To deeply investigate the structural characteristics and activities of nanovesicles derived from Rosa roxburghii Tratt. (RDNs), they were isolated, extracted, and characterized. Additionally, their antioxidant, hypoglycemic, and anti-hemolytic activities against Staphylococcus aureus exotoxin were explored. The RDNs were isolated using ultracentrifugation, and their morphology was characterized through transmission electron microscopy (TEM). The protein, lipid, and RNA composition/concentrations were quantified employing the BCA assay, thin-layer chromatography (TLC), and RNA extraction kits, respectively. The antioxidant capacity was assessed using DPPH and ABTS⁺ radical scavenging assays, while the hypoglycemic activity was evaluated through α-glucosidase and α-amylase inhibition assays. Using 2% rat erythrocytes as the research object, the experiment was divided into blank control group, positive control group, S. aureus-EVs group, RDNs group, and RDNs+S. aureus-EVs group, and in vitro anti-hemolytic rate of RDNs was detected. The results indicated that RDNs had an average hydrodynamic diameter of 155.27±1.39 nm, a Zeta potential of −8.60±0.64 mV, and maintained stability at −80 ℃ for 12 days. The particles remained stable during the first 6 days of storage at 4 ℃, but exhibited significant particle size changes after surpassing the 6-day mark (P<0.01). Particle size remained unchanged (P>0.05) at pH1.2, while pH6.5 showed significant change in particle size (P<0.05). Biochemical analysis uncovered the presence of protein (5.50±0.00 mg/mL), lipid (4.23±0.40 mg/mL), and RNA (3.91±1.97 μg/mL). Notably, protein bands were observed at 24, 50~70, and 70 kDa. Lipid components exhibited an intricate composition, which included phytosterols and lecithins. Concentration-dependent (0~212.30 mg/mL) scavenging of DPPH and ABTS⁺ radicals was observed, with the half-inhibitory concentrations (IC₅₀) for the two radicals being 112.90 and 64.38 mg/mL, respectively. Additionally, when the concentration reached 212.30 mg/mL, the RDNs were capable of eliminating 99.80% of ABTS⁺. The α-glucosidase and α-amylase inhibition rates were 48% and 21%, respectively, significantly lower than positive controls (P<0.01). The hemolysis rates were nearly 0 in the RDNs group, 64% in the S. aureus-EVs group, and 8% in the RDNs+S. aureus-EVs group, which was significantly lower than that in the S. aureus-EVs group (P<0.01). The RDNs had antioxidant and hypoglycemic activities and could exert anti-hemolytic effects against S. aureus exotoxins, laying a foundation for their potential applications in the fields of antioxidants and natural antibacterial agents.

To explore the improvement effect of Poria cocos powder on the quality of traditional noodle products, functional noodle products were developed. The present study systematically analyzed the effects of Poria cocos powder addition (0%, 2%, 4%, 6%, 8%, 10%, w/w) on pasting properties, rheological properties, cooking stability, texture properties, color, microstructure, antioxidant activity, glycemic index (GI) and sensory score of noodles. The results showed that the peak viscosity of the mixed powder decreased significantly from 85.42 cP to 32.37 cP (P<0.05) as the amount of Poria cocos powder added increases. The thermal stability showed an upward trend while the hardness and adhesiveness of noodles showed a downward trend. Noodles achieved optimal texture characteristics when 4% of Poria cocos powder was added (elasticity 1.68 mm, chewiness 32.42 mJ). As the amount of Poria cocos added increased, the microstructure of noodles showed a tighter gluten network and reduced surface pores. The L^* value of the color decreased from 81.30 to 69.66, the a^* value increased from −0.58 to 1.82, and the brightness decreased and became reddish. The cooking loss rate decreased from 3.01% to 2.78%. The antioxidant activity (DPPH, ABTS⁺ free radical scavenging rate and iron reduction ability) was positively correlated with the amount of Poria cocos added. The DPPH and ABTS⁺ free radical scavenging rates of noodles with 10% Poria cocos addition were 83.48% and 79.7%, respectively. The glycemic index (eGI) decreased from 81.48 to 59.68, with significant delaying starch digestion (P<0.05). However, when the amount of Poria cocos powder added was greater than or equal to 8%, the broken rate of noodles increased significantly (P<0.05). Comprehensive quality analysis showed the optimal noodle texture, sensory score (75 points) and thermal stability (peak storage modulus G') when adding 4% of Poria cocos powder, as well as outstanding antioxidant and sugar control effects when adding 10% of Poria cocos powder. This study confirmed that Poria cocos powder could optimize the nutritional and functional properties of noodles by regulating the gluten network, starch crystallization and release of active ingredient, providing a theoretical basis for the development of functional flour products.

Macrobrachium rosenbergii is rich in nutritional components and has delicious flavor, giving it significant commercial value. However, it is prone to spoilage and deterioration due to high moisture content. Drying is an important way for the high-value processing and utilization of aquatic products. In this study, the effects of initial status of M. rosenbergii meat (both the fresh M. rosenbergii meat and the frozen M. rosenbergii meat), microwave power intensities (1~5 W/g), and drying temperatures (45~60 ℃) on the drying efficiency, specific energy consumption, microstructure, and quality attributes of M. rosenbergii meat to obtain dried shrimp products with superior quality and high energy efficiency during microwave vacuum drying (MVD). The optimal drying conditions were selected based on a comprehensive weighted scoring method by a comprehensive assessment of the drying efficiency and quality attributes of dried products. The results demonstrated that compared to fresh M. rosenbergii meat, frozen samples that directly treated by MVD resulted in the dried products possessing a more intact structure with more internal pores and stable protein structure, as well as a higher astaxanthin content (0.93 μg/g), improved color, superior rehydration capacity, enhanced water-holding ability, and a significantly higher comprehensive quality score (P<0.05). At microwave power intensity of 5 W/g, microwave vacuum dried M. rosenbergii meat exhibited a denser porous structure, accompanied by the shortest drying time (15.27 min), lowest specific energy consumption (4.55 kW∙h/kg), highest water-holding capacity (20.34%), and highest comprehensive score among the tested power intensity levels (P<0.05). Among the four controlled temperatures, M. rosenbergii meat dried at 55 ℃ displayed regular internal pores and moderate fiber contraction, along with a lower hardness (200.57 N), and superior rehydration ratio (5.31) and water-holding capacity (20.42%). To sum up, compared to the fresh M. rosenbergii meat, the frozen meat was suitable material during MVD. The frozen M. rosenbergii meat was recommended to be dried at a power intensity of 5 W/g and drying temperature of 55 ℃ to achieve the dried products with superior quality, high drying efficiency and lower energy consumption.

In order to investigate the effect of fermentation with different lactic acid bacteria (LAB) on the digestibility and sensory characteristics of steamed bread, four LAB starter cultures, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus rhamnosus, and Lactobacillus reuteri were respectively employed for sourdough preparation. Commercial yeast was subsequently added for further fermentation and steamed bread production. The fermentation time, organic acid content, and inhibition rate of α-amylase in sourdough were investigated. Additionally, a comparative analysis was performed on the in vitro starch digestibility, simulated in vitro fermentation products, and sensory attributes of the steamed bread. The results showed that the sourdough fermented by L. plantarum and L. fermentum took a shorter time to reach pH 4, thereby exhibited a higher fermentation efficiency. The L. fermentum sourdough contained the highest acetic acid content, and the L. rhamnosus sourdough contained the highest lactic acid content. All the 4 sourdoughs showed an inhibitory effect on α-amylase activity. The inhibition rate of L. fermentum sourdough was more than 2 times than that of other sourdoughs, reaching approximately 15.13%. In vitro starch digestion test indicated that the starch digestibility of L. reuteri steamed bread was higher than that of white steamed bread, whereas the digestibility of steamed bread fermented by other LAB was significantly lower. The proportion of rapidly digestible starch in L. fermentum steamed bread was 13.51%, which was 0.40 times that of white steamed bread. The proportion of resistant starch was 64.29%, which was about 1.70 times that of white steamed bread. In vitro fermentation test showed that L. plantarum steamed bread was more effective in increasing the amount of intestinal short-chain fatty acids (SCFAs) compared to others. L. fermentum showed the best effect on the proliferation of intestinal probiotics. Sensory characteristic analysis revealed that L. fermentum and L. reuteri improved the specific volume and texture of steamed bread more significantly than other cultures. The overall sensory evaluation of steamed bread fermented with L. rhamnosus, L. reuteri, and L. fermentum was superior to that of white steamed bread, with L. fermentum demonstrating a significant enhancement in the structure of the steamed bread and the electronic nose showed that its flavor was more unique. Additionally, the result of electronic tongue indicated that L. rhamnosus steamed bread had a more distinctive salty and umami taste. In summary, Lactobacillus fermentum demonstrates the most comprehensive improvement effects on both the digestive characteristics and sensory qualities of steamed bread.

In this study, 10 Sanghuang strains were collected and identified, and the fermentation performances (mycelia biomass, color difference value and total flavonoid content) were analyzed in order to fully utilize Sanghuang resources and explore the functional activity of its mycelium. Based on the color difference values of mycelium, Pearson correlation analysis was used to analyze the correlation between the total flavonoid content of mycelium and the color difference value. Finally, the in vivo antioxidant activity of Sanghuang mycelium was studied. The results showed that, Sanghuang strains could be roughly divided into three categories: Sanghuangporus vaninii, Sanghuangporus baumii and Inonotus baumii according to the observation of mycelia morphology and ITS sequence molecular identification. The biomass range of liquid fermented mycelium of 10 Sanghuang strains ranged from 4.90 g/L to 12.22 g/L. Among them, the highest total flavonoid content of mycelium was Sanghuang 2 of substitute cultivation (0.7 g/100 g), followed by Sanghuang 10 of basswood cultivation (0.45 g/100 g), with the lowest total flavonoid content of Sanghuang 1 of substitute cultivation was (0.07 g/100 g). Results indicated that the differences in total flavonoid contents of liquid fermented mycelium of Sanghuang strains could be mainly related to geographical origins and bacterial species, with low correlation with cultivation methods. Based on Pearson correlation analysis, it was found that the total flavonoid contents of Sanghuang were significantly negatively correlated with L^* values (P<0.01), significantly positively correlated with b^* values (P<0.01), and significantly negatively correlated with h^* values (P<0.05). The functional test results of mice showed that the liquid fermented mycelia of Sanghuang had good safety, with a promoting effect on the growth performance, and effectively increased the SOD activity and reduced the MDA content in the serum of mice. Meanwhile, the liquid fermented mycelium obtained from basswood cultivation could lower the MDA content in the serum of mice more than that obtained mycelium from substitute cultivation. These results provided important reference for the targeted development and effective utilization of active ingredients of Sanghuang mycelium.

In order to explore the structural and functional properties of the extracellular polysaccharide flippase (Wzx) from Lactobacillus fermentum A51, this paper systematically investigated the Wzx protein using bioinformatics technology. Firstly, the evolutionary characteristics of the Wzx protein were analyzed through multiple sequence alignment and the construction of a phylogenetic tree. Subsequently, the physicochemical properties, subcellular localization, functional domains, hydrophilicity/hydrophobicity, signal peptides, transmembrane regions, phosphorylation modification sites, glycosylation modification sites, advanced structure, and mode of action were predicted and analyzed. The results indicated that Wzx was composed of 472 amino acids, with a relative molecular weight of 53.31 kDa and a total atom count of 7651. The theoretical isoelectric point was 9.50, and the instability coefficient was 33.79, and it was an alkaline stable hydrophobic protein. Wzx lacked a signal peptide and functioned as a flipping enzyme within the cell membrane. Following transmembrane domain prediction, it was determined that Wzx contained 14 transmembrane helix structures. A total of 33 significant phosphorylation sites were identified, comprising 14 serine (Ser) sites, 12 threonine (Thr) sites, and 7 tyrosine (Tyr) sites. Regarding subcellular localization and functional domain prediction, Wzx was predominantly localized in the endoplasmic reticulum (55.6%), indicating its membership in the Multidrug and Toxic Compound Extrusion family. In terms of the secondary structure of Wzx, α-helix constituted 61.44%, random coil accounted for 22.25%, and extended chain represented 16.31%, Based on the “V” shape of the three-dimensional structure of Wzx, it was speculated that it realized the transport of extracellular polysaccharides through its own conformational reversal or its own conformational change. This study offers a theoretical foundation for a deeper understanding of the functional characteristics and mechanisms of action of Wzx, which is crucial for comprehending the transport processes of extracellular polysaccharides.

Objective: To develop tannases resources with excellent enzymatic properties. Methods: Primary screening was performed using the clear zone plate method, followed by a secondary screening using the methanol rhodanine colorimetric assay. A fungal strain with the highest tannase activity was isolated from the Daqu samples. The strain was identified through morphological observation and ITS sequence analysis. The liquid fermentation conditions for tannase production were optimized. The enzyme (PbTanA) was purified through ammonium sulfate precipitation and DEAE weak anion-exchange chromatography, obtaining electrophoretic-grade pure enzyme. The enzymatic properties of PbTanA were further investigated, and its application in hydrolyzing tannic acid to produce gallic acid was evaluated. Results: The strain was identified as Penicillium bilaiae and named Penicillium bilaiae CAU46-1. After fermentation at 30 ℃ and pH5.5 for 4 days, a tannase activity of 28.7 U/mL was produced. This was achieved under conditions where 3% tannic acid served as inducer, 4% wheat bran as carbon source, and 0.2% ammonium chloride as nitrogen source, resulting in a tannase activity 3.3 times higher than the initial level. The tannase (PbTanA) was purified using ammonium sulfate precipitation followed by DEAE weak anion exchange chromatography. Its molecular weight was 79.0 kDa. The enzyme exhibited good acid tolerance and thermal stability, with an optimal pH of 5.0 and good stability within the pH range of 2.0~7.0. Its optimal temperature was 60 ℃, and it remained stable up to 50 ℃. PbTanA hydrolyzed 20 g/L tannic acid for 8 h, producing a gallic acid concentration of 18.4 g/L with a yield of 91.8%. Conclusion: Tannase PbTanA from Penicillium bilaiae CAU46-1 showed excellent enzymatic properties and efficiently hydrolyzed tannic acid to produce gallic acid, demonstrating its potential for application.

To investigate the impact of manual and mechanical methods of making high-temperature Daqu on the microbial community during storage, this study analyzed the differences in microbial community composition and succession patterns of Jiangxiangxing Baijiui high-temperature Daqu made by manual and mechanical methods during the storage period (0~150 days) using Illumina MiSeq high-throughput sequencing technology combined with multivariate statistical analysis methods. Additionally, the bacterial functions and phenotypes were predicted based on BugBase. The results showed that the manual-made high-temperature Daqu had a significantly higher fungal community richness during storage compared to the mechanically-made Daqu (P<0.05), and the fungal community composition was also significantly different. However, there was no significant difference in bacterial community diversity between the two types of Daqu (P>0.05). Thermomyces was a key genus, but the dominant fungal genera varied with different storage times and Daqu-making methods. Lactobacillus was relatively enriched in the mechanical Daqu, while Bacillus was more prominent in the manual Daqu. Linear discriminant analysis revealed the impact of Daqu-making methods on biomarkers. Leptospora rubella and Trichomonascus ciferrii were the biomarkers for manual and mechanical Daqu at different storage periods, respectively. Weissella was the biomarker for the manual Daqu during storage, while Kocuria was the biomarker for the mechanical Daqu during storage. Moreover, different Daqu-making methods also had a significant impact on bacterial functions and phenotypes. Kroppenstedtia and Staphylococcus were the bacterial genera that were significantly positively correlated with multiple metabolic functions during the storage of manual and mechanical Daqu, respectively (P<0.05). Both types of Daqu were dominated by Gram-positive bacteria, but the manual Daqu maintained a higher anaerobic bacterial activity phenotype. This study found that different Daqu-making methods had an impact on the microbial community structure, succession patterns, and bacterial functions and phenotypes during Daqu storage, providing a theoretical reference for the scientific regulation of Daqu storage and the analysis of the aging mechanism.

Objective: To investigate the effect of adjusting the relative humidity of drying medium on the drying characteristics and quality of ginger slices during hot air drying. Methods: To study the drying characteristics, color, shrinkage, rehydration, effective diffusion coefficient of moisture, gingerol content and total flavonoid content under the drying conditions of 60 ℃, 3.0 m/s air velocity, constant humidity (RH of 15%, 25%, 35%, 45%) and phase humidity reduction (RH45% was kept at 15% for 10, 20, 30 and 60 min, respectively). Results: Under the condition of constant humidity, the drying time of ginger slices was prolonged with the increase of relative humidity; Under the condition of stage humidity reduction, the drying time of ginger slices showed a tendency of decreasing and then increasing with the prolongation of the holding time of high relative humidity, and the drying time was shortened by 0.5 h when the RH was kept at 45% for 20 min and then reduced to 15% after 30 min compared with that of the constant humidity (RH of 15%). The drying process of ginger slices was divided into ascending and descending. The drying process of ginger slices was divided into two phases of ascending and descending, and the moisture Deff varied in the range of 5.21×10⁻¹⁰~6.66×10⁻¹⁰ m²/s. The rehydration of ginger slices was the best, and the color difference value and shrinkage were the smallest when RH45% was kept at 20 min and then decreased to 15%, and the difference was significant compared with that of constant humidity (P<0.05); After RH45% was kept for 30 min and then decreased to 15%, the content of gingerol and total flavonoids in ginger slices was significantly higher than that of constant humidity. Considering the drying time, color difference, shrinkage, rehydration, gingerol and total flavonoids content of ginger slices, it was concluded that the highest comprehensive score of ginger slices was 0.76±0.08 when RH45% was kept at 15% for 30 min, which was the optimal drying process. Conclusion: In the initial stage of hot air drying of ginger slices, keeping higher humidity of drying medium and maintaining it for a suitable time can accelerate the drying rate, shorten the drying time, and have better quality. The application of the phase humidity reduction and regulation strategy to the hot air drying process of ginger slices provides important theoretical support and technical guidance for the ginger processing industry.

To improve the survival rate of Lactiplantibacillus plantarum during freeze-drying, this study developed a composite cryoprotectant and prepared freeze-dried bacterial powder using vacuum freeze-drying technology. The composition of the composite cryoprotectant was optimized through single-factor and orthogonal experiments to enhance bacterial viability in the freeze-dried powder. The protective effects were evaluated by comparing viability before and after freeze-drying, measuring cell membrane and cell wall integrity, observing cellular microstructure, and assessing storage stability. The protective mechanism was further investigated via Fourier-transform infrared spectroscopy analysis of the freeze-dried powder, differential scanning calorimetry to determine thermal properties, quantification of subcellular damage, live-dead cell staining, and lactate dehydrogenase activity assays. Results showed that the optimal composite cryoprotectant formulation consisted of 0.15 g/mL skim milk powder, 0.06 g/mL trehalose, 0.03 g/mL Tween 80, and 0.014 g/mL L-glutamic acid. After 60 days of storage at −20 ℃, the freeze-dried powder exhibited a survival rate of 59.64%±1.74% and a viable count of (4.58±0.13)×10⁹ CFU/mL. Scanning electron microscopy revealed that cells treated with the composite cryoprotectant maintained intact morphology with smooth surfaces. Fourier transform infrared spectroscopy analysis indicated integration of cryoprotectant components into bacterial cells, strengthening hydrogen bonding. Differential scanning calorimetry results demonstrated enhanced thermal stability of the freeze-dried powder. Cell membrane and wall damage assays showed significant (P<0.001) reduction in structural damage, while lactate dehydrogenase activity increased significantly (P<0.0001). Correlation analysis suggested that the composite cryoprotectant improved survival primarily by preserving membrane integrity and enhancing lactate dehydrogenase activity. This study developed an effective composite cryoprotectant for Lactiplantibacillus plantarum. It elucidated its protective mechanisms, providing a theoretical basis for the application of cryoprotectants in probiotics, such as lactic acid bacteria.