Abstract:Steam explosion technology, an emerging physical pretreatment method, is increasingly applied in the edible mushroom industry. This technology subjects materials to instantaneous explosion under high-temperature and high-pressure steam, significantly improving their physical structures and chemical composition. It exhibits unique strengths in modifying edible mushroom cultivation substrates, extracting active compounds, and utilizing by-products as resources. This provides a new technical path for the high-quality development of the edible mushroom industry. The author primarily summarizes the equipment, principles, and influencing factors of steam explosion technology, as well as its diverse roles in modifying cultivation substrates, extracting active substances from edible mushrooms, and achieving high-value utilization of edible mushroom by-products. The aim is to promote positive development across all segments of the edible mushroom industry, achieving a win-win scenario for both economic and ecological benefits.

Abstract:Postharvest fruits and vegetables often face issues of senescence and diseases, which lead to a decline in quality. Although conventional preservation techniques are widely applied, some of them have certain health risks. Light treatment, as an emerging non-thermal and non-toxic preservation technology, has attracted attention in the food industry. On the basis of the impacts of light on plant physiology and microbial growth, light treatment helps to maintain the freshness and market value of fruits and vegetables. The light sources for light treatment mainly include light-emitting diodes (LED), ultraviolet (UV), fluorescent lamps (FL), and pulsed light (PL). This review explores the application mechanisms and effects of light treatment in the preservation of fruits and vegetables, analyzes the effects of light treatment on the nutritional value, antioxidant components, and enzyme activity of fruits and vegetables, and discusses the current challenges and future development directions of this technology.

Abstract:Conventional grain storage methods have a variety of drawbacks. Electron beam irradiation, as an emerging non-thermal processing technology, has attracted attention due to its high efficiency, environmental friendliness, and minimal impact on grain quality. The author elaborates on the principles of electron beam irradiation and its applications in the food industry, reviews its effects on harmful organisms, physicochemical properties, and sensory quality of grains during storage, and makes an outlook on its future application prospects, with the expectation of promoting the application and popularization of electron beam irradiation in food storage.

Abstract:[Objective]This study aims to achieve site-directed immobilization of β-agarase at targeted residues, thereby enhancing its thermal stability and operational performance.[Method]Computer-aided design was employed to selectively immobilize the mutant β-agarase Aga50D via sulfhydryl groups introduced at specific cysteine residues, enabling binding to the carrier.[Result]The immobilization conditions were optimized as follows: reaction duration of 12 h, an enzyme loading level (enzyme-to-carrier mass ratio) of 1∶50, and a crosslinker-to-carrier mass ratio of 10∶50. The immobilization efficiency ranged from 40% to 75%, with most mutants retaining the relative enzyme activity >80%. Compared with the wild-type free enzyme, the site-directed immobilized mutant β-agarase Aga50D exhibited superior thermal stability at 40 ℃ and 45 ℃. After four reuse cycles, the enzyme activity retention rate of site-directed immobilized mutant β-agarase Aga50D remained above 30%. Notably, while the wild-type free enzyme completely lost its activity in organic reagents, the enzyme activity retention rate of most site-directed immobilized mutant β-agarase Aga50D remained above 70%.[Conclusion]The site-directed immobilized mutant β-agarase Aga50D demonstrated high enzyme activity and enhanced thermal/operational stability, showing significant promise for industrial applications.

Abstract:[Objective]This study aims at solving the problems such as long drying time, single product shape, and poor 3D printing capacity (easy blockage and weak bracing ability) in conventional processing of hawthorn snack products.[Method]The low-sugar hawthorn jam and high-sugar banana jam were used as gel components. The 3D printing was carried out with the optimization of dual-material combination gel formula and the optimization of dual-nozzle 3D printing process. Furthermore, the drying characteristics of 3D printing were analyzed and compared with those of conventional dried hawthorn products.[Result]The combination of hawthorn jam with the sugar mass fraction of 26% and banana jam with the sugar mass fraction of 38% (A₂B₃ group) had the storage modulus (G′), loss modulus (G″), and apparent viscosity suitable for 3D printing. The dual-nozzle 3D printing accuracy of A₂B₃ group was the highest, with the outer diameter and height deviations of 1.04% and 1.08%, respectively. Compared with the production of conventional dried hawthorn products, dual-nozzle 3D printing with A₂B₃ group showed reductions of 16.67%, 20.65%, and 2.48% in drying time, hardness, and total sugar mass fraction but increases of 23.32% and 25.94% in mass fractions of flavonoids and total phenols, respectively. Moreover, it enhanced the antioxidant capacity and flavor of the product.[Conclusion]This study provides a solid reference of structural support for food 3D printing and the development of the special-shape snacks.

Abstract:[Objective]To explore the application prospects of Citri Reticulatae Pericarpium in the food industry and efficiently extract the active component hesperidin, while developing an effective purification process to enhance the purity and functional value of the active ingredients.[Method]Ultrasonic-microwave assisted extraction (U-MAE) was employed to extract the hesperidin from Citri Reticulatae Pericarpium, followed by a three-stage purification system guided by dissolution characteristics involving alcohol removal by concentration, gradient ethanol washing, and pH adjustment to purify hesperidin. Single factor experiments and response surface methodology were used to optimize the extraction parameters. The antioxidant activity and α-glucosidase inhibitory activity of the final product were also evaluated.[Result]Under the optimal extraction conditions (60% ethanol-water solution by volume, microwave power of 220 W, extraction time of 3.5 min, and material/liquid ratio of 1 g∶45 mL), the hesperidin yield reached (43.3±0.2) mg/g, demonstrating significant efficiency advantages over traditional extraction methods. After three-stage purification, the mass fraction of hesperidin increased from (41.70±0.07)% to (96.09±0.88)%. The final product demonstrated excellent antioxidant activity (ABTS free radical scavenging IC₅₀ of 135.57 μg/mL) and α-glucosidase inhibitory activity (IC₅₀ of 102.13 μg/mL).[Conclusion]The U-MAE and three-stage purification system developed in this study enables efficient extraction and purification of active components from Citri Reticulatae Pericarpium, significantly enhancing their purity and functional values. This provides theoretical basis and technical support for the application of Citri Reticulatae Pericarpium in the development of functional foods and offers new ideas for the development and utilization of other traditional Chinese medicinal materials that are both food and medicine.

Abstract:[Objective]In order to study the effects of germination on the mass fractions of phenolic acids in black wheat, a method was established for simultaneous determination of 11 phenolic acids (gallic acid, protocatechuic acid, 4-hydroxybenzoic acid, chlorogenic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, sinapic acid, and salicylic acid) in germinated black wheat based on high performance liquid chromatography (HPLC).[Method]The mobile phase composed of methanol (containing acetic acid at a volume fraction of 1%) and water (containing acetic acid at a volume fraction of 1%) was used for gradient elution at a flow rate of 1 mL/min, a detection wavelength of 280 nm, and a column temperature of 25 ℃, to determine the mass fractions of 11 phenolic acids in black wheat on the 1st, 3rd, 5th and 7th days of germination.[Result]The results of methodology validation showed that 11 phenolic acids had a good linear relationship between mass concentration and peak area within the mass concentration range from 20 to 200 μg/mL, R²≥0.999 4 (n=6). The established method showed the limit of detection (LOD) ≥1.22 μg/mL and the limit of quantification (LOQ) ≥2.54 μg/mL for the phenolic acids. The relative standard deviations (RSD) of peak area of precision, repeatability, and stability were all less than 2.00%, and the average spiked recovery rates were between 98.02% and 101.12%, indicating that the established method was fast, accurate, and reliable. The extraction conditions were optimized as extraction with the solid-liquid ratio of 1 g∶30 mL and methanol at a volume fraction of 80% by vortex for 6 min, under which the total mass fraction of 11 phenolic acids in germinated black wheat was the highest. The results showed that during germination, the mass fraction of gallic acid in black wheat reached the peak on the 3rd day of germination. The total mass fraction of 11 phenolic acids was the highest on the 5th day of germination, which was 2.13 times of that in the non-germinated control group. This indicated that germination changed the mass fractions of phenolic acids in black wheat.[Conclusion]This study evaluated the effects of extraction conditions on 11 phenolic acids and determined the mass fractions of the 11 phenolic acids in germinated black wheat. The findings lay a foundation for the study of functional components in germinated black wheat and provide a reference for the quality control and evaluation of its products.

Abstract:[Objective]The basic characteristics of L-malic acid and the application of L-malic acid in orange juice were studied.[Method]The basic characteristic differences of L-malic acid, citric acid, and DL-malic acid were compared in terms of thermal stability, pH stability, and taste quality changes of electronic tongue. Subsequently, the three sour agent were added into orange juice. The effects of L-malic acid on the stability and volatile flavor of orange juice were analyzed based on the differences in centrifugal sedimentation rate, pH, electrical conductivity, particle size, Zeta potential, and volatile components.[Result]L-Malic acid had good stability in the ranges of 40~121 ℃ and pH 2.0~7.0. L-Malic acid differed markedly from citric acid in terms of astringency and the aftertaste of astringency, while it had no significant difference in taste indicators from DL-malic acid. Compared with citric acid, L-malic acid at the same mass concentration showed an increase of 63.79% in astringency value, a decrease of 68.07% in astringent aftertaste value, and increases of 37.41% and 26.05% in sour and bitter aftertaste values, respectively. Compared with the addition of citric acid, the addition of L-malic acid as the same mass concentration effectively increased the Zeta potential and improving the stability of the orange juice beverage system.[Conclusion]This study provide technical support for the promotion and application of L-malic acid in improving the taste quality and stability of orange juice products.

Abstract:[Objective]This study aims to investigate the effects of ginger protease on beef tenderness.[Method]Ginger protease was extracted from mature ginger via ammonium sulfate precipitation. The fundamental properties of the ginger protease, including enzyme activity, protein mass fraction, optimal temperature and pH, and relative molecular mass, were evaluated. Furthermore, the effects of ginger protease on the physicochemical properties, sensory quality, microstructure, and protein degradation characteristics of beef were examined.[Result]Ginger protease was mainly composed of two proteins with relative molecular masses of 15 293 and 34 191, with a total protein mass fraction of (574.60±0.25) mg/g, an enzyme activity of (31 787±307) U/g, an optimum temperature of 60 ℃, and an optimum pH of 6. Compared with the control group, 30 to 90 U/mL ginger protease significantly reduced the shear force, hardness, chewiness, and gumminess, while enhancing the lightness value without altering the water-holding capacity of beef. When enzyme activity is the same, there is no significant difference in the tenderness of beef treated with ginger protease and papain. The sensory evaluation results indicated that the ginger protease improved the sensory quality of beef. Microstructural analysis revealed that ginger protease disrupted the integrity of muscle structure. Protein degradation analysis indicated that ginger protease primarily improved beef tenderness by modifying collagens in beef, whereas papain improved beef tenderness through its effects on myofibrillar proteins, myogens, and collagens.[Conclusion] Ginger protease can be applied as an effective enzyme for meat tenderisation.

Abstract:[Objective]This study aims to develop suitable packaging strategies for sweet cherry varieties with different respiratory characteristics.[Method]The sweet cherry cultivars ‘Lapins’ and ‘Regina’ were put in closed systems with different O₂ volume fractions at 0, 5, and 10 ℃. The changes in O₂ consumption rate, CO₂ consumption rate, and respiratory quotient were monitored. Additionally, the changes of gas components, quality, and physiological disorders were assessed for the two cultivars treated with polyethylene (PE) and modified atmosphere packaging (MAP) after 4 weeks of storage at 0, 5, and 10 ℃.[Result]‘Lapins’ had lower O₂ consumption rate and CO₂ consumption rate than ‘Regina’ at the beginning of storage under the same temperature. The O₂ volume fractions of ‘Lapins’ were lower than those of ‘Regina’ during anaerobic respiration. For both cultivars, the O₂ consumption in the MAP accelerated as the storage temperature increased. After storage at 10 ℃ for 4 weeks, the O₂ volume fraction of ‘Regina’ in the MAP fell into the O₂ volume fraction range in the case of anaerobic respiration. The analyses of fruit quality, physiological disorders, and sensory quality showed that the fruit firmness, titratable acid mass fractions, texture scores, and flavor scores of ‘Lapins’ and ‘Regina’ decreased with the increase in storage temperature. At the same storage temperature, the fruit quality and sensory flavor scores of ‘Lapins’ and ‘Regina’ treated with MAP were higher than those treated with PE. In addition, Analysis of variance revealed that cultivar × storage temperature × packaging method significantly affected O₂ volume fractions, CO₂ volume fractions, and flavor scores.[Conclusion]‘Regina’ displayed higher respiratory level and O₂ volume fraction threshold for anaerobic respiration than ‘Lapins’. At 0~5 ℃, MAP inhibited the O₂ consumption, maintained high storage and sensory quality, and reduced the incidences of physiological disorders in both cultivars.

Abstract:[Objective]This study aims to employ synthetic biology and metabolic engineering techniques to engineer Pichia pastoris (P. pastoris) for the efficient heterologous synthesis of the UV resistant compound gadusol.[Method]On the basis of a bioinformatic analysis and codon optimization of the genes involved in the gadusol biosynthetic pathway in Danio rerio, the gadusol fermentation pathway was constructed in P. pastoris via strategies such as promoter engineering, metabolic engineering, and fermentation optimization.[Result]A high-purity gadusol standard was prepared through optimized extraction and chromatographic separation. The gadusol yield in the recombinant strain P. pastoris HME reached 105 mg/L. By screening of gene expression promoters and optimization of the fermentation medium components, the engineered strain, P. pastoris GME, achieved a gadusol yield of approximately 175 mg/L.[Conclusion]This study successfully constructed the strain P. pastoris GME capable of efficiently synthesizing gadusol, providing support and a reference for accelerating the industrial production of gadusol by fermentation and the research on the application of this compound in the food and cosmetic industries.

Abstract:[Objective]This study explored the effects of critical environmental factors [water activity (a_w), pH, and temperature] on the antimicrobial activity of ε-poly-L-lysine (ε-PL), aiming to provide a basis for the application of ε-PL.[Method]With Staphylococcus aureus as an indicator strain, the micro-broth dilution and agar dilution methods as well as antimicrobial growth kinetics were utilized to determine the antimicrobial activity of ε-PL. The protein leakage assay was employed to evaluate the bacterial membrane disruption activity of ε-PL. Live/Dead fluorescence staining was performed to observe the bacterial membrane permeability.[Result]The minimum inhibitory mass concentration (MIC) of ε-PL against Staphylococcus aureus was 40.0 μg/mL. The agar dilution method results indicated that the antimicrobial activity of ε-PL increased with the increase in a_w. Additionally, ε-PL demonstrated strong antimicrobial activity at pH 5.0~7.0, moderate antimicrobial activity at pH 4.0, weak antimicrobial activity at pH 8.0, and no antimicrobial activity at pH 9.0,while the maximum antimicrobial activity of ε-PL occurred at 30 ℃ under neutral conditions. The antimicrobial kinetic results showed that the antimicrobial efficacy of ε-PL under different pH conditions was consistent with the agar dilution method results, with strong inhibitory effects at 25 ℃ and 30 ℃ under neutral conditions. ε-PL had strong membrane disruption activity on Staphylococcus aureus under weakly acidic to neutral conditions (pH 5.0~7.0), and the membrane disruption activity of ε-PL was more pronounced at low temperatures (25~30 ℃) and weak at high temperatures (30~35 ℃). The Live/Dead fluorescence staining showed that the bacterial membrane permeability was enhanced by ε-PL at pH 4.0, while little effect was observed at pH 9.0.[Conclusion]The environmental factors a_w, pH, and temperature demonstrate significant influences on the antimicrobial activity of ε-PL.

Abstract:[Objective]This study aims to improve the utilization of maize resources and address the shortage of feed resources.[Method]The intestinal colonization capacity, tolerance, and antibacterial properties of three Lactobacillus strains, Lactobacillus paracasei ZB-1 (ZB-1), L. paracasei DY-2 (DY-2), and L. rhamnosus DY-4 (DY-4) were evaluated. The most suitable strain for fermenting cornhusks was identified, and its fermentation process was optimized.[Result]ZB-1 exhibited higher intestinal colonization ability and antibacterial properties than DY-2 and DY-4. The antibacterial mechanism of ZB-1 was likely driven by the action of organic acids in an acidic environment and certain protein-based antimicrobial substances. The fermentation conditions for ZB-1 were optimized as follows: hydrolysis of corn husks with cellulase at a volume fraction of 6% (solid-liquid ratio of 4 g∶1 mL during enzymatic hydrolysis) for 24 h, followed by an alkaline treatment with NaHCO₃ at a mass fraction of 2%, ZB-1 inoculation volume fraction of 5%, molasses addition at a volume fraction of 3%, alkaline protease of 1 350 U/g, moisture content of the fermentation material controlled at a mass fraction of 50%, and fermentation at 37 ℃ for 48 h. Under these conditions, the mass fraction of organic acids in the fermented corn husks reached 3.23%, and the mass fraction of small peptides increased to 50.2 mg/g. Additionally, the mass fractions of neutral detergent fiber (NDF) and acidic detergent fiber (ADF) decreased to 63.72% and 15.82%, respectively.[Conclusion]This novel fermentation process for corn husks not only enhances the mass fractions of small peptides and organic acids but also decreases the mass fractions of NDF and ADF. The findings of this study offer significant reference value for the efficient biotransformation of corn husks and the fermentation of other cake and meal feed materials with Lactobacillus.

Abstract:[Objective]This study aims to compare the effects of hesperetin and eriocitrin on the gut microbiota in different enterotypes.[Method]An in vitro gut fermentation model was established, which was combined with 16S rRNA high-throughput sequencing and gas chromatography-mass spectrometry (GC-MS) technique to evaluate the regulatory effects of the two flavonoids on the gut microbiota in different enterotypes.[Result]After fermentation, both flavonoids significantly reduced the Firmicutes-to-Bacteroidota ratio (F/B ratio) in terms of relative abundance at the phylum level in enterotype Bacteroides and enterotype Prevotella. At the genus level, pro-inflammatory bacteria including Paeniclostridium and Sutterella showed decreased relative abundance in treatment groups. LEfSe analysis result identified that both hesperetin and eriocitrin increased the proportions of beneficial genera such as Lactobacillus and Lachnospiraceae_ND3007_group in the enterotype Bacteroides. The quantification results of short-chain fatty acids indicated significant increases in acetate and butyrate production in hesperetin-treated enterotype Bacteroides, while eriocitrin treatment showed no significant alterations. Spearman correlation analysis result revealed a significant positive correlation between the relative abundance of Lachnoclostridium and the butyrate production in the hesperetin-treated enterotype Bacteroides.[Conclusion]Hesperetin significantly enriched beneficial bacteria and enhanced the production of short-chain fatty acids in enterotype Bacteroides. The results can provide a theoretical foundation for the flavonoid-mediated regulation of the gut ecosystem.

Abstract:[Objective]This study aims to understand the potential harmful fungi that may affect the quality of raisins during the drying process of grapes from Turpan, Xinjiang and to explore the relationships between varieties and the fungal community structure and diversity on the surfaces of grapes and raisins.[Method]Four popular grape varieties (‘Thompson Seedless’, ‘Boerte’, ‘Xiangfei’, and ‘Seedless Black’) in a grapery in Turpan were selected as research objects. The fungal diversity on the surfaces of grapes and raisins was analyzed via high-throughput sequencing.[Result]The dominant fungal phyla on the surfaces of grapes and raisins were Ascomycota and Basidiomycota. The average relative abundance of Ascomycota on the surfaces of raisins (92.24%) was higher than that on the surfaces of grapes (81.43%), while Basidiomycota had higher average relative abundance on the surfaces of fresh grapes (9.35%) than that on the surfaces of raisins (2.44%). At the genus level, the dominant fungal genera on the surfaces of grapes were Aspergillus, Cladosporium, Alternaria, and Hanseniaspora. The average relative abundance of Aspergillus on the surfaces of raisins (61.75%) was higher than that on the surfaces of grapes (43.97%), while the average relative abundance of Cladosporium on the surfaces of grapes (8.61%) was higher than that on the surfaces of raisins (5.76%). Additionally, dominant fungal species such as Aspergillus carbonarius, Cladosporium cladosporioides, and Aspergillus versicolor were identified.[Conclusion]At various taxonomic annotation levels of species, the surfaces of grapes and raisins may harbor pathogenic fungi such as Aspergillus carbonarius, Cladosporium cladosporioides, Aspergillus versicolor, and unclassified taxa which potentially produce mycotoxins. These fungi varied between grapes and raisins at different taxonomic levels. Pathogenic fungi were present before and after grape drying with no significant change, indicating their persistence throughout the drying process.

Abstract:[Objective]The effects of different extraction methods on the yield, purity, structural characteristics, and physicochemical properties of tortoise shell collagen were investigated.[Method]The ultrasound-assisted enzymatic method, acid method, and enzymatic method were used to extract collagen from tortoise shell powder.[Result]The yield and purity of tortoise shell collagen extracted by ultrasound-assisted enzymatic method were 2.29% and 85.65%, respectively, significantly higher than those extracted by acid method (0.78% and 73.15%) and enzymatic method (1.77% and 75.63%). Ultraviolet absorption spectroscopy, infrared absorption spectroscopy, circular dichroism spectroscopy, and electrophoresis profiles showed that collagens extracted from tortoise shell by three methods were all type I collagen and retained intact triple helix structures. X-ray diffraction patterns revealed that the molecular structure of tortoise shell collagen treated with ultrasound-assisted enzymatic method was more compact, with a higher degree of order. The particle sizes of tortoise shell collagens extracted by ultrasound-assisted enzymatic method and enzymatic method were both distributed around 340 nm, while tortoise shell collagen extracted by ultrasound-assisted enzymatic method exhibited a lower particle size distribution. The thermal denaturation temperatures (T_d) of the tortoise shell collagens extracted by the three methods were all 44 ℃. Scanning electron microscopy results showed that the microstructure of tortoise shell collagen extracted by ultrasound-assisted enzymatic method was more uniform and regular.[Conclusion]The combination of ultrasound treatment and enzymatic methods provide a new perspective for the extraction of collagen from tortoise shell. Compared with the conventional acid method and enzymatic method, the ultrasound-assisted enzymatic extraction method shows improvements in the yield and purity of tortoise shell collagen, thus demonstrating a broad application prospect.

Abstract:[Objective]This study aims to investigate the mechanism of the interaction between ergosta-7,22E-dien-3β-ol, an active sterol of Poria, and progesterone receptor (PRGR) and the potential therapeutic effects via bioinformatics and molecular docking.[Method]The TCMSP database was used to screen the active ingredients of Poria, and MEGA X (10.0.5) was used for alignment of multiple PRGR sequences. The primary structure of PRGR was analyzed by ProtParam, and the hydrophobicity of PRGR was predicted by Protscale. The amino acid sequence of PRGR was analyzed by Prosite, and the secondary structure of PRGR was analyzed on NPS@SOPMA. The RCSB PDB database was used to predict the tertiary structure of PRGR via the homologous modeling method. DeepLoc-2.0 website was used to predict the subcellular localization of PRGR. SwissDock was employed to simulate the molecular docking between ergosta-7,22E-diene-3β-ol and its potential target PRGR (3O5Q).[Result]The PRGR protein consisted of 933 amino acid residues, with a relative molecular mass of 98 980 and a theoretical isoelectric point of 6.09, being a hydrophilic unstable protein. Its secondary structure was dominated by random coils (70.31% of the total), and this protein contained nuclear receptor ligand-binding domains (NR LBDs) and C4-type zinc-finger structure, which suggested its core function in nuclear signaling. Ergosta-7,22E-dien-3β-ol was anchored to the PRGR ligand-binding pocket through hydrophobic interactions and hydrogen bonding, and the key binding sites involved residues such as Leu and Ala. PRGR was highly conserved in primates, with branching values of more than 98% in the species (chimpanzee and bonobo) with closest affinity to humans. PRGR may be involved in the immune regulation through the nucleus and the outer membrane of mitochondria. Molecular docking revealed that ergosta-7,22E-dien-3β-ol may form a stable complex with PRGR.[Conclusion]This study elucidates the molecular binding mechanism of a sterol in Poria with PRGR, providing theoretical support for the development of immunomodulatory drugs targeting PRGR and the precise utilization of resources with both medicinal and edible values. Meanwhile, this study provides new ideas for the research on natural product-nuclear receptor interactions.