Abstract:Fresh fruits and vegetables in the supply chain continuously consume organic matter (sugar and starch) due to respiration, transpiration, and ethylene release, leading to their quality deterioration. Throughout the supply chain, the physiological and biochemical changes in fresh fruits and vegetables are influenced by intrinsic factors (species and varieties, origin and harvest period, maturity or developmental age) and environmental factors (temperature, humidity, O ₂ and CO₂ concentration, ethylene concentration, extrusion, impact, vibration, and etc.). Currently, numerous post-harvest technologies are applied in the supply chain to reduce the quality deterioration of fresh fruits and vegetables, thereby enhancing their market competitiveness with the highest quality retention rate. This review briefly introduces the mechanisms of quality deterioration (mold, wilting, browning, softening, yellowing, and etc.) of fresh fruits and vegetables within the supply chain, the factors affecting the quality deterioration of fresh fruits and vegetables, as well as the mitigation of the quality deterioration of fresh fruits and vegetables through the adoption of common control technologies. Furthermore, the latest research progress of intelligent labels in freshness detection of fresh fruits and vegetables are reviewed.

Abstract:This study aimed to investigate the alterations in the gut microbiota of mice sensitized with ovalbumin (OVA) without immunologic adjuvant treatment, and to explore the characteristic gut microbiota associated with OVA allergy. An OVA-sensitized mouse model was constructed, and the allergic reactions of the mice were evaluated by the allergic symptom score, detection of serum immunoglobulin E(IgE) level, and observation of colon histological morphology. Gut microbiota analysis was performed using 16S rRNA amplicon sequencing, including diversity analysis, species composition analysis, and functional prediction. The results showed that there were significant changes in the allergic symptom score, total serum IgE, OVA-specific IgE, and HE staining results of colon tissue in the OVA-sensitized group, indicating the success of model construction. The gut microbiota analysis revealed a significant increase in the abundance of Pseudomonadaceae at the family level, a significant decrease in the abundance of Lachnospirales-Lachnospiraceae and Desulfovibrionales-Desulfovibrionaceae, and a significant increase in the abundance of Pseudomonas at the genus level, together with a significant decrease in the abundance of Lachnospiraceae NK4A136 group in the sensitized group. Bacteroidales could be speculated as a characteristic microbiota of OVA allergy.

Abstract:To study the role of mitochondrial function and oxidative stress in the neurotoxicity induced by fumonisin B1 (FB1), the model of Caenorhabditis elegans(C. elegans) was used. The behavioral phenotype of C. elegans treated by FB1, and the changes in indices related to oxidative stress and mitochondrial function were analyzed. The results showed that 20~200 μg/mL FB1 exposure for 24 hours induced abnormal expression of genes (cyp35A2、sod-1、sod-3、ctl-2,andctl-3) related to cytochrome oxidase, superoxide dismutase(SOD), and catalase(CAT) in a dose-dependent manner. Moreover, 100~200 μg/mL FB1 treatment reduced mitochondrial density of C. elegans and significantly decreased the levels of adenosine triphosphate (ATP) and the potential of mitochondrial membrane (P<0.05). The expression levels of mitochondrial respiratory chain complexes I and V were significantly inhibited by 200 μg/mL FB1 treatment, while the expression level of mitochondrial fission gene drp-1 was increased. Correlation analysis demonstrated a significant correlation between the expression of indices related to oxidative stress and mitochondrial function and the behavioral phenotype of C. elegans. In conclusion, FB1 may induce neurotoxicity by participating oxidative stress, mitochondrial respiratory chain, and mitochondrial dynamics in C. elegans.

Abstract:This study was conducted to investigate the changes of trehalose-based maltoheptaose (N-G7) before and after encapsulation in simulated digestive fluid and in vitro fermentation. The mass ratio of N-G7 and the sugar composition of N-G7 microspheres (ALG-Ca) in the solution before and after digestion were analyzed by in vitro digestion models of oral, stomach, and small intestine. The fermentation characteristics of microspheres were evaluated by in vitro fermentation technology. The changes in pH values, OD₆₀₀, gas production, and short-chain fatty acid (SCFA) content at different time points were detected, and their effects on the composition of human intestinal microbiota were studied. The results showed that N-G7 was almost not hydrolyzed in the oral digestion for 2 minutes and in the highly acidic gastric environment. However, the hydrolysis rate of N-G7 reached 82.70% after intestinal digestion. Encapsulation with different concentrations of calcium alginate (1%, 2%, 3%) formed microspheres that retained approximately 80% of N-G7 reaching the colon. During in vitro fermentation, the pH value and OD₆₀₀ of each experimental group decreased and increased continuously with time. The gas production and carbon source consumption rate in the 2% ALG-Ca group were the lowest among all groups from 0 to 6 hours, followed by a gradual increase, indicating that the fermentation system of N-G7 after encapsulation belonged to slow fermentation. Compared with the control group, the 2% ALG-Ca group produced a large amount of SCFA and changed the composition of intestinal microbiota, which was more conducive to the growth of probiotics.

Abstract:In order to screen a wild-type strain with high alkaline protease activity and good stability, and to achieve industrial-scale production of protease, a stable high-yield salt-tolerant alkaline protease-producing strain was isolated from seawater of the East China Sea in the Lin'gang region of Shanghai. The morphological characteristics, physiological characteristics, and 16S rDNA gene sequence of the strain were analyzed and sequenced, and the strain was identified as Bacillus stratosphericus and named B. stratosphericus LK-3. The enzymatic properties study revealed that the optimal conditions for enzyme action were 35 ℃, pH 8.5, and inoculation amount of 7%. Under these conditions, the enzyme activity reached （581.74±0.81） U/mL after 72 h fermentation. In addition, the enzyme showed good salt tolerance and maintained 22.03% of the relative original enzyme activity even under a high saturated salt concentration of 40 g/dL. The salt tolerance of protease is a valuable characteristic, and the alkaline protease produced by strain LK-3 could be purified and used as a biological detergent additive in industrial production.

Abstract:The relationship between wheat flour characteristics and the quality of fresh wet noodles was investigated to provide a theoretical guidance and scientific basis on the germplasm resources screening for wheat breeding and the production of tailored flour for fresh wet noodles. Using 13 types of wheat flours as raw materials, their protein quality, solvent retention capacity, and endogenous enzymes activity were determined, and the appearance, texture, and sensory quality of the prepared fresh wet noodles were analyzed. The results showed that there was a significant negative correlation between the mass concentration glutenin macropolymer and the brightness of dough sheet. The ratio of glutenin to gliadin was significantly negatively correlated with cohesiveness of the cooked noodles. The solvent retention capacity of lactic acid was significantly positively correlated with chewiness and sensory evaluation, and the lipoxygenase activity of flour was significantly positively correlated with hardness and chewiness. Through principal component analysis and clustering analysis, the 13 types of wheat flours could be divided into three categories. Wheat flours of cluster III had significantly better protein quality and dough rheological quality than other wheat flours, yielding the best edible quality of the cooked noodles. Wheat flours of cluster II produced noodles with significantly higher brightness than other wheat flours, exhibiting the optimal appearance quality. Combining domestic wheat with cluster II/III wheat could be used to prepare specialized flour for fresh wet noodles with good appearance and edible quality.

Abstract:Peaches are susceptible to chilling injury(CI) during low-temperature storage, which severely affects their commercial quality. To investigate the variations in various metabolic pathways during the development of CI in peaches, the transcriptional level changes in ‘Hujingmilu’ peaches during low-temperature and room-temperature storage periods were analyzed based on transcriptome analysis. The results indicated that a total of 125 metabolic pathways were identified as altered during the storage of peaches. Through the analysis of five key metabolic pathways, it was observed that the development of CI in peaches accompanied by the activation of pathways involved in the conversion of oxidative or reductive glutathione, synthesis and degradation of sucrose, and degradation of pectin. Additionally, the synthesis pathway of starch and the synthesis and signaling pathway of jasmonic acid were inhibited during this process. The alterations in the above metabolic pathways might be the mechanisms in response to the cold stress in peaches. These findings could provide the theoretical guidance for subsequent investigations into the regulation mechanisms in CI development of peaches.

Abstract:In order to improve the efficiency of denitrification in wastewater treatment, the denitrifying strains N1, N9 and N10, which have been screened out in the laboratory, were prepared into a composite microbial agent. The influence of different temperatures, carbon-to-nitrogen ratios (C/N), and carbon source types on the growth and denitrification characteristics of the composite microbial agent was investigated, showing significant practical value. The results showed that 92.61% nitrate nitrogen, 60.02% total nitrogen, and 58.48% chemical oxygen demand could be removed by the compound microbial agent under the conditions of 30 ℃, C/N ratio of 10, and soluble starch as the carbon source after 48 h. Moreover, the denitrification effect was substantial within the C/N ratio range of 2 to 10, indicating that the composite denitrification microbial agent could have application prospect in the denitrification process of low C/N ratio wastewater.

Abstract:This study investigated the effects of different sterilization conditions on the functional characteristics of homemade meal replacement powders and other product quality attributes. Ultraviolet cold sterilization was found to retain the original functional characteristics of the meal replacement powders to the maximum extent, but with low sterilization efficiency. In contrast, radiofrequency sterilization preserved both functional components and achieved good sterilization effects. Comparing homemade and commercial meal replacement powders, it was revealed that the total phenol content and antioxidant activity of the homemade powders were higher than those of the commercially available ones, while the flavor of the homemade powders was superior to the commercial products. To examine the storage stability of the homemade meal replacement powders, 3-month storage experiment was conducted. The results showed that the functional characteristics and microbial indexes of the homemade powders were within the standard range during the 90-day storage period. To prolong the shelf life of the meal replacement powders, it is recommended to store the powders in a dry and shady place.

Abstract:Bacitracin methylene disalicylate (BMD) has good antibacterial activity and safety, which can be used as a pharmaceutical additive to prevent and treat animal diseases. However, the effects of BMD on white-feathered broilers, particularly regarding growth performance and intestinal microflora structure, remains unclear. This study selected three-day-old healthy white-feathered broilers as experimental subjects, and compared the feeding management of high (60.0 mg/kg), medium (40.0 mg/kg), and low (20.0 mg/kg) dosages of BMD added in the basal ration, with the addition of 50 mg/kg of chlortetracycline preparation as the positive control group. The changes in feed-weight-ratio of white-feathered broilers within 28 days were recorded, and the second generation high-throughput sequencing technology was used to sequence and analyze the changes in their intestinal microflora and composition at 28 d. The differences in intestinal microflora diversity and relative abundance of major dominant groups were compared between and within groups. The results showed that feeding different doses of BMD and chlortetracycline preparation had an effect on the growth performance of white-feathered broilers chickens. The feed-to-weight ratio of white-feathered broilers was the lowest when 60.0 mg/kg dose of BMD was fed, and the effect was the optimal. Meanwhile, feeding BMD and chlortetracycline preparations also affected the intestinal microflora of white-feathered broilers, resulting in decreased diversity and increased abundance. In addition, for the dominant microflora, compared with the blank group, the BMD and chlortetracycline groups had a significant increase in Bacteroidetes and Tenericutes(P<0.05), while a significant decrease in Firmicutes(P<0.05). At the generic level, the relative abundance of Fournierella significantly increased(P<0.05), while that of Faebacterium significantly decreased(P<0.05). Overall, the results reveal that feeding BMD can promote the growth performance and intestinal microflora structure of white-feathered broilers, effectively reducing the feed-to-weight ratio of white-feathered broilers and promote the micro-ecological health of the intestinal microflora.

Abstract:Cigar tobacco leaves can be made into cigar products with unique flavors only after fermentation treatment. It is of great significance to investigate the diversity of microorganisms in tobacco fermentation process to improve the quality of domestic cigar tobacco. In this study, preliminarily air-cured cigar tobacco leaves from eight regions of Yunnan Province and seven high-quality cigar tobacco leaves from Dominican Republic were collected. The microbial species on the surface of each sample were identified based on 16S rRNA gene sequencing technology. Microbial diversity was analyzed by OTU clustering analysis, Alpha diversity analysis, species composition analysis, and other methods to obtain the dominant bacteria on the surface of preliminarily air-cured tobacco leaves. The results showed that the dominant bacterial genus in the cigar tobacco leaves of Yunnan Province was prevalently identified as Staphylococcus, while other common genera included Pseudomonas, Achromobacter, Corynebacterium, Pantoea, and so on. The distribution of microbial species in Dominican cigar samples was more uniform than that in domestic cigar samples, and the overall diversity of microbial species was higher than that of domestic cigar samples. The majority of their dominant bacteria genera were Staphylococcus, Corynebacterium, and Tetralogy. The dominant bacteria genera of cigar leaves in Lincang City of Yunnan Province were similar to those in Dominican cigar samples, and its species diversity and uniformity were higher than those in other domestic regions in China, indicating great development potential.