By combining new natural additives (whey protein, steviol glycosides, and Lactobacillus paracasei) in various proportions, de-sugared freeze-dried jujube powder was prepared. The physical properties, functional components, antioxidant capacity, and sensory characteristics of the de-sugared freeze-dried jujube powder were analyzed, and the performance of the de-sugared freeze-dried jujube powder obtained from different natural additive combinations was studied. The results showed that adding appropriate natural additives can significantly improve the wetting, solubility, and antioxidant capacity of the de-sugared freeze-dried jujube powder. Among these, the formulation JP-WSL1 (jujube powder:whey protein:steviol glycosides:Lactobacillus paracasei ratio of 7:1:1.5:0.5) had the best color, the smallest average particle size (6.25 μm), the lowest moisture content (6.67%±0.04%), the smallest contact angle (39.51°±1.66°), the longest wetting time (66.28±1.42 s), and the highest solubility (57.96%±0.51%). The total phenol content (TPC), total flavonoid content (TFC), DPPH free radical scavenging ability, and ABTS⁺ free radical scavenging ability also reached their highest levels, at 1332 mg GAE/100 g, 462 mg RE/100 g, 49.32% and 36.2%, respectively. In summary, the formulation with JP-WSL1 as a natural additive was more suitable for the production of de-sugared freeze-dried jujube powder. This study provides reliable theoretical support for the industrial production of de-sugared freeze-dried jujube powder and lays the foundation for the application of vacuum freeze-drying technology in the deep processing of fruit and vegetable powder.

This study aimed to simultaneously enhance the enzymatic activity and thermostability of glucose oxidase (AnGOD) derived from Aspergillus niger through a semi-rational design strategy. Mutation sites were designed using the FireProt online tool and consensus sequences analysis, and the optimal mutant was screened via site-directed mutagenesis and a two-stage combinatorial mutation approach. Molecular dynamics simulations were then conducted to elucidate the mechanism of performance enhancement. Results showed that from the initial 83 designed sites, 12 single-point advantageous mutants were selected, and the optimal mutant M5 (T276F/T34V/Q90R/S53F/S74T) was obtained through two-stage combinatorial mutagenesis. Compared to the wild-type (WT), M5 exhibited a 4.2-fold increase in specific activity, with a k_cat value of 755.0 s⁻¹ and a k_cat/K_m value of 34.52 L·mmol⁻¹·s⁻¹, representing 3.67- and 2.48-fold enhancements over WT, respectively. At 65 ℃, the half-life of M5 was 30 min, representing a 30-fold increase compared to WT (1 min). Molecular dynamics simulations revealed that the average RMSD of M5 and the RMSF in non-catalytic regions were reduced by 12.9% and 12.4%, respectively, compared to the wild-type (WT). Additionally, the number of hydrogen bonds between M5 and the substrate/coenzyme increased by 10.3% and 8.8%, respectively. Notably, the S74T mutation introduced a novel hydrogen bond network, while the Q90R mutation introduced a positive charge, enhancing surface electrostatic complementarity. These synergistic effects collectively improved both the thermostability and catalytic activity of AnGOD. Through semi-rational design and combinatorial mutagenesis, this study significantly alleviated the stability-activity trade-off in AnGOD enzyme engineering, laying a foundation for the application of GOD.

Objective: This study systematically investigated the efficient extraction process of purple yam anthocyanins, a gelatin/carrageenan composite-hydrogel delivery system was constructed, and the stability and biosafety in gastrointestinal digestion environments were elucidated. Methods: Anthocyanins were extracted using acidic ethanol method. The apparent viscosity, gel strength, and encapsulation efficiency of gelatin-carrageenan composite-hydrogels (ratio 8:2, w/w) at different concentrations were characterized by a rheometer and texture analyzer. The digestion models in vitro were used to evaluate the stability and swelling properties of anthocyanins in gastric fluid (pH3.0, 2 h) and intestinal fluid (pH6.8, 6 h), and the effect of the hydrogel on IEC-6 cell proliferation was assessed using the CCK-8 assay. Results: Acidic ethanol-assisted extraction achieved an anthocyanin yield of 57.20 mg/g, which was significantly higher than that of the conventional maceration method (P<0.05). The 0.5% composite hydrogel, composed of a gelatin-gellan gum wall material at a mass ratio of 8:2 and encapsulating anthocyanins, exhibited the most favorable performance. The gel strength, apparent viscosity, and encapsulation efficiency were 21.4 g, 0.09 Pa·s, and 90.81%, respectively. The anthocyanin hydrogel formed a stable three-dimensional network structure across a wide range of angular frequencies, effectively ensuring anthocyanin encapsulation. Storage stability tests showed that anthocyanin degradation was significantly lower at 4 ℃ than at 37 ℃, and the hydrogel exhibited good stability at high temperatures. SEM images revealed that the anthocyanin composite-hydrogel formed a typical three-dimensional porous network structure, with pore sizes primarily ranging from 50 to 200 μm. In vitro digestion experiments further confirmed that the hydrogel effectively delayed anthocyanin degradation and promoted its sustained release in the small intestine. The CCK-8 assay demonstrated that the composite-hydrogel exhibited minimal cytotoxicity (P>0.05), confirming its high biosafety. Conclusion: The gelatin/carrageenan composite hydrogel significantly enhanced the gastrointestinal stability and targeted delivery efficiency of purple potato anthocyanins, providing a theoretical basis for its application in functional food development. Future studies should verify its bioavailability enhancement effect through in vivo experiments.

The aim of this study was to evaluate the effects of sunlight exposure and drying temperature on the flavor profile and related physicochemical properties of semi-dried Trachinotus ovatus, with a view to providing insights into optimal drying technique. Five drying treatments were applied: sunlight drying, hot-air drying at 60 ℃, heat pump drying at 20 ℃, combined sunlight/heat pump drying at 20 ℃, and sunlight/heat pump drying with variable-temperature. The sample analysis included content assessment of total volatile basic nitrogen (TVB-N) and malondialdehyde (MDA), identification of volatile compounds through headspace solid-phase microextraction GC-MS, screening of characteristic flavor compounds based on OAV value, and categorization of flavor profile via clustering heatmap. Finaly, the optimal drying technique was identified by principal component analysis (PCA). Results showed that the sunlight drying and hot-air drying groups exhibited elevated levels of TVB-N and MDA, characterised by a rich bouquet but also containing pungent and undesirable odours. In contrast, compared with the sunlight drying and hot-air drying groups, the three groups treated with heat pump drying showed more than 13% and 55% decrease on TVB-N and MDA respectively, and relatively weak flavors. Meanwhile, the total relative contents for key flavor contributors of alcohols, aldehydes and ketones were as follows: Sunlight/heat pump drying with variable-temperature>combined sunlight/heat pump drying at 20 ℃>heat pump drying at 20 ℃. Furthermore, the cluster heatmap demonstrated that, in comparison with hot air drying, the flavor of semi-dried Trachinotus ovatus dried by the three groups of heat pumps was more analogous to that of sun-drying. The highest PCA score was obtained in the group of sunlight/heat pump drying with variable-temperature. In summary, this finding suggests that low temperatures are conducive to preserving the quality of semi-dried Trachinotus ovatus, and reducing the production of unpleasant odors. Besides, the appropriate levels of heat and light can promote the formation of flavor substances. Among the five sample groups, the semi-dried Trachinotus ovatus with the best comprehensive flavor and related physicochemical properties was the group of sunlight/heat pump drying with variable-temperature.

To investigate the effect of phenolic acids on the activity of β-glucosidase, this study systematically evaluated the activation mechanism of p-hydroxybenzoic acid (PHBA) at varying concentrations (0~0.5 g/L) through circular dichroism spectroscopy and molecular docking, with a focus on enzyme conformational dynamics and molecular interactions. The results showed that PHBA significantly enhanced β-glucosidase activity in a concentration-dependent manner. Secondary structural analysis revealed that the content of α-helix significantly decreased by 52.14% (P<0.05), while β-sheet, β-turn, and random coil structures increased by 90.20%, 27.24%, and 50.56%, respectively, at 0.5 g/L PHBA compared to the control group. These structural shifts suggestted that the enzyme's active site might reside within α-helix regions. Fluorescence quenching assays confirmed spontaneous binding between PHBA and β-glucosidase, with one or one class of binding sites identified. Molecular interaction analyses revealed that hydrogen bonding, van der Waals forces, and hydrophobic interactions predominantly stabilized the PHBA-enzyme complex. Molecular dynamics simulations further validated the structural stability of the PHBA-β-glucosidase complex over 100 ns trajectories (RMSD<0.4 nm), confirming PHBA as a potent β-glucosidase activator. This study elucidates the molecular basis of PHBA-driven enzyme activation and provides a theoretical foundation for enhancing β-glucosidase activity in phenolic acid-rich fermented fruit and vegetable products.

In order to improve the current situation of malnutrition in people with dysphagia, a kind of low fat, high fiber and high protein soft gels were developed through a thermal induction method, with whey protein, microcrystalline cellulose, sunflower oil, as well as gellan gum and konjac gum. Besides, the physical properties of the soft gels were analyzed using texture analysis, rheological testing and structural characterization. According to the International dysphagia dietary standard initiative (IDDSI), their application potential as dysphagia-friendly food was evaluated. The results showed that soft gels prepared with 4%~8% whey protein, 2%~6% microcrystalline cellulose, 1%~3% sunflower oil, and 2% polysaccharides (a mixture of gellan gum and konjac gum) exhibit excellent moldability, surface gloss, and freeze-thaw stability, meeting IDDSI Level 4 requirements. Increasing microcrystalline cellulose to 4%~6% resulted in a gel with lower strength and enhanced softness and smoothness, facilitated by the hydrogen bonding of higher amounts of cellulose and oil within the polysaccharide network, making it easier to swallow. Overall, the low-fat, high-fiber, high-protein soft gels developed in this study offer a novel dietary option for individuals with dysphagia and hold significant application potential.

Objective: To separate and purify novel fraction PKP84 of Polygonatum kingianum polysaccharides, and to analyze its structure and effects on Drosophila melanogaster with alcohol dependence. Methods: Polysaccharides were extracted from P. kingianum using water decoction and ethanol precipitation. Fraction PKP84 was isolated using various methods, such as grading-alcoholic precipitation and Sephadex G-100 column chromatography. The physicochemical properties of PKP84 were analyzed using thermogravimetric analysis. The structural characteristics of PKP84 were identified using circular dichroism, scanning electron microscopy, and Congo red experiment. Results: Intervention with PKP84 significantly decreased alcohol levels (P<0.05) in D. melanogaster and reduced the alcohol preference index value to less than zero after 3 d. Moreover, PKP84 increased the activities of certain antioxidant enzymes, such as catalase, and notably decreased malondialdehyde levels (P<0.01). PKP84 had a triple helical structure composed of glucose, galactose, xylose, and rhamnose, and its molecular weight was 1.7×10⁵ Da. There was a strong positive Cotton effect near 212 nm and a weak negative Cotton effect near 198 nm. The micromorphology of PKP84 was complex and multibranched. PKP84 thermally lost weight at the range of 214~390 ℃, and the average weight loss rate was approximately 49%. Conclusion: PKP84 reverses alcohol preference and alleviates oxidative stress in D. melanogaster with alcohol dependence. These findings support the potential application of P. kingianum in the prevention and treatment of alcohol dependence.

To enhance the high-value utilization of Zanthoxylum seeds and develop novel Zanthoxylum-based specialized seasonings, this study utilized Zanthoxylum seed protein as the raw material, subjecting it to sequential enzymatic hydrolysis with alkaline protease and flavor protease, followed by the Maillard reaction to synthesize umami peptides. The Maillard peptide preparation process was optimized by single-factor experiments and response surface methodology with browning degree and sensory evaluation as indicators. The effects of Maillard reaction on the flavor characteristics of Zanthoxylum seed protein hydrolysates were investigated using an electronic tongue in combination with the analysis of molecular weight distribution, amino acid content, peptide sequence, and other characteristic indicators. The results indicated that the optimal conditions for preparing Zanthoxylum seed protein Maillard peptides were as follows: Protein-to-sugar ratio of 3:2 (g/g), reaction temperature of 106 ℃, and reaction time of 52 min. Under these conditions, the product exhibited an electronic tongue response value of 10.06 and a sensory evaluation score of 8.38. The umami-enhancing effect was statistically significant (P<0.01), achieving an effective 44% reduction in monosodium glutamate content. Following the Maillard reaction, the proportion of peptides within the 500~1000 Da molecular weight range increased from 6.14% to 14.88%, while the content of umami amino acids increased by 8.95% and the content of bitter amino acids decreased by 5.32%. These results suggest that the Maillard reaction effectively enhances the umami taste of Zanthoxylum seed protein peptides and enriches their flavor complexity. This study provides important theoretical support for the development of novel seasonings that can replace sodium salts.

This study delved into the inhibitory activity and underlying mechanism of a combination of three flavonoids against pancreatic lipase (PL), aiming to furnish a robust theoretical foundation for the development of natural anti-obesity pharmaceuticals. The optimal proportion of these three flavonoids for combination was determined through the use of a combined equivalent line graph. Subsequently, ultraviolet (UV) spectroscopy and fluorescence spectroscopy were employed to explore the binding reactions and mechanisms between genistein (Gen), chrysin (Chr), naringenin (Nar), and PL. To comprehensively elucidate the impact of these flavonoids on the structure and properties of PL, synchronous fluorescence, infrared spectroscopy, differential scanning calorimetry, and particle size analysis were simultaneously utilised to characterize the formed complexes from multiple perspectives. The results showed that when the molar ratio of the three flavonoids was 4:1, the combined inhibitory effect was the most pronounced, exhibiting a synergistic action. Both endogenous fluorescence and UV spectrum demonstrated that the quenching of PL by Gen-Chr, Gen-Nar, and Nar-Chr was static quenching. The corresponding binding constants K_a were calculated to be 1.63×10⁵ L/mol, 14.64×10⁵ L/mol, and 7.07×10⁵ L/mol, respectively. Thermodynamic parameter analysis indicated that hydrophobic interaction was the dominat force in the Gen-Chr-PL complex, electrostatic attraction played a predominant role in the Gen-Nar-PL complex, and hydrogen bonding along with van der Waals force were the main driving forces in the Nar-Chr-PL complex. The results from synchronous fluorescence and particle size results indicated that as the concentration of the inhibitors increased, the hydrophobicity of the complexes decreased. Infrared spectroscopy results indicated that the inhibitors altered the secondary structure of PL. Differential scanning calorimetry (DSC) results showed that the thermal stability of PL diminished after the formation of complexes with the three compounds. Collectively, these results suggest that the pairwise combinations of Gen, Chr, and Nar exert inhibitory effects on PL activity and can significantly alter the structure and properties of PL, providing new insights for the development of novel PL inhibitors.

This study aimed to elucidate the interactions among β-conglycinin (7S), glycinin (11S) and glycerol, as well as their effects on film-forming properties. Molecular dynamics simulations with experimental characterization were systematically combined to analyze changes in molecular interactions and their impact on the physicochemical properties of protein films. The results showed that as the glycerol content increased, the radius of gyration and solvent-accessible surface area between the 7S and 11S globulins gradually increased, while the number of hydrogen bonds, electrostatic interactions, van der Waals forces, non-polar solvation energies, and absolute value of binding free energies progressively decreased. At a glycerol concentration of 40%, interactions such as hydrogen bonding and van der Waals forces between glycerol and the 7S-11S complex reached a maximum, and glycerol began to exhibit aggregation. As glycerol content increased from 10% to 50% in the 7S-11S protein films, the elongation at break (EAB) increased from 13.72% to 208.01%, while tensile strength (TS) decreased from 30.62 MPa to 2.51 MPa. A strong correlation was observed between TS, EAB, and the absolute value of the binding free energies, with a correlation coefficient exceeding 0.8. Glycerol addition enhanced the film peak intensity at 1040 cm⁻¹ in the Fourier-transform infrared spectrum. The proportion of hydrogen bonds and hydrophobic interactions between proteins in the 7S-11S films decreased with increasing glycerol content. Additionally, the high molecular weight components involved in hydrophobic interactions gradually decreased. The water contact angles on both film surfaces decreased from 115.82° and 112.33° to 94.00° and 84.33°, respectively, as the glycerol content increased. These findings suggest that glycerol modulates the intermolecular forces between 7S and 11S globulins, shifting the hydrophobic interactions among high-molecular-weight components toward ionic and hydrogen bonds, thereby affecting the mechanical properties and surface characteristics of the films.