Pomegranate peel pectin is an important acidic anionic plant polysaccharide which can be used as a natural emulsifier. In order to study its emulsifying properties, this paper systematically analyses pomegranate peel pectin samples from Chinese Xinjiang, Sichuan and Yunnan provinces, through rheometer, interfacial rheometer, Zetasizer Nano-ZS and mastersizer. It is shown that pomegranate peel pectin can effectively reduce the oil-water interfacial tension, reaching an emulsion droplet size of only 0.507 μm, 0.669 μm and 0.569 μm, respectively, while the pectin concentration is 1.5% and the oil phase (MCT) is 10%. It has also shown that the extreme conditions of pH and ion strength can not significantly change its emulsion stability. However, freeze-thaw cycles can cause the pomegranate peel pectin emulsion to become less stable. Furthermore, the effects of decolourization, protein removal and dialysis on the emulsifying properties of pomegranate peel pectin are investigated using mastersizer rheometer and interfacial rheometer. It is found that the protein and pigment in pomegranate peel pectin have little effect on its emulsifying properties, while the results from dialyzed pectin show that the small molecule substances can reduce the emulsion particle size and increase the emulsion stability. The research outcomes of this study provide technical support for the further application of pomegranate peel pectin in the food industry.

Walnut peptides (WP) were prepared from walnut protein. Single-factor experiments and Box–Behnken response surface methodology were used to optimize the preparation of walnut peptide–calcium chelate (WP–Ca), followed by evaluation of its structural characteristics, stability, and in vitro digestion properties. The optimized conditions were a WP concentration of 27.8 mg/mL, reaction temperature of 55.7 °C, pH 7.9, reaction time of 10.1 min, and WP-to-CaCl₂ mass ratio of 3:1, giving an experimental Ca²⁺ chelation rate of 54.21%. Chelation altered the amino acid composition, particle size, functional group environment, molecular organization, microstructure, and surface charge of the sample. WP–Ca maintained relatively high calcium retention rates under neutral and low-temperature conditions. Calcium release rates during simulated gastric and intestinal digestion were 81.90–92.38% and 39.05–48.57%, respectively, and WP–Ca retained antioxidant activity. These findings provide a basis for developing walnut peptide–calcium nutritional products.

The effects of low (4 °C) versus ambient (25 °C) temperature on cell wall turnover, and redox homeostasis in ‘Jin’Aofen’ figs were investigated. Compared with 25 °C, storage at 4 °C reduced decay and respiration rates, delayed firmness loss and color deterioration. It also suppressed PG, PME and CEL activities, maintained higher contents of protopectin and cellulose; and slowed soluble pectin accumulation. Storage at 4 °C maintained higher activities of SOD, CAT, POD, APX and GR. It also preserved the levels of non-enzymatic antioxidants, including TPC, TFC, ASA GSH. Meanwhile, it reduced H₂O₂ and O₂⁻ production and inhibited MDA. In addition, storage at 4 °C suppressed PPO, thereby alleviating enzymatic browning. Overall, storage at 4 °C maintained postharvest quality of figs by coordinately inhibiting cell wall degradation and regulating antioxidant metabolism.