Covalent conjugation with polyphenol reduced the sensitization of walnut and ameliorated allergy by enhancing intestinal epithelial barrier in mice.

In order to reduce the sensitization of walnut protein (WP), the effects of the interaction between WP and (-)-Epigallocatechin gallate (EGCG), quercetin, trans-ferulic acid, and resveratrol were investigated. Covalent and non-covalent conjugations were compared. The results suggested that covalent conjugation reduced the free amino acid content, sulfhydryl content, and surface hydrophobicity. When compared to non-covalent conjugation, covalent modification showed a lower IgE binding capacity, accompanied by changes in protein conformation. Moreover, animal experiments revealed that there were up-regulation of transforming growth factor-ß, T-box expressed in t cells, and forkhead transcription factor Foxp3 mRNA expression, and down-regulation of IL-4, IL-17, GATA binding protein 3 and retinoid-related orphan nuclear receptor γt mRNA expression in the conjugate groups. These results suggested that covalent conjugation of polyphenols, especially EGCG, likely ameliorated allergy by promoting Th1/Th2 and Treg/Th17 balance and alleviating allergy-induced intestinal barrier damage, which might be a support in reducing the allergenicity of WP.

High Hydrostatic Pressure Treatments Improved Properties of Fermentation of Apple Juice Accompanied by Higher Reserved Lactobacillus plantarum.

This study aimed to assess the feasibility of high hydrostatic pressure (HHP) treatment to obtain high quality juice, and prepared functional apple juice using fermentation technology. The physicochemical properties of HHP (10 min) pasteurized and pasteurized (85 °C, 15 min) apple juices were compared during fermentation. Moreover, the survival of Lactobacillus plantarum after fermentation under simulated gastrointestinal conditions was evaluated. Results showed that HHP-treated apple juice had better properties than that of pasteurized in terms of color difference, total phenol content, and antioxidant activity. After fermentation, about 2.00 log CFU/mL increase in viability of cells was observed and there was around 0.8 reduction in pH value, and the antioxidant capacities were also significantly improved. Additionally, the content of caffeic acid, ferulic acid, and chlorogenic acid significantly increased after 24 h of fermentation. The survival of Lactobacillus plantarum in simulated gastric fluid reached 97.37% after fermentation. Overall, HHP treatment is expected to be a substitute technology to pasteurization in order to obtain higher quality fermented fruit juice. This study could also be helpful for exploitation of fermented juice.

The inhibition of pectin oligosaccharides on degranulation of RBL-2H3 cells from apple pectin with high hydrostatic pressure assisted enzyme treatment.

The conditions for the preparation of pectic oligosaccharides (POS) by high hydrostatic pressure-assisted enzymatic (E-HHP) method were explored. The optimal conditions consisted of the pressure of 350 MPa for 20 min, and enzymolysis for 60 min with 0.011 U/mL enzyme. The products were isolated by ion exchange chromatography, galacturonic acid, di- and tri-galacturonides (Tri-GalA) with high purity were obtained. Additionally, the effects of POS on activation and degranulation of RBL-2H3 mast cells were investigated. It was found that Tri-GalA and POS could attenuate the release of ß-hexosaminidase and histamine, reduce the production of IL-4 and inhibit the extracellular Ca2+ influx of RBL-2H3 cells. Notably, 150 µg/mL POS significantly alleviated the IgE-mediated allergic reaction of RBL-2H3 cells. These results indicate that POS could be used as an inhibitor in regulating mast cell-mediated allergic inflammatory responses.