Rice bean (Vigna umbellata) is a medicinal and dietary legume rich in polyphenols. In this study, the free and bound phenolics in rice bean were extracted by water, 80% methanol, and acid, base, and composite enzymatic hydrolysis, respectively. The polyphenol profiles of the extracted fractions were analyzed. The outcome demonstrated that base hydrolysis was the most effective way to liberate bound phenolics from rice bean (14.18 mg GAE/g DW), which was 16.68 and 56.72 folds higher than those extracted by acid and enzymatic hydrolysis, respectively. The bound polyphenols released by base hydrolysis contributed to 71.15% of the total phenolic content. A total of 35 individual phenolics was identified, of which isoquercitrin, procyanidin B1, rutin, taxifolin, and catechin were the main monomeric phenolics in the free fraction, while gallic acid, protocatechuic acid, p-hydroxybenzoic acid, catechin, and phloroglucinol were the main monomeric phenolics in the bound fraction. In comparison to the free phenolics extracted by water and 80% methanol and the bound phenolics extracted using acid and composite enzymatic hydrolysis, the bound phenolics from base hydrolysis had a superior antioxidant capacity. The antioxidant activity of rice bean is primarily attributed to individual phenolics such as catechin, abundant both in free and bound fractions, and also p-hydroxybenzoic acid, gallic acid, and protocatechuic acid in bound fractions. The bound phenolics of rice bean were first reported and showed large differences with the composition of free phenolics. This work suggests that the bound fraction of rice bean must be taken into account in assessing its potential benefits to health.

Longan (Dimcarpus longan Lour.) is a kind of traditional fruit used as a medicine and a food. Fresh longan is primarily consumed as a fruit, whereas dried longan is commonly employed for medicinal purposes. The differences in the immunomodulatory activities and mechanisms of polysaccharides between dried and fresh longan remain unclear. The present study comparatively analyzed the mechanisms of macrophage activation induced by polysaccharides from dried (LPG) and fresh longan (LPX). The results revealed that LPG and LPX differentially promoted macrophage phagocytosis and the secretion of NO, TNF-α, and IL-6. RNA-seq analysis revealed that LPG and LPX differentially affected gene expression in macrophages. The LPG treatment identified Tnf and chemokine-related genes as core genes, while myd88 and interferon-related genes were the core genes affected by LPX. A comprehensive analysis of the differentially expressed genes showed that LPG initiated macrophage activation primarily through the TLR2/4-mediated TRAM/TRAF6 and CLR-mediated Src/Raf1 NF-κB signaling pathways. LPX initiated macrophage activation predominantly via the CLR-mediated Bcl10/MALT1 and NLR-mediated Rip2/TAK1 MAPK and NF-κB signaling pathways. Interestingly, the non-classical NF-κB signaling pathway was activated by polysaccharides in both dried and fresh longan to elicit a slow, mild immune response. LPG tends to promote immune cell migration to engage in the immune response, while LPX facilitates antigen presentation to promote T cell activation. These findings contribute insights into the mechanisms underlying the differences in bioactivity between dried and fresh longan and their potential applications in immune-enhancing strategies and functional-food development.

Fresh rice noodles (FRNs) are widely consumed starch based foods whose quality and shelf life depend strongly on the structural stability of the starch matrix. γ -Irradiation can effectively extend the shelf life of FRNs but induces starch depolymerization, altering starch structure and functionality. This study investigated the effects of hydroxypropyl starch (HPS) incorporation on the molecular characteristics, ordered structure, and thermal and pasting properties of starch in γ -irradiated FRNs. The results showed that 6% HPS incorporation produced the most balanced structural and functional characteristics. Overall, HPS increased molecular size parameters, apparent α -1,6 linkage ratio, short range molecular order, relative crystallinity, and peak viscosity, while decreasing the long B3 chains proportion and gelatinization enthalpy. Correlation analysis showed that A chains were positively correlated with short-range order, relative crystallinity, and swelling power, and negatively correlated with peak viscosity, whereas B3 chains showed the opposite trend, suggesting that the superior pasting behavior at 6% HPS was associated with a more balanced amylopectin chain architecture. HPS incorporation altered the relative amylopectin chain length distribution of the starch system, with 6% addition increasing the proportion of A and B1 chains relative to B2 and B3 chains, thereby favoring granule swelling and paste viscosity development. However, excessive HPS addition over-enriched short chains and weakened paste stability. These findings clarify the structure–function relationships in γ -irradiated starch systems and provide a scientific basis for optimizing the quality of irradiated rice-based products.