were investigated. RESULTS: Four active bands (G1, 250 kDa; G2, 68 kDa; G3, 66 kDa; G4, 29 kDa) of gelatinolytic proteinases were identified in grass carp fillets by gelatin zymography. The effect of inhibitors and metal ions revealed that G1 was possibly a serine proteinase, G2 and G3 were calcium‐dependent metalloproteinases and G4 was a cysteine proteinase. The effect of the inhibitors phenylmethanesulfonyl fluoride (PMSF), l‐3‐carboxy‐trans‐2,3‐epoxy‐propionyl‐l‐leucine‐4‐guanidinobutylamide (E‐64) and 1,10‐phenanthroline (Phen) on chilled fillets revealed that gelatinolytic proteinase activities were significantly suppressed. Collagen solubility indicated that metalloproteinase and serine proteinase played critical roles in collagen breakdown during the first 3 days, and cysteine proteinase revealed its effect after 3 days. Meanwhile, during chilled storage for 11 days, the final values of shear force increased 19.68% and 24.33% in PMSF and E‐64 treatments when compared to control fillets respectively, whereas the increase after Phen treatment was 49.89%. CONCLUSION: Our study concluded that the disintegration of collagen in post‐mortem softening of grass carp fillets was mainly mediated by metalloproteinase and to a lesser extent by serine proteinase and cysteine proteinase. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]