In this study, the effects of adding mixtures of mono- and di-fatty acid glycerides and Tween 80 with different hydrophilic-lipophilic balance (HLB) values on the stability and whipping characteristics of cream were studied, and the hardness, whipping rate, apparent viscosity, stability, and microstructure of the cream samples were detected. The results showed that with the increase in HLB value, the apparent viscosity of the emulsion decreased, and shear thinning occurred in all cream samples. The centrifugal creaming rate and turbiscan stability index (TSI) decreased first and then increased, and so did the absolute value of zeta potential. The results of whipping characteristics analysis showed that with the increase in HLB value, the whipping time and whipping rate of cream decreased, and the hardness after whipping increased first and then decreased, reaching a maximum of 1 150.1 g when the HLB value was 9. At HLB values in the range of 9–11, cream exhibited a shorter whipping time, higher whipping hardness, appropriate whipping rate, and good mounting performance with no collapse or deformation. Meanwhile, the microstructure showed that the size of the cream bubbles was relatively uniform after whipping, and the fat globules around the bubbles were dense and close to each other, thus forming a better network structure to protect the bubbles and make the foam more stable. Therefore, the HLB value of mixed emulsifiers should be controlled in the range of 9–11 to obtain cream with good stability and whipping characteristics.

In order to investigate the influence of antifreeze peptide properties on its protective effect on myofibrillar proteins in frozen surimi, the present study was conducted to characterize the properties of three antifreeze peptides (sericin peptides, collagen peptides and silver carp hydrolysates), and we analyzed the changing pattern of myofibrillar protein properties under different freezing conditions, and constructed a correlation model between myofibrillar protein properties and frozen storage parameters and antifreeze peptide properties using least absolute shrinkage and selection operator (Lasso) regression. The results showed that all antifreeze peptides used in the study were “hyperactive” antifreeze peptides with thermal hysteresis activity (THA) (> 0.60 ℃), low molecular mass (< 10 000 Da), high hydrophilicity (θ < 30°) , and polar amino acid content of more than 60%; the antifreeze peptides were able to significantly mitigate the negative effects of frozen storage on myofibrillar proteins. The mean content of myofibrillar proteins in frozen surimi with added antifreeze peptides was 50.44–54.47 mg/g, the mean Ca2+-ATPase activity was 1.61–1.67 U/mg, the mean surface hydrophobicity index increased only by 39.91%–42.40% when compared with that of fresh surimi, and the rate of myofibrillar protein denaturation was much lower than that of the control group without antifreeze peptides. The Lasso regression model explained the effects of antifreeze peptide properties on changes in the properties of myofibrillar protein in frozen surimi, demonstrating that antifreeze peptides with lower molecular mass and higher THA contributed to slowing down the decline in myofibrillar protein content, Ca2+-ATPase activity, surface hydrophobicity, and characteristic indexes. The differences in the hydrophilicity/hydrophobicity of antifreeze peptides resulted in differences in their interactions with ice crystals and proteins, and consequently caused different effects on surimi myofibrillar proteins. This study provides a theoretical basis for the application of antifreeze peptides and the quality regulation of surimi products and also provides a direction for the development of novel efficient antifreeze agents.

Lettuce is rich in various phenolic acids and flavonoids, making it a good source of dietary polyphenols. This study measured the contents of total phenols and flavonoids and antioxidant capacity of 50 varieties of lettuce (34 green lettuce varieties and 16 red lettuce varieties). Meanwhile, 17 characteristic phenolic acids and flavonoid compounds in lettuce were identified and quantitated using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-ToF-MS) and ultra-high performance liquid chromatography (UPLC). Then, multivariate statistical analysis was used for classification and correlation analysis. The results showed that the contents of total phenols, total flavonoids, and antioxidant capacity of red lettuce varieties were higher than those of green lettuce varieties. In total, 7 phenolic compounds, namely, chlorogenic acid, caffeic acid, isochlorogenic acid A/B, chicory acid, and luteolin-7-O-β-D-glucuronide, quercetin-3-O-glucuronide, and quercetin-3-O-glucoside were detected, being overall more abundant in red lettuce varieties than the other varieties. The results of multivariate statistical analysis indicated that chlorogenic acid, luteolin-7-O-β-D-glucuronide, and quercetin-3-O-glucoside had higher correlation with the antioxidant capacity of lettuce. In summary, five new red varieties and commercial varieties, such as G21K104, W3088, and H20K6160, and four new green varieties, including G21K212 and G21K117, had higher antioxidant activity. This study provides a reference for lettuce breeding, germplasm resource innovation, and the development of nutritious, healthy and functional products.

In order to construct a suitable pea protein-based 3D printable meat analog system, this study explored the effects and mechanism of the addition of pea dietary fiber, gluten, gellan gum and glutamine transaminase on the 3D printing performance and product quality of mixture systems using one-factor-at-a-time and orthogonal array design methods. The results showed that the 3D printing performance, texture characteristics and product characteristics significantly changed depending on the concentration of each ingredient. Using the orthogonal array method, the optimal formulation that provided the best 3D printing performance was determined as 0.45%, 5:1, 0.4% and 1.2 U/g for pea dietary fiber concentration, ratio of pea protein to gluten, gellan gum concentration and glutamine transglutaminase dosage, respectively. After the optimization, the printing accuracy improved by 27.80%. The hardness of the printed sample after cooking was 3 612.13 g, and the chewiness was 1 540.27 g·mm. In addition, the texture characteristics were better than those of the unoptimized sample. The results of infrared spectroscopy and intermolecular force showed that the addition of the components significantly enhanced the hydrogen bond, disulfide bond and hydrophobic interaction in the system. Compared with three commercially available artificial meat samples, the optimized sample exhibited significant advantages in texture characteristics, cooking loss and water-holding capacity, which were related to the structure formed by 3D printing and the interaction among the components. This study provides theoretical guidance and a basis for the application of pea protein in 3D printed plant-based meat.

This study aimed to investigate the structure-function relationship of angiotensin-converting enzyme (ACE) inhibitory peptides and to elucidate the action mechanism of food-derived ACE inhibitory peptides. Based on the amino acid sequences of recently reported ACE inhibitory pentapeptides and their half-maximal inhibitory concentration (IC50) values, a library of ACE inhibitory pentapeptides was generated and the structures of the ACE inhibitory pentapeptides were characterized using three amino acid descriptors, Z-scales, VHSE and SVHEHS. A partial least square (PLS) model for describing the quantitative structure-activity relationship (QSAR) of the ACE inhibitory peptides with the hydrophobic properties, steric properties, and electrical properties of amino acids as the independent variables and the lg IC50 of the ACE inhibitory pentapeptides as the dependent variable was established using Matlab software. The results showed that the R2 and Q2 of the QSAR model based on Z-scales descriptor were 0.641 1 and 0.536 9, respectively, and Gln-Arg-Pro-Asn-Met showed higher ACE inhibitory activity as predicted by this model. The predicted and measured IC50 were 0.051 7 and (0.040 0 ± 0.008 3) μmol/L, respectively, and the error between them was 0.011 7 μmol/L. The R2 and Q2 of the QSAR model based on VHSE descriptor were 0.763 6 and 0.508 1, respectively, and Leu-Arg-Ala-Phe-Gln exhibited better ACE inhibitory activity as predicted by this model. The predicted and measured IC50 were 0.043 8 and (0.027 3 ± 0.005 3) μmol/L, respectively, and the error between them was 0.016 5 μmol/L. The R2 and Q2 of the QSAR model based on SVHEHS descriptor were 0.840 5 and 0.400 5, respectively, and Leu-Arg-Ala-Phe-Gln displayed better ACE inhibitory activity as predicted by this model. The predicted and measured IC50 were 0.005 5 and (0.031 2 ± 0.004 2) μmol/L, and the error between them was 0.025 7 μmol/L. Among the three QSAR models, the one based on SVHEHS descriptor had the strongest fitting capability but weak predictive capacity, while the models based on Z-scales and VHSE descriptors could allow good QSAR analysis of the pentapeptides. Our modeling analysis showed that the activity of the ACE inhibitory peptides was negatively correlated with the hydrophobic characteristics of amino acids and positively correlated with the steric characteristics of amino acids. Molecular docking of three ACE inhibitory peptides to ACE protein (2X8J) showed that all the ACE inhibitory peptides could bind to ACE protein. This study provides a new tool for developing ACE inhibitory peptides and a theoretical basis for the development and application of food-derived ACE inhibitory peptides.

In light of the shortcomings of the quantitative methods for the determination of fatty acid methyl esters (FAME) using gas chromatography-flame ionization detection (GC-FID) specified by the current Chinese and international standards, this work systematically studied the response pattern, theoretical model, and experimental interfering factors in the GC-FID method for the determination of 37 FAME through theoretical derivation and laboratory validation from the perspectives of instruments, chromatographic columns, split ratio, and standard substances. Then, the concepts of “quality coefficient” and “correlation factor” were proposed to reveal the functional relationship and equivalence conditions between experimental relevance factors (FFE) and theoretical relevance factors (FFT). Through multiple experiments, the stability of the correlation factors was confirmed. It was found that the theoretical quality coefficient (QCT) and the FFT could be fully utilized for relative or absolute quantification of FAME with more than 10 carbon atoms. The experimental quality coefficient (QCE) and FFE for FAME with less than 10 carbon atoms could be accurately measured through methods such as freshly preparing FAME reference materials and be used to correct the amount of FAME for quantitative analysis. This not only improved the accuracy of quantitative results, but also increased the timeliness of the use of reference materials and reduced the amount of reference materials used.

This study was performed in order to investigate the impact of steaming and boiling on the color, free and ester-type astaxanthin contents and in vitro antioxidant activity of different parts of crayfish. The results demonstrated that both cooking treatments had significant effects on the astaxanthin contents, color, and antioxidant activity of the different parts of crayfish. The astaxanthin contents of all crayfish parts increased initially and then declined with cooking time. Fresh crayfish tail shells were found to contain free astaxanthin and five astaxanthin monoesters. Free astaxanthin and one astaxanthin monoester were found in boiled crayfish tail shells, suggesting that boiling could promote the hydrolysis of esterified astaxanthin and the consequent generation of 98% free astaxanthin. With cooking time increasing, the L* value of crayfish increased slowly, and the a* value initially increased and later decreased, while the W value showed no significant change. Moreover, the a* value was strongly correlated with the astaxanthin content (r > 0.4). Both hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity increased first and subsequently declined. All parts of crayfish maintained high scavenging capacity against 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radicals. For all parts of steamed crayfish, astaxanthin contents showed a strong correlation with DPPH radical scavenging capacity (r > 0.9), but had a significant positive correlation with hydroxyl radical scavenging capacity for both claws and meat (P < 0.01). For all parts of boiled crayfish except the head, astaxanthin contents were significantly positively correlated with hydroxyl radical scavenging capacity (r > 0.9, P < 0.05).

This study investigated the effects of treatment with different concentrations of sodium chloride (NaCl) on the characteristics of intramuscular collagen and related endogenous enzyme activities in beef during 72 h postmortem in order to provide theoretical evidence that NaCl contributes to improving postmortem beef tenderness. Enzyme-linked immunosorbent assay (ELISA) was used to determine the changes in the level of mature collagen cross-linking and endogenous enzyme activities in bovine longissimus dorsi muscle after being treated with 1% or 3% (m/m) NaCl solution. At the same time, differential scanning calorimetry (DSC), endogenous and exogenous fluorescence spectroscopy and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were used to determine physicochemical properties such as thermal solubility, thermal stability, surface hydrophobicity to characterize the structural changes and degradation status of collagen. The results showed that treatment of NaCl at both concentrations could regulate the activity of lysine oxidase, β-glucuronidase and β-galactosidase in beef during 72 h postmortem, thereby enhancing the thermal solubility of intramuscular collagen, reducing the thermal stability, promoting conformational changes and degradation of collagen and ultimately contributing to improving the tenderness of postmortem beef.

This study investigated the effects of the addition of Tremella fuciformis polysaccharides on the zeta potential, particle size, contact angle, storage stability, and rheological properties of curcumin-loaded Pickering emulsion. The results showed that the Pickering emulsion stabilized by T. fuciformis polysaccharides had good stability; its particle size decreased from (8.631 ± 0.057) to (6.031 ± 0.056) μm and its zeta potential increased (–51.60 ± 1.51) to (–65.16 ± 0.59) mV with increasing addition of T. fuciformis polysaccharides from 65% to 85% (V/V), showing improved storage stability. The retention rate of curcumin in the Pickering emulsion with 85% T. fuciformis polysaccharides was more than 80% after 21 days of storage. The rheological results showed that all emulsions exhibited weak gel properties and shear-thinning characteristics. As oil-in-water emulsions, they showed a contact angle of less than 90°. The emulsion retained more than 80% curcumin after heat treatment at 65 ℃. Meanwhile, the emulsion had antibacterial activity against both Escherichia coli and Staphylococcus aureus. The results of this study provide a theoretical reference for the development of new Pickering emulsions with T. fuciformis polysaccharides.

In this study, the effects of four Hofmeister salts (KCl, NaCl, CaCl2 and MgCl2) at different concentrations (0.02, 0.04 and 0.06 mol/L) on gel properties and rheological properties of soy protein isolate (SPI) were systematically explored. The results showed that the addition of salt ions could improve the gel strength of SPI, but higher concentrations (0.04 and 0.06 mol/L) of CaCl2 and MgCl2 reduced the gel stickiness of the samples. In the dynamic rheological test, each salt ion increased the storage modulus (G’) and loss modulus (G”) of the samples to varying degrees. Higher concentrations of CaCl2 and MgCl2 caused excessive aggregation of SPI, whereas lower concentrations of CaCl2 and MgCl2 exerted an opposite effect. In the temperature sweep test, CaCl2 and MgCl2 changed the trend of G’ and G”, while KCl and NaCl simply increased G’ and G” without changing their trend. In the steady rheological test, higher concentrations of CaCl2 and MgCl2 reduced the apparent viscosity and shear force of the samples, while an opposite effect was observed under the other salt conditions. The decreasing order of the effects of higher concentrations of salt ions on the apparent viscosity and shear force was K+ > Na+ > Mg2+ > Ca2+. In summary, at specific salt ion concentrations (0.04 and 0.06 mol/L), the changes in gel and rheological properties of SPI were consistent with the Hofmeister effect.

To explore substitutes for natural tropomyosin as basic materials for the diagnosis and treatment of shrimp allergy, total RNA was extracted from Macrobrachium nipponense, and the full-length sequence of the tropomyosin gene was cloned by rapid amplification of cDNA ends (RACE). Specific primers were designed based on the cDNA sequence of tropomyosin and the expression plasmid pET-30a-TM was constructed. Finally, recombinant tropomyosin was expressed under the induction of isopropyl-β-D-thiogalactopyranoside (IPTG). The results showed that the full-length cDNA sequence of tropomyosin was 1 658 bp in length (GenBank accession number: OP974621). Its open reading frame (ORF) was 855 bp in length, encoding 284 amino acids, with a predicted protein isoelectric point of 4.70 and a predicted molecular mass of 32.8 kDa. The highest expression was obtained after 4 h of induction with a final IPTG concentration of 1 mmol/L at 37 ℃. The recombinant tropomyosin mainly existed as a soluble form in the supernatant of cell lysate with a molecular mass of approximately 38 kDa.

In this study, a luxS-deleted mutant of Vibrio parahaemolyticus was successfully constructed by homologous recombination technology, and the growth capacity, 4,5-dihydroxy-2,3-pentanedione (DPD) production, biofilm formation, motility, drug susceptibility, extracellular protein-secreting capacity, and quorum sensing-related gene expression of the wild and mutant strains were compared to understand the effects of luxS gene deletion in the LuxS/AI-2 quorum sensing system on the biological characteristics of V. parahaemolyticus. The results showed that the deletion of the luxS gene did not affect the drug susceptibility or growth capacity of the strain. Compared with the wild-type strain, the DPD production and mobility of the mutant strain was significantly reduced, while the capacity of biofilm formation and extracellular protease secretion after 24 hours of incubation was significantly enhanced. The real-time polymerase chain reaction (PCR) results showed that the expression of the flagellar synthesis gene flgM significantly increased, while the expression of the hemolysin secretion-related gene toxS, the flagella synthesis gene flaA and the outer membrane protein gene ompW decreased significantly in the mutant strain. This study provides a basis for further research on the regulation mechanism of the LuxS/AI-2 quorum sensing system on the biological characteristics of V. parahaemolyticus, which will be helpful for the prevention and control of V. parahaemolyticus.

Physicochemical analysis, headspace-solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) and high-throughput sequencing were used to investigate the potential relationship between the microecology of different flavor types of Daqu and their physicochemical indexes and characteristic flavor compounds. The results showed that the highest saccharification power and fermentation power were found in Fen-flavor Daqu, the highest esterification power and starch content in Luzhou-flavor Daqu, and the highest acidity were found in Maotai-flavor Daqu. In the three types of Daqu, the dominant bacterial genera were Saccharopolyspora, Weissella and Bacillus, and the dominant fungal genera were Saccharomycopsis, Aspergillus and Thermomyces. Correlation analysis showed that Bacillus was positively correlated with saccharification power, liquefaction power, fermentation power, ethyl caprate and phenyl ethanol. Thermomyces was positively correlated with ethyl caproate, isoamyl alcohol, ethyl lactate, acetic acid and ligustrazine.

Response surface methodology (RSM) was employed to optimize the hydrolysis conditions of acid-soluble collagen (ASC) from Takifugu rubripes skin for the preparation of anti-tyrosinase peptides. The anti-tyrosinase and antioxidant activity of ultrafiltration peptides with different molecular masses were tested before and after being subjected to simulated gastrointestinal digestion, and the moisture absorption and retention properties were also evaluated to explore their application potential. The results showed that neutral protease was the most suitable enzyme for releasing anti-tyrosinase peptides from T. rubripes skin collagen. The optimum process conditions were as follows: substrate concentration 2.9 g/100 mL, hydrolysis time 7.8 h, and enzyme dosage 7 862 U/g. The hydrolysate obtained under these conditions inhibited tyrosinase activity by (35.14 ± 0.03)%. The molecular mass of the hydrolysate mainly ranged from 0 to 5 kDa, and the fraction CP-1 (< 3 kDa), with the highest anti-tyrosinase activity, scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation and hydroxyl radicals with half maximal inhibitory concentration (IC50) values of 9.51, 2.03 and 7.29 mg/mL, respectively. CP-1 maintained high anti-tyrosinase and antioxidant activity after in vitro simulated digestion. In addition, CP-1 had high moisture absorption and retention properties and therefore could be used as a substitute for glycerol. This study may provide a theoretical basis for the deep processing and application of collagen peptides from T. rubripes skin.

In this study, Saccharomyces cerevisiae and non-Saccharomyces strains were isolated from sourdough. S. cerevisiae SQJ20, which had a stronger gas-producing capacity than commercial activated dry yeast, was selected from 78 strains of S. cerevisiae. Wickerhamomyces anomalus GZJ2 and Torulaspora delbrueckii SDJ6 were selected to improve the quality of steamed bread. Co-fermentation with S. cerevisiae SQJ20 and W. anomalus GZJ2 at a ratio of 1:2 significantly improved the quality of steamed bread. Furthermore, W. anomalus GZJ2 increased the contents of total protein and free amino acid (13.69%), with the increase being greatest in the sweet amino acid proline (94.69%), the aromatic amino acid phenylalanine (82.63%), and the essential amino acid lysine (66.26%). The electronic nose and sensory evaluation results corroborated that the addition of W. anomalus GZJ2 improved the quality of steamed bread. In conclusion, co-fermentation with S. cerevisiae SQJ20 and W. anomalus GZJ2 could improve the quality of steamed bread without extending the fermentation time. Our observations provide a reference for the industrial production of flavored steamed bread.

In order to explore the effects of in vitro fermentation of quinoa water insoluble dietary fiber and exogenous addition of lactic acid bacteria on the gut microbiota and short-chain fatty acids (SCFAs), fecal filtrate (FF) from healthy subjects either alone or in combination with Lactobacillus plantarum was used to ferment quinoa water insoluble dietary fiber in vitro. The production of SCFAs was determined by gas chromatography (GC), and the changes in microbial community structure and abundance in the fermentation broth were analyzed by 16S rDNA sequencing. The results showed that the addition of quinoa insoluble dietary fiber and L. plantarum could change the structure and abundance of the gut microbiota. At the phylum level, the addition of quinoa insoluble dietary fiber and L. plantarum increased the abundance of Bacteroidota after 12 h of fermentation. At the genus level, quinoa insoluble dietary fiber increased the abundance of beneficial bacteria (Prevotella). Compared with the in vitro fermentation of quinoa water insoluble dietary fiber with FF, the exogenous addition of L. plantarum significantly increased the production of SCFAs. In summary, the in vitro fermentation of quinoa water insoluble dietary fiber by L. plantarum could significantly change the abundance and diversity of the intestinal microbiota, and promote the production of SCFAs, which is beneficial to intestinal health.

The anti-aging effects of four Bifidobacterium species (B. pseudospermum BP-1, B. longum BL-3, B. animalis BA-5 and B. infantis BI-38) on Caenorhabditis elegans were evaluated in terms of its lifespan, reproductive capacity, vitality, body shape, stress resistance, lipofuscin levels, antioxidant enzyme activity and malondialdehyde (MDA) content. The results showed that compared with the control group (Escherichia coli OP50), BA-5 and BI-38 effectively extended the lifespan of C. elegans (P < 0.05), while BP-1 and BL-3 had no significant effect on the lifespan of C. elegans (P > 0.05). Meanwhile, BA-5 and BI-38 did not impair the reproductive or locomotory capacities of C. elegans (P > 0.05), but could effectively enhance its pharyngeal pumping and reduce its body size (P < 0.05). BA-5 and BI-38 were able to enhance tolerance to heat or oxidative stress and thus prolong the lifespan of C. elegans (P < 0.05), significantly reduce lipofuscin accumulation and MDA content (P < 0.05), and significantly increase the activity of two antioxidant enzymes (catalase and superoxide dismutase) in C. elegans (P < 0.05). In conclusion, B. infantis BI-38 and B. animalis BA-5 had stronger anti-aging activity in vivo.

Objective: To investigate the protective effect and mechanism of docosahexaenoic acid-enriched phosphatidylserine (DHA-PS) against cyclophosphamide (CTX)-induced renal injury in mice. Methods: Thirty-two male institute of cancer research (ICR) mice were randomly divided into four groups: control (CON), model (MOD), 50 mg/kg mb DHA-PS (50 DHA-PS), and 100 mg/kg mb DHA-PS (100 DHA-PS), with eight mice in each group. The renal injury model was established by intraperitoneal injection of 80 mg/kg mb CTX. Five days later, the mice in the MOD and DHA-PS groups were gavaged for 7 days with an equal volume of physiological saline and DHA-PS, respectively and then sacrificed. Kidney indexes, serum biochemical indicators, the levels of renal oxidative stress and inflammatory factors, histopathological changes, and non-targeted metabolomics of renal tissues were evaluated. Results: Compared with the MOD group, DHA-PS significantly decreased kidney indexes, creatinine, blood urea nitrogen, cystatin C, and kidney injury molecule-1 levels (P < 0.05), increased the activities of antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) (P < 0.05), reduced the content of malondialdehyde (MDA) (P < 0.05), downregulated the expression of pro-inflammatory cytokines including interleukin (IL)-6, IL-1β, tumor necrosis factor-α (P < 0.05), and upregulated the level of the anti-inflammatory cytokine IL-10 (P < 0.05). Staining results showed a significant restoration of kidney tissue structure in the DHA-PS group. Additionally, the results of renal tissue metabolomics indicated that DHA-PS mitigated CTX-induced metabolic disorders in mouse kidneys mainly by affecting glycerophospholipid metabolism, purine metabolism, and their metabolites. Conclusion: DHA-PS can alleviate CTX-induced renal injury in mice through reducing oxidative stress and inflammatory response, and regulating the glycerophospholipid and purine metabolism pathways.

In order to explore the application value of different grape varieties in fruit beer brewing and their effects on beer quality, we studied the effects of addition of different levels (30% and 40%, V/V) of Syrah or Merlot grape mashes on the aroma, physical and chemical indexes and antioxidant activity of fruit beer. Besides, grape beer with better quality was determined by sensory evaluation. The results showed that both grape varieties increased the concentration and antioxidant properties of phenols including 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity, ferric and cupric ion reducing power abilities, and significantly elevated the acidity and alcohol concentration of beer. The beer made with the addition of 30% Syrah or 40% (V/V) Merlot exhibited the highest content of aroma compounds, which increased by 190.55% and 152.65%, respectively, when compared with the control group. Sensory evaluation showed that the beer made with the addition of 30% Syrah tasted best. In general, the addition of different varieties of grape mashes had a positive effect on improving beer quality and aroma, which could become an important direction for the development of diversified beer products in the future.

In order to investigate the burnt flavor substances of Nongxiangxing base baijiu, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the flavor components of base baijiu with normal and burnt flavor. The results showed that a total of 139 flavor substances were detected, of which 20 could be used to differentiate between the two types of base baijiu. Cluster heatmap analysis showed that nine flavor substances, 2,4-di-tert-butylphenol, ethyl laurate, butyl caproate, hexyl caprylate, heptyl heptanoate, pentyl caproate, hexyl caproate, caproic acid, and caprylic acid, were more predominant in burnt-flavor base baijiu. Sensory reconstitution, omission, and addition experiments revealed that the burnt flavor was not ascribed to a single compound but rather to the interaction of multiple compounds. 2,4-Di-tert-butylphenol and esters were found to be significantly associated with the burnt flavor of Nongxiangxing base baijiu.

In order to explore the differences in the flavor characteristics of fermented hot pepper prepared from different varieties, the volatile compounds of fermented hot pepper made from four varieties widely planted in Guizhou, Huangping line (HP), Linka (LK), Qian 8 (Q4) and Layan 101 (LY), were analyzed by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The results showed that 60, 71, 55 and 65 volatile compounds were detected in HP, LK, Q4 and LY, respectively. Acetic acid was the most abundant volatile component in HP, LK and Q4, while geraniol was the most abundant volatile component in LY. In total, 24 volatile compounds were common to the four fermented hot peppers. Correlation analysis showed significantly negative correlations (P < 0.05) between alcohols and alkanes and alkenes, between esters and ketones. Conversely, there was a significantly positive correlation between alkenes and alkanes. Using orthogonal partial least squares-discriminant analysis (OPLS-DA), more than 10 differential volatile compounds were selected among the four varieties, with 2-phenylethyl acetate being the major one in HP vs Q4 and LK vs Q4, acetic acid being the major one in LY vs Q4 and LK vs LY, and phenylacrylonitrile being the major one in LK vs HP. A comprehensive quality evaluation model was established based on nine classes of volatile compounds in fermented peppers, and the decreasing order of volatile flavor quality was HP > LY > LK > Q4. This study could provide a reference for the choice of raw materials for fermented peppers.

The longissimus dorsi muscle of sheep was treated with cold plasma (CP) induced by dielectric barrier discharge (DBD) at different time points (6, 12, 24, 48, 72 and 120 h) after slaughter. By analyzing changes in the color, myoglobin content, fat oxidation, total sulfhydryl content and surface hydrophobicity of samples during postmortem cold storage, the effects of DBD-CP treatment at different time points after slaughter on the color and oxidation stability of mutton at different time points after slaughter were determined. The results showed that DBD-CP treatment at different time points after slaughter had no significant effects on L* or a* values of mutton (P > 0.05), but significantly increased the b* value compared to the untreated control group (P < 0.05). DBD-CP treatment reduced the color stability of the meat and accelerated the deterioration of meat color. DBD-CP treatment at 6 and 12 h postmortem had little impact on the color stability. DBD-CP treatment at all selected time points after slaughter had no significant effect on the myoglobin content of mutton (P > 0.05). The thiobarbituric acid reactive substances (TBARS) value of the DBD-CP treatment group was higher than that of the control group (P < 0.05), and the treatment significantly reduced the total sulfhydryl content in mutton and increased the surface hydrophobicity (P < 0.05). In summary, DBD-CP treatment at 6 to 12 h after slaughter had the most significant effect on stabilizing and maintaining meat color. In addition, it could accelerate the oxidation of myofibrillar protein (MP). Therefore, DBD-CP treatment has potential application value in improving the quality of mutton.

The effects of adding dried Lyophyllum decastes (DLR) or dried L. decastes by-products (DBY) on physicochemical properties and nutritional functions of extruded barley flour (BF) were analyzed. Results revealed a notable decrease in the degree of starch gelatinization in the DLR and DBY groups compared to the control group with nothing added. Gastrointestinal digestion simulation using the INFOGEST 2.0 method indicated that the antioxidant capacity of DBY was significantly higher than the BF group and DLR group (P < 0.05) due to its rich soluble dietary fiber content derived from L. decastes by-product. All the BF, DLR and DBY groups showed increased acetic acid production between 0 and 24 h of simulated colonic fermentation, thus leading to a significant reduction in pH (P < 0.05). Butyric acid levels significantly rose in all groups from 24 to 48 h. The DBY group displayed higher levels of acetic, butyric and propanoic acid compared to the DLR group at 72 h. Analysis of the gut microbiota highlighted the significant influence of individual variability on the regulatory effects of DLR and DBY, both of which notably promoted the growth of Dorea and Anaerostipes. Correlation analysis suggested that DBY augmented the levels of acetic and propanoic acid by stimulating Bifidobacterium (r > 0.5, P < 0.05). In summary, the incorporation of L. decastes or its by-products effectively enhanced the quality and functional attributes of barley flour products. Notably, DBY exhibited superior antioxidant activity and modulation of the gut microbiota. These findings offer theoretical support for the development of extruded L. decastes-barley products.

In order to investigate the effects of different doses of 60Co-γ-ray irradiation on rice, this experiment employed a texture analyzer, a rapid viscosity analyzer, a differential scanning calorimeter, a rheometer, an X-ray diffractometer, and a Fourier transform infrared spectrometer to characterize the eating quality of rice and the physicochemical properties and structure of rice starch. The results indicated that as irradiation dose increased, the water absorption and volumetric expansion of rice during cooking, and the pH, dissolved solid content and iodine blue value of rice broth fell significantly (P < 0.05). High doses of irradiation resulted in a noticeable increase in the total color difference (ΔE) of rice compared with that before irradiation, and a ΔE of 12.53 was obtained at 10 kGy, indicating a significant color change. Also, the irradiation notably affected the hardness of cooked rice. The peak viscosity, setback value, and gelatinization enthalpy of rice starch decreased significantly (P < 0.05) with the increase in irradiation dose; the irradiation also reduced the rigidity, elasticity, relative crystallinity and orderliness of rice starch, with the crystallinity being decreased from 23.68% to 15.69%. The measurement results of cooking indicators, rice soup properties, ΔE, and texture characteristics indicate that higher irradiation doses reduced the edible quality of rice. Moreover, the contents of slowly digestible starch and resistant starch in irradiated rice starch increased, with the latter being increased to 20.22% after irradiation treatment at 4 kGy. Compared with the unirradiated control, the irradiation reduced the hydrolysis rate of starch. Overall, γ-ray irradiation altered the crystalline structure of starch, thereby enhancing its pasting and rheological properties and inhibiting its digestibility, but rice is not suitable for high doses of irradiation treatment. This study provides theoretical guidance for the production of irradiated rice and its products, as well as for the modification of starch.

This study was conducted to evaluate the effect of low-frequency alternating magnetic field assisted freezing (LF-MFF, –18 ℃) for different periods (12, 24, 36 and 48 h) on the quality of pork using fresh meat and conventional refrigerator freezing (–18 ℃, 36 h) as controls. The changes in the freezing rate, water-holding capacity, tenderness, color, pH, water migration and rheological properties of meat samples subjected to different freezing treatments were analyzed. The results indicated that compared with conventional refrigerator freezing, LF-MFF treatment at a magnetic intensity of 3 mT exhibited higher freezing rates and significantly improved pork quality (P < 0.05); among all freezing treatments, LF-MFF for 36–48 h improved the water-holding capacity, color and tenderness of pork (P < 0.05), thus maintaining better physicochemical properties. Low-field nuclear magnetic resonance (LF-NMR) results showed that the proportion of immobilized water was significantly increased and the proportion of free water was decreased after 36–48 h LF-MFF when compared with conventional refrigerator freezing (P < 0.05). Furthermore, dynamic rheological results suggested that the samples subjected to LF-MFF for 36–48 h had higher G’ values and lower degrees of protein denaturation, indicating the formation of protein gels with better viscoelasticity. The Pearson correlation analysis indicated that the changes in physicochemical properties and moisture migration of pork after different freezing treatments were significantly correlated. Therefore, LF-MFF for 36–48 h could be the optimal freezing treatment for pork, which could maintain the physicochemical properties of pork, reduce moisture migration and inhibit protein denaturation, thereby improving the quality of frozen pork.

In order to investigate the quality changes and shelf life of blueberries stored in different temperature, 21 quality indexes, including color parameters, mass loss rate, spoilage rate and texture parameters, were measured on “Freedom” blueberries at three storage temperatures (0, 4 and 25 ℃). Using five machine learning algorithms with a self-contained function of feature selection, seven key features affecting the shelf life were selected as input variables to construct a shelf life prediction model using gated recurrent unit (GRU) alone or in combination with convolutional neural network (CNN) and/or attention (AE) mechanism. The results showed that compared with the GRU model, the mean absolute error (MAE), mean square error (MSE) and mean absolute percentage error (MAPE) of the CNN-GRU-AE model decreased by 75.83%, 91.46%, 61.58%, respectively, and the coefficient and determination increased by 2.25%, indicating significantly improved accuracy of shelf-life prediction. This study provides theoretical support for the shelf life prediction of blueberries at different storage temperatures.

In this study, cellulose films loaded with different concentrations (0%, 0.1%, 0.5% and 1%) of curcumin (C-Cux-F) having good mechanical properties, water resistance, photosensitive antibacterial properties, and high oxygen-barrier performance were successfully prepared. Due to its strong interaction with the cellulose chain, curcumin could significantly improve the mechanical properties and water resistance of cellulose film. The doping level of curcumin significantly affected the oxygen permeability of cellulose film (P < 0.05). The oxygen permeability of the film gradually decreased with the increase in curcumin level. The oxygen permeability of the films loaded with 0%, 0.1%, 0.5%, and 1% curcumin was approximately (29.71 ± 1.66), (4.79 ± 0.13), (3.52 ± 0.45), and (0.90 ± 0.09) cm3/(m2·d) at room temperature (23 ℃), respectively. The addition of curcumin in the range of 0% to 0.5% significantly reduced the moisture permeability of cellulose film due to the enhancement of intermolecular forces (P < 0.05). Curcumin-loaded cellulose film exhibited a good photosensitive antibacterial effect against S. aureus, which increased with the extension in light exposure time. This is probably ascribed to the fact that photosensitization of curcumin generates singlet oxygen. After white light exposure for 10 and 20 min at an intensity of 60 mW/cm2, the inhibitory activity of 1% curcumin-loaded cellulose film (C-Cu1-F) against S. aureus was (61.00 ± 1.73)% and (91.67 ± 1.53)% , respectively. In the preservation of fresh chilled pork, C-Cu1-F could significantly inhibit the production of total volatile basic nitrogen (TVB-N), and reduce the total bacterial count (P < 0.05), implying a significant inhibitory effect on the growth of microorganisms and the production of biogenic amines. Therefore, curcumin-loaded cellulose film not only showed excellent mechanical and antibacterial properties, but also had a preservation effect on fresh pork.

Phyllostachys praecox shoots were frozen using liquid nitrogen at –60, –90 or –120 ℃ to an internal temperature of –18 ℃, or frozen at –90 ℃ to an internal temperature of –6, –12 or –18 ℃, vacuum-packed and stored in a freezer at –18 ℃ for 24 weeks. In order to analyze the effect of liquid nitrogen freezing on physiological and biochemical characteristics of P. praecox shoots during frozen storage, L-phenylalanine ammonialyase (PAL) and peroxidase (POD) activities, total phenolic content, relative electrical conductivity, and water state were measured and ice crystal structure and cell morphology were observed. The results showed that with increasing freezing time, the PAL and POD activities, total phenolic content, and peak area of free water in all six groups decreased significantly (P < 0.05), while the relative electrical conductivity increased significantly (P < 0.05), with the ice crystals and cells being deformed and damaged to varying degrees. Lower freezing temperature led to smaller ice crystals, lower PAL and POD activities and relative electrical conductivity, higher total phenolic content, and better maintenance of cell morphology, but there was no significant difference in physiological and biochemical properties between P. praecox shoots frozen at –90 and –120 ℃ (P > 0.05). The PAL and POD activities and relative conductivity of P. praecox shoots frozen at –6 ℃ were higher than those frozen at –12 and –18 ℃, and the size of ice crystals was smaller and the degree of cell damage was greater in P. praecox shoots frozen at –6 ℃ than at –12 and –18 ℃. The difference between P. praecox shoots frozen at –12 and –18 ℃ was not significant (P > 0.05). Collectively, these findings indicated that the most suitable liquid nitrogen freezing conditions of P. praecox shoots are –90 and –12 ℃ for freezing and internal temperature, respectively.

To study the effect of 6’-O-caffeoylarbutin (CA) treatment on the prevention and control of gray mold in postharvest blueberry fruit and its effect on fruit phenylpropane metabolism, blueberries were soaked in 2.5 mmol/L CA solution or distilled water as the control. The results showed that CA treatment significantly reduced the incidence of gray mold in postharvest blueberry fruit and inhibited the expansion of lesion diameter when compared with the control. Meanwhile, it increased the activities of phenylalanine ammoniase (PAL), cinnamic acid-4-hydroxylase (C4H), 4-coenzyme coenzyme A ligase (4CL), cinnamyl alcohol dehydrogenase (CAD), polyphenol oxidase (PPO) and peroxidase (POD), as well as the contents of total phenols, flavonoids and lignin, with few adverse effects on the storage quality. It is concluded that CA treatment could promote the synthesis and accumulation of resistance-related substances and consequently enhance the resistance to gray mold by activating the enzyme activities related to phenylpropane metabolism in postharvest blueberry fruit.

In this study, the effects of different freezing methods and temperatures (freezer at −20 and −50 ℃, and liquid nitrogen at −50 and −80 ℃) on the water-holding capacity and structural properties of myofibrillar proteins from the hind leg muscle of Rana nigromaculata were investigated. The results showed that the time required for hind legs frozen in freezer at −20 and −50 ℃ and with liquid nitrogen at −50 and −80 ℃ to pass through the zone of maximum ice crystal formation temperature (−1 to −5 ℃) were 91.5, 57.0, 1.5 and 0.5 min, respectively. Compared with the freezer freezing groups, the liquid nitrogen freezing groups exhibited reduced thawing loss, increased content of immobilized water, and decreased content of free water. Compared with fresh samples, the water-holding capacity, solubility, total sulfhydryl content and endogenous fluorescence intensity of myofibrillar proteins decreased significantly after freezing, and the particle size, surface hydrophobicity and relative content of random coil showed an increasing trend. In the −50 ℃ liquid nitrogen freezing group, the water-holding capacity, protein solubility, total sulfhydryl content and endogenous fluorescence intensity decreased by 8.10%, 9.57%, 10.50% and 67.36%, respectively, and the volume average particle size, surface hydrophobicity and random coil content increased by 100.05%, 82.24% and 13.65%, respectively; these changes were significantly lower than those in the other freezing groups (P < 0.05). The degree of myofibrillar protein denaturation in the −80 ℃ liquid nitrogen freezing group was significantly lower than that in the −20 ℃ freezer freezing group, but higher than that in the −50 ℃ liquid nitrogen freezing group (P < 0.05). According to the results of scanning electron microscopy (SEM), muscle fibers were more tightly and regularly arranged in the −50 ℃ freezer freezing and −50 ℃ liquid nitrogen freezing groups, while those in the −80 ℃ liquid nitrogen freezing group were arranged regularly but slightly cracked, and those frozen in the −20 ℃ freezer freezing group were obviously broken. These findings indicate that liquid nitrogen freezing can slow down the migration of water in the hind leg muscle of R. nigromaculata and effectively inhibit the cold denaturation of myofibrillar proteins, the effect being more pronounced at −50 ℃ than at −80 ℃.

Gas chromatography-ion mobility spectrometry (GC-IMS) was used to determine the flavor components of Citri Reticulatae Pericarpium (Chenpi) from 10 different geographical origins including Xinhui. To establish a method for the identification of Xinhui Chenpi, the 75 identified flavor components were analyzed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The results showed that the proposed method could distinguish Xinhui Chenpi from those from other regions. Meanwhile, by analyzing the variable importance in projection (VIP), we selected 20 key characteristic markers to distinguish Xinhui Chenpi from other Chenpi. In conclusion, the combined application of GC-IMS and PLS-DA allows the accurate identification of Xinhui Chenpi, providing a new technical reference for the protection and origin tracing of Xinhui Chenpi as a national geographical indication product in China.

Diterpenoids are terpenoids containing four isoprene units with a total of 20 carbon atoms. They are derived from geranyl pyrophosphate, including acyclic diterpenes, monocyclic diterpenes, dicyclic diterpenes, tricyclic diterpenes, and tetracyclic diterpenes. These compounds are widely found in plants, insects, fungi and marine organisms, and are important bioactive substances in plant extracts. Diterpenoids have a variety of biological activities due to their structural diversity. Particularly, their outstanding antioxidant and antibacterial activities make them widely applied in meat preservation. In this article, the chemical and structural characteristics, biological activities and sources of diterpenoids are reviewed, and recent advances in the application of diterpenoids in the preservative of meat are summarized, aiming to provide a reference for the theoretical research and commercial application of diterpenoids in meat products.

Gluten-induced celiac disease (CD) is a serious autoimmune disorder whose symptoms in most gluten-sensitive populations can only be relieved by strict lifelong adherence to a gluten-free diet (GFD). Sensors for immediate, on-site and quick detection of the gluten content in foods can effectively ensure the quality of life of gluten-sensitive people. In this article, gluten sensitivity and the pathogenesis of CD are introduced, and the recognition principle of gluten detection biosensors is elaborated. Finally, the application scenarios of biosensors with three different types of signal output: colorimetry, fluorescence and electrochemistry for the rapid detection of gluten in foods are summarized in order to provide a basis for research on sensors for the rapid detection of gluten in foods.

Coaxial electrospinning is a new technology for the preparation of multi-structure nanofibers, with the advantages of simple equipment operation, mild processing conditions and adjustable structure. This technology uses a direct current (DC) high voltage electrostatic field to continuously transform a variety of polymer solutions into multi-structure nanofibers, such as core-shell, hollow and porous ones. These special structures endow nanofibers with excellent encapsulation and controlled release properties, diverse interface structures, and a large number of reaction sites, which have potential applications in functional ingredient encapsulation, slow release of bioactive ingredients, and food detection. This article briefly introduces the basic principle of coaxial electrospinning technology and the major factors affecting nanofiber formation, such as spinning solution properties, process parameters, and environmental conditions. Moreover, it elaborates on the strategies for preparing multilevel structure nanofibers by using coaxial electrospinning and its structural advantages, focusing on the application of this technology in active food packaging, encapsulation and targeted delivery of bioactive ingredients, food detection, and juice filtration and concentration. It is our hope that this article will promote the wide application of coaxial electrospinning technology in the field of food.

Docosahexaenoic acid (DHA) is an n-3 polyunsaturated fatty acid that is essential for human nutrition. Currently, DHA is commonly produced using Aurantiochytrium, and omics technologies are widely used to investigate the mechanism underlying high DHA production in Aurantiochytrium, providing a foundation for genetic modification of Aurantiochytrium and control of the fermentation process. In this article, the history and major research directions of DHA production by Aurantiochytrium are summarized, and the application of omics technology in Aurantiochytrium is reviewed. It also summarizes recent progress in the application of genomics, transcriptomics, proteomics, metabolomics and multi-omics approaches as well as mathematical models based on omics data to reveal the mechanism underlying high DHA production in Aurantiochytrium. This review concludes with a discussion of future prospects for the development and application of omics technology.

Sweetness is an important driver for food intake and one of the most popular taste sensations. At present, there is a preliminary understanding of the signaling pathways of sweetness and the mechanisms that affect sweetness sensation. Human sweetness sensation is expressed through at least two types of signaling pathways, one of which is mediated by heterodimers formed by the taste receptor family 1 member 2 (T1R2) and the taste receptor family 1 member 3 (T1R3), whereas the other by sodium glucose co-transporters (SGLT) and glucose transporters (GLUT). This article reviews the structure of T1R2/T1R3 heterodimer and the mechanism of sweet signal transduction, and discusses the effects of internal and external factors such as bitterness, sourness, umami, anti-sweetness substances, aroma compounds, saliva, obesity and age on sweetness sensation. The shortcomings of the current research are presented, such as little effect of the current available noncaloric sweeteners (NCSs) in attenuating obesity and diabetes, few studies on the interactions of sweet taste with the other four taste sensations, unclear understanding of the molecular basis of the regulation mechanisms of anti-sweetness substances at the receptor level, and limitations of using rodents as an experimental substitute for humans in sweet taste research. This article aims to understand how sweet substances exert their functions in complex food matrices, hoping to provide theoretical support and ideas for future development and application of NCS-containing foods.

Rice bran, a byproduct of rice processing, holds great nutritional value. However, its application in the food industry is greatly restricted due to its high susceptibility to rancidity and spoilage during storage. Currently, it is primarily used as animal feed with low added value. The presence of lipase and lipoxygenase is the major cause of rapid rancidity of rice bran, and other factors such as water activity, microorganisms and phenolic substances also affect the rancidity reaction. Stabilization treatment of rice bran is a key prerequisite to achieving high-value utilization of the product. This paper provides an overview of the rancidity mechanism of rice bran, the common methods for stabilizing rice bran and their impact on its quality and nutritional characteristics, with a view to providing guidance and reference for the research and development of rice bran as a food-grade raw material.

Lactic acid bacteria play a dual role by enhancing both the flavor and nutritional benefits of fermented foods, and helping the body to prevent a variety of diseases caused by oxidation. The fulfillment of these beneficial functions is inseparable from the antioxidant activity of lactic acid bacteria. This article elaborates on the antioxidant mechanism of lactic acid bacteria including regulating antioxidant enzymes, regulating signaling pathways, scavenging free radicals, and inhibiting lipid peroxidation and metal ion chelation. The current status of the application of the antioxidant activity of lactic acid bacteria in dairy, meat, aquatic, and fruit and vegetable products is also reviewed. Finally, this article outlines the in vitro and in vivo evaluation methods for the antioxidant activity of lactic acid bacteria, aiming to provide a reference for deepening the application of lactic acid bacteria in the food processing sector.

Milk is an excellent medium for the growth of microorganisms, which is easily contaminated by microorganisms from the environment. Psychrophilic bacteria are the most common microorganisms in cold-stored raw milk. Moreover, psychrophilic bacteria produce heat-resistant proteases and lipases in low-temperature environments, which remain active even after heat treatment, and decompose proteins and fats in liquid milk during storage, thereby affecting the quality of milk. The counting method for psychrophilic bacteria in milk specified by the agricultural industry standard of China takes 10 days to culture samples at 6.5 ℃ for 10 days, which is time-consuming and has low application value in actual production. Therefore, the development of detection technologies for psychrophilic bacteria and their heat-resistant enzymes is very important for ensuring the quality of milk and dairy products. This article reviews a variety of methods for the identification and analysis of psychrophilic bacteria in milk, including polymerase chain reaction (PCR), sequencing, fluorescence in situ hybridization, and loop-mediated isothermal amplification. It provides a reference for the development of new detection technologies for psychrophilic bacteria in milk.

Lactic acid bacteria (LAB) are widely used in the development of plant-based fermented foods, which play an important role in forming and improving the unique flavor, and promoting the diversification of nutritional and health benefits of fermented products. This article introduces the health benefits of LAB and reviews the recent applications of LAB in fermented tea with special reference to the basis, the fermentation process and its impact on tea quality. Meanwhile, future prospects for the application of LAB in the production of fermented tea are discussed, hoping to provide a reference for the development of LAB fermented tea products and high-value utilization of summer and autumn tea.