In order to explore the quality evaluation indicators of Phyllanthus emblica L. preserved fruit and establish an evaluation system, taking eight commercially available kinds of P. emblica L. preserved fruit as samples, this study measured and analyzed 20 quality indicators, including fuzzy mathematical sensory evaluation, color values (L^*, a^*, b^*, C^*, and h^* values), texture (hardness, adhesion, cohesion, elasticity, and chewiness), and physicochemical properties (moisture, total sugar, reducing sugar, total acid, ascorbic acid, total phenols, flavonoids, ABTS⁺, and DPPH radical scavenging rate). Correlation analysis, principal component analysis, and cluster analysis were used to analyze the quality indicators and screen out the key quality evaluation indicators of P. emblica L. preserved fruit. The results showed that there were varying degrees of variation in the quality indicators of the eight commercially available varieties, with a coefficient of variation ranging from 6.42% to 56.34%. Among the color parameters, a^* showed the largest change, there were significant differences in hardness, adhesion, and chewiness among the texture parameters, and there were also significant changes in the content of moisture, total sugar, total acid, ascorbic acid, and total phenols among the physicochemical parameters. Among the 20 quality indicators, there was a significant correlation (P<0.05) between 22 pairs of indicators, and a highly significant correlation (P<0.01) between 60 pairs of indicators. Sensory evaluation was highly positively correlated with moisture content, ascorbic acid content, and L^* (P<0.01), while hardness was highly negatively correlated with sensory evaluation (P<0.01). The principal component analysis of quality indicators extracted four principal components, with a cumulative contribution rate of 92.77%. Using partial least squares analysis, seven key quality indicators were obtained and validated using cluster analysis, and they could distinguish different qualities of P. emblica L. preserved fruit effectively. Therefore, based on multivariate statistical analysis, it was ultimately determined that moisture content, ascorbic acid content, DPPH radical scavenging rate, L^*, h^*, hardness, and chewiness were key quality indicators for evaluating the quality of P. emblica L. preserved fruit. The research results of this study could provide a theoretical basis and scientific basis for the quality evaluation and processing of P. emblica L. preserved fruit.

To investigate the effects of different fixation methods on the flavour of flat-shaped green bud tea, high-performance liquid chromatography (HPLC), headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS) were conducted to analyse the biochemical components and aroma changes during processing. The results showed that microwave supplementary fixing improved the quality of the soup color, aroma, and taste of the flat-shaped green bud tea. It benefited the transformation and generation of tea polyphenols, free amino acids and soluble sugars in the processed tea, as well as the later generation of catechin (C), gallocatechin (GC) and epicatechin (EC) during the processing. A total of 972 and 966 volatile metabolites were detected in the control group (CK) and the microwave supplementary fixing group (WB) respectively. In the two fixation treated groups, significant differences in volatile metabolites were detected among the fresh leaves, fixation leaves and processed teas. Microwave supplementary fixing enriched the types of tea aroma, with more differential metabolites between fixation leaves and processed tea identified than those between fixation leaves and fresh leaves. Analysis of the relative odor activity value (rOAV) of the differential metabolites showed 6 and 9 differential metabolites with rOAV>1 from the CK group and the WB group respectively, which were speculated to be the key aroma substances responsible for the aroma changes in each treatment. Among them, 1-decanol, (E)-3,7-dimethyl-2,6-octadialdehyde, and citral mainly contributed to the aroma and flavor similar to orange, while p-cymene, methyl anthranilate, and o-cymene exhibited a mild and pleasant aromatic, orange, and floral flavor. They were the main substances responsible for the differences in the aroma quality of the processed teas by different fixation methods. This study provided a theoretical basis for the generation of the different characteristics of flat-shaped green bud tea and the optimization of their processing technology in the Sichuan-Chongqing region.

This study aimed to isolate a yeast strain capable of producing exopolysaccharide (EPS) from vineyard soil. The isolated EPS-producing yeast was identified through morphological observation and phylogenetic analysis based on 16S rDNA sequencing using the Neighbor-joining method. On this basis, EPS produced by PFY49 (PFY49-EPS) was separated and purified by Sephadex G-100 gel column, and its structure was characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy and atomic force microscopy. The results showed that the strain was Sporidiobolus pararoseus, named PFY49, with NCBI GenBank accession number MW784627.1. In addition, the weight average molecular weight of PFY49-EPS was 3.63×10⁵ Da, mainly composed of polysaccharides such as mannose, glucuronic acid, glucose, galactose, and fucose. It was an O-glycosidic linked α-, β- pyranose without a triple helix structure and mainly existed in a disordered amorphous structure. Scanning electron microscopy and atomic force microscopy revealed that the surface of PFY49-EPS was relatively rough and uneven, covered with small holes and films, forming sharp or spike-like structures in aqueous solutions. This study reveals the structural characteristics of PFY49-EPS, providing a theoretical basis for the subsequent structural functional research of S. pararoseus EPS.

In this experiment, myofibrillar proteins were extracted from chicken breast meat to prepared emulsions. The effects of different concentrations of citrus fiber (0%, 1.5%, 3%, 4.5%, CF) on the stability of chicken myofibrillar protein (MP) emulsions under low-salt conditions (0.3 mol/L NaCl) were investigated by measuring the apparent stability, Turbiscan stability index, droplet size, rheological properties, microstructure of emulsion and the content of adsorbed protein in the oil-water phase. The results showed that with the increase of citrus fiber concentration, Turbiscan stability index value and oil droplet size of the emulsions gradually decreased, while the apparent stability, apparent viscosity, storage modulus, loss modulus, and adsorbed protein content of the emulsion layer obviously increased. Laser confocal results showed that myofibrillar proteins were uniformly distributed around the oil droplets, and cryo-electron microscopy results showed that the oil droplets were uniformly distributed in the three-dimensional network structure formed by citrus fibers. When the addition amount of citrus fiber was 4.5%, the prepared emulsions reached a relatively stable state after being stored at 4 ℃ for 7 days, and no emulsion stratification was observed. These above results indicate that citrus fiber might be a potential emulsifier in improving the stability of low-salt myofibrillar protein emulsions.

The objective of this study was to investigate the effects of neutral proteases from different sources on the textural properties and flavor compounds of high-protein fermented milk, so as to improve the taste, flavor, and drinking experience of high-protein fermented milk. In this study, two neutral proteases—ADMIL (AD) and Galaya smooth (GS)—were added at mass concentrations of 0.02% and 0.012%, respectively, to a high-protein yogurt base with a protein content of 6 g/100 g. After fermentation at 42 ℃, the final products were characterized for textural properties including viscosity, gel strength, hardness, friction coefficient, and water-holding capacity, while changes in flavor compounds induced by the two enzymes were also analyzed. Results showed that compared with the control sample without protease addition, the AD-treated and GS-treated samples exhibited decreases in viscosity by 8.9% and 5.3%, respectively, a 42.1% reduction in gel strength, and decreases in hardness by 33.3% and 41.7%, respectively. Particle size and friction coefficient were also reduced, while water-holding capacity slightly decreased with no significant difference (P>0.05). Sensory evaluation indicated that the addition of neutral proteases improved the drinking experience of high-protein fermented milk. Further analysis of volatile compounds revealed an increase in the content and variety of flavor compounds in both enzyme-treated samples. Among them, the concentrations of flavor compounds such as n-pentanoic acid, hydroxyacetone, butyric acid, 2-hydroxy-3-pentanone, sec-butanol, myristic acid, benzoic acid, 2,3-pentanedione, (+)-limonene, and 3-hydroxy-2-butanone were significantly increased in the AD-treated sample. In the GS-treated sample, the concentrations of n-pentanoic acid and butyric acid were significantly increased. The AD-treated sample showing a more pronounced flavor enhancement. In conclusion, neutral proteases effectively reduced the viscosity, particle size, and friction coefficient of high-protein fermented milk, significantly improved its flavor, and demonstrated substantial application potential.

To improve the functional properties of Rosa roxburghii Tratt. polysaccharide (RTFP), this study prepared crude polysaccharides (RTFP-40, RTFP-60) using water extraction, which were then separated, purified, and chemically modified to obtain sulfated polysaccharides (S-RTFP-40, S-RTFP-60) and phosphorylated polysaccharides (P-RTFP-40, P-RTFP-60). The effects of chemical modification on their structure and bioactivity were explored through in vitro antioxidant and hypoglycemic experiments. The results showed that both modifications could significantly alter the triple-helix structure of the RTFP-40 and RTFP-60 extracts and introduce sulfate and phosphate groups into the polysaccharide structure. Both modifications significantly improved the in vitro hypoglycemic ability of Rosa roxburghii polysaccharides, with the GDRI indices of S-RTFP-60 and P-RTFP-60 increasing by 8.27% and 3.73%, respectively. All four derivatives enhanced the inhibitory effect on α-amylase, with S-RTFP-40 and S-RTFP-60 increasing it by 15.19% and 41.53%, respectively. Excessive phosphorylation had a negative effect on antioxidant activity. Comparatively, sulfation was more effective than phosphorylation in enhancing both antioxidant and hypoglycemic activities of the polysaccharides, with S-RTFP-60 showing a notable increase in vitro hypoglycemic activity. In summary, sulfation modification is suitable for improving the hypoglycemic activity of Rosa roxburghii polysaccharides.

It was of great significance to explore new dietary fiber resources with excellent functional activity from available materials in nature for improving human diet level based on quinoa dietary fiber, the structure, by Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron micrographs, physicochemical properties, such as viscosity, water-holding capacity and oil-holding capacity, and functional properties of hypoglycemic and antioxidant properties from Agriophyllum squarrosum seeds of three different regions were systematically analyzed in this paper. The results showed that all dietary fibers had typical infrared spectral characteristics of polysaccharides. Compared with quinoa soluble dietary fiber (SDF), Agriophyllum squarrosum SDF had a compact structure, higher mannose content (14.97~16.82 mg/mg) and DPPH free radical scavenging ability (63.18%~63.42%). Compared with insoluble dietary fiber from quinoa (IDF), Agriophyllum squarrosum IDF had more void space, and binding phenol content, water retention capacity, cholesterol adsorption capacity, in vitro hypoglycemic activity, DPPH radical scavenging activity, hydroxyl radical scavenging activity and reducing power were significantly higher (P<0.05) than quinoa soluble dietary fiber. It could be seen that Agriophyllum squarrosum dietary fiber had different morphological structure, physical properties and functional properties from quinoa dietary fiber, and would be a high-quality dietary fiber resource.

To improve the emulsification properties of porcine plasma protein (PPP), this study focused on investigating the physicochemical characteristics and oil-water interface stabilization capabilities of PPP nanoparticles (PPP-NP) formed through thermal treatment under different pH conditions. Firstly, particle size, zeta potential, secondary structure, microscopic morphology, and oil-water interfacial tension reduction capacity of PPP-NP were characterized by the instruments including nanoparticle size analyzer, circular dichroism spectrometer, field-emission scanning electron microscope (FE-SEM) and interfacial rheometer. Subsequently, the Pickering emulsions were fabricated through using PPP-NP as emulsifier, and then the emulsibility and emulsification stability of PPP-NP were evaluated by analyzing the particle size, apparent viscosity, zeta potential, oil droplet morphology of the emulsion during storage. Finally, emulsion stability was quantitatively assessed through a stability analyzer. The results from analyzing the particle size, zeta potential, FE-SEM, interfacial tension indicated that PPP aggregated orderly at pH6.5, and thereby formed the nanoparticles with an average particle size of about 112 nm and a polydispersity index (PDI) of 0.19. The aggregates were uniform in shape and size and showed good dispersibility and strong capability of reducing oil-water interfacial tension. Compared to the control group, the PPP-NP-stabilized Pickering emulsion displayed high viscosity, relatively large droplet size but better uniformity and storage stability. After 28 days of storage at 45 ℃, the emulsion maintained more uniform droplet distribution. The results from confocal laser scanning microscope (CLSM) combined with backscattered light intensity and Turbiscan stability index (TSI) analysis indicated that the corresponding PPP-NP-based emulsions at pH6.5 were very stable, and the oil droplets in it were uniform in size without aggregation. The TSI values of the emulsion were relatively low, which were 71.4% lower than that of the control group. Overall, PPP could aggregate orderly and form the nanoparticles with excellent emulsifying properties through heating the solution at pH6.5, and the finding could provide some valuable insights for the application of PPP as emulsifier in the structural and functional design of food.

This study investigated moisture migration and quality changes in grape during the far-infrared combined heat pump drying process, utilizing low-field nuclear magnetic resonance and imaging techniques to analyze drying characteristics and proton density imaging. The research further examined the microstructure and nutritional quality of raisins subjected to heat pump temperatures of 60, 80, and 100 ℃. The results revealed that the drying endpoint was reached in 600, 540, and 420 min at temperatures of 60, 80, and 100 ℃, respectively. Under varying heat pump temperatures, the low-field NMR T₂ spectra of raisins exhibited a consistent leftward shift, accompanied by a gradual decrease in signal amplitude. The NMR results suggested that the free water on the surface of the raisins was removed first, while internal moisture migrated outward, with an increased migration rate at higher temperatures. Microstructural observations demonstrated that increased heat pump temperatures correlated with increased structural damage to grape cells. At a heat pump temperature of 80 ℃, the L^* value of raisins increased by 11.23% and 4.68% compared to 60 ℃ and 100 ℃, respectively. The total soluble solids (TSS) content rose by 31.42% and 33.45%, and the titratable acid (TA) content decreased by 13.09% and 6.59%. These findings suggested that treatment at 80 ℃ was more effective in preserving the color, total soluble solids content, and in mitigating the degradation of organic acids in raisins. Furthermore, at this temperature, the contents of Vitamin C (V_C), total phenols, total flavonoids, and anthocyanins decreased by 78.28%, 66.01%, 40.59%, and 77.14%, respectively, compared to their levels before drying. The nutritional loss of raisins was minimal at 80 ℃ when compared to 60 ℃ and 100 ℃. In conclusion, 80 ℃ is identified as the optimal temperature for far-infrared combined heat pump drying, serving as a key process parameter for enhancing the quality of grape products.

In this study, we investigated the physicochemical properties and in vitro antioxidant and antidiabetic activities of a green tea dust polysaccharide (GTDP). GTDP was extracted from green tea dust using hot water extraction followed by alcohol precipitation. Its physicochemical characteristics, including chemical composition, rheological properties, thermal stability, and microstructure, were analyzed. The in vitro antioxidant and antidiabetic activities of GTDP were evaluated using ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability, ferrous ion chelating ability (FIC), and glycosylation and α-glucosidase inhibition assays. The results showed that the GTDP yield was 6.50%, with total sugar, uronic acid, protein, and total phenolic contents of 44.73%, 22.58%, 2.92%, and 4.35%, respectively. GTDP contained three polysaccharide fractions with different molecular weights, of which the major component had molecular weight of 88.88 kDa. Monosaccharide composition analysis revealed that GTDP was composed of glucose, arabinose, galactose, rhamnose, galacturonic acid, mannose, glucuronic acid, and xylose in a molar ratio of 31.59:27.11:22.73:8.26:6.29:1.91:1.24:0.87. GTDP exhibited an irregular flake-like structure, characteristic polysaccharide absorption bands, and good thermal stability. Its solution demonstrated shear-thinning, pseudoplastic, non-Newtonian fluid behavior with weak gel-like viscoelasticity. The half-maximal inhibitory concentration (IC₅₀) values of GTDP in the DPPH, FRAP, and FIC assays were 90.85, 473.37, and 1159.68 mg/L, respectively. Moreover, the IC₅₀ value of GTDP against α-glucosidase was 420.48 mg/L, showing an inhibitory activity approximately 2.21 times higher than that of acarbose. The inhibition rate of GTDP on advanced glycation end products (AGEs) was 56.55% at 1 mg/mL, which was approximately approximately 63% of that that of aminoguanidine. These findings provide a theoretical basis for the comprehensive utilization of green tea dust and highlight the potential of GTDP as a natural antioxidant and antidiabetic agent for functional food and pharmaceutical applications.