In order to explore the mechanism of processing methods affecting protein nutrition in whole grain foods, cooked whole-grain highland barley products (rice) and flour-based products (noodles) were selected as the research objects, with raw highland barley flour used as the control. The effects and underlying mechanisms of cooking and milling on protein nutrition in whole grain highland barley were evaluated based on the nutrient composition of indigestible residues, as well as the structure and amino acid composition of digestion-resistant proteins. The results showed that the digestibility of both rice and noodles was significantly reduced compared to raw flour (P<0.01) and the gastrointestinal digestibility of noodles was increased compared to rice. Cooking promoted the interaction between major nutrients and inhibited the digestion of protein, among which starch had the strongest inhibitory effect on the digestion of protein in highland barley, followed by dietary fiber. Milling improved the digestibility of protein because it promoted the digestion of starch. Both cooking and milling treatments enhanced the indigestibility of the alcohol soluble protein subunits (D, B, B3), partial alcohol soluble protein subunits γ-3 and the albumin subunit Serpin z-type, partly because cooking and milling promoted the formation of disulfide bonds (raw flour 0.91 μmol/g; rice 1.22 μmol/g; noodles 1.68 μmol/g). In addition, the contents of hydrophobic amino acids in indigestible residues of highland barley were significantly different (P<0.05). The contents of rice were the highest, followed by noodles, and raw flour was the lowest. It showed that the indigestibility of protein was positively related to the contents of hydrophobic amino acids. After cooking and simulated digestion, digestible indispensable amino acid score (DIAAS) was reduced, the first limiting amino acid was Lys which remained the same, the second limiting amino acid was leucine (Leu) for rice and isoleucine (Ile) for noodles. The results of the study are helpful to understand the interaction between macromolecular substances in complex food systems, clarify the influence mechanism of cooking and milling processing on protein nutrition, help to understand the bioavailability of highland barley protein in different processed products, and provide a new theoretical basis for protein nutrition evaluation of whole grain foods.

This study comprehensively applied a diverse array of widely targeted metabolomics, network pharmacology, and molecular docking techniques to delve into the potential anti-fatigue mechanism of Crassostrea gigas. The aim was to provide a robust theoretical and experimental foundation for the scientific utilization of Crassostrea gigass. Utilizing an ultra-high performance liquid chromatography-electrospray ionization-triple quadrupole/linear ion trap mass spectrometry (UPLC-ESI-QTRAP-MS/MS) system and database, an extensive targeted metabolomics analysis of the simulated digestive products of Crassostrea gigas in vitro was conducted. This analysis aimed to obtain component transformation information during Crassostrea gigas digestion. Network pharmacological analysis of the anti-fatigue properties of Crassostrea gigas active ingredients was carried out using PubChem, Swiss Target Prediction, GeneCards, and Cytoscape software. From this, a network map of "active ingredients-target" for Crassostrea gigas was constructed. Subsequently, the core targets was verified using molecular docking technology. 1231 active ingredients in 17 categories of Crassostrea gigas were identified. Among these, 106 intersection targets with potential anti-fatigue effects were pinpointed, involving 181 key active ingredients, primarily including 1,5-pentenediamine, tryptamine, 4-tert-octylphenol, etc. Core targets included Estrogen receptor 1 (ESR1), epidermal growth factor receptor (EGFR), and peroxisome proliferator-activated receptor gamma (PPARG). Signal pathway enrichment analysis revealed that the calcium signaling pathway, neuroactive ligand-receptor interaction, and PI3K-Akt signaling pathway were pivotal signaling pathways for fatigue resistance in Crassostrea gigas. Molecular docking results further verified the good combination of key active ingredients and core targets of oyster. Crassostrea gigass may exert an anti-fatigue effect through a synergistic action involving multiple components, targets, and pathways. This study offers theoretical support for further exploration of the active components and molecular mechanisms of Crassostrea gigas, paving a solid foundation for subsequent research and application.

This study aimed to investigate the effects of different ultrasonic treatments on the physicochemical properties of the starch-lauric acid complex. The starch-lauric acid complex between the sea red rice starch (SRS) and lauric acid (LA) was prepared using three ultrasonic treatment methods: pre-treatment, co-treatment, and post-treatment. The complex index, particle morphology, crystalline structure, pasting properties, thermal properties and in vitro digestibility of the complexes were systematically analyzed. The results showed that the complex index of the starch-lauric acid complex without ultrasonic treatment (LA-SRS) was 5.66%. Ultrasonic pre-treatment starch-lauric acid complex (LA-USRS) and ultrasonic co-treatment starch-lauric acid complex (ULA-SRS) significantly increased the complex index to 9.95% and 14.24%, respectively, while ultrasonic post-treatment starch-lauric acid complex (LA-SRS-U) decreased to 4.78%. Ultrasonic treatments complex showed significant decrease in the degree of short-range order structure and relative crystallinity (P<0.05). In terms of gelatinization properties, all ultrasonic treatments complex significantly elevated the gelatinization temperature (P<0.05) and reduced the breakdown value, setback value, and final viscosity (P<0.05). Thermogravimetric analysis indicated that ultrasonic treatments enhanced the thermal stability of complex, with the peak temperature increasing from 305.5 ℃ to 317.0 ℃. Additionally, in terms of in vitro digestibility, LA-USRS showed an increase to 37.65% in resistant starch content, compared to SRS. In contrast, ULA-SRS and LA-SRS-U had significantly higher contents of rapidly digested starch and slowly digested starch than SRS (P<0.05). Correlation analysis revealed that the complex index was significantly positively correlated with gelatinization temperature and peak temperature (P<0.05), and significantly negatively correlated with the degree of short-range ordering and relative crystallinity (P<0.05). Overall, the physicochemical properties of the starch-lauric acid complex were significantly influenced by different ultrasonic treatments. These findings would provide theoretical basis for the development of starch-based foods with tailored digestive behaviors.

This study investigated the effects of high-amylose maize starch (HA) on the pasting properties, gelation behavior, and anti-digestibility of whole wheat flour (WWF) under different high-temperature cooking conditions. Composite flours were formulated by incorporating varying ratios of HA into WWF, with the protein content standardized at 13.8% through gluten adjustment. The composite flours were evaluated for farinograph properties and pasting behavior, thermal characteristics, gel hardness, and digestibility following heat treatments at 100 ℃ and 140 ℃. Results demonstrated that the addition of HA increased water absorption and reduced dough development time. Wheat starch (WHE) in WWF could gelatinize and form a gel network at temperatures below 100 ℃, while HA largely retained its granular form. At 140 ℃, HA could be fully gelatinized, with its granular structure completely destroyed. Notably, gel hardness did not show a consistent trend of reduction with increasing HA content. The enthalpy values of amylose-lipid complexes (ALC) in HA and WWF were determined to be 3.2 J/g and 1.9 J/g, respectively. However, no significant changes in enthalpy values were observed in the composite flour after the addition of HA. The RDS content of the composite flour decreased significantly compared to WWF (P<0.05) and the sum of SDS and RS content was greater than the theoretically expected value after treatments at 100 ℃ and 140 ℃. Therefore, the addition of HA could enhance the anti-digestibility of the starch of the composite system more effectively than its own anti-digestibility effect.

In order to reduce the cooked off-flavor of lychee juice after thermal processing, six inhibitors were screened, including pyrogallol, gallic acid, rosmarinic acid, catechins, ascorbic acid, and glucose oxidase. These inhibitions were evaluated based on flavor and nutritional properties such as color, pH, flavor profile, electronic nose, volatile components, sulfur-reducing rate, as well as total phenols, flavonoids contents, and antioxidant properties. The results showed that the samples treated with ascorbic acid and gallic acid had the smallest color difference compared to fresh juice. The overall aroma profile indicated glucose oxidase was the most effective inhibitor in reducing cooked off-flavor, followed by rosmarinic acid. The electronic nose results showed that the lychee juice treated with glucose oxidase was closest to fresh juice, followed by catechins and pyrogallol. The principal component analysis of volatile components showed that the sample treated with ascorbic acid was closest to fresh juice, followed by gallic acid, catechins, and rosmarinic acid. The sulfur reduction rate showed that glucose oxidase had the most significant sulfur reduction effect, with inhibition rates of 100% for dimethyl sulfide, dimethyl trisulfide, and methional, and 61.11% for dimethyl disulfide. In terms of nutritional quality, polyphenol and ascorbic acid treatment significantly improved the total phenol, total flavonoid contents as well as antioxidant properties (P<0.05), while the total phenol and total flavonoid contents of glucose oxidase-treated sample were higher than those of fresh juice but the antioxidant activities showed no significant difference compared to fresh juice. Partial least squares discriminant analysis (PLS-DA) of lychee juice quality, integrating factors such as color, pH, aroma profile, nutritional quality, and sulfur reduction effect, revealed that glucose oxidase had the best effect on the overall quality. The findings of this study can provide references for quality improvement in lychee and other subtropical fruits processing industry.

Objective: This study aimed to identify thermostable xylanase suitable for mash malting. Methods: A xylanase encoding gene (PtXynA) from Paecilomyces thermophila J18 was cloned and heterologously expressed in Aspergillus niger. A submerged fermentation in a 5 L fermentor was performed for the production of the recombinant enzyme (PtXynA). The enzymatic properties of PtXynA were characterized and its application potential in mash malting was further evaluated. Results: A maximum extracellular xylanase activity of 904.0 U/mL with a protein content of 1.4 mg/mL was obtained after 96 h of fermentation. PyXynA was most active at pH7.0 and 70 ℃, respectively, and it was stable within the pH range of 5.5~9.0 and at temperatures below 75 ℃. The enzyme displayed strict substrate specificity towards various xylans, with the highest specific activity towards wheat arabinoxylan (1993.2 U/mg), followed by oat spelt xylan (1782.5 U/mg), beechwood xylan (1552.0 U/mg) and birchwood xylan (1238.7 U/mg). The addition of PtXynA in mash (200 U/g malt) reduced the filtration time and viscosity of malt by 43.9% and 10.8%, respectively. Conclusion: The excellent properties may enable PyXynA great application potential in beer industry.

This study aimed to establish a systematic framework for enhancing the bioconversion efficiency of ellagic acid to urolithin A by Limosilactobacillus fermentum FUA033 through rational medium engineering, while deciphering the molecular orchestration underlying this metabolic process. Single factor and response surface methodology were used to optimize the culture medium. Transcriptome sequencing technology was utilized to analyze L. fermentum FUA033 before and after ellagic acid supplementation in media, and predict the molecular mechanisms involved in the biotransformation of ellagic acid into urolithin A. The optimized medium was determined to be Wilkins-Chalgren Anaerobe Broth (WAM) supplemented with 0.16% trace element solution, 0.16 mmol/L methyl viologen, and 0.21% vitamin solution. The optimization resulted in biotransformation rate of 74.91%, 20.83% improved as compared to the unoptimized condition. Following the addition of ellagic acid, 64 significantly up-regulated genes, and 123 differentially down-regulated genes. GO enrichment analysis demonstrated that the differentially expressed genes were significantly enriched in molecular functions including transporter activity, membrane, and ion transport. The KEGG pathway enrichment analysis demonstrated significant alterations in oxidative phosphorylation (P<0.05), with substantial enrichment of functional genes related to metabolic pathways and the biosynthesis of secondary metabolites. Notably, two lactonase-encoding genes exhibited significant upregulation, strongly suggesting their catalytic role in hydrolyzing ellagic acid's lactone rings to generate the urolithin A precursor. These findings establish a mechanistic foundation for microbial biosynthesis of urolithin A through fermentation, while systematically delineating the enzymatic determinants governing the bacterial-mediated biotransformation of ellagic acid into urolithin A.

Objective: Soybean residue, a major by-product of soybean processing, possess nutritional value but have low industrial utilization due to low digestibility and poor palatability. The aim of this study was to use soybean residue as a fermentation substrate, take advantage of the characteristics of Bacillus sp. that can grow and multiply in food materials and secrete an extracellular enzyme system, and explore an effective way to prepare small molecule bioactive substances such as antioxidant peptides with the help of ultrasonic-combined microbial fermentation (UAF), thereby enhancing the utilization value of soybean residue. Methods: In this study, 28 high-protease-producing strains were screened from 56 strains of Bacillus sp. by initial screening using the transparent-circle method. Then, their protease activity, superoxide dismutase activity, peptide-producing capacity, and antioxidant capacity were comprehensively evaluated through re-screening in combination with factor analysis. Results: Four strains with antioxidant capacity, namely B. siamensis s4, B. amyloliquefaciens 10, B. subtilis SNBS-3, and B. subtilis 63, were finally screened out. Among them, the protease activity, ABTS⁺ radical scavenging rate, and DPPH radical scavenging rate of B. amyloliquefaciens 10 were significantly increased (P<0.05) 12.23%±0.08%, 8.69%±0.11%, and 3.38%±0.81%, respectively. Meanwhile, the peptide content and DPPH radical scavenging rate of B. subtilis SNBS-3 were significantly increased (P<0.05) 7.20%±0.10%, 3.41%±0.14%, respectively. Conclusion: Using soybean residue as a fermentation substrate, ultrasonication combined with microbial fermentation could be regarded as a method to screen strains with high antioxidant peptide production. Under ultrasonication stress conditions, the two strains, B. amyloliquefaciens 10 and B. subtilis SNBS-3, not only demonstrated good growth ability but also significantly enhanced protease activity, peptide content, and antioxidant capacity. They had strong antioxidant potential and provided theoretical support for the industrialization of antioxidant peptide preparation.

Based on genomic annotation information, this study aimed to explore the β-1,3-/α-1,3-glucan synthetic pathway of Rhizobium pusense. It focused on the action mechanism and potential catalytic efficiency of β-D-fructofuranosidase, the key enzyme in the first step of this synthetic pathway. High-throughput bioinformatic statistical and comparative analysis was conducted by targeting and mining data of β-D-fructofuranosidase from other microbial sources. The results indicated that the sequence and structure of β-D-fructofuranosidase from Rhizobium pusense showed a high degree of similarity and conservation. It was clarified that the key sites Tyr196 and Asp257 in its active site played a crucial role in catalyzing the substrate. Through high - throughput targeted mining of the database, it was found that among the microorganisms with potential β-D-fructofuranosidase expression, there were 6007 bacterial sources and 746 fungal sources. Among them, the β-D-fructofuranosidase of the representative bacterial strain Francisella tularensis OHARA and the fungal strain Fusarium fujikuroi IMI 58289 had relatively high potential catalytic efficiencies, which were 10.73 and 27.40 L·mol⁻¹·s⁻¹ respectively. Further analysis suggested that differences in the size of the active cavity space and the bottleneck radius of β-D-fructofuranosidase from different sources were one of the reasons for the differences in their catalytic efficiencies. This study provides an important basis for a profound understanding of the synthesis mechanism of β-1,3-/α-1,3-glucan in Rhizobium pusense. It also lays the foundation for the development and utilization of other microbial resources for the efficient fermentation production of β-1,3-/α-1,3-glucan, and is of great significance for promoting the development of related fields.

This experiment investigated the ability of an aminopeptidase gene dmpA from microcyst basidiomycete MCA 4210 (Cystobasidium minutum MCA 4210) to catalyze the synthesis of L-carnosine, and constructed a genetically engineered strain to catalyze the synthesis of L-carnosine with L-histidine and β-alanine methyl ester hydrochloride as substrates, aiming to improve the synthesis efficiency of L-carnosine. Codon-optimized DmpA was expressed in Escherichia coli BL21 (DE3) and adding a maltose binding protein (MBP) tag further improved solubility and enzyme activity, yielding BL21 (DE3)-MBP-DmpA. Then the recombinant strain BL21(DE3)-MBP-DmpA was further investigated to optimize induced expression and transformation conditions. The results indicated that the target gene fragment was successfully fused with MBP, yielding the recombinant strain BL21(DE3)-MBP-DmpA. After optimization of the induction conditions, the crude enzyme activity reached 145 U. Through optimization of the transformation conditions, the L-carnosine production reached as high as 55.72 g/L, with a yield of 54.54%. This study successfully expressed DmpA from Cystobasidium minutum MCA 4210 in E. coli, demonstrating its L-carnosine synthesis capability. The MBP tag and condition optimizations significantly improved production, achieving the highest L-carnosine yield reported to date. These findings provided a strong foundation for industrial-scale L-carnosine production using genetically engineered bacteria and highlighted promising application potential.