Abstract:

Fucosylated human milk oligosaccharides (FHMOs), mainly including 2′-fucosyllactose (2′-FL), 3-fucosyllactose (3-FL), and difucosyllactose (DFL), are the most abundant neutral human milk oligosaccharides in breast milk. FHMOs have multiple physiological functions, such as preventing pathogen adhesion, regulating the immune system, promoting probiotic growth, and promoting neurological development. The biosynthesis methods, including enzymatic and precision fermentation, have the advantages of easy operation, environmental friendliness, and mild reaction conditions, and have become a research focus and hotspot for the synthesis of FHMOs. Herein, the latest research progress in the biosynthesis of FHMOs by enzymatic and precision fermentation was systematically summarized. The contents focused on the microbial chassis cells used for FHMOs synthesis, FHMOs synthesis pathways and bypass inhibition, as well as the exploration and modification of fucosyltransferases. The microbial chassis cells used for FHMOs synthesis were introduced. Escherichia coli was the most commonly used chassis cell, followed by microorganisms such as Bacillus sp. and yeasts, and emerging chassis cells were also widely developed, such as Nicotiana benthamiana. The FHMOs synthesis pathway and bypass inhibition were analyzed. The overall idea was to enhance the gene expression level of the FHMOs synthesis pathway and weaken the consumption of carbon resources by bypass metabolism, while balancing the coordinated expression of genes in the synthesis pathway and carbon central metabolism pathway. Subsequently, the exploration and modification of fucosyltransferases were discussed. Various bioinformatics methods were used to discover efficient and highly specific fucosyltransferases, which were effective methods to enhance the biosynthesis of FHMOs. Rational/semi rational molecular modification was used to further improve the performance of fucosyltransferases, which could maximize the production and product singularity of FHMOs. Finally, the future trends of FHMOs biosynthesis were proposed.

Abstract:

In recent years, with increasing attention to the health benefits of natural resources, food and medicinal substances—those possessing characteristics of both food and medicine—have become a research hotspot. These substances are widely used in traditional medicine and modern nutrition, and their bioactive components have shown great potential in regulating health. The development of target identification technologies has provided crucial support for elucidating the health-regulating mechanisms of food and medicinal substances. By utilizing cutting-edge technologies, such as biotinylated molecular probes and chemical proteomics, researchers could accurately identify the bioactive components in food and medicinal substances and their corresponding targets. The research that conducted in-depth analysis of nutritional components in food and their regulatory effects on health through chemical biology technologies formed a new interdisciplinary discipline:food nutrition chemistry and biology (FNChB). As an emerging interdisciplinary field, it integrated the theories and technologies of food science, nutrition, chemical biology, and molecular biology, offering new approaches and methods for exploring the functional factors and mechanisms of action in food and medicinal substances. The definition and characteristics of food and medicinal substances were systematically introduced, the principles and applications of target identification technologies were elaborated, and an in-depth analysis of the research progress on related targets and mechanisms was provided, aiming to offer new directions and theoretical support for the development and application of food and medicine substances.

Abstract:

Homology of medicine and food has a long-standing tradition in China and has become an integral component of the daily dietary practices of people. China' s regulation of substances traditionally used as both food and Chinese medicinal materials (hereinafter referred to as“food and medicinal substances, FAMS”) began in 1982 with the promulgation of the Food Hygiene Law of the People' s Republic of China (Trial), which initiated a catalogue-based regulation model for such substances. This model was subsequently refined through successive amendments to the Food Safety Law. In 2021, the Administrative Provisions on the FAMS Catalogue were issued, for the first time explicitly defining FAMS, specifying the procedures and requirements for their inclusion in the catalogue, and stipulating requirements for their use as well as for their production and operation. These provisions standardized the management of FAMS. In recent years, the range of listed FAMS has expanded. The increasingly improved regulatory policies, while supporting the Healthy China strategy and meeting the diversified health needs of the public, have also significantly boosted regional economic growth and industrial development. However, the current management and industrial development of FAMS and its products in China still face challenges, including incomplete coverage of quality and safety standards and a lag in the development of high-quality products with clear scientific evidence. Therefore, it is necessary to further improve the supporting policies related to FAMS catalogue, and to establish a well-developed support system for the FAMS industry, so as to better leverage the catalogue's role in safeguarding health and promoting development.

Abstract:

Black beans are rich in protein which is easily absorbed and has high bioavailability. Black beans grown in selenium rich soil can absorb selenium from the soil and convert it into selenium-enriched black bean polypeptide (SeBSPP). Using selenium enriched yeast (SeYT) pretreatment as a positive control group, the effects of SeBSPP (molecular weight <7kDa, selenium concentration 122mg/kg) on the intestinal barrier, oxidative indexes, benzo[a] pyrene, (B[a]P) metabolism, short chain fatty acids contents and 16S diversity of intestinal flora in mice were analyzed. The results showed that SeBSPP and SeYT both had preventive effects on B[a]P-induced colonic injury in mice, which could increase T-SOD and GSH-Px enzyme activity, reduce H₂O₂ and MDA levels, improve colonic oxidative stress and intestinal SCFAs relative contents. Compared with SeYT, SeBSPP could increase the level of mucin MUC2 in colon tissues, maintain the intestinal enterocytes and repair the intestinal barrier, efficiently reduce the enzymatic activity of AhR, an enzyme related to B[a]P metabolism, inhibit the formation of BPDE-DNA, and reduce toxicity of B[a]P to colon. In addition, SeBSPP could regulate intestinal flora and protect intestinal health by downregulating g_Butyricicoccus and g_Arryflintia, and upregulating g_Lactobacillus, g_Lachnoclostridium and g_Lachnospiraceae_NK4A136_group, etc. This study showed that SeBSPP could effectively prevent B[a]P-induced colon injury by inhibiting B[a]P metabolism and regulating intestinal flora, providing a new approach for the inhibition of B[a]P colon toxicity and the application of selenium polypeptides.

Abstract:

Synergistic antimicrobial effects of bacteriocins and essential oils are an effective way to address food safety issues caused by foodborne pathogens, but the related synergistic antibacterial mechanisms are still unclear. This study investigated the synergistic antibacterial mechanisms of enterocin Gr17 and cinnamaldehyde against Listeria monocytogenes from the perspectives of morphological structure, cell wall, cell membrane and energy metabolism. Time-killing experiments showed that enterocin Gr17 and cinnamaldehyde synergistically inhibited the growth of Listeria monocytogenes in a time-dependent manner, with a reduction of bacterial counts by 6.22lg CFU/mL for 24h. Scanning electron microscopy and transmission electron microscopy analysis revealed that enterocin Gr17 and cinnamaldehyde synergistically disrupted the morphology and internal tissue of cells, resulting in the disintegration of cell structure. Alkaline phosphatase activity and Zeta potential analysis indicated that enterocin Gr17 and cinnamaldehyde synergistically disrupted the cell wall integrity of Listeria monocytogenes via disrupting its surface potential and targeting cell wall constituents. The leakage of K⁺ and adenosine triphosphate and the massive release of nucleic acids, proteins, and lactate dehydrogenase indicated that enterocin Gr17 and cinnamaldehyde synergistically formed non-selective pores in the cell membrane of Listeria monocytogenes, disrupted membrane permeability, further inhibited energy metabolism, and ultimately caused irreversible structural damage to the membrane integrity and cell death. Notably, enterocin Gr17 mainly targeted and destroyed the cell wall, while cinnamaldehyde primarily acted on the cell membrane. Their synergistic interaction exacerbated the loss of structural integrity in both the cell wall and membrane, culminating in compromised energy metabolism. This study provided a theoretical reference and scientific basis for understanding the synergistic antimicrobial mechanism of natural antimicrobial agents.

Abstract:

Antifreeze peptides (AFPs) represent an emerging class of antifreeze agents, offering significant advantages over traditional cryoprotectants and natural antifreeze proteins. To develop a high-activity AFPs derived from silver carp parvalbumin (PV),and explore their potential application in the preservation of frozen foods, PV was purified from fish muscle, and high-activity AFP fractions were obtained through controlled enzymatic hydrolysis and ultrafiltration, with the cryoprotective efficacy of the resulting products on yeast serving as the screening index. The generated optimal fraction was further characterized by UPLC-MS/MS analysis. The results showed that PV from silver carp muscle could be purified effectively by heat treatment. The hydrolysate exhibited optimal antifreeze activity under the conditions of a mass concentration of 30g/L PV, 3000U/g trypsin, and a hydrolysis time of 120min. Under this condition, the prepared AFPs increased the survival rate of freeze-thawed yeast cells to over 90%. Ultrafiltration separation yielded a high-activity fraction F1 (molecular weight of less than 1kDa), which had a thermal hysteresis activity of 1.20℃ and significant ice recrystallization inhibition activity. Yeast treated with the F1 fraction exhibited a survival rate of 51% after three freeze-thaw cycles, and concurrently the OD₆₀₀ showed a moderate decline from 20.6 (fresh) to 11.8. In contrast, the untreated control yeast demonstrated significantly lower survival rate (1%) and OD₆₀₀ (0.9). UPLC-MS/MS analysis identified 417 PV-derived peptides in F1, with 86% of them exhibiting molecular weights ranging from 0.5 to 2.0kDa. Seven of the eight most abundant peptides were predicted to be AFPs, aligning with the good antifreeze activity of F1. The research aimed to innovate a method for preparing highly active antifreeze peptides using pure silver carp PV, laying a foundation for further research on the structure-activity relationship of its highly active AFPs.

Abstract:

The study of transformation mechanisms of volatile terpenoids in hybrid citrus can help to reveal the aroma formation of hybrid citrus and improve the quality and flavor of processed hybrid citrus products. The pulp of three kinds of hybrid citrus, namely, Orah mandarin, Harumi tangor, and Ehime No. 38, were used as the study objects. The qualitative and quantitative analysis of terpenoids in three hybrid citrus was carried out by head space-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). A total of 16 terpenoids, including 3 terpenes (D-limonene, γ-terpinene, p-1,3,8-menthatriene), 7 terpenoid alcohols (linalool, p-2,8-menthadien-1-ol, terpinen-4-ol, α-terpineol, carveol, nerol, citronellol), 4 terpenoid ketones (6-camphenone, dihydrocarvone, L-carvone, isopiperitenone) and 2 other oxygenated terpenoids(rose oxide, perillyl aldehyde), were detected in the three varieties of hybrid citrus, and D-limonene and α-terpineol were detected in all the three varieties of hybrid citrus. Transformation reactions were simulated using standards of the detected terpenoids under the acid and enzymatic environments of the pulp of the three varieties of hybrid citrus. The results revealed that there were inter-transformation relationships among the 10 terpenoids under acid catalysis. Under enzyme catalysis, interconversion relationships existed among 12 terpenoids. Possible transformation mechanisms were proposed according to their transformation pathways. The study could provide a theoretical basis for the optimization of aroma preservation and aroma enhancement processes for processed products of hybrid citrus.

Abstract:

The flavor of raspberry wine is strongly influenced by its organic acid composition and concentration. To investigate the impact of organic acids on flavor, the composition, content, differential metabolites, and metabolic pathways of organic acids were analyzed. Liquid chromatography-tandem mass spectrometry was employed to quantify the organic acids in raspberry wine, and principal component analysis and significant difference testing were used to identify differential metabolites. KEGG metabolic pathway annotation and type analysis, along with sensory evaluation, electronic nose and electronic tongue technologies were utilized to explore the flavor of raspberry wine and investigate the impact of differential organic acid metabolites on the flavor of raspberry wine at various aging stages. The results identified 23 significantly differential metabolites between two wines of different aging time. Among them, the contents of five metabolites, including caffeic acid and shikimic acid, were upregulated with longer aging, while the contents of 18 metabolites, such as 4-aminobutyric acid and α-ketoglutarate, were down-regulated over aging. A total of 68 metabolic pathways were annotated through the analysis of differential metabolites, including the citrate cycle and C₅-branched dibasic acid metabolism. Sensory evaluation revealed that raspberry wine aged for 6 weeks exhibited superior scores in indicators such as acidity and bitterness compared to the 4-week-aged sample. Electronic tongue analysis demonstrated that raspberry wine with 6 weeks' aging time had a higher score in the test of umami and richness, alongside reductions in bitter and sour taste attributes. Electronic nose profiling identified that prolonged aging generated a more complex and intense aromatic profile. Based on metabolomics technology, this study aimed to explore the potential effects of differential metabolites on the flavor of raspberry wine with different aging time by analyzing the changes in differential metabolites in metabolic pathways, elucidate the shifts in organic acid composition and concentration during the aging process, and provide insight into the underlying material basis for flavor evolution in raspberry wine aging from the perspective of organic acid metabolism.

Abstract:

To clarify the nutritional value, aromatic composition and anti oxidation activity of a newly introduced Gu Nin Chio banana in China, spectrophotometry, HPLC(high-performance liquid chromatography), ICP-MS (inductively coupled plasma-mass spectrometry), and GC-MS (gas chromatography-mass spectrometry) were employed to analyze the basic nutritional components (soluble sugars, titratable acids, proteins, and vitamin C), free amino acids, minerals, active compounds (flavonoids and carotenoids, etc.) as well as aromatic components in Gu Nin Chio banana. DPPH free radical scavenging activity assay was used to evaluate the antioxidant activity of total flavonoids and carotenoids from Gu Nin Chio banana. Results showed that the soluble sugar and titratable acid mass fraction in Gu Nin Chio banana were (85.50±0.22)mg/g and (13.7±0.008)mg/g (fresh weight), respectively. Protein and vitamin C mass fraction were (125.14±2.13)μg/g, (84.43±2.86)μg/g (fresh weight), respectively. 24 free amino acids were detected, including eight essential amino acids for adults, two essential amino acids for children, and several active amino acids with physiological functions such as taurine and β-aminoisobutyric acid. In addition, 12 minerals were found in Gu Nin Chio banana including macro-elements (sodium, potassium, magnesium, and calcium) and trace elements (iron, zinc, manganese, cobalt, nickel, copper, strontium, and barium). Among them, the potassium mass fraction was 2841.07mg/100g (dry weight), significantly higher than that of Fenjiao banana, Red banana, Dajiao banana and Haigongjiao banana [829.33-2732.89mg/100g (dry weight)]. Active compounds including flavonoids such as quercetin, kaempferol, and β-carotene as well as 5-hydroxytryptamin were also present in Gu Nin Chio banana. The total flavonoids mass fraction in Gu Nin Chio banana was 11.15mg/g (dry weight), which was much higher than that of Baxi banana, Fenjiao banana, Emperor banana [0.9-5.8mg/g (dry weight)]. 20 compounds such as 2-pentyl acetate, nonanal and isoamyl acetate had rOAV (relative odor activity value) greater than 1, which were the main aroma components contributed to its special elegant fragrance. The DPPH radical scavenging activity assay showed both the total flavonoids and carotenoids exhibited certain antioxidant activity, while their antioxidant activity was significantly lower than that of vitamin C. The results of this study provided a theoretical basis for the development and utilization of new banana variety Gu Nin Chio, and offered basic data and theoretical references for optimizing banana variety structure in the banana planting industry and the research and development of banana processed foods with higher added value.

Abstract:

To explore the influence of the distribution of substituents within starch granules on the physicochemical properties of waxy corn starch, waxy corn starch was used as the raw material. Enzymatic hydrolysis was performed using pullulanase and glucoamylase. Enzymatically hydrolyzed acetylated starches with different degrees of modification were prepared by controlling the conditions of enzymatic hydrolysis and acetylation modification. The enzymatically hydrolyzed acetylated starches were subjected to surface gelatinization treatment. The changes in the degree of substitution in different regions within the granules were determined by the degree of gelatinization and gel permeation chromatography. The starches with different substituent distributions were analyzed by scanning electron microscopy, differential scanning calorimetry, infrared spectroscopy, and X-ray diffractometry. The freeze-thaw stability of starches with different substituent distributions was measured. The results showed that based on the analysis of the gelatinization degree of starch granules and the degree of substitution before and after gelatinization, with the increase in the degree of enzymatic hydrolysis and modification, the degree of substitution of the remaining starch after gelatinization increased, acetyl groups were introduced into the interior of starch granules, resulting in a relatively uniform distribution of the substituents in the starch granules. The scanning electron microscopy results indicated that as the degree of modification deepened, the surface structure of starch granules was damaged, with depressions and holes appearing, and the internal substitution of starch granules increased. The results of infrared spectroscopy, differential scanning calorimetry, X-ray diffractometry, and freeze-thaw stability analyses showed that as the degree of acetyl substitution inside the starch granules increased, the glass transition temperature of starch molecules decreased, the characteristic crystallization peaks weakened, the relative crystallinity decreased, and the freeze-thaw stability enhanced. The purpose of this study was to provide a reference for the further application of composite modified starch in the food industry and the subsequent study of substituent distribution.

Abstract:

The protein content in bone extract was abundant, and the nutrients in bone can be extracted through recycling to synthesize meat flavoring. In order to study the optimal Maillard process of thermal reaction chicken bone flavoring, and to obtain the chicken bone flavoring with rich meaty aroma and mellow taste, chicken bone extract was used as the raw material. The double enzyme of complex protease (ProtamexTM) and complex flavor protease (FlavourzymeTM) was used for hydrolysis, and the enzymatic hydrolysate was subjected to the Maillard heat-reaction. Through the preliminary experiments, four factors, such as the addition of hydrolyzed vegetable protein (HVP), the ratio of the addition of cysteine and its hydrochloride to the addition of reducing sugar (glucose, xylose), the thermal reaction time, and the thermal reaction temperature were taken for the single-factor experiment optimization. The sensory scores and the total weights of equivalent umami concentration were taken as the indexes to design the response surface experiments. The optimal thermal reaction conditions were HVP mass fraction of 6.5%, temperature of 106℃, time of 40min, mass ratio of cysteine and its hydrochloride to reducing sugars (glucose and xylose) of 1∶1, and the total weights of sensory score and equivalent umami concentration was 7.735. The volatile odor compounds were qualitatively and quantitatively detected by comprehensive two-dimensional gas chromatography-olfactometry-mass spectrometry. The volatile odor compounds with strong olfactory intensity were accurately and quantitatively analyzed, and the odor activity value (OAV) was calculated to identify the key aroma active compounds of the thermal reaction chicken bone flavoring under the optimized conditions. It was found that sulfur-containing compounds such as 2-methyl-3-furanethiol and furfuryl mercaptan and pyrazines such as 2,5-dimethyl-3-ethylpyrazine, 5-methyl-2-ethylpyrazine, and 2,3-diethyl-5-methylpyrazine were significantly increased in the thermal-reaction chicken bone flavoring compared to the chicken bone hydrolysate before the thermal reaction and the OAVs of these substances was greater than 1. The increase of these substances was the reason for the richness of meat aroma and aroma of thermal reaction chicken bone flavoring. It was hoped that this study could provide a theoretical basis for the industrialized production of thermal reaction chicken bone flavoring, and provide a reference idea for the utilization of animal husbandry by-products.

Abstract:

To compare the flavor difference between electric oven roasted grass carp with and without sunflower oil-brushing treatment, volatile flavor compounds were analyzed by solid phase microextraction combined with gas chromatography-mass spectrometry and aroma extract dilution analysis of gas chromatography-olfactometry. Fatty acid composition analysis showed the roasted fish with sunflower oil-brushing contained the highest content of linoleic acid, instead of the oleic acid. 11 important aroma-active compounds for differentiating the flavor of the two samples of roasted fish were found by orthogonal partial least square-discrimination analysis, all of which formed from the lipid oxidation and degradation reaction, except for acetoin formed from the Maillard reaction. Based on calculation of odor activity values (OAVs), 20 compounds [e.g. decanal, (E,E)-2,4-decadienal, hexanal, (E)-2-decenal] with OAVs ≥1 were considered to be the key aroma compounds in both roasted fish. However, there was a greater number of key aroma compounds (OAVs ≥1) in the roasted fish with oil-brushing, resulting in better flavor. Pearson correlation analysis showed that all the key aroma compounds primarily accounted for the aroma attributes in sensory analysis. For the lipid oxidization and degradation compounds from linoleic acid or oleic acid, (E)-2-decenal, γ-nonalactone and so on had fatty and sweet flavor odors were positively correlated with the scores in likeness and had increased concentrations in the roasted fish with oil-brushing. On the other hand, hexanal of grass odor was negatively correlated with the scores in likeness and had a lower concentration in the roasted fish with oil-brushing. Conclusively, through changing the fatty acid composition and lipid oxidation and degradation reaction, the oil-brushing treatment enhanced formation of the pleasant flavor compounds and inhibited formation of the off flavors, thereby improving the flavor of the roasted fish.

Abstract:

Italian Riesling wine grapes, a white varietal grown from Helan Mountains East Foothill region in Ningxia were taken as raw materials. Dry white wine was made by conventional winemaking methods and Saccharomyces cerevisiae was added. Prior to fermentation, SO₂ was added at varying mass concentrations of 0,20, 40, and 60mg/L. After fermentation, the wine's physicochemical indicators, microbiological stability, antioxidant qualities, volatile components and fragrance sensory attributes were all identified. The findings demonstrated that the completion of fermentation was unaffected by the SO₂ addition of 0~60mg/L prior to fermentation. These included adding 40 and 60mg/L of SO₂ had no discernible influence on the wine's color but significantly increased the wine's alcohol, titratable acid, total phenol, and chroma value (P<0.05), while decreasing its volatile acid content (P<0.05). The viable numbers of bacteria and yeast decreased with increasing SO₂ addition prior to fermentation. The wine exhibited excellent antioxidant qualities, with a low redox potential value, and high DPPH and ABTS⁺ free radical scavenging rates upon the SO₂ addition of 40 and 60mg/L. 58 different volatile odor components were detected in the wines of the four treatment groups. The wine without SO₂ additio n had the highest total contents of volatile odor components and also had high levels of alcohols, fatty acids, and esters, all of which frequently resulted in bad tastes. Wines without or with low SO₂ addition generated more off-flavor chemicals such as isobutyric acid, which were detrimental to the wine's odor, according to principal component analysis. The wine exhibited flowery and fruity aromas and had moderately high levels of phenethyl alcohol and isoamyl acetate when 40mg/L and 60mg/L of SO₂ were added. According to the results of aroma sensory characteristics, the wine had low sensory scores and strong off flavors when SO₂ was added in small amounts or none. Total aroma score, total taste scores, and overall acceptability were highest when 40mg/L SO₂ was added. The best quality Italian Riesling dry white wine was obtained when 40mg/L SO₂ was added prior to fermentation, as indicated by the three evaluation markers of microbial stability, antioxidant properties, and sensory evaluation scores of the wine. The minimum effective SO₂ addition amount was investigated by study the effects of varying SO₂ addition levels prior to fermentation on the quality of Italian Riesling dry white wine to provide a theoretical foundation and technical direction for the low-sulfur winemaking process.

Abstract:

In order to explore the effect of shaping methods on the sensory quality of Keemun black tea-Jinzhen, fresh shoots of “Wancha 4” tea variety were used as raw material. The same manufacturing stages of withering, rolling and fermentation were adopted. Then, Keemun black tea-Jinzhen samples were produced by four different shaping modes. Sensory evaluation, ultra-high performance liquid chromatography-quadrupole-exactive-mass spectrometry and headspace-solid phase microextraction-gas chromatography-mass spectrometry were used to analyze the differences of key taste and aroma compounds. Four shaping modes were twice mechanical shaping after a first-drying (mode 1), single mechanical shaping after a first-drying (mode 2), single mechanical shaping with an additional manual shaping after a first-drying (mode 3), and twice mechanical shaping without a first-drying (mode 4). The results of sensory evaluation showed that the shaping mode affected the appearance, taste and aroma of Keemun black tea-Jinzhen. The scores of sensory evaluation in high to low order for shaping mode were mode 3, mode 2, mode 4 and mode 1. Sample prepared by mode 4 had a straighter and better appearance than others. Mode 3 enhanced tea samples with a more trichome character. Manual shaping could improve the shape quality of tea. The moisture content of fermented leaves decreased after first-drying, which was not conducive to the shaping of tea strips, but was conducive to the aroma and taste quality. Keemun black tea-Jinzhen made by mode 3 obtained a stronger sweet floral fragrance and the taste was mellow and fresh, and the comprehensive score was the highest. The samples of mode 4 had stronger sweet floral aroma, but lower mellow and thick taste than those of mode 3. The sample of mode 2 had a lower appearance score, but had strong sweet floral and mellow taste. The analysis of taste components showed that mode 3 could better retained the content of catechin, thearubigins, free amino acids, soluble sugar and theaflavin-3,3′-digallate in the sample. Mode 2 retained a higher content of theaflavins, but the content of 3-O-galloylquinic acid was also higher, which increased the astringent taste of tea infusion. However, the higher quinic acid content in mode 1 and mode 4 samples was not conducive to the taste quality of the tea infusion. The results of volatile compounds analysis showed that geraniol, benzyl alcohol, phenylethanol, linalool, methyl salicylate, and 2-hexenal were important compounds affecting the aroma quality of Keemun black tea-Jinzhen with different shaping methods. The ratio of odor activity values of volatiles with a flowery and fruity character and volatiles with other odors (such as fat, green, etc.) was highest in mode 3 sample, with best aroma quality. The results of this study elucidated the effect of four shaping methods on the flavor quality of Keemun black tea-Jinzhen, which could provide theoretical basis and technical reference for the improvement of the process of Keemun black tea-Jinzhen.

Abstract:

To evaluate the performance of hydrophobic deep eutectic solvents (HDESs) and explore their capacity to extract flavonoids from rapeseed pollen, menthol and betaine were selected as hydrogen bond acceptors to prepare a series of HDESs. The structure and physicochemical properties of these HDESs were comprehensively characterized using infrared spectroscopy, rotational rheometry, and differential scanning calorimetry. The study found that the synthesized HDESs exhibited a blue shift in their characteristic infrared absorption peaks compared to the original components. Rheological analysis indicated that their viscosity remained largely unaffected by shear rate, with the menthol-lauric acid system demonstrating relatively low viscosity. Thermal property analysis revealed a significant decrease in the melting point of the synthesized HDESs. HDESs synthesized from menthol-lauric acid exhibited the best extraction efficiency for rapeseed pollen flavonoids. Through single-factor experiments and response surface methodology, the optimal extraction conditions were temperature 61℃, extraction time 85min, and solid-liquid ratio of 1∶25g/mL. Under these conditions, the extraction rate of flavonoids reached 7.209%, which was close to the predicted value, confirming the reliability and practical application potential of the optimized model. Through UPLC-Q-Orbitrap MS component analysis, 33 compounds were identified in the rapeseed pollen flavonoid extract. Among them, naringin chalcone showed the highest content at 295.3157ng/mg, followed by other relatively high-content compounds including kaempferol-3-O-glucoside (64.0583ng/mg), naringenin (56.8966ng/mg), quercetin-3-O-glucoside (18.6507ng/mg), benzoic acid (15.9760ng/mg), p-coumaric acid (10.7606ng/mg), and kaempferol (8.8864ng/mg). The results of this study indicated that the use of HDESs as a novel and efficient extraction approach demonstrated significant advantages for the extraction of rapeseed pollen flavonoids.

Abstract:

The dietary fiber in quinoa has excellent physicochemical properties and functional activities, and is considered a high-quality dietary fiber. This study focused on the quinoa bran soluble dietary fiber (QBSDF), which was modified by ultrasonic treatment with different powers (0,200, 400,600, 800, 1000W). The particle size, molecular weight, porosity, specific surface area, Zeta-potential, monosaccharide composition, infrared spectrum, microstructure, water-holding capacity, oil-holding capacity, glucose adsorption capacity, and viscosity were determined before and after modification to explore the effect of ultrasonic treatment on the physicochemical and structural properties of QBSDF. The results showed that the water-holding capacity, oil-holding capacity, and glucose adsorption capacity of QBSDF were significantly improved after ultrasonic modification (P<0.05). The analysis of rheological properties showed that the viscosity value and storage modulus of QBSDF increased significantly and the loss modulus decreased after ultrasonic modification. After ultrasonic modification, the molecular weight and average particle size of QBSDF were significantly reduced (P<0.05), and the surface structure became looser and showed honeycomb-like porous characteristics. The porosity and specific surface area of QBSDF increased significantly (P<0.05), and showed an upward trend with the increase of ultrasonic power. No changes occurred in the monosaccharides and chemical group types, but the composition ratio of monosaccharides and the peak intensity of chemical groups changed significantly, indicating that ultrasonic modification disrupted the chemical bonds related to —OH, C—H and other groups in dietary fiber. Therefore, ultrasonic treatment could significantly change the microstructure of QBSDF, increase its contact area and binding sites with substances, and improve its physicochemical properties, such as water-holding capacity, oil-holding capacity and glucose adsorption capacity. In addition, it was also found that the water-holding capacity and oil-holding capacity of QBSDF were higher than those of oat dietary fiber after ultrasound modification. Therefore, ultrasonic treatment could be used as an excellent method to modify the physicochemical properties of QBSDF, providing a theoretical basis for improving the utilization of quinoa dietary fiber and further exploring its functional value.

Abstract:

To achieve rapid and low-cost risk identification of veterinary drug residues in raw milk, this study proposed a machine learning and federated learning based method for rapidly detecting veterinary drug residues in raw milk, focusing on the routine detection indicators of raw milk and veterinary drug residue data in various regions of China provided by a large dairy enterprise from 2022 to 2024. This model served as an effective supplement to traditional chemical detection methods. To address the data imbalance characteristic where positive samples of veterinary drug residues were far fewer than negative samples, a combined strategy of SMOTE upsampling and random downsampling was adopted to optimize the training set. Through comparative experiments of various machine learning algorithms such as Random Forest, Decision Tree, Bayesian Network, eXtreme Gradient Boosting, and Support Vector Machine, eXtreme Gradient Boosting model had the optimal comprehensive performance in both binary-classification and multi-classification prediction of veterinary drug residues. Feature importance analysis using the eXtreme Gradient Boosting model showed that, “region” feature was the primary factor affecting the status of veterinary drug residues, revealing the overall impact of regional differences on the quality and safety of raw milk. By constructing a client-side learning model based on regional division, this study introduced a federated learning framework in eXtreme Gradient Boosting to achieve dual effects of data privacy protection and prediction accuracy comparable to that of centralized learning, and also improve model stability. This research could provide a fast, low-cost, data-driven risk identification paradigm and warning mechanism for the detection of veterinary drug residues in raw milk, serving as an effective supplement to chemical detection technologies and a new solution for food safety assurance.

Abstract:

For problems of food safety caused by microbial contamination and environmental safety due to drug-resistant strains, the development of emerging natural food additives with broad-spectrum and high-efficiency has been vital study trends in a modern food safety. Antimicrobial peptides(AMPs) are paid much attention for its advantage of broad-spectrum, good stability, unique antimicrobial mechanism of action and lower residue. With the further research, AMPs are expected to play a vital role in the application of food safety. Considering it, AMPs-related researches abroad were concluded in recent years. A review of the exploring and classification situation of AMPs,the development of bio-resistance and mechanism for bacteria, fungi, parasites, virus and tumor cells was provided. Meanwhile, the potential application fields of AMPs in food safety and scientific problems urgent to solve were analyzed. The resolution strategy also is provided for researchers as a reference in the field.

Abstract:

Non-targeted detection technique has been extensively applied in the food safety and quality in recent years. In general, a non-targeted detection combines analytical approaches,fingerprinting techniques and chemometrics to detect toxicants or foreign components in foods without knowing their chemical structures. The key purpose of non-targeted detection technique is to detect whether the sample is abnormal, without prior knowledge of what caused the abnormality. This manuscript introduces and reviews the current progress and the prospect non-targeted food detection techniques, including chromatographic, mass spectrometric, spectroscopic, cell-based non-targeted detection techniques. Foods and ingredients including milk, Chinese wolfberries, Chinese angelica,oregano, honey, etc., were introduced. The non-targeted detection technique can help the healthy development of food industry and play an important role in protecting public welfare and human wellbeing.

Abstract:

Cadmium -Cd- , a kind of heavy metal pollutant, can enter the food chain though soil, dust, and crops. As a staple crop in China, rice can easily enrich Cd from soil, which can represent a health risk to consumers. Cd concentration in soil shows obvious heterogeneity in China. Cd concentration in rice is over the limit in some regions of China, due to the geological environment or soil pollution. At present, remedying polluted soil, screening low-accumulation material, and processing polluted rice have been developed to deal with Cd contamination. This paper summarized the present situation of cadmium contamination in rice and soil, analyzed the main factor of Cd enrichment in rice, reviewed the control technology of Cd contamination, and provided suggestions on Cd contamination research.

Abstract:

Aquatic product freshness evaluation standards were reviewed in this paper, including the traditional freshness evaluation methods and some kinds of new methods in recent years. Meanwhile, shelf-life predicting models of aquatic products were also introduced, including primary shelf-life model, secondary shelf-life model and tertiary shelf-life model. Moreover, the main problems and the research tendency of freshness comprehensive evaluation and establishment of shelf-life model of aquatic products were discussed, aiming to provide the convenience for the future research of aquatic products.

Abstract:

The existence of granular crystals seriously impairs the quality of plastic fats, and consequently, it is important to investigate the formation mechanisms and inhibitions of granular crystals in order to optimize the processing parameters and improve the product properties. The migration and aggregation of high-melting triglycerides as well as β polymorphism evolution are the possible mechanisms for the formation of granular crystals when temperature fluctuates. The fats composition and processing parameters have influences on the granular crystals formation such as shearing rates, temperature, cooling rates. To prevent their generation, modifying lipids by blending and interesterification and the application of emulsifiers were adopted to reduce the content of the high-melting triglycerides and stabilize the β′ polymorphism. Emulsifiers are mainly associated with the triglycerides present in the fat through acyl-acyl interactions, thus the chemical structures' similarity between the acyl groups would likely promote the cocrystallization, while the dissimilarities in fats structure might delay the nucleation and possibly inhibit crystal growth. Emulsifiers have different effects on the crystallization of plastic fats which strongly depend on their concentration and the molecular structure. In addition, when the degree of undercooling is high enough, addictive effects of emulsifiers will be weakened.

Abstract:

Chemometrics is a novel and unique interdisciplinary technique that integrates mathematics, statistics, chemistry and computer science. Pattern recognition and multivariate calibration method, as the core aspects of the technique, have exhibited overwhelming advantages in massive data mining and processing, as well as resolution and analysis of analytic signals. In addition, it is able to solve complex problems which are difficult to be solved by conventional analytic methods, resulting in the method to be widely used in many research fields, including food analysis. This paper reviews the fundamental principles of chemometrics in regards of its advantages and disadvantages,applications, and recent progresses. Furthermore, the review has pointed out problems which need to be solved in current researches, and highlighted the prospective aspects of the technique.

Abstract:

In this paper,the principles and the application of the molecular imprinted polymer-based sensors, such as lectrochemical sensors,piezoelectric sensors, and optical sensors, were discussed. Meanwhile, the developing trend of the molecular imprinted polymer-based sensor was addressed.

Abstract:

The dairy industry is related to the people's livelihood and a lot of attentions have been paid to its current situation and future development tendency. This paper introduced the current situation of Chinese dairy industry and analyzed the main problems occurred during the developing process. Moreover, the development tendencies of the basic research, and quality control were also discussed.

Abstract:

The effects of culture conditions on the growth of Chlorella. sp were studied. The nutrient factors showed obvious effect on Chlorella.sp. The culture conditions based on BG-11 were optimized by orthogonal experiments: Na2CO 3 0.02g/L, the initial pH 6, the ratio of nitrogen to phosphorus 30, inoculum 5%, temperature 25℃, illumination 8800lx. Under the optimal culture conditions, the growth rate of Chlorella.sp was enhanced significantly.

Abstract:

The current situation, main existing problems and trends of post-harvest processing of leafy vegetables were clarified in this study, and the key technologies to be solved during leafy vegetables processing were also discussed. The solution methods of fresh-cut process, freeze-drying process, disinfection process, packaging technology and equipment automation were emphatically analyzed. All these would give a clear instruction for the processing of leafy vegetables.

Abstract:

Flavonoids are plant secondary metabolites, which are valuable natural products widely used in human health and nutrition due to its biochemical properties such as antiviral, antiobesity, and anticancer. The efficient production of pure flavonoid compounds through plant extraction or chemical production continues to be a major challenge for drug development. Hence, the microbial production of flavonoids has emerged as an interesting and commercially attractive approach. The emergence of systems metabolic engineering offers new perspectives on strain and process optimization. In this review, the strategies of systems metabolic engineering used to overcome these challenges are summarized, which will offer insights into overcoming the limitations and challenges of large-scale microbial production of these important pharmaceutical compounds.

Abstract:

The water and oil content in the instant noodle are two important factors for the quality of the noodle. In this paper, the effect of fried time and fried temperature on the quality of the instant noodle was investigated. The results showed that the longer fried time and higher fried temperature would lead the lower water and higher oil content in the noodle. In addition, the effect of fried time was correlative with that of fried temperature on the quality of the noodle.

Abstract:

Started from food processing, modern food science and food industry have provided the world enormous amount of food and always played a vital role in the development and evolution of human society. To date, food science has systematically studied the food storage, nutrition and sensory characteristics, while the interaction between food and body remains as a puzzle except a few pieces revealed by nutrition science and toxicology. Modern food industry has totally changed the way food is produced and consumed, and more importantly the way food interacts with human body. The ignorance of such changes in food science has made the debates in safety and health risks of industry food even more confusing. Three research topics are proposed for food-body interaction:elucidate the existing status of food compositions; interpret the body response to food; methods to utilise the complementary characteristics of different food compositions. From these new perspectives, some unique approaches and original discoveries of food science ought to be achieved, to provide answers to the major criticism upon food industry and transform food science to an intact science of food, an independent discipline of science.

Abstract:

China is the world's largest fruits processing country. The fruits processing industries have become an industry with comparatively superiority and international competitive capability. The importance to develop the processing industry of fruit was elaborated in this article as well as the overseas trend and current situation. The major restriction of the development were analysed, and the countermeasures for the development of this industry in China were also pointed out.

Abstract:

Olfaction visualization technology is a gas imaging technology and a new branch of artificial olfactory technology, which can solve common problems of traditional gas sensor. In order to detect the dominant spoilage bacteria (Clostridium, Brochothix thermosphacta and Pseudomonas) and evaluate freshness of pork, porphyrins and pH indicators were used as gas-sensing materials. The three spoilage bacteria were inoculated into three groups of pork samples and stored under three temperatures (16,4℃and 20℃). The images before and after the colorimetric sensor array interacted with pork's volatile flavors were collected, then image processing techniques was used to get digital signals which reflected the freshness of pork. The results showed that the olfaction visualization technology can be applied in rapid detection of dominant spoilage bacteria and evaluation freshness of pork.

Abstract:

Antifreeze proteins (AFPs) are the thermal hysteresis proteins that have the ability to modify the growth and inhibit the recrystallization of the ice. Antifreeze proteins aroused great interests of many researchers due to its special structure and functions. In this article, the recent advance in antifreeze protein was reviewed, and the types, properties, measurements, gene structures of antifreeze protein, and its applications in food industry were introduced. The application trials indicated that antifreeze protein could significantly improve the qualities of frozen foods, which suggested the potential food additives of antifreeze protein in future frozen food industry.

Abstract:

Mycotoxins, including aflatoxins (AFT), ochratoxin (OT), fumonisin (F), zearalenone (ZEN), deoxynivalenol (DON) and patulin (PAT) frequently contaminating agricultural products and feed were summarized. And then the influences of mycotoxin contaminants on human health and animal production were expatiated.

Abstract:

The research on aquatic products safety and the quality control technology was summarized and analyzed to reveal the present situation of aquatic products safety and quality control in China. Most of the research was focus on quality detection and control technology, others were about tracing system, early warning mechanism and risk assessment. At present, the enormous progress was made in technologies of quality detection and control. However, comparing with the advanced technology at abroad, the technology and management system in China still need to be improved. In the future, the aquatic food quality security technology should be promoted furtherly.

Abstract:

There has been growing concern about the frying oil quality due to its remarkable deterioration during the frying process. To investigate the performance of LF-NMR in the rapid determination of frying oil from various frying conditions, deep frying oil samples (n=107) including 96 soy bean oil samples and 11 shortening samples were collected from street vendors in 10 districts of Shanghai. Total polar compounds (TPC) and viscosity of the oil samples were determined. TPC values of 6 oil samples (56% of all the oil samples) were above the national standard for frying oil, indicating the quality problem of frying oil from the street vendors. The linear analysis showed a good linear relationship (R2=0892) between TPC and viscosity, while R2 was 0927 after the removal of shortening samples. After the analysis of the ratio of T21 areas (S21) in transverse relaxation (T2) spectra, the good correlations between S21 and TPC and viscosity were obtained and R2 was 0860 and 0840. After removing the shortening samples, R2 slightly increased to 0865 and 0854. The results demonstrate that LF-NMR has the potential to rapidly evaluate the quality of deep frying oil.

Abstract:

Aim at the problems about camera calibration for train wheel flange of dynamic testing system,the paper discusses the radial constraint-based camera calibration,chooses the camera calibration which contains distortion factors and developed the method of it by LabVIEW. This method makes use of the LabVIEW graphical development environment, embed core programs written in Matlab, has powerful data processing and nice interactive interface.