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Premade meat and poultry dishes refer to the finished or semi-finished products that use meat and poultry materials as the main ingredients, which undergo pretreatments and stored, transported and sold under room temperature or cold chain conditions. Flavor is an important factor that determines consumers' willing for premade dish purchase. However, due to raw material characteristics, microbial metabolism, nutrients oxidation or degradation, inappropriate reheating, the premade meat and poultry dishes might generate some unpleasant off-flavors. The off-flavors might have strong negative impact on the sensory quality of premade dishes, which restricts the further development of the whole industry. The commonly seen off-flavor substances in premade meat and poultry dishes include hexanal with sour note, nonanal, octanal, decanal and (E,E)-2,4-decadienal with waxy and oily note, (E)-2-decenal with greasy fatty note, 3-methylbutyraldehyde and 2-methylbutyraldehyde with musty note, butyric acid with a strong cheesy note, 3-methylbutyric acid with sweaty note, dimethyl trisulfide, dimethyl sulphide with sulphurous note, and 1-octen-3-ol with earthy note etc. This paper reviews the main sources of premade meat and poultry dishes off-flavors, summarizes the off-flavors inhibiting and masking techniques applied in premade dish preparation. This study would provide practical guidance and reference for the innovation and development of the flavor quality control in premade dish industry.

Lily is a perennial herbaceous plant with ornamental, and its bulb is commonly used for food and medicine. Recently, fresh lilies gain growing favors from consumers as special vegetable. This review focuses on analyzing edible lilies bulbs from the perspective of different varieties, the detailed composition of nutrients such as carbohydrate (including bioactive polysaccharides), protein and amino acid, lipids, minerals and vitamins, summarizing the phytochemicals and biological activities involving steroid saponins (including spirostanols, isospirostanols, deformed spirostanols and furostanols), phenolic acids (including monophenolic acids, phenolic glycerides and glycosides), flavonoids (including flavonols, flavanols, chalcones, flavanones, flavanones, anthocyanins, and so on) and alkaloids (including isoquinoline, pyrroline, piperidine, and steroid glycosides). Finally, the application of lily in functional food is analyzed. Collectively, this review is capable of providing theoretical basis and research ideas for the study of lily and its non-medicinal processing and utilization.

Introduction: Entry into the viable but nonculturable (VBNC) state is a survival strategy adopted by bacteria to survive harsh environment. Although VBNC cells still have metabolic activity, they lose the ability to form colonies on nonselective culture media. Thus, conventional bacterial detection methods, such as plate counting, are unable to detect the presence of VBNC cells. When the environmental conditions are appropriate, VBNC cells can initiate resuscitation, posing a great risk to the safety of public health. The study of the VBNC resuscitation mechanism could provide new insights into the prevention and control of VBNC resuscitation. Objectives: Uncovering the molecular mechanism of VBNC cell resuscitation by investigating the role of O-antigen ligase (RfaL) in inhibiting the resuscitation of Escherichia coli O157:H7 in the VBNC state. Methods: RfaL was screened and verified as a resuscitation inhibitor of VBNC Escherichia coli O157:H7 by detecting resuscitation curve and time-lapse microscopy. The mechanism of RfaL impacts VBNC E. coli resuscitation was investigated by detecting the single cell ATP content, metabolomic changes, NAD(H) content and new protein biosynthesis of WT and ΔrfaL at different stage of resuscitation. Results: Mutation of rfaL, which encoded an O-antigen ligase, markedly shortened the resuscitating lag phase. Further studies indicated that ΔrfaL VBNC cells contained higher ATP levels, and ATP consumption during the resuscitating lag phase was highly correlated with resuscitation efficiency. Metabolomic analysis revealed that ATP was utilized to activate the Handler and salvage pathways to synthesize NAD+, balancing redox reactions to recover cell activity and promote cell resuscitation. Conclusion: Our findings revealed a strategy employed by VBNC cells for revival, that is, using residual ATP to primarily recover metabolic activity, driving cells to exit dormancy. The synthesis pathway of lipopolysaccharide (LPS) in rfaL null mutant was inhibited and could supply more ATP to synthesis NAD+ and promote resuscitation.

To explore the profiles of phytochemical components in geographical indication product of China Lilium davidii var. unicolor, the bulbs of which derived from five major producing areas of Gansu Province (Yuzhong County, Lanzhou City, Qilihe District, Lanzhou City, Lintao County, Dingxi City, Weiyuan County, Dingxi City, Yongjing County, Linxia City) were detected using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). Based on untargeted metabolomics technology, a total of 62 phytochemical components were putatively annotated in the bulbs of L. davidii var. unicolor. Among them, there were 22 kinds of amino acids, peptides and their derivatives (e.g., glutathione), 9 kinds of lipids and phospholipids (e.g., lyso-phosphatidylcholin), 7 kinds of saccharides (e.g., rhamnose), 7 kinds of phenolic acids (e.g., ferulic acid and caffeic acid), 4 kinds of flavonoids (e.g., kaempferol), 4 kinds of natural vitamins (e.g., riboflavin and vitamin C), 3 kinds of phenolamines (e.g., feruloyl putrescine), 2 kinds of coumarins (e.g., gerberinside), 2 kinds of alkaloids (e.g., trigonelline), terpenoids (e.g., abietic acid) and triterpenoid saponins (e.g., eleutheroside E). The study would provide richer data and scientific evidence for the investigation and utilization of L. davidii var. unicolor.

Casein micelle has a structure of outer hydrophilicity and inner hydrophobicity, its typical digestion characteristic is gastric coagulation. Based on calcium content as the key factor to control this process, high hydrostatic pressure (HHP) was firstly used to modify the micelle structure by mediating the tight connection between casein molecules themselves and with colloidal calcium, then the quercetin-loaded delivery systems were prepared. And in order to investigate the effect of exogenous calcium, calcium chloride was added for digestion. The results indicated that HHP broke the limitation of casein micelles as delivery carriers for hydrophobic components and increased the EE from 51.18 ± 3.07 % to 76.17 ± 3.41 %. During gastric digestion, higher pressure and exogenous calcium synergistically increased the clotting ability and inhibited the release of quercetin. In the small intestine, curds decomposed more slowly under higher pressure and calcium concentration, so the degradation of quercetin was effectively inhibited.

The Leuconostoc citreum SJ-57 strain isolated from the sweet potato starch production showed great potential as a microbiological flocculant, but its underlying flocculation mechanisms are yet unknown. In this study, infrared spectroscopy and thermodynamic analysis were performed to elucidate the short-range and long-range interactions between Leuc. citreum SJ-57 and starch granules, revealing that bacteria cells bond starch granules via metal-bridging ionic bonds. A high repulsive energy barrier of ~8 × 10−18 J must be overcome to initiate the flocculation process. Heat, protease, lipase, lysozyme, dextranase, and guanidine hydrochloride were used to treat the bacterial cell, confirming that its flocculation ability originated from surface proteins, including GW structural domain proteins, DnaK, GroEL, elongation factor Tu, and lysozyme M1. The primary flocculation mechanisms of Leuc. citreum was proposed to provide a deep understanding of microbiological flocculants and a foundation for future industrial applications in starch production.

Starch is a major component of the human diet and has several hierarchies including granule, shell, blocklet, amylose and amylopectin, which can be used as the raw materials in food processing. In order to be applied in a suitable range, this involves the selection of separation methods and the accurate characterization of the structural properties of each starch hierarchy. Therefore, this paper analyzes the separation and characterization methods for each starch hierarchy, introduces their different applications, and thus provides some references for the development and utilization of starch resources.

Unsaturated fatty acids (UFAs) play a fundamental role in maintaining human health and serve as an important raw material for functional foods. However, UFAs are prone to oxidization during processing and storage, leading to deterioration. Microencapsulation of UFAs is an effective processing method to minimize oxidation and enhance its stability. In this paper, the physiological functions of UFAs and their applications in food, medicine, and other fields are summarized. The research progress of microencapsulation technology of UFAs is systematically reviewed, aiming to provide a theoretical basis and rationale for their applications in the food industry. Research has shown that the wall materials widely used were mainly proteins and carbohydrates, whereas their combination can overcome their disadvantages. Spray drying, freeze drying, molecular encapsulation, and coacervation method are most commonly used in the fabrication of microencapsulated UFAs. Using various wall materials and fabrication methods leads to very different encapsulation efficiency, which also greatly impacts the stability of UFAs during processing and storage. Hence, it is still necessary to select appropriate materials and methods according to the properties and functions of the food products. Microencapsulated UFAs exhibited slow-release properties and improved physiological functions. Therefore, it may have broad applications and excellent future development prospects in the food industry.

Objective: Xinjiang is one of the main producers and exporters of dried chilies in China. Dried chilies in Xinjiang are mainly dried by natural drying methods, however, relying too much on experience and lacking scientific theoretical guidance, the dried products are prone to problems such as breakage and mold. Therefore, it is urgent to monitor the quality changes in the drying process of chilies and to standardize the technical process of dried chili production. Methods: The Honglong series of rambutan peppers (Honglong 18 and Honglong 23), grown on a large scale in Xinjiang, were selected. Three key points in the natural drying process have been selected: Flattening (starting point of drying), gathering of small piles and gathering of large piles (end point of drying). The study followed four batches and monitored changes in the quality of chilies, including moisture content, water activity, seed to flesh ratio, sugar content, total phenolic content, antioxidant capacity, color value, texture, moldiness and microbiological composition. Results: The moisture content of the chilies at the end of drying was below 13%. The drying process significantly reduced the sugar content, total phenolic content and antioxidant capacity of the chilies (P

Abstract Astringency is a major sensory property and plays an important role in the overall quality of juice and wines. A major contributor to astringency is condensed tannins, which can precipitate with salivary glycoproteins. And thus, it is vital to develop methods to measure the tannin accurately. Recently, the interest in the application of condensed tannin assays has been increasing in various fields. Condensed tannin assays broadly include the determination of concentration, activity, mean degree of polymerization and its derivative flavan‐3‐ol sulfonates content. In this guideline, the mechanisms and the practice of the most common condensed tannin assays applied in research labs are discussed in detail.

The loss of distinctive aromas due to sterilization significantly hinders efforts to enhance the sensory quality of fruit and vegetable juices. This study aimed to elucidate the impacts of high-hydrostatic pressure (HHP) and high-temperature short-time (HTST) sterilization methods on the loss of C6 aldehyde aroma-active compounds in red raspberry juice. External standard quantification and quantitative descriptive analysis (QDA) revealed a notable decline in the levels of hexanal and (Z)-3-hexenal following the HHP and HTST treatments (p < 0.05), resulting in a marked attenuation of the grassy aroma characteristic of red raspberry juice. Furthermore, a comprehensive examination of the precursors, pivotal enzymes, intermediates, and downstream aromas within the fatty acid metabolism pathway in different raspberry juice samples indicated that the C6 aldehydes loss induced by HHP and HTST sterilizations was primarily ascribed to the competitive inhibition of β-oxidation and the hindered enzymatic oxidation of fatty acids. These insights suggest that modifying sterilization protocols and enhancing enzymatic stability may help preserve the aroma integrity of raspberry juice. Our findings offer practical guidance for optimizing juice processing techniques to maintain flavor.

Objective: Exploring the disinfection effect of high-pressure carbon dioxide (HPCD) on human coronavirus 229E (hCoV-229E). Methods: The human coronavirus 229E (hCoV-229E) was treated by HPCD at different temperatures (10, 25, and 37 ℃) and pressures (6.3 and 10 MPa) for different time (15 and 30 min). Result: Compared with the control groups under the corresponding temperatures, the virus titer in 50 mL tube treated with HPCD at 10 ℃ and 6.3 MPa for 30 min was significantly decreased (P

Starch and polyphenols can interact through predominant non-covalent bonds to form a range of distinctive starch-polyphenol complexes, which exhibit varied physicochemical properties, nutritional characteristics, and bioavailability. This paper mainly reviews the current regulation methods and effect, as well as the regulation mechanism of different food processing methods to the interactions between starch and polyphenol in perspective of thermal, non-thermal and the combined processing methods in recent decades. Different food processing methods turn out to modulate the interactions between starch and polyphenols by changing the multi-scale structure of starch. Thermal processing methods affect starch structure through strong thermal effect, which is beneficial to strengthen the interactions between starch and polyphenols and induce the formation of new crystalline structure. Non-thermal processing methods are considered to have a less obvious effect on starch structure in comparison of thermal processing methods, but could have more precise modifications. And the combined processing methods can further improve efficiency. This review is expected to provide reference for future quality control in food system by appropriate processing technology.

To analyze the quality discrepancies of pod pepper, line pepper and horn pepper , the integrated structural characteristic values ( the seeds content and sarcocarp content), crude fiber, sugar, fat, protein, moisture, ash, carotenoids, capsaicins, and volatile compounds in nine dried pepper varieties were detected in this study, which test samples of pepper varieties included three pod peppers (Neihuang-xinyidai, Huaxi-dangwu pepper and Qiubei pepper), four line peppers (Dafang wrinkly pepper, Shawan line pepper, Shaanxi qin pepper and Gangu line pepper) and two horn peppers (Tuoxian red pepper and Yidu red pepper), respectively. Principal component analysis and cluster analysis were carried out to evaluate the comprehensive quality of dried peppers. The results indicated that the seeds and sarcocarp in whole dried pepper constituted 21%~47% and 52%~79%, respectively. The crude fiber, sugar, fat and protein were 35%~46%, 11%~28%, 13%~19% and 14%~18%, respectively. The reducing sugar was made up 77%~99%. Unsaturated fatty acids represented over 80% among total fatty acids, linoleic acid accounted for 61%~73%. Capsanthin (37~221 mg/100 g) was the dominant in total carotenoids (73~458 mg/100 g), and the contents of capsaicins vary 18~206 mg/100 g. Eleven types of volatile compounds were detected in test samples, and total volatile constituents content was 1.12~7.65 mg/100 g. For principal component analysis, three principal components were extracted, and their cumulative variance contribution rate was up to 85.29%, which reflected mostly the quality characteristics of dried peppers. Nine dried pepper varieties samples were divided into two classes by cluster analysis, the first class includes three pod pepper varieties, the second class inludes six samples of line peppers and horn peppers. The analysis of the integrated structural characteristic values and their correlations with quality indicators revealed that seeds in pod pepper samples were higher, which contained higher fat, crude fiber, and more abundant volatile compounds, the sarcocarp in the samples of line peppers or horn peppers were higher, which contained higher sugar and carotenoids. Meanwhile, the contents of crude fiber and fat were significant positively correlated with seeds content (P

To investigate the changes of lipids and volatile flavor components of Chinese braised pork in brown sauce after sterilization processes, quantitative analysis of the whole lipid components of unpasteurized, pasteurized, and ultra-high pressure (UHP) braised pork in the brown sauce was conducted using ultra-performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry. A total of 251 different lipids were identified. Partial least squares discriminant analysis and hierarchical clustering analysis were used to successfully distinguish the braised pork samples processed with different sterilization methods. Among them, 24 lipid substances were the key compounds to effectively distinguish the lipids, including 15 types of triglycerides (TG), 8 types of phospholipids, and N-acylethanolamine. According to the relative contents of lipid compounds, the braised meat after UHP sterilization was closer to the control group than the ones pasteurized. Using solid-phase micro-extraction coupled with gas chromatography-mass spectrometry, the types and contents of volatile components in braised pork under different sterilization methods were compared. A total of 31 volatile flavor components were identified, including 4 types of alcohols, 4 types of acids, 4 types of lipids, 7 types of alkanes, 2 types of ketones, and 9 types of aldehydes and furan. Based on these results, it was found that the UHP sterilization could maintain the original flavor and lipid composition of Chinese braised pork in brown sauce, which had great potential in meat processing and Chinese cuisine preparation.

As a non-thermal technology, high hydrostatic pressure (HHP) has been widely investigated for inactivating microorganisms in food. Few studies have been presented on the pressurization/depressurization rate and mode of microbial inactivation. In this study, effect of pressurization rate and mode on Escherichia coli and Staphylococcus aureus cell damage during HHP treatment was investigated. The results showed that fast pressurization + linear mode (FL) treatment has the best bactericidal effect on E. coli and S. aureus, followed by fast pressurization + stepwise mode (FS) and slow pressurization + stepwise mode (SS) treatments. FL treatment caused more morphological damage to the cell wall, cell membrane, and cytoplasmic components compared with FS and SS treatment detected by SEM and TEM. Additionally, the damage to membrane permeability of them was also enhanced after FL treatment. Therefore, our results indicated that FL treatment could be applied to enhance the bactericidal effect of HHP on bacteria by increasing the damage to cell morphological structure and membrane integrity.

High-pressure homogenization has been extensively studied for its excellent homogenization effect and the prospect of continuous liquid food production, but its sterilization ability still needs to be improved. In this study, we replaced the homogenization valve with two opposing diamond nozzles (0.05 mm inner diameter) so that the fluid collided at high velocity, corresponding to high-pressure micro-fluidization (HPM). Moreover, HPM treatment significantly inactivated Staphylococcus aureus ~7 log in the liquid with no detectable sub-lethal state at a pressure of 400 MPa and a discharge temperature of 50 °C. The sterilization effect of HPM on S. aureus subsp. aureus was attributed to a significantly disrupted cell structure and increased membrane permeability, which led to the leakage of intracellular proteins, resulting in bacterial death. At the same time, HPM treatment was able to significantly reduce the ability of S. aureus subsp. aureus to form biofilms, which, in turn, reduced its virulence. Finally, compared to the simulated system, more effective sterilization was observed in apple juice, with its color and pH remaining unchanged, which suggested that HPM can be used to process other liquid foods.

A high intake of sugar-sweetened fruity beverage (FB) is associated with a higher risk of metabolic syndromes, but the health outcome of 100% fruit juice (FJ) intake remains unclear. We aim to reveal health outcomes of diet intervention (FJ or FB) with system profiling via interaction of gut microbiota and metabolomics in a rat (Rattus norvegicus) model. Firstly, the glucose, sucrose, fructose, and bioactive metabolites of FJ and FB were analyzed, and FJ possessed higher sucrose and flavonoids, while FB showed higher glucose and fructose. Secondly, C0 was set as the control group on Day 0, and a 4-week diet invention was performed to control, FJ-intake, and FB-intake groups with normal saline, FJ, and FB, respectively. The results showed that FJ improved alpha diversity and decreased the Firmicutes/Bacteroidota ratio (F/B ratio) of gut microbiota and prevented insulin resistance. However, FB possessed unchanged microbial diversity and enhanced F/B ratio, causing insulin resistance with renal triglyceride accumulation. In summary, FJ, although naturally containing similar amounts of total free sugars as FB, could be a healthier drink choice.

The fast and robust identification of fault elements is essential for the security and continuous operation of the power grid. The existing methods might be maloperation for bad data disturbance and require strict and exact synchronization. To address the challenge, this paper uses the conflict graph to propose a new sensitivity graph signal model for the power grid fault diagnosis. Next, a novel graph Fourier transform (GFT)-based method is proposed to diagnose the fault branch. Firstly, the measurement sensitivity graph signals are constructed by the conflict graph model, where the data is from activated recorders and protection devices. Next, the eigenvalue and GFT coefficient are used to extract the frequency characteristics of the signals. The fault branches provide the maximum contribution rate to the high-frequency coefficient of GFT. Then, for each node, the importance degree of the measurement sensitivity conflict graph signal is defined. The high-frequency importance degree-based method is proposed to discriminate the fault branch. Finally, simulations and practical cases verify the correctness and effectiveness of the proposed method. The proposed method owns fast faults diagnosis and good practicability. Additionally, the identification accuracy is high and the method is robust to bad data interference, due to considering measured data from whole activated fault recorders and protection devices.

For the better standardization and widespread application of the determination method of carotenoids in both chili peppers and their products, this work reports for the first time the simultaneous determination of five main carotenoids, including capsanthin, zeaxanthin, lutein, β-cryptoxanthin and β-carotene in chili peppers and their products, with optimized extraction and the high-performance liquid chromatography (HPLC) method. All parameters in the methodological evaluation were found to be in good stability, recovery and accuracy compliance with the reference values; the R coefficients for the calibration curves were more than 0.998; and the LODs and LOQs varied from 0.020 to 0.063 and from 0.067 to 0.209 mg/L, respectively. The characterization of five carotenoids in chili peppers and their products passed all the required validation criteria. The method was applied in the determination of carotenoids in nine fresh chili peppers and seven chili pepper products.

Previously, a new copper-zinc SOD (CuZnSOD) isolated from chestnut rose (Rosa roxburghii) with good stability was described. In this study, the biosynthetic approach was used to create recombinant CuZnSOD. RACE PCR was also used to amplify the full-length CuZnSOD gene from chestnut rose, and the ORF segment was expressed in E. coli BL21 and P. pastoris GS115. For characterization, the enzyme was isolated in two steps in E. coli and one step in P. pastoris. The biochemical properties of the two recombinant enzymes were similar, and their optimal reaction pH and temperature were 6.0 and 50°C, respectively. According to molecular dynamics simulation, the CuZnSOD showed high stability from 70 to 90°C, and eight amino acids are important for enzyme thermal stability at high temperatures. This study set the stage for industrial manufacture by filling gaps in the link between conformational changes and the thermal stability of the new CuZnSOD.

To investigate the effect of lactic acid bacteria fermentation on jujube bioactivity, Streptococcus thermophilus was used to ferment jujube puree. The number of viable bacteria cells, physicochemical properties, phenolics profile and antioxidant capacity were analyzed, and their correlation were investigated. Streptococcus thermophilus exhibited a high growth capacity in jujube puree, and significantly (p

Abstract Currently, numerous pieces of evidence have demonstrated that the health gut microbiota contributed to physiological homeostasis for the host. Accumulating methods appear to detect microbial population, including denaturing gradient gel electrophoresis (DGGE), high‐throughput sequencing, and quantitative real‐time polymerase chain reaction (qPCR). With characteristics of flexibility and high‐sensitivity, qPCR technique plays a critical role in determining the dynamic alteration of bacterial abundances, which entirely exhibits the microbial activity in various external situations. In these guidelines, taking Akkermansia muciniphila for example, we provide experimental details in specific primer design and validation, standard plasmid construction, qPCR assay, and data analysis for microbial detection, which also can be used for bacterial determination in other environmental systems. In addition, we offer the solution preparation and operation procedures of in vitro gastrointestinal digestion system. Furthermore, these guidelines can contribute to verify the high‐throughput sequencing results and reveal the underlying mechanism of the microbial shift in response to the dietary intervention or the development of diseases.

Pomegranate is widely cultivated across China, and the phenolics in its peel are principal components associated with health benefits. Ultra-high performance liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer (UHPLC-QTOF-MS) and ultra-performance liquid chromatography coupled to a triple quadrupole mass spectrometer (UPLC-QQQ-MS) were used in this study, aiming at profiling the total phenolic composition in pomegranate peel from nine selected cultivars in 7 production areas. Sixty-four phenolic compounds were identified or annotated, and 23 of them were firstly reported in pomegranate peel. Principal component analysis (PCA) plots show differences and similarities of phenolics among nine cultivars. Furthermore, 15 phenolic compounds were quantified with the standards, and punicalagin, ellagic acid, gallocatechin, punicalin, catechin, and corilagin were found to be dominant. Punicalagin weighed the highest content (28.03–104.14 mg/g). This study can provide a deeper and more detailed insight into the phenolic composition in pomegranate peel and facilitate the health-promoting utilization of phenolics.

(1) Background: (-)-Epigallocatechin-3-gallate (EGCG) has been reported to improve mitochondrial function in cell models, while the underlying mechanism is not clear. Cyclophilin D (CypD) is a key protein that regulates mitochondrial permeability transition pore (mPTP) opening. (2) Methods: In this study, we found that EGCG directly binds to CypD and this interaction was investigated by surface plasmon resonance (SPR), nuclear magnetic resonance (NMR) and molecular dynamic (MD) simulation. (3) Results: SPR showed an affinity of 2.7 × 10−5 M. The binding sites of EGCG on CypD were mapped to three regions by 2D NMR titration, which are Region 1 (E23-V29), Region 2 (T89-G104) and Region 3 (G124-I133). Molecular docking showed binding interface consistent with 2D NMR titration. MD simulations revealed that at least two conformations of EGCG-CypD complex exist, one with E23, D27, L90 and V93 as the most contributed residues and E23, L5 and I133 for the other. The major driven force for EGCG-CypD binding are Van der Waals and electrostatic interactions. (4) Conclusions: These results provide the structural basis for EGCG-CypD interaction, which might be a potential mechanism of how EGCG protects mitochondrial functions.

Capsaicin, a natural bioactive component, has been reported to improve cognition and ameliorate the pathology of Alzheimer’s disease (AD). Studies have linked AD to alterations in gut microbiota composition and serum metabolites. In the present study, we examined the alterations in serum metabolome and gut microbiome in APPswe/PS1dE9 (APP/PS1) mice treated with capsaicin. Capsaicin treatments resulted in a significant increase in the abundance of Akkermansia, Faecalibaculum, Unclassified_f_Atopobiaceae, and Gordonibacter and a significant decrease in the abundance of Adlercreutzia, Peptococcaceae, Alistipes, Oscillibacter and Erysipelatoclostridium. Furthermore, the species Akkermansia muciniphila (A. muciniphila) was significantly enriched in capsaicin-treated APP/PS1 mice (p = 0.0002). Serum metabolomic analysis showed that capsaicin-treated APP/PS1 mice had a significant higher level of tryptophan (Trp) metabolism and a significantly lower level of lipid metabolism compared with vehicle-treated mice. Capsaicin altered serum metabolites, including Kynurenine (Kyn), 5-Hydroxy-L-tryptophan (5-HIT), 5-Hydroxyindoleacetic acid (5-HIAA), indoxylsulfuric acid, lysophosphatidyl cholines (LysoPCs), and lysophosphatidyl ethanolamine (LysoPE). Significant correlations were observed between the gut bacteria and serum metabolite. With regard to the increased abundance of A. muciniphila and the ensuing rise in tryptophan metabolites, our data show that capsaicin alters both the gut microbiota and blood metabolites. By altering the gut microbiome and serum metabolome, a diet high in capsaicin may reduce the incidence and development of AD.

Capsaicin is a pungent alkaloid abundantly present in peppers with outstanding biological activities, including the anti-atherosclerosis effect. Previous studies revealed that gut microbiota played an important role in the beneficial effects of capsaicin, but whether it is essential for the anti-atherosclerosis effect of capsaicin is unclear. This study evaluated the anti-atherosclerosis effect of capsaicin in ApoE−/− mice and further explored the role of depleting gut microbiota in the improvement of atherosclerosis. The results showed that capsaicin administration could prevent the development of atherosclerosis and improve serum lipids and inflammation, while antibiotic intervention abolished the alleviation of atherosclerosis by capsaicin. In addition, capsaicin administration could significantly increase the abundance of Turicibacter, Odoribacter, and Ileibacterium in feces, and decrease the abundance of deoxycholic acid, cholic acid, hypoxanthine, and stercobilin in cecal content. Our study provides evidence that gut microbiota plays a critical role in the anti-atherosclerosis effect of capsaicin.

In this study, high pressure processing (HPP) and thermal treatment were comparatively evaluated by examining their impacts on the binding behavior and interaction between α-lactalbumin (α-La) and pelargonium-3-glucoside (P3G) under pH values of 6.0, 7.4, and 8.0. The methods of circular dichroism spectroscopy, fluorescence quenching, dynamic light scattering, and molecular simulation were used to characterize the effects of processing-induced changes in protein structure, size distribution, binding site conformation, and residue charges on their binding characteristics between them. The results indicated that the thermal treatments significantly increased the quenching constants of the complex at pH 7.4/8.0 and 60/80 °C, as well as the accessible fraction of protein at pH 8.0/80 °C. Both HPP and thermal treatments increased the random coil content and showed limited effects on the α-helix and β-sheet contents of α-La and caused the aggregation of the complex to varying degrees. Molecular dynamic simulation and docking analyses revealed that the binding site of the complex did not change under different processing conditions, but the solvent-accessible surface area varied under different conditions.

This study is to evaluate the athermal forward osmosis (FO) concentration process of blueberry juice using food additives as a draw solution (DS). The effects of food additives, including citric acid, sodium benzoate, and potassium sorbate, on the concentration processes are studied, and their effects on the products and membranes are compared. Results show that all these three food additives can be alternative DSs in concentration, among which citric acid shows the best performance. The total anthocyanin content (TAC) of blueberry juice concentrated by citric acid, sodium benzoate, and potassium sorbate were 752.56 ± 29.04, 716.10 ± 30.80, and 735.31 ± 24.92 mg·L−1, respectively, increased by 25.5%, 17.8%, and 19.9%. Meanwhile, the total phenolic content (TPC) increased by 21.0%, 10.6%, and 16.6%, respectively. Citric acid, sodium benzoate, and potassium sorbate all might reverse into the concentrated juice in amounts of 3.083 ± 0.477, 1.497 ± 0.008, and 0.869 ± 0.003 g/kg, respectively. These reversed food additives can make the TPC and TAC in juice steadier during its concentration and storage. Accordingly, food additives can be an excellent choice for DSs in the FO concentration process of juices, not only improving the concentration efficiency but also increasing the stability of blueberry juice.

The proteomics of donkey milk from China’s major producing areas have not been well documented. To explore the protein profiles of donkey milk from China, this study preliminarily investigated caseins and whey proteins in products from two major producing areas using quantitative proteomics approach. Total 15 caseins genetic variants and 620 whey proteins were identified and relatively quantified. Functional categorization of whey proteins was clustered into 46 terms based on Gene ontology (GO) and 42 Brite B classes based on Kyoto Encyclopedia of Genes and Genomes (KEGG). Six of the seven identified isoforms of caseins were firstly observed in donkey milk. Whey proteins including α-lactalbumin, β-lactoglobulins and lysozyme were identified, but no immunoglobulins or lactoferrin was determined. An unprecedented low ratio of casein/whey indicated that the products were very good sources with high biological value. This study enhanced knowledge of protein composition and established proteins profiles of differentially expressed proteins in the selected products of donkey milk from China.

Photodynamic sterilization technology (PDT) is widely used in disease therapy, but its application in the food industry is still at the research stage because of the limitations of food-grade photosensitizers. Curcumin exhibits photosensitivity and is widely used as a food additive for its natural color. This study aimed to determine the effect of curcumin-mediated photodynamic technology (Cur-PDT) on Bacillus subtilis and to elucidate the anti-bacterial mechanism involved. First, the effects of curcumin concentration, duration of light irradiation, light intensity, and incubation time on the inactivation of B. subtilis were analyzed. It was found that Cur-PDT inactivated 100% planktonic cells with 50 μmol/L curcumin in 15 min (120 W). Then, the cell morphology, oxidation state and the expression of membrane structure- and DNA damage-related genes of B. subtilis vegetative cells were investigated under different treatment conditions. The membrane permeability of cells was enhanced and the cell membrane structure was damaged upon treatment with Cur-PDT, which were exacerbated with increases of treatment time and curcumin concentration. Meanwhile, the production of reactive oxygen species increased and the activities of the antioxidant enzymes SOD, GPX, and CAT decreased inside the cells. Furthermore, the Cur-PDT treatment significantly downregulated the mRNA of the membrane protein TasA and upregulated the DNA damage recognition protein UvrA and repair protein RecA of B. subtilis. These results suggested that curcumin-mediated PDT could effectively inactivate B. subtilis by inducing cell redox state imbalance, damaging DNA, and disrupting membrane structures.

The viable but non-culturable (VBNC) state, in which bacteria fail to grow on routine culture media but are actually alive, has been widely recognized as a strategy adopted by bacteria to cope with stressful environments. However, little is known regarding the molecular mechanism of VBNC formation. Here, we aimed to elucidate the specific roles of cell division regulatory proteins and the cell growth rate during VBNC Escherichia coli O157:H7 formation. We have previously found that expression of dicC is reduced by 20.08-fold in VBNC E. coli O157:H7 compared to non-VBNC cells. Little is known about DicC except that it, along with DicA, appears to act as a regulator of cell division by regulating expression of the cell division inhibitor DicB. First, our results showed that the VBNC cell number increased in the ΔdicC mutant as well as the DicA-overexpressing strain but decreased in the DicC-overexpressing strain induced by high-pressure carbon dioxide, acid, and H2O2. Furthermore, the growth rates of both the DicA-overexpressing strain and the ΔdicC mutant were higher than that of the control strain, while DicC-overexpressing strain grew significantly more slowly than the vector strain. The level of the dicB gene, regulated by dicA and dicC and inhibiting cell division, was increased in the DicC-overexpressing strain and decreased in the ΔdicC mutant and DicA-overexpressing strain, which was consistent with the growth phenotypes. In addition, the dwarfing cell morphology of the ΔdicC mutant and DicA-overexpressing strain were observed by SEM and TEM. Taken together, our study demonstrates that DicC negatively regulates the formation of the VBNC state, and DicA enhances the ability of cells to enter the VBNC state. Besides, the cell growth rate and dwarfing cell morphology may be correlated with the formation of the VBNC state.

This study investigates the effects of a high pressure processing pre-treatment (pre-HPP) on the juice yield of persimmon (Diospyros kaki L.) pulp and the pre-HPP plus HPP or thermal processing (TP) on microorganism inactivation and quality changes of the persimmon juice. The “Gongcheng” persimmon was selected with the highest juice yield (48.9%), and the pre-HPP set at 300 MPa/8 min increased the juice yield by 60% through an increasing pectin methylesterase (PME) activity of 25.03% and by maintaining polygalacturonase (PG) activity. For different processing modes, namely, pre-HPP plus HPP at 550 Mpa/5 min and pre-HPP plus TP treatment at 95 °C/5 min, both of the guaranteed microorganisms in the juice were below 2.0 lg CFU/mL; however, the persimmon juice treated by the pre-HPP plus HPP had higher contents of total phenol and ascorbic acid which were 16.07 mg GAE/100 g and 17.92 mg/100 mL, respectively, a lower content of soluble tannin which was 55.64 μg/mL, better clarity which was 18.6% and less color change where the ΔE was only 2.68.

Obesity has become a serious public health threat worldwide and recent evidence demonstrates that gut microbiota plays an important role in obesity. To the best of our knowledge, no research has been presented demonstrating the effects of a chlorophyll-rich spinach extract supplementation on obesity and associated changes in gut microflora of mice. The present study found that a chlorophyll-rich spinach extract supplementation effectively alleviated body weight gain and low-grade inflammation, and improved the glucose tolerance in HFD-fed mice (p

The pressure-assisted ultra-high temperature (PAUHT) system was built by using soybean oil as pressure-transmitting medium, and the multiple regression equation of soybean oil temperature change (ΔTP) during pressurization as a function of initial temperature (Ti) and set pressure (P) was developed: ΔTP = -13.45 + 0.46 Ti + 0.0799 P - 0.0037 Ti2 - 2.83 × 10-5 P2. The fitted model indicated that the temperature of the system would achieve ≥121°C at 600 MPa when the initial temperature of soybean oil was ≥84°C. The PAUHT system could effectively inactivate spores of Bacillus subtilis 168 and Clostridium sporogenes PA3679 (less than 1 min). Treatment of 600 MPa and 121°C with no holding time resulted in a 6.75 log reductions of B. subtilis 168 spores, while treatment of 700 MPa and 121°C with pressure holding time of 20 s achieved more than 5 log reductions of C. sporogenes PA3679 spores. By comparing the PAUHT treatment with high pressure or thermal treatment alone, and also studying the effect of compression on spore inactivation during PAUHT treatment, the inactivation mechanism was further discussed and could be concluded as follows: both B. subtilis 168 and C. sporogenes PA3679 spores were triggered to germinate firstly by high pressure, which was enhanced by increased temperature, then the germinated spores were inactivated by heat.

Dense phase carbon dioxide (DPCD) offers advantages of enhanced physical and nutritional qualities during the processing of juices. Here, freshly squeezed orange juice was treated with DPCD, and changes of physical properties and volatile components were investigated and compared with the original untreated and thermally treated samples. The correlations among physiochemical properties were also examined based on Pearson correlation, cluster analysis (CA), and principal component analysis (PCA). Significant correlations were found among the particle size, color parameters, and volatile compounds in the DPCD-treated samples. The 12 parameters were clustered into three groups using CA and PCA, and the eight volatile compounds were separated within the three groups. Nonanal and citronellol were clustered in group I, and they increased for a longer duration of more than 40 min with higher levels than the control. Parameters in group II included D (4,3), L∗, a∗, ethyl butyrate, and trans-2-hexenol, and they linearly decreased after 10–60 min DPCD treatment. The parameters of b∗ and monoterpenes were clustered in group III, and they decreased within 40 min of DPCD treatment and then increased to an intermediate level. In addition, PCA clearly showed that the orange juice samples under DPCD for 10–60 min formed a “U” shape on the two-dimensional plot and that the samples treated by DPCD for 10 min and 20 min were closer to freshly squeezed orange juice than the heat-treated orange juice. This indicated that the nonthermal DPCD process offers the potential to be used more extensively in juice products.

This work aimed to evaluate the effects of N2-assisted high-pressure processing (HPP, 400 MPa/7.5 min and 500 MPa/7.5 min) on the microorganisms and physicochemical, nutritional, and sensory characteristics of fresh-cut bell peppers (FCBP) during 25 days of storage at 4 °C. Yeasts and molds were not detected, and the counts of total aerobic bacteria were less than 4 log10 CFU/g during storage at 4 °C. The total soluble solids and L* values were maintained in HPP-treated FCBP during storage. After the HPP treatment, an 18.7–21.9% weight loss ratio and 54–60% loss of hardness were found, and the polyphenol oxidase (PPO) activity was significantly inactivated (33.87–55.91% of its original activity). During storage, the weight loss ratio and PPO activity of the samples increased significantly, but the hardness of 500 MPa/7.5 min for treated FCBP showed no significant change (9.79–11.54 N). HPP also effectively improved the total phenol content and antioxidant capacity of FCBP to 106.69–108.79 mg GAE/100 g and 5.76–6.55 mmol Trolox/L; however, a non-negligible reduction in total phenols, ascorbic acid, and antioxidant capacity was found during storage. Overall, HPP treatments did not negatively impact the acceptability of all sensory attributes during storage, especially after the 500 MPa/7.5 min treatment. Therefore, N2-assisted HPP processing is a good choice for the preservation of FCBP.

Proanthocyanidins (PAs) are responsible for several health benefits of many fruits, but they could cause a generally disliked sensation of astringency. Traditional deastringency methods remove bioactive ingredients, resulting in the loss of valuable nutrients and associated health benefits. This work aimed to microencapsulate PAs from grape seeds using oxidized starch hydrogel (OSH) and mask its perceived astringency in beverages while maintaining its bioavailability. The maximum PA uptake capabilities of OSH, as well as the binding site and primary binding force between these two components, were determined. The resulting PA-OSH complex was stable under in vitro digestion, with only 1.6% of PA being released in the salivary digestion, and it has an intestine-specific release property. The reaction of PA with α-amylase in artificial saliva was substantially reduced by OSH microencapsulation, leading to 41.5% less precipitation of the salivary proteins. The sensory evaluation results showed that the microencapsulation was able to mask the astringency of PA-fortified water, as the perceived threshold of astringency increased by 3.85 times. These results proved that OSH could be used as a novel food additive to reduce the astringency of beverage products due to its hydrogel properties and ability to encapsulate phenolic compounds.

The diversity of indigenous lactic acid bacteria (LAB) in fermented broccoli, cherry, ginger, white radish, and white-fleshed pitaya juices was analyzed using culture-independent and -dependent approaches. The major properties of selected probiotic strains, including dynamic variations in pH, viable cell counts, antibiotic resistance, bacterial adhesion to hydrophobic compounds, and survivability during simulated gastrointestinal transit, were investigated using broccoli as the fermentation substrate. In broccoli and ginger juices, the genus Lactobacillus occupied the dominant position (abundances of 79.0 and 30.3%, respectively); in cherry and radish juices, Weissella occupied the dominant position (abundances of 78.3 and 83.2%, respectively); and in pitaya juice, Streptococcus and Lactococcus occupied the dominant positions (52.2 and 37.0%, respectively). Leuconostoc mesenteroides, Weissella cibaria/soli/confusa, Enterococcus gallinarum/durans/hirae, Pediococcus pentosaceus, Bacillus coagulans, and Lactococcus garvieae/lactis subspecies were identified by partial 16S rRNA gene sequencing. In general, the selected autochthonous LAB isolates displayed no significant differences in comparison with commercial strains with regard to growth rates or acidification in fermented broccoli juice. Among all the isolates, L. mesenteroides B4-25 exhibited the highest antibiotic resistance profile (equal to that of L. plantarum CICC20265), and suitable adhesion properties (adhesion of 13.4 ± 5.2% ∼ 36.4 ± 3.2% and 21.6 ± 1.4% ∼ 69.6 ± 2.3% to ethyl acetate and xylene, respectively). Furthermore, P. pentosaceus Ca-4 and L. mesenteroides B-25 featured the highest survival rates (22.4 ± 2.6 and 21.2 ± 1.4%, respectively), after simulated gastrointestinal transit. These results indicated a high level of diversity among the autochthonous bacterial community in fermented fruit and vegetable juices, and demonstrated the potential of these candidate probiotics for applications in fermentation.

The physico-chemical and bio-chemical compositions of Hongyan, Tiangxiang, Tongzi Ι and Zhangji strawberries inChinawere analyzed. Their values were pH 3.42~3.73, titration acidity 0.63~0.79%, total soluble sugars 5.26~8.95 g/100 gfresh weight (FW), ascorbic acid 21.38~42.89 mg/100 gFW, total phenolics 235.12~444.73 mg/100 gFW, pectin 82.84~96.13 mg/100 gFW, total organic acids 874.30~1216.27 mg/100 gFW, Individual phenolic compounds other than anthocyanins 7.60~12.18 mg/100 gFW, free amino acids 13.35~32.66 mg/100 gFW, monomeric anthocyanins 4.47~47.19 mg/100gFW, antioxidant capacity of ·DPPH 14.14~18.87 and FRAP 7.97~10.54 equal to mg/100 gVc, polyphenol oxidase (PPO) activity 0~0.42 Abs/min, peroxidase (POD) activity 0.17~0.34 Abs/min and pectin methyl esterase (PME) activity 0.012~0.018 mL/min. Tongzi Ι was most suitable for food processing due to the highest titration acidity, total phenolics, pectin, total organic acids, monomeric anthocyanins, antioxidant capacity of ·DPPH and FRAP with lower PPO, POD and PME activity.

High pressure carbon dioxide (HPCD) could cause sublethally injured cells (SICs), which may cause food poisoning and spoilage during food storage and limit its application. Therefore, the formation of SICs of Escherichia coli O157:H7 was investigated by isobaric tag for relative and absolute quantification (iTRAQ) proteomic methods in this study for better controlling the SICs induced by HPCD. A total of 2,446 proteins was identified by iTRAQ, of which 93 and 29 were significantly differentially expressed in the SICs compared with live control cells (CKL) and dead control cells (CKD), respectively. Among the 93 differentially expressed proteins (DEP) in the SICs compared with CKL, 65 proteins showed down-regulation and 28 showed up-regulation. According to the comprehensive proteome coverage analysis, the SICs survived under HPCD by reducing carbohydrate decomposing, lipid transport and metabolism, amino acid transport and metabolism, transcription and translation, DNA replication and repair. Besides, the SICs showed stress response, DNA damage response and an increased carbohydrate transport, peptidoglycan synthesis and disulfide bond formation to HPCD. Among the 29 DEP in the SICs compared with CKD, 12 proteins showed down-regulation and 17 showed up-regulation. According to the comprehensive proteome coverage analysis, the SICs survived under HPCD by accumulation of cell protective agents like carbohydrates and amino acids, and decreasing transcription and translation activities. Results showed that the formation of the SICs with low metabolic activity and high survival ability was a survival strategy for E. coli O157:H7 against HPCD.

ABSTRACT The formation of viable but nonculturable (VBNC) Escherichia coli O157:H7 induced by high-pressure CO2 (HPCD) was investigated using RNA sequencing (RNA-Seq) transcriptomics and isobaric tag for relative and absolute quantitation (iTRAQ) proteomic methods. The analyses revealed that 97 genes and 56 proteins were significantly changed upon VBNC state entry. Genes and proteins related to membrane transport, central metabolisms, DNA replication, and cell division were mainly downregulated in the VBNC cells. This caused low metabolic activity concurrently with a division arrest in cells, which may be related to VBNC state formation. Cell division repression and outer membrane overexpression were confirmed to be involved in VBNC state formation by homologous expression of z2046 coding for transcriptional repressor and ompF encoding outer membrane protein F. Upon VBNC state entry, pyruvate catabolism in the cells shifted from the tricarboxylic acid (TCA) cycle toward the fermentative route; this led to a low level of ATP. Combating the low energy supply, ATP production in the VBNC cells was compensated by the degradation of l-serine and l-threonine, the increased AMP generation, and the enhanced electron transfer. Furthermore, tolerance of the cells with respect to HPCD-induced acid, oxidation, and high CO2 stresses was enhanced by promoting the production of ammonia and NADPH and by reducing CO2 production during VBNC state formation. Most genes and proteins related to pathogenicity were downregulated in the VBNC cells. This would decrease the cell pathogenicity, which was confirmed by adhesion assays. In conclusion, the decreased metabolic activity, repressed cell division, and enhanced survival ability in E. coli O157:H7 might cause HPCD-induced VBNC state formation. IMPORTANCE Escherichia coli O157:H7 has been implicated in large foodborne outbreaks worldwide. It has been reported that the presence of as few as 10 cells in food could cause illness. However, the presence of only 0.73 to 1.5 culturable E. coli O157:H7 cells in salted salmon roe caused infection in Japan. Investigators found that E. coli O157:H7 in the viable but nonculturable (VBNC) state was the source of the outbreak. So far, formation mechanisms of VBNC state are not well known. In a previous study, we demonstrated that high-pressure CO2 (HPCD) could induce the transition of E. coli O157:H7 into the VBNC state. In this study, we used RNA-Seq transcriptomic analysis combined with the iTRAQ proteomic method to investigate the formation of VBNC E. coli O157:H7 induced by HPCD treatment. Finally, we proposed a putative formation mechanism of the VBNC cells induced by HPCD, which may provide a theoretical foundation for controlling the VBNC state entry induced by HPCD treatment.

The inactivation effects of high pressure CO2 + nisin (simultaneous treatment of HPCD and nisin, HPCD + nisin), HPCD→nisin (HPCD was followed by nisin), and nisin→HPCD (nisin was followed by HPCD) treatments on Bacillus subtilis spores in aqueous solutions were compared. The spores were treated by HPCD at 6.5 or 20 MPa, 84-86ºC and 0-30 min, and the concentration of nisin was 0.02%. Treated spores were examined for the viability, the permeability of inner membrane (IM) using flow cytometry method (FCM) and pyridine-2, 6-dicarboxylic acid (DPA) release, and structural damage by transmission electron microscopy (TEM). A synergistic effect of HPCD + nisin treatment on inactivation of the spores was found, and the inactivation efficiency of the spores was HPCD + nisin > HPCD→nisin or nisin→HPCD. Moreover, HPCD + nisin caused higher IM permeability and DPA release of the spores than HPCD. A possible action mode of nisin-enhanced inactivation of the spores was suggested as that HPCD firstly damaged the coat and cortex of spores, and nisin penetrated into and acted on the inner membrane (IM) of spores, which increased the damage to the IM of spores, and resulted in higher inactivation of the spores.

The objective of this study was to investigate the inactivation mechanism of Bacillus subtilis spores by high pressure CO2 (HPCD) processing. The spores of B. subtilis were subjected to heat at 0.1 MPa or HPCD at 6.5-20 MPa, and 64-86ºC for 0-120 min. The germination, the permeability of inner membrane (IM) and cortex, the release of pyridine-2, 6-dicarboxylic acid (DPA), and changes in the morphological and internal structures of spores were investigated. The HPCD-treated spores did not lose heat resistance and their DPA release was lower than the inactivation, suggesting that spores did not germinate during HPCD. The flow cytometry analysis suggested that the permeability of the IM and cortex of HPCD-treated spores was increased. Furthermore, the DPA of the HPCD-treated spores were released in parallel with their inactivation and the fluorescence photomicrographs showed that these treated spores were stained by propidium iodide (PI), ensuring that the permeability of IM of spores was increased by HPCD. The scanning electron microscopy (SEM) photomicrographs showed that spores were crushed into debris or exhibited a hollowness on the surface, and the transmission electron microscopy (TEM) photomicrographs exhibited an enlarged core, ruptured and indistinguishable IM and a loss of core materials in the HPCD-treated spores, indicating that HPCD damaged the structures of the spores. These findings suggested that HPCD inactivated B. subtilis spores by directly damaging the structure of the spores, rather than inducing germination of the spores.

The viable but nonculturable (VBNC) state is a survival strategy adopted by many pathogens when exposed to harsh environmental stresses. In this study, we investigated for the first time that whether high pressure CO2 (HPCD), one of the nonthermal pasteurization techniques, can induce Escherichia coli O157:H7 into the VBNC state. By measuring plate counts, viable cell counts and total cell counts, E. coli O157:H7 in 0.85% NaCl solution (pH 7.0) was able to enter the VBNC state by HPCD treatment at 5 MPa and four temperatures (25°C, 31°C, 34°C and 37°C). Meanwhile, with the improvement of treatment temperature, the time required for E. coli O157:H7 to enter VBNC state would shorten. Enzymatic activities in these VBNC cells were lower than those in the exponential-phase cells by using API ZYM kit, which were also reduced with increasing the treatment temperature, but the mechanical resistance of the VBNC cells to sonication was enhanced. These results further confirmed VBNC state was a self-protection mechanism for some bacteria, which minimized cellular energetic requirements and increased the cell resistance. When incubated in tryptic soy broth at 37°C, the VBNC cells induced by HPCD treatment at 25°C, 31°C and 34°C achieved resuscitation, but their resuscitation capabilities decreased with increasing the treatment temperature. Furthermore, electron microscopy revealed changes in the morphology and interior structure of the VBNC cells and the resuscitated cells. These results demonstrated that HPCD could induce E. coli O157:H7 into the VBNC state. Therefore, it is necessary to detect if there exist VBNC microorganisms in HPCD-treated products by molecular-based methods for food safety.

High pressure processing (HPP) is a non-thermal technology that can ensure microbial safety without compromising food quality. However, the presence of pressure-resistant sub-populations, the revival of sub-lethally injured (SLI) cells, and the resuscitation of viable but non-culturable (VBNC) cells pose challenges for its further development. The combination of HPP with other methods such as moderate temperatures, low pH, and natural antimicrobials (e.g., bacteriocins, lactate, reuterin, endolysin, lactoferrin, lactoperoxidase system, chitosan, essential oils) or other non-thermal processes (e.g., CO2, UV-TiO2 photocatalysis, ultrasound, pulsed electric fields, ultrafiltration) offers feasible alternatives to enhance microbial inactivation, termed as "HPP plus" technologies. These combinations can effectively eliminate pressure-resistant sub-populations, reduce SLI or VBNC cell populations, and inhibit their revival or resuscitation. This review provides an updated overview of microbial inactivation by "HPP plus" technologies and elucidates possible inactivation mechanisms. [ABSTRACT FROM AUTHOR]

Fermentation is a traditional method utilized for vegetable preservation, with microorganisms playing a crucial role in the process. Nowadays, traditional spontaneous fermentation methods are widely employed, which excessively depend on the microorganisms attached to the surface of raw materials, resulting in great difficulties in ideal control over the fermentation process. To achieve standardized production and improve product quality, it is essential to promote inoculated fermentation. In this way, starter cultures can dominate the fermentation processes successfully. Unfortunately, inoculated fermentation has not been thoroughly studied and applied. Therefore, this paper provides a systematic review of the potential upgrading strategy of vegetable fermentation technology. First, we disclose the microbial community structures and succession rules in some typical spontaneously fermented vegetables to comprehend the microbial fermentation processes well. Then, internal and external factors affecting microorganisms are explored to provide references for the selection of fermented materials and conditions. Besides, we widely summarize the potential starter candidates with various characteristics isolated from spontaneously fermented products. Subsequently, we exhibited the inoculated fermentation strategies with those isolations. To optimize the product quality, not only lactic acid bacteria that lead the fermentation, but also yeasts that contribute to aroma formation should be combined for inoculation. The inoculation order of the starter cultures also affects the microbial fermentation. It is equally important to choose a proper processing method to guarantee the activity and convenience of starter cultures. Only in this way can we achieve the transition from traditional spontaneous fermentation to modern inoculated fermentation. [ABSTRACT FROM AUTHOR]