Abstract:To elucidate whether milk oligosaccharides can improve antibiotic-associated diarrhea, the effects of milk oligosaccharides on diarrhea, intestinal flora, and metabolic functioning were investigated in an antibiotic-associated diarrhea C57BL/6J mouse model undergoing treatment with ampicillin. Mice were divided into a normal control group, a model group, and low-and high-dose milk oligosaccharide groups, and one week after intervention, the diarrhea phenotype, inflammatory factor levels, tight junction protein expression levels, and intestinal flora and short-chain fatty acid metabolism of the mice were analyzed through 16S rRNA high-throughput sequencing and gas chromatography. The results showed that, compared to the model group, the body weight and AQP3 levels of the high-dose milk oligosaccharide group increased by 8.65%, and 128.46%, respectively, along with a decrease of 24.51% in the fecal moisture content and respective reductions of 26.98%, 30.31%, and 37.60% in the IL-6, TNF-α, and IL-1β levels and an increase of 59.21% in the IL-10 level. The mRNA expression levels of the tight junction proteins ZO-1, claudin-1 and occludin were significantly higher in the milk oligosaccharide group than the MC group, whereas Akkermansia, Bacteroidetes, Parabacteroides, and Duberella were significantly enriched in the high-dose milk oligosaccharide group. The acetic acid, propionic acid, and butyric acid contents in the intestines of mice in the high dose bovine milk oligosaccharide group were 2.18, 2.31, and 2.25 times that of those obtained for the MC group, respectively. We conclude that the milk oligosaccharides negated antibiotic-associated diarrhea by improving the diarrhea phenotype, regulating the intestinal inflammatory response, promoting the intestinal barrier function, enriching beneficial bacteria, and producing short-chain fatty acids in the mice. This study provides theoretical support for the application of milk-derived functional ingredients in the development of food or health products for those suffering from diarrhea.

Abstract:The potential of Haematococcus pluvialis powder in alleviating urinary tract obstruction-induced renal fibrosis by ameliorating mitochondrial dysfunction and epithelial–mesenchymal transition (EMT) was investigated in this study. Various methods, including the CCK8 assay, immunofluorescence, mitochondrial membrane potential measurement, mitochondrial reactive oxygen species detection assay, and immunohistochemical staining, were used for validation. The results demonstrated the ability of H. pluvialis powder in mitigating renal pathological changes in rats induced by unilateral ureteral obstruction (UUO) surgery. Compared with the model group, treatment with H. pluvialis powder significantly decreased fibronectin 1 expression (65.52%). In vitro, H. pluvialis powder ameliorated transforming growth factor-β1-induced changes in EMT markers in HK-2 cells, with the positive area fraction of E-cadherin increasing by 51.35%, and those of N-cadherin and vimentin decreasing by 62.30% and 39.36%, respectively. An increase in mitochondrial membrane potential and a decrease in mitochondrial superoxide accumulation were also observed. Subsequently, astaxanthin (AST) was used to intervene in the rat UUO and HK-2 pro-fibrotic cell models. The results revealed that H. pluvialis powder outperformed AST at equivalent dosages/concentrations. In summary, this study found that H. pluvialis powder could alleviate the pathological progression of renal fibrosis caused by urinary tract obstruction via mechanisms that include improving extracellular matrix deposition, reducing renal cortical injury, modulating the EMT process, and mitigating mitochondrial dysfunction. Therefore, H. pluvialis powder shows potential for the development of functional foods with renoprotective effects.

Abstract:The tolerance of probiotics delivered to the gastrointestinal tract, characterized by high acidity and the abundant presence of digestive enzymes and bile salts, remains unknown. To this end, investigations were conducted involving the compounding of cellulose nanofibril (CN) and sodium alginate (SA), as well utilizing techniques such as Fourier transform infrared spectroscopy differential scanning calorimetry, Luria-Bertani medium liquid culturing, artificial simulated gastrointestinal liquid digestion method, compatibility testing of embedding materials, evaluation of thermal stability after embedding Bacillus coagulum, analysis of pH changes during liquid culture, and assessment of in vitro digestion characteristics (swelling rate, swelling behavior, and pH sensitivity) in artificial simulated gastrointestinal fluids. The results showed that SA had good compatibility with CN, with the addition of nanocellulose effectively enhancing the thermal stability of the SA-CN-BC structure. The pH value of the embedded B. coagulans exhibited minimal fluctuation in the liquid culture, its pivotal contribution to the sustained release. The highest degree of looseness in the gel sphere network and largest swelling rate of 3 243% were observed at a SA:CN ratio of 1:1. The SA-CNBC contracted in the simulated gastric fluid and were expanded in the simulated intestinal fluid, indicating notable pH sensitivity. A pH-sensitive alginate gel-nanocellulose hydrogel sphere was successfully prepared in this study for the delivery of probiotics, demonstrating the potential for hydrogels to serve as biocompatible carriers for drug and nutrient delivery.

Abstract:Despite being indispensable, zinc and selenium are often severely deficient trace elements in humans. To achieve optimal zinc and selenium supplementation for deficient populations, dietary supplements of these elements can be investigated by harnessing the nutrient-absorbing properties of germinating peanuts. In the present study, peanut was used as a carrier of dietary supplements, with zinc sulfate (0, 10, 20, 30, 40, 50 mg•L-1) and sodium selenite (0, 100, 200, 300, 400, 500 mg•L-1) solutions added during seed soaking to attain zinc and selenium enrichment through germination. The results showed that the enrichment of zinc and selenium in peanut sprouts was highest at exogenous zinc and selenium concentrations of 40 and 420 mg•L-1, respectively, with contents being higher than 2.0 and 23.76 times than those in the control peanut sprouts, respectively. Zinc and selenium enrichment also increased the polyphenol content of peanut sprouts. The contents of catechin, salicylic acid, quercetin, and rutin were significantly increased (P<0.05), while that of toxic gossypol was significantly decreased (P<0.05). The significant increases in polyphenol and selenium contents (P<0.05) also enhanced the antioxidant capacity of peanut sprouts. The findings of this study suggest zinc- and selenium-enriched peanut sprouts as a novel zinc-selenium dietary supplement for daily supplementation in zinc- and selenium-deficient populations, providing additional bioactive substances for the human body.

Abstract:The effects of ergosterol-rich Lentinus edodes stalk extracts on lipid metabolism remain unknown; thus, the content of ergosterol in the cap and stalk of L. edodes was analyzed using high performance liquid chromatography and the regulatory effects of the n-hexane extract (SEHE) and methanol/dichloromethane extract (SEMD) of the stalk on serum lipids, liver lipids and fecal lipids investigated in a rat model induced by a high-cholesterol diet. The ergosterol content of 7.82 mg∙g-1 in the L. edodes cap was found to be significantly higher than the 5.24 mg∙g-1 in the stalk, and the ergosterol content of SEHE was 20.31% (m/m) was higher than the 6.12% (m/m) obtained for SEMD. Animal experiments showed that both SEHE and SEMD could significantly reduce the level of low-density lipoprotein cholesterol (LDL-C), with reductions of 51.02% (P<0.05) and 58.34% (P<0.05), respectively, and effectively reduce the LDL-C/high-density lipoprotein cholesterol (HDL-C) ratio, with reductions of 54.61% (P<0.05) and 53.04% (P<0.05), respectively, in the rat serum. The two extracts were also found to reduce the cholesterol content (-19.31%, P<0.05; -23.73%, P<0.05) and triglyceride content (-9.82%, P=0.11; -24.83%, P<0.05) in rat liver. SEMD was also found to significantly reduce the total cholesterol (TC) level in rat serum (-13.31%, P<0.05). These findings indicate that both stalk extracts effectively regulated lipid metabolism in rats and have the potential to be used as functional food ingredients for the prevention of cardiovascular disease.

Abstract:The effect of continuous nutritional supplementation on the postoperative nutritional status and quality of life (QOL) of patients with esophageal cancer under the Hospital-To-Home (H2H) nutritional management model was investigated in this study. A total of 81 patients first diagnosed with esophageal cancer and who had received surgical treatment at the Department of Thoracic Surgery of our hospital were randomly assigned to an experimental or a control group. Routine nutritional management was implemented in the control group, while the H2H nutritional management model was adopted in the experimental group to provide continuous nutritional supplementation. The results showed that postoperative hemoglobin concentration decreased to varying degrees in both groups; however, the experimental group had a lower concentration at 3 days postoperatively than the control group (P=0.037). The concentrations of serum albumin (38.2 g•L-1) and prealbumin (256.7 g•L-1) at 3 days postoperatively were higher in the experimental than in the control group (36.3 and 180.9 g•L-1, respectively; both P<0.05). In both groups, total protein and prealbumin concentrations decreased postoperatively, followed by a gradual increase after discharge, with the experimental group showing a steeper overall trend than the control group. QOL assessment indicated that the experimental group achieved significantly higher scores in physical functioning (81.7 vs 70.2), emotional functioning (85.5 vs 75.0), and overall health (73.0 vs 62.8) at 6 months postoperatively than the control group (all P<0.05). In conclusion, the results of this study indicate that continuous nutritional supplementation based on the H2H nutritional management model simultaneously enhances postoperative nutritional status and QOL in esophageal cancer patients, thereby improving postoperative outcomes. The H2H nutritional management model can serve as a reference for long-term nutritional management of postoperative cancer patients.

Abstract:To clarify the material basis, therapeutic targets, and potential mechanisms of functional food black sesame in improving anemia, provide a scientific basis for its precise application in anemia regulation, and offer new ideas for the development of related functional foods, this study employed a systematic approach combining network pharmacology and molecular docking technology. Active components of black sesame with oral bioavailability (OB) ≥20% and drug-likeness (DL) ≥0.05 were screened using the TCMSP database; anemia-related diseases and targets were identified through databases including SymMap and Metascape platform; a "component-target-disease" network was constructed with Cytoscape, and core targets were recognized by the MCODE algorithm; molecular docking verification was performed via AutoDock Vina, with results visualized as a molecular docking heatmap, and GO functional enrichment and KEGG pathway analyses were also conducted. A total of 24 active components, 12 types of anemia-related diseases, and 16 therapeutic targets were identified, with ESR1, BCL2, and SERPINE1 confirmed as core targets. Molecular docking results showed that MOL009834 (sesamolin) formed stable bindings with BCL2 (binding energy: -8.8 kcal•mol-1) and SERPINE1 (binding energy: -8.6 kcal•mol-1), while MOL000492 ((+)-catechin) stably bound to ESR1 (binding energy: -9.0 kcal•mol-1). Enrichment analyses verified that core targets involved synergistic effects of multiple pathways such as apoptosis regulation and JAK-STAT signaling pathway.Black sesame may improve anemia through the synergistic action of multiple pathways by acting on key targets including ESR1, BCL2, and SERPINE1 via core active components like MOL009834 and MOL000492, confirming the scientific connotation of its anemia-regulating effect and providing a theoretical basis for the development and application of black sesame as a functional food in anemia regulation.

Abstract:The antibacterial effect of Litsea cubeba oil on wild strains of Cronobacter sakazakii in infant formula milk powder is currently unknown. Thus, the continuous double dilution, plate counting, and growth curve methods were used to investigate the antibacterial mechanism by detecting the β-galactosidase activity, alkaline phosphatase activity, intracellular DNA content, and bacterial structure changes. The results showed a strong antibacterial effect for L. cubeba oil against C. sakazakii, with a minimum inhibitory concentration (MIC) of 6.62 μg•mL-1 and significant inhibition in the growth of C. sakazakii after one treatment. The activity of extracellular alkaline phosphatase and intracellular β-galactosidase in C. sakazakii showed significant 2- and 13.50-fold increases as compared to the control (P<0.05), and the cell morphology of the bacteria was destroyed. The cell contents were leaked, with the leaked nucleic acid and protein reaching 1.03 times that observed in the control (P<0.05). The intracellular DNA content was reduced to 0.17 μg•mL-1, the DAPI fluorescence area was decreased, the brightness of the gel block electrophoresis bands darkened, and the DNA was damaged. In summary, L. cubeba essential oil could be utilized as a highly effective bacteriostatic agent for C. sakazakii due to its action in destroying both the cell membrane and the DNA and interfering with the normal physiological activity of the bacteria, resulting in death. This study is expected to provide a theoretical basis for the development of the essential oil of L. cubeba as a new antibacterial agent.

Abstract:Staphylococcus aureus is a pathogenic bacterium responsible for food-borne infections. The overuse of antibiotics has led to a lack of effective pharmacological treatments for S. aureus infection. To identify candidate therapeutic agents, the metabolic potential and active components of Streptomyces strain TRM74023 were analyzed. Metabolic potential was comprehensively assessed based on a genomic analysis, and antibacterial activity was analyzed by adopting S. aureus as the target bacterium. Biologically active secondary metabolites were obtained through modern techniques for isolation, purification, and identification. The bacterium had a genome size of 6 885 644 bp and a G+C content of 72.24%. The average nucleotide identity (ANI), DNA-DNA hybridization (DDH) values, and phylogenetic analysis collectively suggested that TRM74023 is a novel species. In total, 29 natural product biosynthetic gene clusters and three resistance genes were found in Streptomyces strain TRM74023. Two monomeric compounds were isolated based on an antibacterial activity analysis and were identified as actinolactomycin and 6-methylnicotinic acid. Actinolactomycin (1 mg•mL-1) exhibited strong activity against S. aureus, with an inhibition zone diameter of 21.40 mm and MIC and MBC values of 1×10-3 mg•mL-1 and 1×10-2 mg•mL-1, respectively. Significant antibacterial effects were detected against Enterococcus faecalis, Acinetobacter baumannii, and Erwinia amylovora. In summary, Streptomyces strain TRM74023 demonstrated substantial metabolic potential, and actinolactomycin isolated from the bacterium exhibited strong antibacterial effects against S. aureus. These results can serve as a scientific basis for the development of drugs to prevent and control food-borne pathogenic bacteria, such as S. aureus.

Abstract:Bacterial community diversity was analyzed at various stages of the high-temperature Daqu fermentation process using 16S rRNA sequencing technology. Bacterial gene function was also predicted using PICRUSt software. The bacterial richness and community structure of high-temperature Daqu differed significantly among fermentation stages (P<0.05). As fermentation progressed, bacterial richness tended to exhibit a an initial increase and subsequent decrease, reaching a maximum at the first Daqu flipping stage. Three dominant bacterial phyla and ten dominant bacterial genera were detected during the high-temperature Daqu fermentation process, with obvious community succession occurring in samples at different fermentation stages. Ten core OTUs were detected in all samples, mainly belonging to the genera Saccharopolyspora, Thermoactinomyces, Bacillus, Kroppenstedtia, and Lentibacillus, with a cumulative average relative abundance of 52.62%. There were significant differences in bacterial microbial networks in high-temperature Daqu among different fermentation stages. In particular, the bacterial community structure of first-flipped Daqu samples possessed higher complexity and connectivity, with Scopulibacillus and Bacillus being the key genera that maintained microbial community structure stability during the hightemperature Daqu fermentation process. Metabolism was an important functional pathway in the high-temperature Daqu fermentation process. This included energy production and transformation, and the transport and metabolism of biological macromolecules, such as amino acids, carbohydrates, and lipids. The study results contribute to a better understanding of bacterial community succession during the high-temperature Daqu fermentation process and provide a useful reference for the optimization of Daqu production and improvement of product quality in related enterprises.

Abstract:The effects of fermentation temperature on the microorganisms and product quality of low-salt soy sauce were investigated. In particular, low-salt soy sauce was fermented at 45 ℃, 35 ℃, 25 ℃, and natural conditions for analyses of the microbial count, physicochemical indicators, and quality indicators of mature soy sauce mash during the fermentation process. Different temperatures had varying degrees of influence on the fermentation of low-salt soy sauce. Yeast cells underwent rapid death during high-temperature fermentation at 45 ℃, while the yeast count remained relatively high (6.00 lg CFU/g) throughout the entire fermentation process at other temperatures. This resulted in significant differences in total microbial counts among temperatures. High-temperature fermentation at 45 ℃ improved the fermentation rate; however, the contents of reducing sugars (2.52 g/100 g) and sweet amino acids (11.92 g•kg-1) were higher and the biogenic amine content (78.88 mg•kg-1) was lower than those for fermentation at other temperatures. Fermentation at 45 ℃ was not conducive to the formation and accumulation of volatile flavor compounds in low-salt soy sauce, particularly phenolic and ester compounds, while a lower fermentation temperature was more favorable for the accumulation of phenols and esters. A sensory evaluation indicated that soy sauce fermented at 35 ℃ had the best sensory quality, followed by soy sauce fermented at 45 ℃. Soy sauce fermented at 25 ℃ and under natural conditions had poorer color and aroma attributes. In addition, fermentation at medium-to-low temperatures (35 ℃, 25 ℃, and room temperature) led to significant film production on the surface of the soy sauce mash during the late stage of fermentation. In summary, fermentation at 45 ℃ ensured normal liquid-state fermentation of low-salt soy sauce; however, the flavor and color were less favorable. The results of this study can serve as reference for the optimization and control of the low-salt soy sauce fermentation process in the future.

Abstract:To enhance the added value of silkworm pupae, the composition, structure, and emulsion properties of polysaccharides from silkworm pupae (PSP) were investigated in this study. An analysis of the composition and structure of PSP extracted from silkworm pupae was conducted. High internal phase emulsions (φ=74%) were prepared with the obtained PSP, and the effects of PSP mass concentration on emulsion properties were analyzed by measuring the zeta potential, droplet size, emulsifying activity index (EAI), emulsion stability index (ESI), rheological properties, and storage stability of the emulsions. The results showed that PSP was primarily composed of fucose, galactosamine hydrochloride, rhamnose, arabinose, glucosamine hydrochloride, galactose, glucose, mannose, and glucuronic acid. PSP and its primary components, PSP2 (1.01×106 u) and PSP3 (1.24 ×106 u), were acidic polysaccharides. The mass concentration of PSP significantly influenced emulsion stability. With an increase in PSP mass concentration from 5 to 80 mg•mL-1, EAI increased from 3.43 to 17.24 m2•g-1, ESI improved from 10.39 to 548.30 min, absolute zeta potential rose from 15.77 to 28.10 mV, and droplet size decreased from 135.80 to 62.07 μm. In particular, the emulsion stabilized with 80 mg•mL-1 PSP exhibited the lowest stability index, the highest viscosity, and the best storage stability. The present study demonstrated that PSP consists of natural polysaccharides with excellent emulsifying properties, which can potentially be used to stabilize high internal-phase emulsions. The results of this study can provide a theoretical basis for the development and use of PSP, which has potential for widespread application as a novel green emulsifier and thickener in food processing.

Abstract:Brassica rapa L. is an economic crop unique to plateau regions; its polysaccharides possess antioxidant, anti-fatigue, and anti-hypoxic properties. To investigate the structure of B. rapa L. polysaccharides and assess their antioxidant activity, crude polysaccharides were extracted using the water extraction and ethanol precipitation method, and BRP-5 was separated and purified. The composition, morphology, and structure of BRP-5 were analyzed using high-performance gel permeation chromatography, ion chromatography, scanning electron microscopy, scanning tunneling microscopy, infrared spectroscopy, and synchronous thermal analysis. The in vitro antioxidant activity of BRP-5 was evaluated by measuring its ability to scavenge superoxide, hydroxyl, and DPPH radicals. The results indicated that BRP-5 is an acidic polysaccharide with galacturonic acid as the primary monosaccharide and has a weight-average molecular weight of 16 670 Da. Cracks and fissures were identified on its surface, with the ten-point height (Sz), root-mean-square height (Sq), and roughness average height (Sa) being 24.40, 2.84, and 2.01 nm, respectively. Further analysis revealed that BRP-5 may contain pyranose rings and exhibited an amorphous structure. BRP-5 also exhibited certain antioxidant properties: scavenging rates of DPPH and hydroxyl radicals showed dose dependence within the range of 0.1~1.5 mg•mL-1, with the 50% inhibiting concentration (IC50) values being 0.96 mg•mL-1 and <0.1 mg•mL-1, respectively; the scavenging rate of superoxide anion radicals was <50%. The findings of this study provide novel insights into the structure of B. rapa L. polysaccharides and will aid in the development of related antioxidant products.

Abstract:Crude polysaccharides from different origins differ in their functional component content and structure. This study compared and analyzed the differences in the functional component content and structural features of crude polysaccharides extracted from Phellinus igniarius collected from different regions (Jilin, Hebei, Yunnan, and Tibet). Crude polysaccharides were obtained from P. igniarius using water extraction and ethanol precipitation methods. Preliminary structural characterization and analysis of the functional component content were performed using high-performance liquid chromatography, Fourier-transform infrared spectroscopy, and ultraviolet-visible spectroscopy. The results showed that crude polysaccharides of P. igniarius from Tibet contained the highest levels of functional components with polysaccharide, total phenol, total flavonoid, and total triterpene contents of 58.81%, 11.11%, 20.96%, and 4.49%, respectively. These samples exhibited the greatest thermal stability, as indicated by the highest residual mass (mass fraction of 40.40%) obtained from thermogravimetric analysis. The crude polysaccharides of P. igniarius were primarily composed of glucose, mannose, and galactose. Characteristic O-H and C-H peaks were observed in their spectra, indicating the presence of acidic polysaccharides in all four samples and revealing no significant differences in their crystalline structures. In summary, this study comparatively analyzed the crude polysaccharides of P. igniarius from four different origins, demonstrating that the Tibetan samples possessed the highest concentrations of the four functional components and the greatest thermal stability, while showing distinct variations in the chemical composition and structure of crude polysaccharides from different regions. These findings provide a valuable reference for the development and utilization of crude polysaccharides of P. igniarius from diverse regions.

Abstract:The differences in composition and activity of pectin polysaccharides in the cell walls of Goji berry peel and flesh were investigated using the cell wall pectin polysaccharides extracted from them. The basic structural characteristics of the cell wall pectin polysaccharides were analyzed using ultraviolet–visible spectrophotometry and Fourier–transform infrared spectroscopy. Monosaccharide composition and molecular weight distribution of the cell wall pectin polysaccharides were determined using anion exchange chromatography and gel permeation chromatography. The inhibitory effects on pancreatic lipase and α-amylase were measured via enzymatic activity inhibition experiments. The results indicated that the cell wall pectin polysaccharide content in Goji berry peel was significantly higher than that in the flesh (P<0.05). Cell wall pectin polysaccharides of both the peel and flesh were primarily composed of arabinose, galactose, galacturonic acid, rhamnose, xylose, and glucose, with peel pectin polysaccharides having a higher molecular weight. The half-maximal inhibitory concentration (IC50) of flesh pectin polysaccharides against pancreatic lipase was 4.334 mg•mL-1, indicating a stronger inhibitory effect than the peel. However, peel pectin polysaccharides demonstrated a superior inhibitory effect on α-amylase (IC50: 6.939 mg•mL-1) to the flesh pectin polysaccharides. Both types of pectin polysaccharides exhibited mixed-type inhibition, suggesting that the peel and flesh pectin polysaccharides can potentially regulate glucose and lipid metabolism. The results of this study provide a theoretical basis and novel approach for the high-value utilization of peel residue by-products derived from Goji berry processing.

Abstract:Changes in proteins and the taste-active substance content of oysters sterilized with ozonated water were investigated in this study. Shelled fresh oyster meat was treated with 4 mg•L-1 ozonated water for 2 min, and the changes in fluorescence and infrared spectra, particle size, solubility, turbidity, and the taste-active nucleotide and amino acid contents of oyster meat following sterilization were analyzed during storage at 0 ℃. Ozonated water sterilization led to protein aggregation in oyster meat, as evidenced by increased particle size and turbidity. The content of active sulfhydryl groups in oysters was significantly decreased (P<0.05); however, the degree of aggregation in oyster meat during the late stage of frozen storage was improved. No significant changes were observed in the secondary and tertiary structures of oyster myofibrillar proteins (P>0.05). Inosine 5′-monophosphate (IMP) was the primary taste-active nucleotide of the oysters. Ozonated water sterilization increased IMP content (P<0.05) and decreased that of guanosine 5'-monophosphate (P<0.05) in oyster meat. The taste-active nucleotide content of all groups significantly decreased (P<0.05) during the late stage of storage. Six taste-active amino acids were detected in oyster meat, accounting for 33.48% of the total amino acid content. Following ozonated water sterilization, the proportion of taste-active amino acids decreased to 30.18%. In conclusion, this study found no significant changes in the myofibrillar protein structure of ozonated water-sterilized oyster meat during frozen storage. Protein stability during the late stage of frozen storage was enhanced, while the content of taste-active substances was reduced. The results of this study can serve as a reference for the application of ozonated water in the preservation of the freshness of aquaculture products.

Abstract:To reduce the potential hazards of synthetic chemical preservatives (e.g., prochloraz and chlorine dioxide) on lychee (Litchi chinensis Sonn.) preservation and enhance its safety and quality, the preservation effects of the combined use of a compound plant-based preservative and preservation paper were analyzed. Lychees were treated with a compound preservative (CPP) alone, tea tree essential oil paper (TTP) alone, or a combination of CPP and TTP (CTP); untreated lychees served as the control (control check, CK) group. The treated lychees were stored at 4 ℃ for 21 days, during which appearance qualities, such as decay rate, nutritional qualities, such as anthocyanin content, metabolism of reactive oxygen species (ROS), such as superoxide dismutase (SOD), and activities of related enzymes, such as polyphenol oxidase (PPO), were assessed. The results showed significant differences in the decay rate between the CPP and TTP treatment groups and the CK group; CTP exerted the most potent inhibitory effect on lychee decay rate. After 12 days of storage, the anthocyanin content in the CPP, TTP, and CTP groups significantly increased by 34.67%, 68%, and 90.67%, respectively, compared with that in the CK group. After 21 days of storage, the malondialdehyde (MDA) content in the CPP, TTP, and CTP groups decreased by 47.22%, 56.83%, and 68.18%, respectively, compared with that in the CK group. During storage, the PPO activity in the CTP group was consistently lower than that in the CPP, TTP, and CK groups. In conclusion, combination treatment with CPP and TTP effectively mitigated the metabolism of ROS and reduced the activity of related enzymes, thereby maintaining the integrity of cell membranes and significantly delaying lychee browning. The combination treatment proposed in this study has thus demonstrated immense potential for application in lychee preservation.

Abstract:Walnut oil extraction residues are currently under-utilized; thus, hydraulically pressed walnut meal was used as raw material for the extraction of crude polyphenols using a microwave-ultrasound co-assisted extraction process optimized by singlefactor experiments and response surface design, and ultra-high-performance liquid chromatography-tandem mass spectrometry-time of flight mass spectrometry (UPLC Q-TOF/MS) employed to analyze and identify polyphenolic compounds. The antioxidant activity was evaluated through DPPH, ABTS, and hydroxyl radical scavenging assays, and the extracts were added back into the walnut oil to verify their impact on the oxidative stability. The results indicated that the solid-liquid ratio and volume fraction of ethanol significantly affected the extraction of polyphenols from walnut meal (P<0.05). The optimal extraction conditions of a solid-liquid ratio of 1:57.33 g•mL-1, an ethanol volume fraction of 69.13%, ultrasonic power of 100 W, and microwave power of 109.92 W resulted in a crude polyphenol extraction yield of 40.59 mg GAE (gallic acid equivalents)•g sample-1. A total of 24 polyphenolic compounds were identified, with higher contents of 3,4-dihydroxybenzoic acid (8 233.93 μg•g-1), kaempferol-3-O-rutinoside (4 504.20 μg•g-1), and ellagic acid (1 882.50 μg•g-1) observed. Walnut meal crude polyphenols exhibited good DPPH and ABTS radical scavenging effects (over 95%) at a mass concentration of 0.80 mg•mL-1 and maintained a hydroxyl radical scavenging rate of 60%~70%. The addition of walnut meal crude polyphenols at a mass concentration of 0.08 mg•g-1 increased the oxidative stability of walnut oil by more than 30%. As natural antioxidants, walnut meal polyphenols are expected to have high application value in the food industry after further separation and purification.

Abstract:Salted duck is a local specialty dish of Nanjing and has been designated as a Geographical Indication (GI) product of China. It is popular among consumers owing to its unique flavor and production process. However, comprehensive quality analyses of Nanjing salted duck are limited. Therefore, the present study aimed to compare the quality of different brands of Nanjing salted duck. In particular, six brands of commercially available Nanjing salted duck products were selected for comprehensive analysis of quality attributes (protein, fat, inosinic acid, and free amino acid contents and fatty acid composition and content) using multivariate statistical methods. There were significant differences (P<0.05) in quality among the six brands of Nanjing salted duck. The protein content was 20.9%~31.46%, while the inosinic acid and total free amino acid contents were 36.45~128.05 mg/100 g and 20.47~36.78 g•kg-1, respectively. Glutamic acid and valine were the main taste-active amino acids in Nanjing salted duck. The saturated fatty acid and polyunsaturated fatty acid contents were 9.82%~14.67% and 52.69%~60.69%, respectively, with the former being significantly higher in brand H1 and the latter being significantly higher in brand H2 than in other brands. A total of 11 differential substances (protein, IMP, C16:0, C18:0, C16:1, C18:1n-9c, C18:2n6c, C18:2n6t, C18:3n3, C18:3n6, and C22:6n3) were screened by OPLS-DA, with brand H1 having the highest IMP and C22:6n3 contents. These findings explain the savory flavor and diverse quality attributes of Nanjing salted duck from the perspective of nutrient compositions and can serve as reference for purchasing decisions of consumers.

Abstract:This study aimed to improve the preservation effect and extend the shelf life of Lanzhou lily during storage. Potato and pea starches were used as raw materials to optimize oxidized starch preparation via single-factor and response surface experiments. The physicochemical properties of the oxidized starches and their application in the preservation of Lanzhou lily were analyzed. Under optimal preparation conditions, the carboxyl contents of the oxidized potato and pea starches were 0.65% and 0.45%, respectively. The erosion and rupture of oxidized starch grains, along with the appearance of absorption peaks corresponding to carbon-oxygen double bond vibrations, indicated successful oxidation. Crystallinity, swelling capacity, and retrogradation decreased following oxidation, whereas transparency and solubility significantly increased. Oxidized potato starch exhibited a more porous structure, lower heat requirement for swelling, higher storage stability, fewer impurities, and better solubility than oxidized pea starch. The results of the preservation experiment demonstrated that both types of oxidized starch film significantly mitigated quality deterioration during the postharvest storage of Lanzhou lily; notably, however, the oxidized potato starch film provided a better preservation effect than the oxidized pea starch film. The results of this study provide a theoretical basis for the preparation of oxidized starch using hydrogen peroxide and its application in freshness preservation films for fruits and vegetables, and will aid in advancing the field of fruit and vegetable preservation.

Abstract:Natural waxes, with distinctive hydrophobic structures, have demonstrated notable emulsification properties. The present study aimed to provide insights into the microstructure of emulsion gels formed by different natural waxes and the assembly process of such gels in property modulation. Plastic fats were formed by inducing gelation of highly unsaturated liquid oil using four different natural waxes. Characterization and analysis were conducted using differential scanning calorimetry (DSC) and polarized light microscopy (PLM). The results demonstrated that upon modulation of the glycerol monostearate (GMS) concentration, the Japanese candelilla wax and sunflower wax (SFW) gels exhibited a gradual deepening of color, a homogeneous texture, and a milky sheen. With an increase in the mass concentration of wax from 6 to 10 wt.%, a solid-like behavior of storage modulus (G′)>loss modulus (G′′) was observed. Within the shear range of 1~100 s-1, apparent viscosity increased to 102~103 Pa with increasing wax concentration. All four gels exhibited high thixotropic recovery during thixotropic scans conducted at 0.1, 1, and 0.1 s-1. In DSC and X-ray diffraction (XRD) analysis, wax-based gels showed a tendency toward wider peaks. The sugarcane wax (SW) gel showed the highest melting peak and largest enthalpy under the same concentration conditions. SFW and SW gels exhibited the lowest crystallization points during the crystallization process, with two distinct sharp β′ crystalline peaks of 3.8 Å and 4.2 Å observed in the XRD spectra. PLM revealed smaller wax crystals with denser lattices and greater thermal stability in the gels. The results of this study demonstrated the potential for these gels to replace conventional solid fats, facilitating the application of novel oils and fats to improve the nutritional and physicochemical status of foods.

Abstract:The optimal wet-aging conditions for Tibetan sheep meat are currently unknown; thus, the pH, shear force, chromatic aberration, total number of colonies, cooking loss, centrifugal loss, fat oxidation, and protein oxidation indexes were investigated in meat subjected to wet-aging over 0, 1, 3, 5 and 7 days at 4 and 10 ℃. The results showed that the Tibetan sheep meat was fully aged after 3 days at 10 ℃, and an increase in the pH value was observed as compared to fresh meat (0 days), along with a significant decrease in the shear force (to 49.69 N), a cooking loss of 30.85%, and a centrifugal loss of 9.37% (P<0.05). The meat was also fully aged after 5 days at 4 ℃ , with an increase in the pH value as compared to fresh meat (0 d) accompanied by a significant decrease in the shear force (to 51.52 N), and decreases in the cooking and centrifugal losses of 29.37% and 10.12%, respectively, with the difference significant at P<0.05. Although the meat was fully aged when kept at 4 and 10 ℃, the color, fat oxidation and protein oxidation of the Tibetan sheep meat were not significantly different. The results suggest that the time required for the complete aging of Tibetan sheep is shorter, the tenderization speed is faster, and the water holding capacity is superior at 10 ℃. The study is expected to provide a theoretical basis for improving the quality of Tibetan sheep meat.

Abstract:Temperature- and humidity-controlled pile fermentation can affect the quality of tea. This study investigated the changes in the quality components of Liupao tea during temperature- and humidity-controlled pile fermentation. Tea samples of the Wantian, Cangwu group, Lingyun, and Guihong No.4 varieties were collected during the pile fermentation. The sensory attributes, tea infusion color, and major biochemical components of the tea samples were comparatively analyzed using sensory evaluation and high-performance liquid chromatography, combined with correlation and partial least squares discriminant analyses. The results showed that after 12 days of temperature- and humidity-controlled pile fermentation, the tea infusion color changed from orange-yellow to deep red, the dregs shifted from yellow to copper-brown, and the taste evolved from robust to mellow. The water extract, amino acid, tea polyphenol, thearubigin, and total catechin contents significantly decreased to 42.20%~44.89%, 2.44%~2.73%, 11.03%~14.76%, 1.68%~3.38%, and 32.13~43.45 mg.g-1 (P<0.05), respectively. In contrast, caffeine, theobromine, and theabrownin significantly increased to 34.10~39.98 mg.g-1, 0.98~2.08 mg.g-1, and 6.12%~8.23% (P<0.05), respectively. Epigallocatechin and gallic acid initially increased, followed by a decrease (P<0.05). The L* value of the tea infusion color decreased, whereas the a* and b* values showed an increasing trend. L* was highly negatively correlated with theabrownin, theaflavin, and caffeine (P<0.01), whereas a* and b* were highly positively correlated with theabrownin and caffeine (P<0.01). Among the varieties, Lingyun demonstrated the best quality, characterized by a deep red tea infusion color, mellow taste, high epicatechin and theaflavin content, low tea polyphenol, thearubigin, and esterified catechin contents, and a tea infusion color with a low L* value and high a* and b* values. These findings provide a theoretical basis for optimizing the temperature- and humidity-controlled pile fermentation of Liupao tea.

Abstract:To investigate the changing law of chemical and sensory characteristics of craft beers under different additions of chrysanthemum (0, 5, 10 and 15 g•L-1) in the main fermentation stage, the basic physicochemical indices, total polyphenol and flavonoid contents, antioxidant activity and sensory indices of craft beers were measured. In addition, the correlation between the indexes determined by Spearman’s correlation analysis. The results showed that with an increase in the amount of chrysanthemum addition, pH, color difference of the craft beer, alcohol content, total polyphenol content, flavonoid content, and antioxidant activity were also significantly increased (P<0.05). In terms of sensory characteristics, the taste of the beer varied with the amount of chrysanthemum addition, with the highest sensory score (76.3 points) obtained at 5 g•L-1 of chrysanthemum. Spearman’s correlation analysis showed that the total polyphenol and flavonoid contents were the primary factors influencing the antioxidant activity and flavor of the craft beer. In summary, the quality and sensory characteristics of the craft beer were superior with improved antioxidant activity by incorporating chrysanthemum at 5~10 g•L-1 during the main fermentation stage. The study may serve as a valuable theoretical and practical reference for the application and functionality of chrysanthemum in craft beer brewing, contributing to the development of diversified beer products.

Abstract:To investigate the effect of ovalbumin (OVA) encapsulation on the stability and antioxidant activity of polyphenolic compounds, OVA was employed as a delivery carrier that encapsulated hydrophobic polyphenol kaempferol (KAE) and hydrophilic polyphenol tannic acid (TA) as the active compounds. OVA-TA, OVA-KAE, and OVA-TA-KAE composite nanoparticles were prepared, and their physicochemical properties and antioxidant activities were characterized. The results showed that OVA exhibited good encapsulation effects for both KAE and TA. KAE enhanced the thermal stability of the nanoparticles, while TA improved the structural stability and antioxidant activity, thereby enabling better encapsulation by OVA. Particle size, zeta potential, intrinsic fluorescence analysis, Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy indicated that KAE/TA were effectively encapsulated within OVA, with the three types of nanoparticles exhibiting structural stability and uniform dispersion. OVA showed better binding with TA, resulting in the highest protein structural stability and the maintenance of a stable three-dimensional protein structure. Differential scanning calorimetry analysis indicated that KAE enhanced the thermal stability of the nanoparticles' spatial structure. Analyses of total phenol content and antioxidant activity revealed that OVA encapsulation inhibited polyphenol degradation. In particular, OVA-TA-KAE had a total phenol content of 141.33 mg.g-1 and DPPH scavenging activity of 4 909.36 μmol Trolox/g. The results of this study provide novel insights into the loading of KAE/TA in OVA nanoparticles and the effectiveness and feasibility of OVA encapsulation in preserving the antioxidant properties of KAE and TA.

Abstract:This study aimed to improve the heat resistance of Lactobacillus rhamnosus and its stability during the digestion process. Using the layer-by-layer (LbL) assembly technique, with zein nanoparticles (ZNP) and gum arabic (GA) as wall materials, four groups of L. rhamnosus-containing microcapsules with varying layer numbers were prepared. The microcapsules were named as (ZNP/GA)1 (one layer), (ZNP/GA)2 (two layers), (ZNP/GA)3 (three layers), and (ZNP/GA)4 (four layers). Microcapsule structure, encapsulation efficiency, and gastrointestinal tolerance were analyzed via single-factor experiments, scanning electron microscopy, and in vitro simulated digestion. The results showed that the optimal microencapsulation effect was achieved with a zein concentration of 2 mg.mL-1, a GA concentration of 2 mg.mL-1, and a pH of 4. Under these conditions, the encapsulation efficiency of the four groups of microcapsules was in the following order: (ZNP/GA)1 > (ZNP/GA)2 > (ZNP/GA)3 > (ZNP/GA)4. The number of viable bacteria was 9.53 lg colony-forming units [CFU]/mL in the (ZNP/GA)1 group, and reached 9.18 lg CFU/mL even in the (ZNP/GA)4 group. Following in vitro simulated gastrointestinal digestion for 6 h, the microcapsules with two layers of encapsulation demonstrated the best protection performance, with the number of viable bacteria being 8.34 lg CFU/mL. In conclusion, the present study demonstrated that two-layer (ZNP/GA)2 microcapsules prepared using the LbL technique provided effective encapsulation, improving the gastrointestinal tolerance of L. rhamnosus, whereas the three-layer (ZNP/GA)3 microcapsules showed better tolerance to heat treatment. The results of this study will facilitate subsequent research on protein-polysaccharide-encapsulated probiotics.

Abstract:To enhance the drying rate and quality of blueberries, the effects of different ultrasonic treatment times (400 W; 10, 20, and 30 min) on the texture, cell wall structure, pectin and cellulase activities, cell wall polysaccharide content, moisture status, and drying characteristics and quality of blueberries were investigated. The results indicated that the hardness values of blueberries treated with ultrasound for 20 and 30 min significantly decreased (4.33 and 3.99 N, respectively); cell walls became wrinkled and loose, and the activities of pectin and cellulase were markedly reduced. Ultrasonic pretreatment facilitated the conversion of chelated and alkali-soluble pectin into water-soluble pectin, increasing its content by 12.64%~34.36%. Furthermore, ultrasonic pretreatment increased the mobility of free water in blueberries. The T23 value increased from 231.88 ms (control group) to 344.56 ms (ultrasonic treatment for 20 min), thereby promoting the outward migration of moisture. Compared with the control group, ultrasonic pretreatment significantly reduced the medium- and short-wave infrared drying time of blueberries by 10.90%~27.24%, and improved the retention of phenolic substances and antioxidant capacity. The optimal ultrasonic pretreatment time was 20 min, resulting in the shortest drying time (22.7 h), a higher retention rate of phenolic compounds, and stronger antioxidant capacity. In conclusion, ultrasonic treatment can effectively improve the drying rate and product quality of blueberries. The results of this study will facilitate future research on blueberry drying.

Abstract:The aroma and quality of Enshi Yulu tea are known to be affected by temperature; thus, sensory evaluation, colorimetry, physicochemical testing, and headspace solid-phase microextraction were coupled with gas chromatography-mass spectrometry-olfactometry (HS-SPME-GC-MS-O) to examine the sensory attributes, color quality, physicochemical components, and aroma quality of tea subjected to different temperatures (90, 100, 110, 120, and 130 ℃) for a fixed duration of 15 minutes. The results indicated the increased temperature led to a change in the green color of dry Enshi Yulu tea to yellow (P<0.05), an increase in the brightness of the tea infused leaves and dregs (P<0.05), and a decrease in the polyphenol and catechin contents (P<0.05). In particular, Enshi Yulu tea that was brewed at 120 ℃ had relatively higher water-soluble sugar and amino acid contents and the highest overall sensory score and aroma component content, with dimethyl sulfide (2.57 μg•L-1), linalool (0.55 μg•L-1), nonanal (2.37 μg•L-1), heptanal (0.74 μg•L-1), hexanal (0.49 μg•L-1), and (+)-limonene (0.39 μg•L-1) accounting for 80.52% of the total. Substances with an aroma intensity value of >1 were identified by GC-O, and included floral aroma compounds such as linalool, nonanal and (+)-cis-nerolidol, the sweet corn aroma compound, dimethyl sulfide, and green aroma compounds such as hexanal, heptanal, and octanal. Overall, the aroma enhancement at 120 ℃ effectively improved the quality of the tea and may thus serve as an effective technique for enhancing the quality of Enshi Yulu tea.

Abstract:The changes in volatile compounds during the preparation of double-layer steamed milk custard (DLSMC) were investigated in this study. Volatile substances at four key stages of the preparation process, namely the raw material stage (group A), boiling stage (group B), skin separation stage (group C), and steaming stage (group D), were analyzed using an electronic nose and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). The analysis identified methyl compounds, alcohols, ketones, and aldehydes as volatile components with highly significant differences across the stages (P<0.01). Meanwhile, HS-GC-IMS identified 38 compounds, including esters, alcohols, ketones, aldehydes, ethers, acids, and pyrazine derivatives. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) indicated that the changes in volatile compounds were primarily attributed to the boiling and steaming stages. During the boiling stage (B group), the unpleasant flavor of 1-pentanol in raw buffalo milk was significantly ameliorated (P<0.05), while the levels of 2-butanone, 2-butanol, and dimethyl sulfide were significantly increased (P<0.05). In the steaming stage (group D), the levels of 2-pentanone, 2-heptanone, acetone, and diallyl disulfide were significantly increased (P<0.05). Ultimately, flavor characteristics, such as grassy, oily, fruity, milky, sweet, buttery, fruity, and roasted-nut aromas, were formed in the DLSMC. The present study revealed changes in volatile compounds during the DLSMC preparation process and provided a theoretical basis for elucidating the mechanisms underlying its flavor characteristics.

Abstract:To determine the types of volatile compounds in major peach balsamic vinegar brands in Hebei and distinguish the differences in their compound compositions, an electronic nose and gas chromatography-ion mobility spectrometry (GC-IMS) were used to analyze the characteristic flavor components of different brands of peach balsamic vinegar. The differences in aroma were also evaluated using multivariate statistical analysis. The results showed that the sensors responded more strongly to the sulfide and aromatic compounds of the volatile components of peach balsamic vinegar in the order of brand B>brand C>brand A. GC-IMS identified 79 volatile compounds, including 25 esters, 12 aldehydes, nine alcohols, eight ketones, six ethers, six pyrazines, three acids, three furans, and seven compounds of other types. The GC-IMS fingerprint also revealed 35 marker compounds shared by the three types of peach balsamic vinegar, with ethyl acetate and 2,6-dimethyl-5-heptenal (melonal) contributing to the fruity sweetness, and 2,6-dimethoxyphenol (syringol) contributing to the medicinal aroma of the vinegars. Principal component analysis validated effective discrimination between products using GC-IMS spectral data. Using an orthogonal partial least squares discriminant analysis model, 25 differential volatile compounds were identified by screening variables with a variable importance in projection value>1, followed by combined analysis with an S-plot. Total acids and sugars did not significantly differ among the products, and the overall acceptability in sensory evaluation was high for all three brands. The results of the present study demonstrated the utility of the electronic nose and GC-IMS in discriminating peach balsamic vinegars, providing a reference for quality assessment.

Abstract:To compare the influence of chili seeds on the flavor of dried chili peppers, four common types of dried chili seeds, namely Shizhu Red, Tianying Small Chili, Lantern Chili, and Tiaozi Chili, were subjected to electronic nose (e-nose) and gas chromatography-ion mobility spectroscopy (GC-IMS) measurements to detect changes in their compounds. The changes in compound characteristics were also analyzed using multivariate chemometrics. The results indicated that the e-nose distinguished the odor characteristics of the four types of chili seeds. Tiaozi Chili had the highest response value, and marked differences were observed between samples. GC-IMS identified 69 compounds, including 13 aldehydes, 15 alcohols, 11 esters, eight ketones, six olefins, four acids, six heterocyclic and sulfur-containing compounds, and two compounds of other types. Four compounds could not be identified. The highest acetic acid content in the chili seeds ranged from 19.20% to 31.53% and was formed through temperatureinduced fermentation during sun-drying. 3-(methylthio)propionaldehyde and 4-hydroxy-2,5-dimethyl-3(2H)furanone (M) imparted roasted potato-like and caramel-like aromas to Shizhu Red. Acetic acid, 4-isopropylbenzaldehyde, 3-methyl-butan-1-ol (M, D), and ethanol conferred sour, whiskey-like, malty, and sweet aromas to Tianying Small Chili. Styrene imparted gasoline-like and balsamic vinegar-like aromas to Lantern Chili, and 2,3-diethylpyrazine provided a fruity sweet aroma to Tiaozi Chili. These compounds constituted the flavor characteristics of the different types of chili seeds. The results of this study will facilitate future research on flavor characteristics and the quality discrimination of dried chili peppers.

Abstract:The degradation in the organic acid levels and aroma-producing characteristics of Lactobacillus fermentum strains during the fermentation of Choerospondias axillaris juice remain unknown; thus, high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) were employed to measure such changes before and after fermentation. The results showed significant reductions in the citrate (from 4.91 g•L-1 to 0.90 g•L-1) and malate (from 4.94 g•L-1 to 4.61 g•L-1) contents of the juice following fermentation with L. fermentum, and a considerable amount of lactic acid (approximately 6.18 g•L-1) and small amount of acetic acid (approximately 0.18 g•L-1) were produced during the fermentation process. Aroma compounds such as ethyl acetate, 2-octanone, ethyl benzoate, linalool, and geraniol, which were generated during fermentation, enhanced the grassy, citrusy, and rosy floral-fruit aromas of the C. axillaris juice, resulting in a rich and mellow aroma profile, with multivariate statistical analysis indicating six differential volatile aroma components in the L. fermentum-fermented C. axillaris juice. The findings thus suggest that L. fermentum degrades citrate and malate, as well as exhibiting strong aroma-producing capabilities during fermentation. The results of this study are expected to provide key approaches for improving the quality of Lactobacillus-fermented fruit juices and developing new products.

Abstract:Raw milk and farm environment samples were collected from six farms in three regions of China for the isolation and characterization of Pseudomonas fluorescens. The biofilm-forming ability of P. fluorescens was evaluated for the screening of representative strains to investigate environmental adaptability under different culture temperatures, conditions, and surfaces. A total of 25 P. fluorescens strains were isolated and divided into five sequence types (STs). In particular, P. fluorescens 18 exhibited a more stable biofilm-forming ability at 24 h and 36 h, with a significantly higher OD value than those of other strains. P. fluorescens 18 was capable of biofilm production in tryptic soy broth, skim milk, and whole milk at 25 ℃ , 15 ℃ , and 4 ℃ , albeit with different production capacities. At a culture time of 36 h, a low temperature inhibited the formation of extracellular substances in the P. fluorescens 18 biofilm, while milk-based culture media promoted their formation. Scanning electron microscopy results showed that the adhesion ability of the P. fluorescens 18 biofilm differed among surfaces and followed the order of stainless steel>glass>plastic. These results demonstrated the risk of biofilm formation in milk-based media by wild-type P. fluorescens isolated from raw milk and its farm environment during production, with a higher risk being on stainless steel than on other surfaces. The present study provides a scientific basis for future research on the hazards of wild-type P. fluorescens.

Abstract:To achieve the rapid detection of key indicators of Jiang-flavor baijiu (Chinese spirit) base liquor, analytical models of seven key components in Jiang-flavor baijiu were established using near infrared (NIR) spectroscopy combined with a partial least squares (PLS) algorithm, with gas chromatography and titration used as reference methods. Characteristic bands of various substances were screened by the interval partial least squares (iPLS) method, and the optimal spectral preprocessing method was determined from twelve individual or combined approaches. The coefficients of determination of cross-validation (R2Val) of optimized models for acetic acid, propionic acid, ethyl acetate, ethyl lactate, furfural, isoamyl acetate, and total acid were in the range of 0.854 2~0.963 8, and the root mean square errors of cross-validation (RMSECV) were in the range of 0.003 8~0.515 8. The standard errors of prediction (SEP) for external validation were in the range of 0.002 8~0.478 5, and residual predictive deviations (RPD) were in the range of 2.41~6.43, indicating good model prediction accuracy and robustness. In summary, NIR spectroscopy achieved rapid detection of the acetic acid, propionic acid, ethyl acetate, ethyl lactate, furfural, isoamyl acetate, and total acid contents in Jiang-flavor baijiu base liquor, improving the detection efficiency considerably and enabling rapid feedback in the production process. The results of this study support the application of online NIR spectroscopy in intelligent brewing.

Abstract:A rapid, sensitive, and accurate detection method for tetracycline (TC) antibiotic residues in food was developed. Shared structural characteristics of TC antibiotics were exploited for the preparation of a broad-spectrum TC-targeting monoclonal antibody (mAb), and a colloidal gold-based immunochromatographic assay (GICA) was established for rapid detection of TC antibiotic residues in food. Through hapten design, mAb preparation, and optimization of key GICA parameters, such as the antibody labeling and artificial antigen coating concentrations, rapid TC antibiotic residue detection in food was achieved. The half-maximal inhibitory concentrations (IC50) of the broad-spectrum mAb towards TC, chlortetracycline, oxytetracycline, and doxycycline were 1.29, 1.04, 1.34, and 2.33 μg•L-1, respectively. Under optimal conditions, the limit of detection of GICA was 20 μg•kg-1 for TC, chlortetracycline, and oxytetracycline and 40 μg•kg-1 for doxycycline, with a reaction time of approximately 15 min. Therefore, the GICA developed in this study achieved highly sensitive, accurate, and rapid detection, making it suitable for rapid batch screening of TC antibiotic residues in animal food products, such as chicken, pork, and grass carp. The results of this study provide a theoretical basis and effective technical support for future research on broad-spectrum mAbs against TC antibiotics and the detection of TC antibiotic residues in food.

Abstract:Fish is rich in various nutrients, such as proteins and fatty acids. Steaming is a commonly adopted method for cooking fish in China. Many researchers have investigated the changes in the flavor and protein structure of fish meat during steaming; however, systematic reviews and summaries of pertinent research are lacking. Heat and mass transfer during the steaming process alters fish meat quality to various degrees, and the doneness of fish meat is a key indicator for evaluating the degree of steaming. The present paper aimed to summarize research progress on heat and mass transfer mechanisms and doneness evaluation in the fish meat steaming process. Specific changes in fish meat quality during the steaming process were elucidated, including changes in sensory quality, flavor substances, and protein structure. This review provides a theoretical basis for future research on fish meat cooking, processing quality, and parameter tuning for cooking equipment.

Abstract:Livestock and poultry blood is rich in active substances, including hemoglobin, hemoglobin peptides, superoxide dismutase (SOD), and immunoglobulin. Using advanced separation technology and biological engineering methods these the active substances in the blood can be converted into a variety of high value-added products. The application and research progress of livestock and poultry blood as a potential biological resource for use in high value-added products is reviewed in this article. The separation, purification, and modification of active substances such as hemoglobin, hemoglobin peptide, SOD and immunoglobulin are comprehensively discussed. The research status of its application in the fields of food additives, functional food, animal feed and medicine is summarized, and the current challenges and future research directions are analyzed. This paper is expected to provide a scientific basis for the efficient utilization and industrialization of livestock and poultry blood resources and promotes the wide application of this product in the food and medicine industries.

Abstract:Citrus fruits have garnered increasing attention owing to their prominent position in commerce, and valuable essential oils can be extracted from the by-products of citrus fruit processing. Citrus fruit essential oils mainly consist of monoterpenes, sesquiterpenes, and their oxygenated derivatives, along with other components that confer a variety of biological activities, including antibacterial, anti-inflammatory, antioxidant, and anti-anxiety properties. The essential oils that are extracted from citrus fruits thus possess broad prospects for application in the food, healthcare, and cosmetics industries. This paper provides an overview of the major components, key biological activities, mechanisms of action, and safety of essential oils extracted from citrus fruits such as sweet orange (Citrus sinensis), mandarin (Citrus reticulata), and lemon (Citrus limon), with the aim of providing a scientific reference for the practical application of such oils.

Abstract:Foodborne pathogens pose a major threat to human health, society, and economy. Contamination by pathogenic bacteria can cause foodborne diseases at any stage of the farm-to-table food supply chain. As drug resistance becoming an increasingly serious global issue, there is an urgent need to develop novel methods for controlling foodborne bacteria. Lysins are enzymatic proteins produced by most virulent phages that can degrade bacterial cell walls. These antibacterial proteins have attracted growing interest from researchers because of certain favorable characteristics, such as strong bactericidal activity, high host specificity, low tendency to induce drug resistance, and potential for engineering modification. This review summarizes the classification, structure, and antibacterial mechanisms of lysins, explores strategies to enhance their activity against gramnegative bacteria, highlights recent advances in their application for preventing and controlling foodborne pathogens, and provides perspectives on their future development and use. The insights presented herein aim to inform the design of novel strategies for combating drug-resistant foodborne pathogens.

Abstract:Improvements in living standards have led to increased consumer expectations regarding food quality. Consequently, the safety of food preservatives and preservation packaging has received growing attention. Propolis is a natural gelatinous solid produced by bees from plant resins. Owing to its rich content of various bioactive compounds and inherent antibacterial and antioxidant properties, propolis is considered an ideal food preservative with broad potential applications in food preservation. However, its bitter taste and strong aromatic flavor limit its use as a food additive, particularly regarding concentration and dosage. In recent years, strategies such as microencapsulation and film-casting technologies have been explored to enhance the utilization of propolis in food, thereby expanding its applications in food preservation. This study provides an overview of the classification, chemical composition, and physicochemical properties of propolis, examines its antibacterial and antioxidant mechanisms, as well as its notable film-forming properties, and summarizes recent advances in its application for food preservation in China and internationally. The findings of this study provide theoretical and technical support for the practical implementation of propolis in the food preservation industry.