Abstract:In order to achieve rapid detection of the contents of four physicochemical indicators related to freshness of mutton, a multi-task spectral feature extraction algorithm named ERC-RF is proposed in this study. By integrating the Ensemble Regression Chain (ERC) and Random Forest (RF), the correlation between freshness indicators was used to assigns varying weights to the characteristic spectra to ascertain the importance of spectral band features. During the experiments, data were first preprocessed by combining the SG (Savitzky-Golay) smoothing filter and Multiplicative Scatter Correction (MSC). Subsequently, the RF and ERC-RF models were used to select characteristic bands, respectively, and the spectral data were used for two freshness indicator contents prediction models: models for integrating Support Vector Regressio (SVR) with Multi-Output Regressor (MOR): SVR-MOR, and integrating SVR with Multi-Output Regression Chain (MORC): SVRMORC. The results showed that the Coefficient of Determination (R2), average Relative Root Mean Squared Error (aRRMSE), and Mean Absolute Error (MAE) values of the spectral feature data extracted by ERC-RF were 0.974 5, 1.302 7, 0.385 2, and 0.975 2, 1.495 6, 0.391 8, respectively in the two prediction models, which were significantly improved compared with models based on other band selection, with the number of bands being reduced from 125 to 31. These results confirm that ERC-RF is an effective multi-task feature wavelength screening method, which not only improves the accuracy of multioutput regression model, but also reduces the model complexity.

Abstract:To address the issue of adulteration in grape seed oil, a quantitative analysis method for detecting adulteration of grape seed oil with sunflower seed oil was studied. Simulation experiments were conducted by applying portable near-infrared Raman spectroscopy combined with a least absolute shrinkage and selection operator-least squares support vector machine (LASSO-LS-SVM) algorithm to samples with varying adulteration levels. A total of 11 mixed oil samples with varying adulteration concentrations were prepared in this research. A portable 785 Raman spectrometer was utilized to acquire the Raman spectra of all mixed oil samples. A wavelet algorithm was adopted for the baseline correction, noise reduction, and normalization of the raw spectral data. A machine learning algorithm was used to extract the eigenvectors of the Raman spectra, and a quantitative analysis model was established. The LASSO algorithm reduced the dimensionality and extracted features of the spectral data, and the LSSVM algorithm enabled successful construction of a quantitative analysis model for adulteration. The coefficient of determination (R2) of the model for the test set is 0.984 6, and the RMSE is 0.024 9. The integration of the LASSO-LS-SVM algorithm enables the application of Raman spectroscopy for quantifying adulteration levels in grape seed oil. The proposed method demonstrates substantial application value and promising commercial potential for promoting the domestic grape seed oil market.

Abstract:The potential of microscale near-infrared spectroscopy (MicroNIR) in determining the dry mixing endpoints of powdered formula and the effects of different nutrient structures on the mixing homogeneity were thoroughly investigated. A MicroNIR spectrometer was installed onto the dry mixing equipment to analyze the formula. The mixing endpoint was calculated using various algorithms, and the accuracy of the endpoint calculation was validated using the national standard method. Furthermore, the impact of nutrient structures on the dry-mixing homogeneity at the microscopic level was examined using optical and scanning electron microscopy. Spectral differences between raw materials and additives in formula are the most prominent in the 1 093~1 285 nm and 1 459~1 645 nm wavelength range, and homogeneous mixing is achieved at 32 min, 48 s. During the investigation of the effects of nutrient structures on the mixing homogeneity, three distinct categories of nutrient structures were discovered: irregular spheres, irregular rectangles, and irregular plate-like crystals, each exerting unique effects on dry-mixing homogeneity. Although MicroNIR can serve as a technique to determine mixing endpoints, this does not imply that the RSD values of all nutrients are less than 10%. This study not only establishes a method for identifying formula mixing endpoints but also provides a theoretical foundation for real-time monitoring of the mixing process.

Abstract:The rich forage resources in the Xinjiang region have bred excellent horses and also brought abundant mare milk resources. To investigate the differences in volatile flavor substances in the mare milks from Altay, Tacheng, and Yili regions in Xinjiang, and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GCMS) was used to detect and analyze the volatile flavor substances in fresh mare milks and naturally fermented mare milks (mare yoghurt/koumiss) from the three regions. The results showed that 59 kinds of substances were detected in 6 samples, including 22 esters, 14 acids, 7 alcohols, 4 aldehydes, 6 ketones, 1 other, and 5 aromatic substances. The results of relative odor activity value (ROAV) calculation showed that there were 29 volatile flavor substances with ROAV ≥ 0.1, among them, ethyl caprylate, ethyl caprate, caproic acid, caprylic acid, capric acid, and styrene were the key volatile flavor substances (ROAV>1) in the 6 samples. The results of orthogonal partial least squares discriminant analysis (OPLS-DA) showed that the differences in the contents of 20 substances, such as ethyl caprylate, ethyl lactate, and acetic acid, were the main reason for the differences in flavor between fresh mare milk and Koumiss products in the three regions. This study analyzed the differences in volatile flavor substances in mare milks from the Altay, Tacheng, and Yili regions of Xinjiang, and provided a theoretical basis for improving the research and development as well as quality evaluation of mare milk products in Xinjiang.

Abstract:Oil was extracted from pork, beef, mutton, as well as chicken and duck meat samples. The changes in volatile flavor compounds, fatty acid composition, and lipid composition of fresh oil and oxidized oil (heated at 120 ℃ for 2 h) were determined by sensory evaluation, electronic nose analysis, solid-phase microextraction-gas chromatography-mass spectrometry, thin-layer chromatography-flame-ionization detection, and ultrahigh performance liquid chromatographyquadrupole-orbitrap mass spectrometry. The ultimate aim was to investigate the lipid oxidation and aroma formation patterns in different muscle tissues during thermal oxidation. The sensory quality significantly changed during oxidation. Oxidized beef and mutton oil emanated a prominent milky aroma. The types and contents of aldehydes in lipids increased significantly after oxidation. The lipid compositions of different muscle tissues differed, and the contents of different lipid species changed significantly during oxidation. The triglyceride content of beef oil decreased from 4 085.44 ng/g to 1 363.12 ng/g, and the phosphatidylcholine content of chicken oil decreased from 1 060.53 ng/g to 503.46 ng/g after thermal oxidation. This indicates that the esterified forms of fatty acids affect the formation of volatile compounds after thermal oxidation. Heptanol, heptanal, and 2-heptanal in oxidized beef oil are possibly produced by C18:1 and C18:2 on the triglyceride, and hexanal and heptanal in oxidized mutton oil are probably produced by the oxidative degradation of C18:2 on phosphatidylcholine and phosphatidylethanolamine. Lastly, 1-octen-3-ol in oxidized chicken and duck oil samples may be produced by the oxidative degradation of C18:1 on phosphatidylethanolamine. This study aimed to provide research methods and theoretical support for lipid flavor control.

Abstract:To detect mildew in lotus seeds during storage and processing, gas chromatography-ion mobility spectrometry (GC-IMS) was applied to analyze the volatile organic compounds (VOCs) in the fungal infection process of lotus seeds through accelerated in vitro mildew infection simulation. Seven strains of fungi were isolated and identified from naturally contaminated lotus seeds. Next, accelerated in vitro mildew infection of normal lotus seeds was carried out by inoculation with Aspergillus tamarii, Aspergillus pseudoglaucus, Penicillium citrinum, and Penicillium cinnamopurpureum. The GC-IMS results reveal a total of 73 VOCs, mainly esters, alcohols, aldehydes, ketones, and acids. The study employed cluster heat map and principal component analysis to explore the differences and similarities among the various VOCs. The VOCs were found to vary widely across the different stages of fungal infection. Ethyl lactate, 1,3-butanediol, and isoamyl butyrate were proven to be potential biomarkers for early mildew detection in lotus seeds. This study aimed to evaluate the role of VOCs in the monitoring and early warning of lotus seed mildew. These findings have important implications for the storage and quality control of lotus seeds.

Abstract:To investigate the anti-caries effect of Ramulus mori oligosaccharides microcapsules, the in vitro cariescausing dental plaque biofilm model was constructed by inoculating natural saliva and Streptococcus mutans on the surface of hydroxyapatite tablets, before culturing for 21 days. The caries-causing dental plaque biofilm model was treated daily via soaking with low, medium and high doses (24.00, 48.00 and 96.00 mg/mL) of Ramulus mori oligosaccharides microcapsules solution to evaluate its anti-caries effect. The results showed that Ramulus mori oligosaccharides microcapsules could effectively destroy the structure of the dental plaque biofilm, and the biofilm thickness (65.95 μm) was significantly reduced in the high dose group compared with the control group (103.08 μm) (P<0.05). The number of bacteria adhering to the surface of hydroxyapatite tablets was reduced upon the treatment with Ramulus mori oligosaccharides microcapsules, resulting in the death of bacteria inside the plaque biofilm and the reduction of biofilm’s activity. The microhardness values (244.25, 265.25) and the calcium-phosphorus ratios of the hydroxyapatite tablets (1.20, 1.49) treated with medium and high doses (48.00, 96.00 mg/mL) of Ramulus mori oligosaccharides microcapsules solution significantly increased compared with the control group (P<0.05). Ramulus mori oligosaccharides microcapsules could effectively reduce enamel demineralization. The high-dose Ramulus mori oligosaccharides microcapsules had the best anti-caries effect. This study aimed to provide a theoretical basis for the development of anti-caries functional foods and daily chemical products from Ramulus mori.

Abstract:In order to study the amino acid and fatty acid compositions of different parts of yak meat and systematically analyze the differences in nutritional characteristics of these parts of yak, yak carcasses were finely segmented, and the characteristic differences in amino acid and fatty acid compositions of 20 parts of yak meat were analyzed, and the nutritional value of each part of yak was evaluated by using methods such as amino acid ratio coefficients, standard pattern spectrum and whole egg pattern spectrum ratio of the Food and Agriculture Organization/World Health Organization. The nutritional value of each part of yak meat was evaluated by using amino acid ratio coefficient, Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO) standardized pattern spectrum and whole egg pattern spectrum ratio, etc. A total of 18 amino acids and 35 fatty acids were detected in the 20 parts of yak meat, and the smallest Ratio Coefficient of Essential Amino Acids (RC) was with tryptophan, which is the first limiting amino acid, and the Scores of RC (SRCs) of all the parts were over 77, among which the SRC of yak’s tendon part was the highest (84.21), indicating that this part had a relatively high nutritive value; and the fatty acid with the highest content was C18:1n9c, which was especially high in the tendon part of the plate with 38.5%. The highest content of fatty acids was with C18:1n9c, especially in the tendon part (38.76%), with the ratios of monounsaturated fatty acids/saturated fatty acids ranging from 0.81 to 1.08, and the ratios of polyunsaturated fatty acids/saturated fatty acids ranging from 0.07 to 0.50. The amino acid patterns of all parts of yak meat conformed to the recommended patterns of the FAO/WHO, and there were some differences in amino acids and fatty acids among the different parts of yak meat. The comprehensive evaluation showed that the tendon had a high nutritive value. The results of this study provide a theoretical basis for the quality evaluation and deep processing of yak meat.

Abstract:The key components of Grifola frondosa polysaccharide F2 that contribute to lowering blood sugar were examined. A Sephacryl S-200 column was used for the isolation and purification of G. frondosa polysaccharide F2 to obtain polysaccharides F21 and F22. These polysaccharides were then subjected to structural analyses and assessment of their hypoglycemic activity. Structural analyses revealed that polysaccharide F21 is composed of fucose, galactose, glucose, and mannose, and its molecular weight is approximately 17.9 ku. F22 consists of mannose and glucose, with a molecular weight of approximately 3.16 ku. Animal experiments revealed that F21 (i.g.) administration significantly reduced fasting blood glucose and triglyceride levels in T2DM mice by 16.36% and 26.53% (P<0.05), respectively. F22 (i.g.) administration significantly decreased the low density lipoprotein level in T2DM mice by 31.48% (P<0.01). F21 (i.p.) administration decreased the fasting blood glucose level in T2DM mice by 22.32% (P<0.05). Plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) decreased by 32.96% (P<0.001), 36.12% (P<0.05), and 42.35% (P<0.001), respectively, compared with the diabetes group. Hepatic malondialdehyde (MDA) content decreased by 42.95% (P<0.001), whereas superoxide dismutase (SOD) and catalase activities are increased by 36.08% (P<0.05) and 24.34% (P<0.01), respectively. F22 (i.p.) administration decreased liver ALP by 32.38% (P<0.01), increased SOD activity by 37.32% (P<0.05), and reduced MDA content by 68.16% (P<0.001). These results demonstrate that the active component of G. frondosa polysaccharide F2 is F21, which has the ability to alleviate symptoms in T2DM model mice. This study provides a theoretical framework for the development and application of G. frondosa polysaccharides in food and medicine, highlighting their diverse prophylactic benefits.

Abstract:Helicobacter pylori (H. pylori) infection is the main cause of chronic gastritis, and dietary interventions with probiotics may inhibit H. pylori colonization. A mouse model of gastric H. pylori infection via oral gavage to explore the inhibitory efficacy of Lactobacillus plantarum 543, Lactobacillus paracasei S6, and postbiotics derived from Lactobacillus plantarum LP220 on gastric infection by H. pylori in mice was established. The gastric viable H. pylori count in the model group was 9.69 log CFU/g. Treatments with Lactobacillus plantarum 543, Lactobacillus paracasei S6, and postbiotics significantly reduced the respective viable H. pylori counts in mouse stomachs to 7.22, 7.89, and 7.19 log CFU/g (P<0.01). These three treatments also significantly reduced gastric mucosal thickness (P<0.05) in the model group and alleviated structural damage in gastric tissues. Additionally, the mRNA levels of H. pylori virulence factors and inflammatory factors including tumor necrosis factor-α (TNF-α) in gastric tissues were notably suppressed after treatments with Lactobacillus paracasei S6 and postbiotics, while this was not observed with Lactobacillus plantarum 543 exposure. In conclusion, Lactobacillus plantarum 543, Lactobacillus paracasei S6, and postbiotics all inhibit H. pylori infection, with Lactobacillus paracasei S6 and postbiotics demonstrating superior efficacy in mitigating gastric inflammation and reducing H. pylori virulence factor expression, compared to Lactobacillus plantarum 543. These findings provide new evidence supporting the use of probiotics and postbiotics as nutritional interventions to ameliorate chronic gastritis induced by H. pylori infection.

Abstract:The effects of geraniin (GER), an ellagitannin extracted and purified from the rind of Nephelium lappaceum L., on ameliorating transforming growth factor-β1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) in human renal tubular epithelial (HK-2) cells were investigated. The CCK-8 cell viability assay was used to detect the effects of different concentrations of GER on cell viability, and the optimal concentration was determined. HK-2 cells were divided into five groups: control, TGF-β1 induction (10 ng/mL TGF-β1), and TGF-β1 induction+GER treatment (5, 10, and 20 μg/mL GER) groups. The expression levels of key EMT-related factors, such as α-smooth muscle actin (α-SMA), E-cadherin, and vimentin were detected using western blotting and immunofluorescence staining. The changes in the intracellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and adenosine triphosphate (ATP) content between different experimental groups were determined to evaluate the effects of GER on mitochondrial function. Compared with the model group, the high-dose GER group exhibited significantly increased E-cadherin levels (increased by 128.36%) (P<0.01) and significantly decreased vimentin levels (decreased by 47.78%) (P<0.01). Further, the immunofluorescence staining results revealed that GER reduced the protein level of α-SMA and eliminated the excessive ROS produced in TGF-β1-induced HK-2 cells. Furthermore, MMP reduction was considerably improved and the ATP level was significantly increased by 24.01% (P<0.05). In conclusion, the study findings suggested that GER could inhibit TGF-β1-induced EMT in HK-2 cells by ameliorating mitochondrial dysfunction and reducing the oxidative stress levels.

Abstract:To evaluate the antioxidant and lipid-lowering effects of the alcohol extract of Grifola frondosa (G. frondosa), the total sugar, protein, polyphenol, and triterpene contents of the alcohol extract were determined, and the antioxidant capacity was subsequently analyzed in in vitro antioxidant assays and Caenorhabditis elegans (C. elegans) models. In addition, lipid deposition in C. elegans was observed by Oil Red O staining, and the TG concentration and LPS activity were measured to explore the lipid-lowering potential of the alcohol extract. The results show that the alcohol extract of G. frondosa mainly consists of proteins, with a total protein content of 233.67 mg/g. The alcohol extract demonstrates significant DPPH, ABTS, and hydroxyl radical scavenging activities, and the corresponding IC50 values are 3.25, 0.38, and 1.73 mg/mL, respectively. Compared with those of the blank group, the CAT, T-SOD, GSH-Px, and LPS activities in the high-dose treatment group significantly increase by 4.33-, 4.88-, 2.28-, and 3.93-fold, respectively. Furthermore, lipid deposition, as well as the MDA and TG levels, decreases significantly. More specifically, the levels of MDA and TG in the high-dose group reduce by 55.62% and 50.66%, respectively. In conclusion, the alcohol extract of G. frondosa exhibits in vitro antioxidant capacity and can enhance the antioxidant enzyme activity in C. elegans. It also reduces lipid deposition and the TG concentration in C. elegans, indicating that it has a good lipid-lowering effect. This study provides a theoretical basis for the high-value utilization of G. frondosa.

Abstract:In this study, the bi-directional fermentation conditions of Ganoderma lucidum and Rosa roxburghii Tratt were optimized by single-factor combined with orthogonal experiments. The content of active ingredients and in vitro antioxidant activity of Ganoderma lucidum fermentation broth and Ganoderma lucidum-Rosa roxburghii Tratt fermentation broth were determined. When the initial pH was 5.50, the Ganoderma lucidum inoculum amount was 4% (V/V) and the addition amount of Rosa roxburghii Tratt was 20 g/L, the polysaccharide content of the fermentation system was high, and the order of influence of the factors was Ganoderma lucidum inoculum amount>addition amount of Rosa roxburghii Tratt>initial pH. Under the optimum conditions of the single factor experiments, compared with the fermentation broth of Ganoderma lucidum alone, the addition of Rosa roxburghii Tratt powder significantly increased the contents of active ingredients such as polysaccharides, flavonoids, polyphenols, and triterpenoids (P<0.05), and theie mass concentrations were 25.20 mg/mL, 41.47 μg/mL, 93.00 μg/mL and 254.55 μg/mL, respectively. The hydroxyl radical scavenging rate, DPPH radical scavenging rate, ABTS radical scavenging rate and reducing power of the Ganoderma lucidum-Rosa roxburghii Tratt fermentation product (3.00 mg/mL) were 51.54%, 84.87%, 94.79% and 0.60, which were significantly higher than those of the fermentation products without Rosa roxburghii Tratt (45.16%, 74.55%, 73.34%, 0.43). With Ganoderma lucidum strain as the fermentation strain and Rosa roxburghii Tratt as the culture medium, the antioxidant properties of the bi-directional fermentation products increased, indicating that the bi-directional liquid fermentation process of Ganoderma lucidum-Rosa roxburghii Tratt had certain advantages over the traditional fermentation process. The finding of this research provides a basis for the development of medicine and food homologous products based on Ganoderma lucidum-Rosa roxburghii Tratt fermentation system.

Abstract:Excessive accumulation of reactive oxygen species (ROS) can lead to oxidative stress, thus disrupting intracellular homeostasis. A genome-wide transcriptional analysis was performed to compare the Aspergillus niger wild type and the transcription factor knockout strain ΔYap1 under normal and oxidative stress conditions. The results demonstrated that, in response to oxidative stress, Yap1 in A. niger activated the expression of antioxidant enzymes, such as superoxide dismutase and peroxidase, which enhanced its resistance to ROS. Additionally, a glucose oxidase-expressing strain was generated, and the transcription factor Yap1 was integrated into the genome of this strain. This process resulted in a 55% reduction in the intracellular ROS level, which reached 283.61 A.U./mg in the modified strain compared with that in the parent strain. Furthermore, the glucose oxidase activity increased by 102%, reaching 321.36 U/mL, and the total protein secretion increased by 38%, reaching 26.11 mg/mL. Transcriptome sequencing revealed that A. niger predominantly utilizes Yap1 to cope with intracellular oxidative stress. Through Yap1 overexpression, the intracellular ROS level was reduced and the protein secretion capacity was enhanced. Overall, these findings provide valuable insights for increasing industrial protein (enzyme) production.

Abstract:The appropriate degradation of starch can expand its application scope. Compared with conventional chemical and enzymatic degradation methods, physical methods like ultrasonic treatment are green, convenient, and easy to operate. In this research, gelatinized normal corn starch was taken as the object, the degradation process and trend of the amylose-amylopectin mixed system was investigated in an ultrasonic field. After 30 min of ultrasonic treatment, the molecular weight of normal corn starch decreased from 1.68×107 g/mol to 8.33×105 g/mol, showing a trend of fast degradation followed by slow degradation. The results revealed a "size-dependent" degradation process for the starch molecules, that is, larger molecules were more easily degraded. Therefore, the degradation rate of amylopectin molecules was higher than that of amylose during the initial phase of ultrasonic treatment, and their degradation tended to be synchronized when their sizes reached the same. Based on the "intermediate degradation" of starch by ultrasound and the tendency that large molecules are more easily degraded, it was found that the Fb3 chain of starch molecules was broken down first, and as the ultrasonic treatment time increased, the Fb2 chain broke down, leading to the increase in the proportion of Fa chain. In addition, the breakage of α-1,4 glycosidic bonds of amylose led to the increases of Fb2 and Fb3 components. The 1H NMR results showed that both the α-1,4-glycosidic bond and the α-1,6-glycosidic bond of starch molecules were broken, but the breakage of the α-1,6-glycosidic bond was more significant. In summary, the ultrasound-induced degradation of the gelatinized amyloseamylopectin system was selective. The application of ultrasound as a means of physical modification in the starch industry is of great significance.

Abstract:In order to improve the comprehensive utilization rate of pitaya peel and enhance consumers’ confidence in food safety, fresh pitaya peel was used as the raw material in the experiments for extracting and characterizing the anthocyanin components of the pitaya peel. The anthocyanin extracts were used to prepare a meat freshness indicator film, and its pH and temperature stability, as well as its final application to pork freshness monitoring, were examined. The results showed that the optimal process for extracting anthocyanins from pitaya peel was: 50% ethanol by volume fraction, materialliquid ratio (mass of pitaya peel: volume of ethanol) as 1:39 g/mL, ultrasonication time as 19 min, and pectinase addition as 1.6 wt.%. Under these conditions, the content of anthocyanins was 218.25 mg/100 g. Seven anthocyanins were identified in the anthocyanin extract from pitaya peel, among which the relative content of petunidin and its derivatives was up to 89.76%; the color of anthocyanin extract was more stable under the conditions of 5~25 ℃ and pH 4~5; the total volatile basic nitrogen (TVB-N) of pork reached the spoilage threshold (15 mg/100 g) at the 12th h of storage (25 ℃). The meat freshness indicator film changed from purplish red to light yellow, with the color difference ΔE of the freshness indicator film being 5.38 (>5, which could be easily recognized by human eyes). The Pearson's r between TVB-N and ΔE was 0.961 2 (P<0.01), indicating that there was a strong correlation between the two, and that the indicator film was able to indicate the freshness of meat. This study provides a scientific basis for the high-value utilization of pitaya by-products.

Abstract:In order to investigate the impact of gradient warming on the quality preservation of the litchi stored at low temperature during shelf life, "August Red" litchi was selected as the experimental material. After 1 day of storage at 1 ℃, the litchi fruits were gradually brought back to room temperature (25 ℃) in three different temperature environments: 9, 18, and 25 ℃ , which was set as the "gradient rewarming" treatment group. Meanwhile, another group of litchi fruits stored at 1 ℃ for 1 d were directly placed in a room temperature environment (25 ℃) to restore to room temperature, which was set as the “direct rewarming” group as the control, to simulate the shelves placed under room temperature conditions for 0, 1, 3, and 5 d, respectively, and various indicators related to litchi fruit quality during the shelf life were measured. The results demonstrated that the "gradient rewarming" treatment effectively mitigated browning of litchi fruits. After the "gradient rewarming" treatment followed by standing at room temperature for five days, the browning coefficient of the “direct rewarming” litchi was 1.50, whilst the browning coefficient of the "gradient rewarming" litchi was only 1.00. In addition, "gradient rewarming" was found to delay the decreases in soluble solids content, titratable acids content, total phenols content, flavonoids content, and anthocyanins content, while also inhibiting effectively the increases in the activities of polyphenol oxidase and peroxidase in the peels. Therefore, the use of gradient rewarming treatment can effectively alleviate the quality deterioration of litchi stored at low temperature, extend litchi’s shelf life, indicating broad application prospects.

Abstract:To investigate the impact of freeing-temperature storage on reactive oxygen metabolism and cell wall metabolism in prune plums, French prune plums were stored for 49 days under three conditions: refrigeration temperature (2±0.5 ℃), chilling temperature (0±0.5 ℃), and freezing temperature (–2±0.5 ℃). Every seven days, samples were assessed for antioxidant enzyme activities and cell wall metabolism enzymes. Transmission electron microscopy was utilized to observe ultrastructural changes in the cells of prune plums from each group. The findings reveal that freezing-temperature storage, in comparison to storage at refrigeration and chilling temperatures, suppresses the generation of superoxide radicals (O2-•) in plums. Also, this storage condition increases the activities of enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). Moreover, freezing-temperature storage slows the conversion of proto-pectin (PP) to soluble pectin (SP) during storage and inhibits the activities of enzymes such as polygalacturonase (PG), pectin methylesterase (PME), cellulase (Cx), β-galactosidase (β-Gal), and β-glucosidase (β-Glu). After 49 days of storage at freezing temperature, the structural integrity of the prune plum cell wall was maintained, and the middle lamella remained distinctly visible. Although slight indentations were observed in the cell walls, they were markedly less pronounced than those in the other two groups. Overall, freezing temperature storage significantly enhances the antioxidant capacity of prune plums, impedes the degradation of cell wall components, and delays fruit softening.

Abstract:The effects of four sterilization methods on the storage stability of instant sea cucumbers at room temperature were studied. The results show that, after sterilization at 110 ℃ for 10 min and 121 ℃ for 5 min, the body wall tissues of instant sea cucumbers exhibit better water-holding capacities, and the corresponding hardness values are 522.78 g and 470.22 g, respectively. After 15 days of storage, the mass-loss rates were 7.64% and 12.26%, respectively, while the moisture content was between 82.98% and 86.63%. Meanwhile, the pH is relatively stable, and the total viable counts were 505 CFU/g and 0 CFU/g, respectively. The volatile odor changed significantly during storage, and the characteristic volatile substances of instant sea cucumbers mainly consist of methyl compounds. In addition, no notable changes in microstructure were observed. After sterilization at 90 ℃ for 30 min, the hardness, chewiness, and elasticity of instant sea cucumbers were 685.90 g, 616.30 g and 0.93, respectively. The total viable count exceeded the acceptable limit on the 9th day of storage. After 15 days of storage, the mass-loss rate was 17.20%, while the collagen fiber structure of the body wall loosened. In addition, the pH decreases by 3.62%. After sterilization with water at 80 ℃ and 90 ℃ for 30 min, the volatile odor faded. On the 3rd day of storage, the body wall began to soften, and adhesiveness was detected. The instant sea cucumbers began to rot on the 6th day of storage. In the late stage of storage, the sulfide content increased, while the fiber structure was flakey and gelatin-like. After 15 days of storage, the hardness of the instant sea cucumbers sterilized with water at 80 ℃ and 90 ℃ decreased by 81.57% and 87.96%, respectively. At the same time, the adhesiveness increased to about -40 g.s. In conclusion, sterilization at 90 ℃ for 30 min, 110 ℃ for 10 min, and 121 ℃ for 5 min prolonged the room-temperature storage time of instant sea cucumbers to 6, 12, and 15 days, respectively. This study provides a theoretical basis for the storage and preservation technology of instant sea cucumbers at room temperature.

Abstract:To determine a suitable treatment method for tomato preservation, antibacterial chitosan (CS) packaging cartons and 1-methylcyclopropene (1-MCP) sustained-release treatment were used for tomato storage. Changes in the sensory, quality, cell membrane metabolism, and antioxidant indexes of tomatoes were measured during storage. The results indicate that CS+1-MCP treatment can better reduce the weight loss and decay of tomatoes than pure CS or 1-MCP treatments alone during the 0~18 d storage period. In particular, on the 18th day, the weight loss and decay rate of the CS+1-MCP group are 0.97% and 23.3% lower than those of the CS group, respectively, and are 0.58% higher and 6.67% lower than those of the CK+1-MCP group, respectively. 1-MCP sustained release treatments also help to maintain the physiological and antioxidant properties of tomatoes. More specifically, on the 18th day, the respiratory intensity of the CS+1-MCP group is 3.37 and 11.4 mg/(kg•h) higher than that of the CK+1-MCP and CS groups, respectively, and the hardness of the CS+1-MCP group is 1.93 and 0.64 kgf/cm2 higher than that of the latter two groups, respectively. At the same time, the CS+1-MCP group also maintains a better appearance and color and higher contents of titratable acid, soluble solids, ascorbic acid, and total phenols. In addition, CS+1-MCP treatment effectively slows the increase of malondialdehyde and cell membrane permeability, delays the peak activities of peroxidase and catalase, and inhibits the their activity reduction in the later stage. In conclusion, CS+1-MCP effectively improves the preservation of storage quality of tomatoes compared with pure CS or 1-MCP treatments alone. Therefore, CS cartons combined with 1-MCP sustained-release treatment can be successfully applied to the postharvest storage and preservation of tomatoes.

Abstract:The effects of the core lipid, shell moisture, product processing, and storage conditions on the color and viable bacterial count of probiotic crystal ball products during storage were studied. The reasons for the browning and gradual decline in the viable bacterial count of the products during storage were analyzed, and the shell formulation of the probiotic crystal ball product was optimized. The results are as follows: at 37 ℃ and 65% RH, the lipid in the core does not change significantly during storage, but the probiotic powder crystals in the core noticeably brown. When the moisture content of the shell exceeds 14.10%, product browning is more obvious after two months of storage at 37 ℃ and 65% RH, and the viable bacterial count is lower than 106 CFU/g. When the moisture content of the shell is decreased to 10.30%, the probiotic crystal balls fracture. Exposing probiotics to high temperatures for two hours during product processing has no significant effects on the color of the probiotic powder in the core. Compared with 25 ℃ storage, 37 ℃ storage leads to more serious browning and more significant viable bacterial count reduction in the probiotic powder. The elongation at break of the outer shell is increased by optimizing the shell formulation, and rupturing of the product at low shell moisture content (3.45%) is avoided. After shell optimization, the viable bacterial count of the probiotic crystal balls is increased by 1.85-fold. The problems of browning and low viability of the probiotic crystal ball products during storage were effectively solved in this research. The results provide theoretical guidance for the industrial production of probiotic crystal balls.

Abstract:Protein aggregation and recovery in surimi-rinsed wastewater under the influence of a low-voltage direct current (DC) electric field were investigated. As the electric field voltage, treatment time, initial temperature of the wastewater, and mass fraction of salt in the wastewater increase, the protein recovery rate significantly increases initially (P<0.05), but then tends to level off or decrease. Meanwhile, as the electrode spacing increases from 3 cm to 15 cm, the protein recovery rate significantly decreases (P<0.05). In addition, the turbidity reaches its minimum (0.16) when the electrode spacing is 3 cm. With the help of the Box-Behnken response surface methodology, the optimal parameters for protein recovery were determined using an electrode spacing of 3 cm. At the same time, a protein-recovery prediction model was established. The optimal parameters are as follows: an electric field treatment time of 34 minutes, electric field voltage of 55 V, initial wastewater temperature of 22 °C, and a salt mass fraction of 0.06%. Under these conditions, the protein recovery rate from the rinsed wastewater reaches 92.23%, significantly higher than that of the thermal coagulation treatment group (66.35%) (P<0.05). Furthermore, the chemical oxygen demand removal rate is 89.54%, approximately 1.81-fold that of the thermal coagulation treatment group (49.38%). The recovery performance of the electric field treatment group is significantly better than that of the thermal coagulation treatment group (P<0.05). In conclusion, low-voltage DC electric field treatment enhances the aggregation and recovery of protein in surimi-rinsed wastewater. This study provides new ideas for protein recovery from wastewater.

Abstract:The exploration of new protein sources will have a significant impact on future food development. This study examined the effects of various factors involved in alkaline ultrasonic extraction on Euglena protein yield by employing the single factor, Plackett-Burman, and response surface methods. UV-Vis spectroscopy, FT-IR spectroscopy, and automated amino acid analysis were adopted to evaluate the functional group composition, secondary structure, and amino acid profile of Euglena protein. Additionally, the functional properties, such as water absorption, oil-holding capacity, and emulsification capacity, were studied. The optimal extraction parameters are as follows: a solid-to-liquid ratio of 1:20, an ultrasonic power of 100 W, an alcohol-to-base ratio of 1:3.5, a sodium hydroxide concentration of 0.35 mol/L, an extraction temperature at 40 ℃, an extraction time of 120 min, and an ultrasonic treatment time of 5 min. These conditions result in an extraction yield of 93.81%. Structural characterization reveals that the secondary structure of Euglena protein primarily consists of β-turns and β-sheets, accounting for 98.80% of the total structure. Essential amino acids account for 66.09% of the total composition, with hydrophobic amino acids constituting 67.81%. At 60 ℃, Euglena protein exhibits the highest maximum water absorption, reaching up to 13.19 g/g. Meanwhile, the highest oil-holding capacity of 7.33 g/g is observed at 40 ℃. Euglena protein demonstrates good emulsification capacity, emulsification stability, foaming capacity, and foam stability, with percentages of 34%, 64.62%, 53.90%, and 81.79%, respectively. This study utilized alkaline ultrasonic extraction to enhance the extraction yield of Euglena protein, laying the groundwork for its application as a novel protein source.

Abstract:To investigate the influence of molecular weight on the production of chitin nanofibers, we used chitin of different molecular weights to produce nanofibers under identical chemical bleaching, high-speed shearing, and ultrasonication conditions. The yield and morphological characteristics of nanofibers produced under the same preparation conditions using chitin with different molecular weights were examined. Because low-molecular-weight chitin (SSHC) yields shorter fiber lengths and fewer entanglement points, SSHC facilitates fibrillation, resulting in a higher nanofiber yield. Processing does not alter the chemical structure and crystalline phase of SSHC, enabling efficient production of chitin nanofibers with diameters ranging from 50 to 125 nm with relatively short ultrasonication times (30 min), ultimately achieving yields of up to 32.07%. This research reveals the benefits of using low-molecular-weight chitin for nanofiber fabrication and highlights their promise as stabilizers in Pickering emulsion systems. These finding provide strong technical support for value added chitin utilization.

Abstract:To investigate the quality differences among Lilium davidii var. willmottiae (E. H. Wilson) Raffill from different places of origin, the sensory scores of L. davidii var. willmottiae samples sourced from 13 different places were recorded, and the contents of soluble solids, moisture, sucrose, and other chemical components were determined. Subsequently, the sensory and chemical analysis results were statistically analyzed using Pearson correlation, principal component, and orthogonal-partial least squares discriminant analyses. The results show that the overall preference scores of the samples from Guanshan Township in Yongjing County and Xiguyuan Town in Qilihe District are the highest, at 4.25 and 3.93, respectively. The polysaccharide and total saponin contents in L. davidii var. willmottiae from Weiling Township in Qilihe District are higher, at 259.52 mg/g and 3.64 mg/g, respectively. The contents of soluble solids, sucrose, and starch in the samples from Chenjing Town (Nianjiwan Village) in Yongjing County are even higher, reaching up to 316.00, 654.63, and 425.37 mg/g, respectively. Sweetness, aroma, and crispness are positively correlated with the starch and sucrose contents, while bitterness and astringency are positively correlated with the total saponin content. The OPLS-DA results can distinguish L. davidii var. willmottiae samples of different origins. The cluster analysis results indicate that the quality of the samples from Agan Town of Qilihe District is considerably different from that of the samples sourced from other places. The comprehensive quality score of L. davidii var. willmottiae grown in Nanping Town in Lintao County is the highest (0.903). Sensory evaluation combined with chemical analysis is a new approach for evaluating the quality of L. davidii var. willmottiae, and these findings can serve as a reference for promoting cultivation and product development of L. davidii var. willmottiae.

Abstract:In order to compare the quality characteristics of the excellent third-generation large-fruit Russian seabuckthorn varieties, eight varieties of imported third-generation large seabuckthorn fruits from Russia as the research objects of this study, and the main cultivated large-fruit seabuckthorn variety ‘Shenqiuhong’ that is currently promoted widely in the “Three North” region as the control. The 20 quality indicators such as fruit quality, total phenolic content, and vitamin E content were measured, and the principal component analysis and regression analysis methods were used for a comprehensive evaluation. The results showed that the fruit mass of the eight third-generation Russian sea buckthorn varieties was 25.27~73.18 g, with their vitamin E contents ranging in 7.21~158.54 μg/g, their total phenolic contents ranging in 1.26~2.68 mg/g, their soluble sugar contents ranging in 18.46~29.86 mg/g, and their sweet-acid ratios ranging in 0.85~2.00. The principal component analysis extracted a total of 5 principal components, representing 93.767% of the information of the above indicators. Using stepwise regression analysis, the original 20 evaluation indicators were simplified into three indicators: vitamin E content, sweet-acid ratio, and total phenolic content. The comprehensive evaluation found that, except for 'Danbang', the comprehensive scores of the other seven Russian varieties all exceeded that of the control variety ‘Shenqiuhong’, and ‘Sudalusika’, ‘Yilishabai’, ‘Huangguan’, ‘Chengbang’ were scored higher. The research results provide a basis for evaluating the quality of large-fruit seabuckthorn berry planted in different regions and determining their main quality indicators. And four excellent varieties, ‘Shenqiuhong’, and ‘Sudalusika’, ‘Yilishabai’, ‘Huangguan’, ‘Chengbang’ were screened out, which can be promoted and utilized as key high-quality seabuckthorn resources.

Abstract:To improve the stability and flavor-release characteristics of mustard oil (MO), three kinds of MO microcapsules were prepared using the complex coacervation method, with beeswax (BW) as the oleogelator and sodium octenylsuccinate (OSA) combined with whey protein (WP), soy protein isolate (SPI), or chitosan (CS) as wall materials. Based on turbidity and zeta-potential measurements, the optimal pH values for OSA-WP, OSA-SPI, and OSA-CS complex coacervation are 4.2, 4.1, and 7.8, respectively, and the corresponding mixing ratios are 1:6, 1:4, and 1:2, respectively. The FT-IR spectra indicate that electrostatic interactions exist between OSA-WP molecules, forming complex coacervates. The same occurs for the OSA-SPI and OSA-CS molecules. The thermogravimetric analysis results show that the temperature at which rapid mass loss begins is higher for OSA-WP and OSA-SPI microcapsules than that for OSA microcapsules, and reaches up to 210 ℃. Furthermore, the maximum mass-loss temperature increases from 286 ℃ for OSA to 290 ℃ and 295 ℃ for OSA-WP and OSA-SPI microcapsules, respectively, indicating that the microcapsules formed effectively improved the thermal stability of MO. In addition, OSA-SPI microcapsules exhibit the best encapsulation performance, and the retention rate of allyl isothiocyanate increased by 24.78% compared with that of the OSA microcapsules on the 60th day. In this study, the complex coacervation method was used to improve the mechanical properties of microcapsule wall materials, so as to enhance the stability and flavor-release characteristics of the microcapsules. These findings are conducive to expanding the application scope of MO.

Abstract:Fresh bullfrogs and pickled peppers were used as the main raw materials to prepare pickled pepper bullfrog, along with spices, salt, and other ingredients. Firstly, the effects of the mass fraction of pickled peppers, cooking temperature, cooking time, and pickling time on the sensory properties, color, and texture of pickled pepper bullfrog were investigated through single-factor experiments. Secondly, based on the single-factor experimental results, three single factors were selected to optimize the processing technology for pickled paper bullfrog with the help of response surface methodology by using the sensory score as the response value. Finally, the water-holding capacity and the total number of colonies of the finished pickled bullfrog were measured. The optimal parameters for preparing pickled pepper bullfrog are as follows: a 30% mass fraction of pickled peppers, cooking temperature at 80 ℃, cooking time of 15 min, and pickling time of 3 h. The results show that the water-holding capacity of pickled pepper bullfrog is reduced by 9.42%, to 80%. This loss is relatively small, and the flesh is still fresh and tender. The total number of colonies is 55 CFU/(g•mL), which is lower than the national limit. In addition, the flavor and taste of the pickled pepper bullfrog were determined and analyzed. The pickled pepper bullfrog obtained under the optimal parameters is light yellow and shiny. It possesses a sour and spicy aroma characteristic of pickled pepper products without any peculiar smell. The bone and meat are closely connected, and no bone detachment is noted. The pickled pepper bullfrog has a layered, delicious taste and good chewing texture. The final product has a sensory score of 83 points and good acceptability. This study can serve as a reference for the development and standardized production of pickled pepper bullfrog products in China.

Abstract:The effects of ultrasonic power on the gel properties, including textural characteristics, gel strength, color, and water-holding capacity (WHC), of silver carp surimi with varying salt levels (3% and 1.5% m/m) were investigated to improve the gel properties of low-salt surimi. The influencing mechanism of ultrasonic treatment was investigated by determining the protein solubility, intermolecular interactions, and infrared spectrum of surimi gel. The results indicate that, as the ultrasonic power increases, the hardness, elasticity, and gel strength of surimi gel with varying salt levels increased. At an ultrasonic power of 360 W, no significant differences in the hardness and elasticity of the high- and low-salt surimi gels were apparent. The WHC of surimi gels containing 3% and 1.5% salt increased by 10.48% and 22.08%, respectively. Ultrasonication had no significant effect on the whiteness of high- and low-salt surimi gels. The solubility, intermolecular interaction, and infrared spectroscopy analyses reveal that ultrasonic treatment can increase the gel solubility and reduce the hydrogen bonds in surimi. The α-helix content of surimi protein decreases after ultrasonic treatment. The results indicate that ultrasonic treatment increases the exposure of active groups, promotes the interaction between active groups and water molecules, and improves the gel formation ability of surimi. This research demonstrates that the gel properties of lowsalt surimi can be significantly improved by ultrasonic treatment at 360 W, enabling the reduction of salt addition to surimi products and thus the development of low-salt, high-quality surimi products.

Abstract:The harvest time significantly impacts the quality of Huangjinya green tea. This study, adopting sensory evaluation, physicochemical analysis, antioxidant capacity assays, and untargeted metabolomics methods, delves into the effects of the harvest time on the flavor compounds and sensory attributes of Huangjinya green tea. H-1, harvested on March 9th, stands out for its superior quality (a score of 87.71 points) and is characterized by a refreshing and floral aroma. H-2, harvested on March 15th, exhibits a unique floral and fruity fragrance. Conversely, H-3, harvested on April 6th, features pronounced astringency and a astringent and bitter aftertaste of astringency, and aftertaste of bitterness, which is attributable to its highrich contents of polyphenols (183.38 mg/g), flavonoids (181.51 mg/g), purine alkaloids (37.65 mg/g), and bitter amino acids (7 926.62 μg/g). In addition, H-3, alongside demonstratesing the strongest in vitro antioxidant capacity. Meanwhile, H-4, harvestedcollected on May 6th, boasts exceptional sweetness and freshness due to high levels of total free amino acids (53 274.52 μg/g), theanine (29 336.40 μg/g), and sweet amino acids (2 690.12 μg/g). Similar to H-3, H-4 possesses a complex flavor profile comprising refreshing, citric, fatty, and sweet attributes, sharing complex flavor characteristics like freshness, citrus, fat, and sweetness with H-3. Untargeted metabolomics analysis highlights that the lengthduration of the harvestpicking interval significantly influences the number of differential metabolites. Essentially, the precise timing of harvest intricately molds the unique flavor profile and sensory attributesquality of Huangjinya green tea by modulating its internal volatile and non-volatile compound contents. This groundbreaking research not only deepens our understanding of Huangjinya green tea but also lays a robust scientific foundation for its resource development, utilization, and optimal harvestpicking time management. The findings provide insight intoBy guiding production practices and enhancing tea quality improvement, it significantly contributes to the pursuit of excellence within the tea industry.

Abstract:To investigate the production process and quality stability of Osmanthus fragrans hydrosol, GC-MS was used in this study to conduct a comparative analysis of the aroma components extracted from the fresh flowers of Osmanthus fragrans obtained by different methods and from various origins. The results showed that the aroma components of Osmanthus fragrans hydrosol extracted by different processes were quite different, with only 19 identified components in common. Among them, the Osmanthus fragrans hydrosol extracted by water distillation had β-ionone (19.64%), γ-decalactone (15.82%), and dihydro-β-ionol (12.26%) as the dominant components, which had a high aroma content and obvious impurities. The Osmanthus fragrans hydrosol extracted by the vacuum freeze-drying method primarily contained dihydro-β-ionone (43.59%), β-ionone (25.73%), and linalool (15.48%), with a significantly higher dihydro-β-ionone content but weaker aroma than those of the other methods. The relative content of linalool oxide in the hydrosol obtained via microwave vacuum drying exceeded 50%, with γ-decalactone accounting for 16.67%, balanced composition of individual compounds, and typical and rich aromas. The Osmanthus fragrans hydrosols extracted from the fresh flowers from different origins had a total of 43 aroma components, with linalool oxide, γ-decalactone, β-ionone, geraniol, and dihydro-β-ionone as the dominant aroma active substances. This finding shows that the processing technology had a great influence on the quality stability of Osmanthus fragrans hydrosol, with microwave vacuum drying emerging as a process worthy of promotion based on a comprehensive consideration. In addition, although there are differences among origins, the primary components remained essentially stable. This research provides a foundation for the industrialization, development, and utilization of Osmanthus fragrans hydrosol.

Abstract:Fengtong multifloral honey is produced in the “Fengtong Apis cerana Fabr. Genetic Resource Conservation Area,” located in the selenium-rich region of Wanyuan, Dazhou, Sichuan province. It is a certified product under the Geographical Indication system of China for agricultural products. In this work, the flavor characteristics, chemical composition, and bioactivities of Fengtong multifloral honey were investigated. A total of 34 compounds were detected using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). The key flavor substances of Fengtong multifloral honey are dodecanal, decanal, 2-undecanone, 2-nonanone, phenyl-acetaldehyde, and 1-nonanol, giving the honey sweet and floral flavors. In particular, high-altitude samples also possess a rose aroma. The selenium content of Fengtong multifloral honey is 22 μg/kg, and the total phenolic content ranges from 0.63 to 0.72 mg GAE/g, while the total flavonoid content is 0.26~0.31 mg RE/g. A total of 95 compounds were identified using ultra-performance liquid chromatography-electrospray ionization time-of-flight tandem mass spectrometry (UPLC-ESI-TOF-MS/MS) combined with widely targeted metabolomics. The non-sugar compounds commonly detected in all samples were interiotherins A, deoxyneocryptotanshinone, ellagic acid, quercetin 3-sulfate, and isostearic acid. Auraptene and ostruthin were only identified in high-altitude samples, while 2α, 3β-dihydroxdeoxypterodontic acid was found in low-altitude samples. Remarkable antioxidant activities were noted in all Fengtong multifloral honey samples, with IC50 values for DPPH and ABTS+ radical scavenging and a ferric reducing antioxidant power of 0.79~0.82 g/mL, 0.27~0.30 g/mL, and 2.84~3.75 mmol/100 g, respectively. In summary, Fengtong multifloral honey is selenium-containing honey produced by Apis cerana Fabr. with abundant flavonoids, phenolic acids, and terpenes, and remarkable antioxidant activities. These findings offer data support for the development of Fengtong honey products and their quality control standards.

Abstract:In order to optimize the fermentation process of kiwi wine and improve its overall quality, kiwifruit was the as raw material in this study, yeast powder, FN502 yeast nutrients (yeast extract), diammonium hydrogen phosphate, ammonium sulfate, ammonium chloride, and ammonium carbonate were used as the supplementary nitrogen sources for fermenting kiwifruit wine. The quality and volatile components of the resulting kiwi wine were analyzed and compared. The results showed that except for ammonium chloride, other nitrogen sources could significantly promote the fermentation rate and shorten the main fermentation time by 2 to 3 days. The total acid contents of the organic nitrogen source group and the ammonium carbonate decreased by 1.75%~10.23% group, compared with the control group, decreased by 1.75% to 10.23%. The addition of inorganic nitrogen sources resulted in a notable reduction in the content of phenolic substances, with the total phenol content decreasing by 1.50%~19.48%, the chlorogenic acid content decreasing by 48.56%~ 94.95%, whilst the organic nitrogen source group exhibited a less pronounced effect. In terms of volatile components, a total of 60 volatile components were identified in the samples with different nitrogen sources, mainly alcohols and esters, accounting for 56.56% and 36.26% of the volatile components, respectively. Compared with the control, the organic nitrogen source led to significant increases in the contents of alcohol and ester components, among which the alcohol content of the yeast extract group increased by 10.06%, and the content of esters of the FN502 group increased by 9.49% in. In the sensory evaluation, the FN502 group was scored the highest, and the aroma score was significantly higher than that of the control group. In summary, this study provides a theoretical foundation for the rational addition of nitrogen sources during the fermentation process of kiwi wine, and has guiding significance for improving quality and production applications.

Abstract:An improved QuEChERS method was established and combined with high-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-MS/MS) for the simultaneous detection of nine new pesticide residues, including formetanate hydrochloride, cyclaniliprole, and pyflubumide, in plant-based foods. In the national standards of China for plant-based food safety, the detection standards for these nine pesticide residues are not yet established. However, when fruits and vegetables are exported to the European Union (EU) and Japan, pesticide residues are one of the main targets in food safety testing. Firstly, methyl cyanide is used for extraction, followed by water removal using magnesium sulfate (anhydrous) and sodium chloride. Subsequently, the supernatant is purified with 150 mg of N-propyl ethylenediamine and 900 mg of magnesium sulfate (anhydrous). Finally, HPLC-MS/MS is used for pesticide residue detection. The results suggest that all nine pesticide substances show good linear relationships at 0.000 2~0.02 mg/L, with correlation coefficients (r2) exceeding 0.998. The limit of detection (S/N=3) is 0.028~1.493 μg/kg, and the limit of quantification (S/N=10) is 0.093~4.975 μg/kg. At spiked levels of 5, 10, and 20 μg/kg, the average recovery rates are 70.60%~108.75%, and the relative standard deviations (n=6) are 1.35%~12.99%. The results all comply with the standards for pesticide residue limits in fruits and vegetables set by EU countries and Japan. This study offers a reference method for the import and export inspection of such pesticides in plant-based foods originating from China.

Abstract:The demand for protein continues to increase due to the rapid growth of global population and improvement of living standards. Sesame is a widely planted oil crop in China, and is listed as an important crop in China’s modern agricultural industrial technology system. Sesame and the sesame cake after oil extraction are rich in protein, approximately 20% and 38%~50%, respectively. It was reported that sesame protein contains abundant essential amino acids and has a relatively balanced amino acid composition. Therefore, efficient utilization of sesame protein not only improves the resource utilization rate of sesame, but also is one of the important ways to ensure the balance of protein supply in China. This article focuses on summarizing the composition, nutritional value, extraction methods, structure and physicochemical properties, functional properties, modification approaches, and food processing applications of sesame protein, to provide support for the promotion of deep processing and high-value utilization of sesame protein.

Abstract:Pomelo (Citrus grandis (L.) Osbeck) is a subtropical fruit with a unique flavor and high nutritional value. China has a long history of pomelo cultivation and has developed several varieties. Several studies have shown that pomelo is rich in bioactive compounds, such as polysaccharides, flavonoids, and terpenes, and possesses, antioxidant, anticancer, antiinflammatory, lipid-lowering, hypoglycemic, and antibacterial properties, suggesting that it has broad application prospects in food, dietary supplement, and pharmaceutical industries. Despite the growing interest among researchers on the bioactive compounds and functional properties of pomelo, there is a lack of a comprehensive review on the bioactive compounds and functional properties of pomelo, thereby hindering the development and utilization of these active components. Therefore, this study summarizes the research progress on the main bioactive compounds and functional properties of pomelo in recent years, and extensively explores potential research directions for the future development of these active compounds. Additionally, this study serves as a valuable resource for further research, development, and utilization of pomelo.

Abstract:Kefir is a low-alcohol, carbonated, and slightly sour fermented beverage offering health benefits such as intestinal microbiota regulation, antioxidation, and hypolipidemic effects. Kefir is produced using kefir grains, a fermentation starter, and is classified as either water kefir or milk kefir according to the fermentation substrate. Water kefir is produced with the help of water kefir grains by using a sugar-containing aqueous solution or fruit and vegetable juice as the substrate, whereas milk kefir is mainly made from cow milk, goat milk, or camel milk fermented by milk kefir grains. Compared with milk kefir, water kefir has a relatively recent consumption history. Yet, because it can be produced from many different fermentation substrates and offers more health benefits, water kefir has also received widespread attention from lactose-intolerant individuals and vegetarians. However, research on water kefir is scarce, which impedes the improvement of the associated production and processing technology. This review begins by highlighting the differences between milk kefir and water kefir, and then introduces the microbial diversity, functional properties, and applications of water kefir in detail. The ultimate aim is to provide a theoretical basis for further research and development of water kefir.

Abstract:The bitter active ingredients in functional foods have antioxidant, anti-inflammatory, and metabolic regulation effects, but their poor taste affects consumer acceptance. Therefore, this paper systematically expounds the mechanisms of bitterness production and signal transduction mechanism through literature survey, and discusses the development of bitterness suppression technologies and the application of new bitterness suppressants. This paper summarizes the previous studies on the mechanisms of bitter taste transduction and found that the activation of bitter receptors leads to an increase in intracellular Ca2+ level, releasing neurotransmitters and generating bitter taste, and inhibiting Ca2+ levels provides a new idea for bitterness suppression technology. Additionally, the paper outlines three main mechanisms of bitterness suppression: taste interaction, bitter taste receptor masking, and inhibition of bitter receptor cells. On this basis, this paper summarizes traditional bitterness inhibitors commonly used in food processing and the newly discovered bitterness inhibitors in recent years, particularly the novel bitterness-suppressing peptides extracted from natural animal proteins that block bitter signal transduction to reduce bitterness and improve product acceptance. In recent years, bitter inhibitory peptides derived from animal proteins like chicken, beef, and fish have been continuously reported. By comparing different bitterness suppression technologies, this review concludes that blocking the binding of bitter substances to human bitter receptor cells is a promising bitterness inhibition technology, which can not only effectively reduce bitterness intensity but also retain the activities of functional components. The results of this study help promote the application of bitterness inhibitors in bitter foods and provide a theoretical reference for improving the acceptance of functional foods.

Abstract:The rapid development of metabolomics technology has provided a powerful tool and new research perspectives for in-depth study on pork quality traits, which is crucial for in-depth understanding of the formation mechanism of pork quality traits, improving pork quality, and promoting the development of the meat industry. This article reviews the concepts related to metabolomics technology, summarizes the analysis strategies suitable for different research purposes, and briefly introduces the main separation and detection techniques in metabolomics. Meanwhile, a systematic review of recent research on pork quality using metabolomics technology is provided, summarizing the analysis routes and research results of various traits including slaughter meat quality (including pH, meat color, water-holding capacity, intramuscular fat), edible quality (including flavor, processing methods), additional quality (including freshness, storage methods, spoilage contamination), and meat quality identification (including meat adulteration, breed identification, feeding conditions). The review reveals the application value of metabolomics in the study of pork quality traits, providing a certain reference for pig breeding and the discovery of key markers related to pork quality.

Abstract:Isothiocyanates are a class of secondary metabolites mainly derived from cruciferous plants. They give food a unique flavor and exhibit a variety of biological activities, such as anticancer, antidiabetic, neuroprotective, antimicrobial, anti-inflammatory, and antioxidant properties. They are widely used in food, medicine, and agriculture. The yields of isothiocyanates from natural sources are generally low, while chemical synthesis often leads to significantly contaminated isothiocyanates. In the meantime, with the development of synthetic biology, new methods have emerged for the green, efficient, and stable production of isothiocyanates. In this review, the classification, biological activities, bioavailability, biosynthesis pathways, and molecular biology methods that improve the yields of isothiocyanates in species are systematically expounded in detail. The aim is to deepen the understanding of the role and value of isothiocyanates and to provide technical support for their further development and utilization. This study is expected to provide a theoretical basis for the development of functional foods as well as insights into the high-yield preparation of isothiocyanates.

Abstract:Fruits and vegetables are an important and indispensable food source in the diet of Chinese residents, and pesticides play a key role in ensuring the efficiency of fruit and vegetable production. With the improvements of living standards and scientific and technological means, the problems of pesticide residues in fruits and vegetables and their removal have attracted much attention. This study systematically summarizes the current situation of pesticide residues in fruits and vegetables, the cleaning methods for removing pesticide residues, the principles, advantages and disadvantages of various methods, and future development directions. The research results show that emerging pesticide residue removal technologies such as ultrasound, ozone, non-thermal plasma, and electrolytic water cleaning have shown significant effects in fruit and vegetable cleaning applications. However, the degradation rate and deactivation degree of pesticide residues by these technologies are also influenced by multiple factors such as equipment type, processing parameters, surface characteristics of fruit and vegetable products, treatment conditions, and pesticide properties. In order to remove the pesticide residues on food surface more effectively, further research is needed on the applied technologies to deal with the complicated types of pesticide residues in order to provide consumers with more accurate and feasible cleaning methods.