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Yongchuan douchi is a famous soybean product that is widely used as a condiment in China due to its attractive aroma and can be categorized into traditional and rapid Yongchuan douchi (TYD and RYD). However, the key aroma compounds in TYD and RYD and their differences remain poorly understood. In the present study, the key aroma compounds in TYD and RYD were characterized and compared by a molecular sensory approach. The results obtained by multidimensional gas chromatography-mass spectrometry/olfactometry (MDGC−MS/O) demonstrated that a total of 125 volatiles and 71 aroma-active compounds were identified. Moreover, 36 aroma-active compounds with relative odor activity values (rOAVs) ≥ 1 and flavor dilution (FD) ≥ 16 were screened and quantified by an external standard method. The recombination and omission experiments revealed that TYD and RYD contained 18 and 13 key aroma compounds, respectively. TYD and RYD contained 10 identical compounds, whereas 8 (ethyl 2-methylbutyrate, ethyl 3-methylbutyrate, ethyl isobutyrate, ethyl caproate, ethyl acetate, ethyl benzoate, 4-methyl-2-phenyl-2-pentenal, acetophenone) and 3 (phenylacetaldehyde, 4-ethyl guaiacol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone) were unique to TYD and RYD, respectively. This is the first report of key aroma compounds in TYD and RYD, and it provides insights into improving the aroma of Yongchuan douchi. • The key aroma-active compounds between traditional and rapid Yongchuan douchi were revealed. • Traditional Yongchuan douchi has 8 unique aroma-active compounds and 6 of them were esters. • Aldehydes and acids were the most important aroma-active compounds in rapid Yongchuan douchi. [ABSTRACT FROM AUTHOR]

The degradation conditions of aflatoxin B1 (AFB1) by T. halophilus in MRS liquid culture were studied. The inoculum amount of T. halophilus, fermentation time, and fermentation temperature were recorded as experimental factors, and the degradation rate of AFB1 was measured as the experimental index. AFB1 degradation increased with the increase of temperature, with a maximum value of 75.9 ± 4.92%. When the temperature exceeded 32 °C, the degradation rate showed a downward trend. Experimental results showed that the degradation of AFB1 by T. halophilus was related to the starting concentration of the strain. The molecular weight of the extracellular enzymes that degraded AFB1 ranged from 55 KD to 70 KD,Zn2+ can promote the activity of AFB1 degradation by this enzyme, while Al3+, Ba2+, Ca2+ and Mn2+ can inhibit the activity of AFB1 degradation by this enzyme. Especially, the inhibitory effect of Ca2+ is the strongest, up to 48.54%, and the optimal temperature is 32 °C. The degradation products of AFB1 were identified as M/Z327.08 (C 17 H 10 O 7) and M/Z285.08 (C 16 H 12 O 5). Taken together, these results demonstrated that T. halophilus has application potential for AFB1 degradation. • Degradation of AFB1 by Tetralococcus halophiles. • The degradation of AFB1 by extracellular enzymes by Tetragenococcus halophilus. • Halophilus the degradation products and pathways of aflatoxins B1. [ABSTRACT FROM AUTHOR]

1-methylcyclopropene (1-MCP) and sulfur dioxide (SO 2), two chemical preservatives for table grapes, can delay senescence and prevent gray mold infection via different mechanisms. This research utilized a combination of metabolome and transcriptome analyses to investigate the impact of two preservatives on the metabolic and regulatory effects of various compounds, particularly phenols, throughout the storage period of 'Shine Muscat' grapes. In comparison to the control, the syntheses of phenolic acids, stilbenes, and certain flavonoids were hindered by 1-MCP and SO 2 through the downregulation of structural genes in the phenylpropane pathway. Compared with SO 2 treatment, 1-MCP treatment significantly reduced the contents of stilbenes, quercetins and kaempferols at the later stage of storage. Furthermore,1-MCP reduced flavan-3-ol accumulation during each stage of storage, owing to its inhibition of leucoanthocyanidin reductase expression. In addition, 1-MCP was more effective than SO 2 in inhibiting berry drop, decay, some genes of ethylene/abscisic acid synthesis and signal transduction pathway. This study offers new perspectives on the impact of two chemical preservatives on phenol metabolism in grapes throughout the storage period. • Compared with SO 2 , 1-MCP was more effective in inhibiting berry drop and decay. • 1-MCP and SO 2 inhibited the synthesis of phenolic acids, stilbenes, and some flavonoids. • 1-MCP significantly reduced the contents of stilbenes, quercetins and kaempferols at the later stage of storage. • 1-MCP reduced almost all flavan-3-ol accumulation, which can be attributed to the inhibition of LAR expression. • 1-MCP was more effective than SO 2 in inhibiting some genes of ethylene/ABA synthesis and signal transduction pathway. [ABSTRACT FROM AUTHOR]

Because the effect of nanoplastics (NPs) on muscle nutrition is poorly understood, a systematic study of the growth performance, tissue damage, and amino acid composition of Asian clam (Corbicula fluminea) under polystyrene nanoplastic (PS-NP) treatment was performed by combining short- and long-term treatments together. The primary results showed the shell length, height, and width increased as time progressed, whereas the body weight of C. fluminea revealed no significant difference between the PS-NP–treated clams and the blank control during the entire experiment. Histopathology analyses manifested the inflammatory cell infiltration and vacuolization rates of gill, gut, gonads, and muscle were elevated under PS-NP treatment in comparison with those of the blank control, indicating PS-NP–induced tissue damage occurred irreversibly. Downregulated SOD activity and upregulated CAT and GPX activities were detected, accompanied by increased MDA and GSH levels, suggesting PS-NPs induced tissues damage associated with its role as an antioxidant system disruptor. Levels of four bitter amino acids (Val, Met, Ile, Leu) significantly increased in the PS-NP-treated group compared to levels in the blank control, which was the dominant variation in muscle nutrition. As a result of these changes, the meat quality of C. fluminea decreased, which is a novel discovery of this work. • No growth inhibition of Corbicula fluminea exposed to polystyrene nanoparticles. • Polystyrene nanoparticles mainly induce tissue damage of Corbicula fluminea. • Polystyrene nanoparticles disrupt the antioxidant system of Corbicula fluminea. • Muscle bitter amino acids elevation affect the meat quality of Corbicula fluminea. [ABSTRACT FROM AUTHOR]

Excessive use of traditional food preservatives has raised concerns about their adverse effects. α-Copaene is a natural terpene compound with excellent biological activity; however, the antibacterial activity and mechanism of α-copaene are unclear. Therefore, this study aimed to explore the antibacterial activity and mechanism of action of α-copaene against four common foodborne pathogens: Staphylococcus aureus , Escherichia coli , Bacillus cereus , and Shigella bogdii. α-Copaene inhibited bacterial growth with a minimum inhibitory concentration of 0.5–1 μL/mL and a minimum bactericidal concentration of 2–4 μL/mL. Scanning electron microscopy and flow cytometry showed morphological changes and damage to the cell membrane in cells treated with α-copaene. Confocal microscopy and cell content leakage further confirmed cell membrane damage and increased permeability caused by α-copaene treatment. α-Copaene suppressed biofilm formation by decreasing the hydrophobicity of the cell surface. Furthermore, the hemolytic activity and cytotoxicity assays showed that α-copaene had good biosafety. In conclusion, 4 μL/mL of α-copaene inhibited the growth of S. aureus , E. coli , B. cereus , and Sh. bogdii in beef soup. These results provide evidence of the antibacterial activity and mechanism of α-copaene and pave the way for developing α-copaene as a novel food preservative. • α-Copaene exhibits antibacterial activity and inhibits four foodborne pathogens. • α-Copaene disrupts the cell membrane structure of foodborne pathogens. • Biofilm formation is inhibited via reduced cell surface hydrophobicity. • Hemolytic and cytotoxicity tests indicate satisfactory α-copaene biosafety. • This study paves the way for the development of α-copaene as a novel preservative. [ABSTRACT FROM AUTHOR]

The Maillard initial products, Amadori compounds (N-(1-Deoxy-D-fructos-1-yl)-amino acid), are considered as the beneficial component with various physiological functions. This study systematically demonstrated that 12 Amadori compounds have effective chelating effect of Cu2+, Fe2+ and Zn2+, and the chelating effect of Cu2+ and Fe2+ is better than that of Zn2+. The chelating strength of Amadori compounds is positively correlated with their concentration. Among them, N-(1-Deoxy-D-fructos-1-yl)-histidine (Fru-His) has the strongest chelating ability. UV spectrum and SEM demonstrated the formation of chelates and the change of surface structure after the chelation reaction. In addition, Amadori compounds have obvious inhibitory effect on the formation of oxidative free radicals caused by metal ions, which can effectively inhibit the oxidative damage of DNA caused by Cu2+ ion and Fenton reaction caused by Fe2+ ion, and reduce Fe3+ ion. Therefore, the Amadori compounds can be applied as a potent metal ion chelator in the development of functional foods. • 12 Amadori compounds all showed chelating ability of Cu2+, Fe2+ and Zn2+ ions. • Amadori compounds chelate Cu2+ and Fe2+ more effectively than chelating Zn2+. • Fru-His has the best ability to chelate metal ions among 12 Amadori compounds. • The UV spectrum and microstructure will change after the chelation. • Amadori compounds have inhibitory effect on the oxidation caused by metal ions. [ABSTRACT FROM AUTHOR]

Stigmasterol is an important natural compound with the ability to lower cholesterol and prevent cardiovascular disease. It is often esterified with fatty acids to enhance its range of applications and improve its bioaccessibility. In this paper, stigmasteryl oleate was efficiently synthesized via lipase catalysis under optimized ultrasound pretreatment conditions, and the physicochemical properties of stigmasteryl oleate were investigated. The results showed that the stigmasterol conversion reached 91.37% with an ultrasound power of 200 W, ultrasound pretreatment time of 1 h, lipase dosage of 50 g/L, and ultrasound pretreatment temperature of 50 °C. The chemical structure of the final stigmasteryl oleate product was identified using Fourier transform infrared spectroscopy, mass spectrometry and nuclear magnetic resonance spectroscopy. The melting and crystallization temperatures of stigmasteryl oleate were significantly decreased to 22.8 and 12.9 °C, respectively, while its solubility in edible oil was more than 20 times higher than that of stigmasterol. The peroxide value of stigmasteryl oleate was much lower than that of oleic acid (27.53 and 41.39 mmol/kg). The product of stigmasteryl oleate with more favorable physicochemical properties greatly facilitates the widespread use of stigmasterol in oil-based foods. • A efficient method of ultrasound pretreatment lipase catalysis was used. • Ultrasound pretreatment method shorten the reaction time than conventional method. • The physicochemical properties of stigmasterol were improved. • Esterified stigmasterol pronounce good oxidation stability during long-term storage. [ABSTRACT FROM AUTHOR]

The co-inoculation fermentation of different microorganisms plays a crucial role in soy sauce fermentation in terms of enriching the composition of the volatile compounds. Therefore, the present study sought to investigate the effect of co-inoculation fermentation of Aspergillus oryzae and Zygosaccharomyces rouxii on the dynamics of volatile compounds in soy sauce using the combination of gas chromatography-mass spectrometry (GC-MS) and multivariate correlation analysis. A total of 124 volatile compounds were identified by A. oryzae and Z. rouxii inoculation alone and co-inoculation, including hydrocarbons, fatty acids, phenols, fatty esters, and benzamides. The content of phenylethyl alcohol, ethyl linoleate, and ethyl palmitate was significantly increased, and the metabolic pathways of multiple volatile compounds were affected in soy sauce inoculated with Z. rouxii. The present study results potentially contribute to the optimization of soy sauce fermentation processes. [Display omitted] • Volatile compounds of soy sauce are closely related to co-inoculation of A. oryzae and Z. rouxii in koji-making. • Inoculation with Z. rouxii increased the concentration and number of volatile compounds. • Co-inoculation of A. oryzae and Z. rouxii significantly increased the contents of phenylethyl alcohol and ethyl palmitate. [ABSTRACT FROM AUTHOR]

The acid sensitivity and moisture absorption of dry probiotic products during digestion and storage are challenges. In this study, different mass ratios (1, 1.5, 2, 2.5, 5) of buckwheat protein (BWP) and hydrophobic polyester shellac were firstly combined by a pH-shifting method and then applied for the construction of Lactobacillus plantarum (L. plantarum) microcapsules. Circular dichroism (CD) and fluorescence spectroscopy results revealed that the complexes were stabilized primarily by hydrophobic interaction forces and the conformational changes after co-folding with shellac. With a decreasing ratio of shellac, the enthalpy (ΔH) and peak temperature increased, resulting in enhanced thermal stability. BS2 encapsulated probiotics successfully enhances the survival of L. plantarum during freeze-drying and gastrointestinal (GI) digestion. The probiotic was fully coated by the complex, determined through scanning electron microscopy (SEM) images. After encapsulated, the colon adhesion efficiency enhanced 30.92% than free cells. The encapsulated probiotics presented a maximum reduction of 0.89 log CFU/mL after 30 days of storage at 25 °C, and probiotics protected by the BS1 complex had superior storage stability under an Aw of 0.76, for which K value was 1.218. BWP-based shellac pH-shift complexes exhibit enormous potential for the encapsulation of probiotics. [Display omitted] • Interactions between BWP and shellac through pH-shift were investigated. • L. plantarum efficiently encapsulated in BWP-shellac complex fabricated by pH-shift. • L. plantarum microcapsule had higher survival during GI tract and ambient storage. • Probiotic released from microcapsule increased 30.92% higher colon-adhesion efficiency. [ABSTRACT FROM AUTHOR]

Edible films based on chitosan, coix seed starch (CSS), nano zinc oxide (ZnO) and Artemisia annua essential oil (AO) were obtained through solvent casting method. Physico-chemical, biological properties and structures of the edible film were analyzed and the preservation effect of it on the quality of cold-stored pork was also investigated. Fourier-transform infrared spectroscopy (FTIR) indicated that some possible intermolecular interactions could exist between film matrix and ZnO or AO. Scanning electron microscope (SEM) and thermogravimetry (TG) showed that ZnO and AO had good compatibility with the film biopolymers, no any phase separation. Results suggested that appropriate content of ZnO could enhance the film's compactness. Tensile strength (TS), barrier properties and antibacterial activities of the film was significantly enhanced with 5% ZnO was added. Incorporation of AO into the edible film decreased the TS, but increased the flexibility, barrier properties, antibacterial and antioxidant activities. When content of ZnO and AO were 5% and 8%, the physico-chemical, biological properties of the edible film could reach optimum. For pork preservation, pH, thiobarbituric acid reactive substances (TBARS), total viable count (TVC), and total volatile basic nitrogen (TVB-N) values of the pork which treated with 5% ZnO-8% AO film were significantly lowest (p ≤ 0.05) than other groups. Therefore, this edible film system has potential as food packaging materials. [Display omitted] • The edible film was transparent and almost colorless and had a uniform structure. • The edible film had excellent antibacterial activity and antioxidant Activity. • The edible film could effectively improve the quality of pork during storage and prolonging its shelf life. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate prevalence and characteristics of mcr-9 -positive Salmonella isolated from retail food in China. For this purpose, 2486 Salmonella isolated from retail foods from 2007 to 2016 in China were investigated. Based on PCR methods, 5.6% (140/2486) of the isolates were confirmed carrying mcr-9. Those mcr-9 -positive isolates distributed in 9 of 10 provinces and municipalities and in 8 of 12 food types including poultry-related foods (5.9%, 136/2314) and non-poultry-related foods (2.3%, 4/172). Among 138 Salmonella serotypes, isolates of 8 serotypes were detected carrying mcr-9. Interestingly, S. Thompson was the most dominant serotype (90.7%, 127/140). Most mcr-9 -positive isolates were susceptible to colistin, but 91.4% of which were multi-drug resistant. Among 140 mcr-9- positive isolates, 116 (82.9%) exhibited extended spectrum β-lactamase (ESBL) producing phenotype, 87.1% of them co-carried bla CTX-M-3 and bla TEM-1. Significant difference was found between mcr-9- positive isolates recovered before/including 2010 and after 2010, as well as S. Thompson and non- S. Thompson, in terms of detection rate and antibiotic resistance. PFGE revealed close genetic relatedness of mcr-9 -positive ESBL-producing S. Thompson. Our findings indicated that the specificity of transmission of mcr-9 -positive Salmonella in retail foods in China, providing valuable baseline data for food safety risk assessment. • mcr-9 -positive Salmonella were prevalent in poultry-related foods in China. • S. Thompson was the most dominant serotype in mcr-9 -positive Salmonella. • Most mcr-9 -positive S. Thompson were susceptible to colistin and polymyxin B, but showed MDR and ESBL phenotype. • Close genetic relatedness of mcr-9 -positive S. Thompson was found based on PFGE analysis. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of sea buckthorn on the fermentative properties of different lactic acid bacteria (LAB) and physicochemical characteristics of fermented milk. Fermented milk was supplemented with 0% (v/v), 2.5%, 5% and 7.5% sea buckthorn and fermented using 8 different LAB strains that isolated from 5 different fermented foods. Results showed that addition of sea buckthorn in fermented milk could significantly increase the total phenolics contents (TPC), total flavonoid contents (TFC) and total antioxidant activity, also made fermented milk showed more redness and yellowness. In addition, the addition of 5% sea buckthorn could shorten the coagulation time of fermented milk (from >9 h to 4–5 h), improve the texture of fermented milk and increase the viable LAB counts in fermented milk. Furthermore, the water holding capacity (WHC) was kept stable by adding 5% of sea buckthorn during a 30-day storage period at 4 °C. The study demonstrated that sea buckthorn may be used as a functional food ingredient for improving fermentative properties and extending shelf-life of fermented milk. [Display omitted] • Screened potential probiotics from fermented foods and applied in yogurt preparation. • Sea buckthorn may serve as a new prebiotic source for functional foods. • Sea buckthorn addition enhanced lactic acid bacteria activity in yogurts. • Yogurt with sea buckthorn had improved texture and rheological properties. [ABSTRACT FROM AUTHOR]