Abstract:Bile salt-stimulated lipase (BSSL) is a lipolytic enzyme. In the human body, BSSL is primarily secreted by the pancreas and is also found in the mammary glands during lactation, secreted with milk, which is one of the most abundant whey proteins. BSSL can hydrolyze a variety of substrates, including cholesteryl esters, fat-soluble vitamins, ceramide, etc., and plays a crucial role in the early digestion and absorption of milk lipids by newborns. Recent domestic and international studies have shown that in addition to promoting the digestion of milk fat in infants and young children, BSSL also plays significant roles in pathogen resistance, thrombosis regulation, inflammation modulation,atherosclerosis prevention and so on. The author summarizes the characteristics and functions of BSSL and explores its potential applications in infant formula.

Abstract:Plant polyphenols are one of the most abundant antioxidants in human diets, which are involved in the regulation of body activity by interacting with cell signaling cascade and regulating the activity of transcription factors. In addition, polyphenols have been shown to influence microRNA (miRNA) expression. Moreover, miRNA can participate in most cell differentiation and homeostasis, playing an important role in many pathological. In recent years, advances in network-biology have fuelled our understanding of the regulatory networks controlled by multiple miRNA. In this paper, we have discussed the characteristics and mode of co-expressing miRNA in signal networks along with the complex and ordered relationship between miRNA and transcription factors. We also summarized the mechanism of action of single and multiple miRNA mediating plant polyphenols in regulating cardiovascular diseases, diabetes, inflammation and cancer, which is thought to help reveal more comprehensively and accurately the actual situation of plant polyphenols and other food nutrition and health factors in regulating physiological functions.

Abstract:The successful use of antagonistic yeasts to control postharvest diseases of fruits and vegetables relies on commercializing yeast preparations. Antagonistic yeast, namely Debaryomyces hansenii (D. hansenii) was used as the research object to analyze the effect of its freeze-dried formulation on the postharvest soft rot of strawberry. Firstly, the impact of different protective agents at different concentrations on the survival rate of D. hansenii in freeze-drying process was examined by a single-factor test. Then, the response surface methodology was used to optimize the protectant regimen. Finally, the survival rate of freeze-dried D. hansenii preparation during storage and its control effect on postharvest soft rot of strawberry was verified under the optimal protectant regimen. The study exposed that the optimal protectant regimen for freeze-drying of D. hansenii preparation was 2.22% alginate, 17.83% skimmed milk powder, 0.06% L-ascorbic acid and 4.06% sodium L-glutamine. D. hansenii in he freeze-dried formulation obtained by the optimal protectant regimen maintained a high survival rate of 70%~80% during prolonged storage of 90 d, and this formulation effectively controlled the postharvest soft rot of strawberry caused by Rhizopus stolonifer (R. stolonifer).

Abstract:The mycolic acid layer in Corynebacterium glutamicum (C. glutamicum) plays important role in maintain cell permeability, however, its synthesis consumes substantial energy and substrate in the synthesis process. A mutant strain, Δpks13, was constructed by deleting the polyketide synthase gene pks13 in C. glutamicum ATCC13869. Compared to the wild type, the mutant strain Δpks13 cells were larger, more rounded, and with a loosely bound cell wall that tended to detach easily,while the L-glutamate yield increased 8-fold. Thin layer chromatography and liquid chromatography mass spectrometry analysis revealed that phospholipids were the primary cell wall lipids in Δpks13. Quantitative real-time PCR analysis revealed that, compared with wild-type strain,the transcript level of the glutamate efflux-related gene mscCG was upregulated, while the transcription levels of the α-ketoglutarate dehydrogenase-encoding gene odhA and the downstream arginine synthesis-related gene (argB, argC, argD, argF, argG, argH and argJ) were downregulated in Δpks13 cells. These changes in genes transcription levels explain the mechanism underlying the enhanced L-glutamate production in Δpks13.

Abstract:To elucidate the effects of clove essential oil or acid-etch halloysite nanotubes/clove oil (HNTs-4M-clove) on the properties of poly-butylene adipate-co-terephthalate/poly-propylene carbonate (PBAT/PPC) composite films, HNTs-4M-clove was obtained by mixing the acid-etched HNTs with clove essential oil. With the addition of clove essential oil or HNTs-4M-clove, the color of the films became yellow-green, and their transparency and gas barrier properties decreased, while the films exhibited good antibacterial activity against Escherichia coli, Staphylococcus aureus and Sivarella putrefaciens. The film containing HNTs-4M-clove demonstrated higher tensile strength and gas barrier properties compared to the film with clove essential oil. Additionally, HNTs promoted the dispersion of clove essential oil in the film and slowed down its release rate. Therefore, HNTs-4M-clove gave the PBAT/PPC film a good antibacterial activity with a retarded release rate of clove essential oil, which provided a reference for the development of biodegradable slowed-release active packaging film.

Abstract:As the quality of life improves, the consumption of alcoholic beverages is gradually increasing, leading to heightened market supervision and consumer focus on quality and ethanol testing. Consequently, there is a pressing need to develop novel ethanol detector that is simple to operate, provides rapid detection, and yields intuitive results. The author has designed and developed polydiacetylene (PDA) vesicles for detecting ethanol volume fraction in beverages. The ethanol in the alcoholic beverage disrupts the structure of the PDA vesicles and interacts with their functional groups, causing a gradual color change in the vesicles from blue in the absence of ethanol to red in its presence, thereby allowing for the detection of the ethanol volume fraction in the product. The results demonstrated a good linear relationship between the ethanol volume fraction (30%~90%) and the colorimetric response （CR) of the PDA vesicles. The relative standard deviation in real wine sample detection ranged from 1.45%~2.23%, with color changes being easily detectable to the naked eye. This method is both efficient and convenient, offering the advantages of visual accessibility and rapid response, thereby providing a novel approach for ethanol detection in alcoholic beverages.

Abstract:Lipopolysaccharide (LPS), a major component in the outer membrane of Escherichia coli, possesses immunogenic properties and holds significant potential for medical applications. The LPS molecule typically consists of three parts: lipid A, a core oligosaccharide and O-antigen. Individual deletion of rapZ、fabF or ptsO gene in E. coli MG1655 increased LPS production by 25.0%, 27.6% or 14.6%, respectively. MWD001 was constructed by simultaneously deleting all the three genes in MG1655, and a 30.6% increase in LPS production was achieved, with LPS yield per gram of dry cell weight (DCW) rising from 7.73 mg in the parental strain MG1655 to 10.10 mg in MWD001. Finally, an arabinose-induced promoter P_BAD was inserted upstream of the key gene cluster lpxD-fabZ-lpxA-lpxB in MWD001 genome, further increasing LPS production to 12.24 mg. These findings demonstrate that deletion of rapZ、fabF and ptsO genes, combined with overexpressing of the gene cluster lpxD-fabZ-lpxA-lpxB, significantly improves LPS production in E. coli.

Abstract:Human milk oligosaccharides play a crucial role in promoting infant health, safeguarding newborns against infection and inflammation, and serving as the optimal natural source of nutrition for infants. Among these oligosaccharides, 2’-fucosylactose (2’-FL) stands out as a prominent constituent with the highest content. Due to its significant application potential in medicine and infant formula production, 2’-FL has rapidly emerged as a focal point of research interest. Natural product extraction and chemical synthesis are the main methods of traditional synthesis of 2’-FL, but these two methods are difficult to extract 2’-FL in large quantities, and there is serious pollution. Consequently, there is growing attention towards employing whole cell fermentation as an environmentally friendly approach that offers mild reaction conditions for efficient 2’-FL production. By heterologously expressing polyphosphate-dependent mannose kinase AsPPGMK and α-1,2-fucosyltransferase in Escherichia coli while co-expressing key enzymes involved in the synthesis pathway and knocking out the gene encoding UDP-glucose lipid carrier transferase wcaJ to prevent intermediate metabolite degradation, we successfully enhanced the yield of 2’-FL. Ultimately, through optimization of catalytic transformation conditions, the addition of 200 mmol/L substrate to the 100 mL system further enhanced the yield of 2’-FL to 79 g/L in a yield of 81% in 8 h.

Abstract:Dog chews is a kind of snack for pet with oral cleaning effects. This research studied the effect of adding tea or tea polyphenols in dog chews on oral deodorization and dental care using in vitro simulation and animal experiments. The effect of Oolong tea, black tea and Pu'er tea on removing hydrogen sulfide was determined in vitro, which showed that Oolong tea had the best deodorization efficiency. The dog chews with the Oolong tea mass fraction of 0.5%~2.0% and tea polyphenols of 0.25%~0.75% were tested on dogs for 3 weeks. The results showed that the elimination rate of hydrogen sulfide in the oral of experimental dogs increased with the increase of the added effective substances. As the amount of Oolong tea was 2.0% or the mass fraction of tea polyphenols was 0.75%, the elimination rate of hydrogen sulfide in the oral cavity was close to 100%, and the tartar reduction rate was significantly increased to more than 60%. Fits of the total phenolics mass fraction and the effects showed that the elimination rate of hydrogen sulfide and the reduction rate of tartar both increased with the increasing of total phenolics mass fraction. Notably, there was a strong correlation between the total phenolics mass fraction and the elimination rate of hydrogen sulfide and the reduction rate of tartar. This study demonstrated the positive effect of polyphenols dog chews on dog oral health.

Abstract:In order to investigate the differences in flavor quality between Daiginjo and Junmai sake, basic physical and chemical indicators, sensory evaluation and gas chromatography-mass spectrometry (GC-MS) were used to analyze the sensory qualities and aroma compounds. The key flavor compounds and aroma differences were determined by odor activity value (OAV) and variable importance in projection (VIP). The results indicated significant differences in the physical and chemical indicators, sensory quality and key flavor substances between Daiginjo and Junmai sake. Daiginjo sake had a rather high level of alcohol and nitrogen amino acid but relatively low content of total sugar and total acid. It also performed a mellow taste, full-bodied ginjo-ka, and sweet aroma, while Junmai sake displayed a monotonous taste, cereal and herbaceous aroma. The two varieties of sake contained 62 volatile flavor components. Daiginjo showed the highest percentage of esters, while Junmai had the highest proportion of alcohol, both of which exceeded 50%. The orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed a significant cluster separation between the two varieties of sake. According to OAV and VIP analysis, various aroma compounds were detected, including caproic acid, ethyl hexanoate, isoamyl acetate, phenethyl acetate, ethyl butyrate, isoamyl alcohol, ethyl caprylate, ethyl heptanoate, and 1-heptanol. The particular key aroma compounds of Daiginjo sake were ethyl caprylate, ethyl heptanoate and phenylethyl acetate. The identification of different aroma compounds in this study can theoretically support further investigation for the characteristics variations between Daiginjo and Junmai sake as well as domestic sake production and processing.

Abstract:To identify and test the quality of commercially available goat milk powder (pure and formulated) from different regions (Shaanxi, domestic non-Shaanxi regions and foreign regions), electronic nose and electronic tongue technology were used to analyze and discriminate 35 such samples from these regions with different formulations. The analysis results showed that electronic nose was able to achieve effective differentiation between pure and formulated goat milk powder, as well as between pure goat milk powder from domestic and foreign regions. Additionally, the electronic tongue technology can achieve effective differentiation between pure and formulated goat milk powder, and between pure goat milk powder from Shaanxi and domestic non-Shaanxi regions. Therefore, electronic nose and electronic tongue can be used to analyze goat milk powder from different origins and different formulations, to identify its origin and evaluate the quality. It is believed that this study provides a theoretical basis for a rapid and accurate evaluation of the quality of goat milk powder and its standardized production.

Abstract:Fermentation is the most critical step in black tea processing. To address the limitations of traditional methods that rely on manual experience, a rapid and non-destructive detection approach for assessing black tea fermentation quality was developed using a data fusion strategy that combines computer vision and electronic nose technologies. The fermentation degree of black tea was classified into different levels based on the mass fraction of tea polyphenols, and a correlation was established with image and odor information. Qualitative discriminant models for black tea fermentation were developed using different data fusion strategies in combination with random forests (RF), K-nearest neighbors (KNN), and support vector machine (SVM) models, and these were compared with the single sensor models. The results showed that data fusion strategies integrated information from different sensor, providing more comprehensive data, and their discrimination result was better than that of a single sensor. The feature-level data fusion strategies extracted the eigenvalues of different sensors information, simplifying the model data and achieving the superior performance compared to data-level fusion strategies. Among them, the SVM model based on feature-level data fusion achieved the best classification performance, with a classification accuracy rate of 100% in the training set and 95.56% in the prediction set, realizing the rapid and accurate identification of different fermentation degrees of black tea.

Abstract:The aromatic amino acid synthesis pathway in Saccharomyces cerevisiae is very important for the production of many aromatic fine chemicals. Mandelic acid and 4-hydroxymandelic acid like intermediates are vital fine chemicals, which are widely used in foods, medicines, beverages and cosmetics. In order to explore the gene regulation mechanism in aromatic amino acid synthesis pathway in S. cerevisiae to explore the synthesis pathway of aromatic intermediates, this study summarized the whole aromatic amino acid synthesis pathway and its branches from glucose in S. cerevisiae, it also lists 14 genes and intracellular functions involved in the whole process. The phenotypes of 12 single gene deletion strains were detected in sodium dodecyl sulfate (SDS), while 5 deletion strains, including aro2/aro2, aro1/aro1, aro7/aro7, trp1/trp1 and trp5/trp5, showed obvious sensitive phenotypes to 0.03% SDS. Moreover, the intracellular reactive oxygen species (ROS) levels of five sensitive strains were measured. Results showed that the intracellular ROS levels of aro1/aro1, aro7/aro7 and trp1/trp1 strains were significantly increased, compared with the wild-type strain. The whole aromatic amino acid synthesis pathway and its branches in S. cerevisiae were strictly regulated by genes. A systematic study of these genes functions will provide a theoretical basis for a high-yield biosynthesis of aromatic fine chemicals and genomics of S. cerevisiae.

Abstract:In order to improve the thermal process of Exopalaemon carinicauda (E. carinicauda) and avoid the degradation of product quality and energy waste caused by inappropriate thermal process, the author investigated the influence of boiling treatment at 85, 90, 95 ℃ and steam cooking on the quality of E. carinicauda. On the basis of the determination of heat transfer curve, a comprehensive evaluation was conducted using the following indicators: total bacterial count, relative enzyme activity of polyphenol oxidase (PPO), cooking loss rate, water-holding capacity, crude protein mass fraction, texture characteristic and color. The results showed that steam cooking for 1 min can effectively inactivate PPO, reduce the total bacterial count to the edible safety standard. Compared with the other groups under the same time, this group showed higher protein mass fraction, greater elasticity, cohesiveness and chewiness, as well as a more intense red color. However, it exhibited lower water-holding capacity, resulting in greater moisture loss. If the shrimp is further processed into dried shrimp products, the lower moisture mass fraction prior to drying would facilitate the drying process. In conclusion, steam cooking for 1 min is an optimal thermal process for E. carinicauda.

Abstract:As a physical cold sterilization technology, electron beam (E-beam) irradiation offers unsubstitutable advantages in microbial control for prepared foods such as beef patties. However, high dose irradiation can easily lead to the deterioration in the sensory quality such as flavor and color of fat-containing foods. In order to reduce the undesirable effect of E-beam irradiation on the sensory quality of beef patties, the author investigated the combined effects of E-beam irradiation and food additives on the microbial level and sensory qualities such as color, flavor, and taste of beef patties. A method for low dose E-beam irradiation combined with food additives for preservation and sterilization was established. The results showed that the treatment with 1.6 kGy of E-beam irradiation combined with clove oil effectively reduce the microbial levels in irradiated beef patties. Furthermore, the treatment of 1.6 kGy irradiation combined with a color fixative significantly inhibited the color deterioration caused by irradiation. Notably, E-beam irradiation at dose of 1.6 kGy had no significant effect on the flavor sensory score of beef patties. However, the W1W sensor of the electronic nose exhibited substantial difference in response values among different treatment groups, indicating that sulfides are the main components responsible for flavor differences. The sensor with the highest response value on the electronic tongue for beef patties was umami, which decreased after 1.6 kGy E-beam irradiation. Beef patties treated with E-beam irradiation combined with clove oil and color fixatives exhibited no significant differences in total microbial counts after 7 days of refrigeration at 4 ℃ compared to the samples subjected to E-beam irradiation at day 0. Sensory evaluations revealed no significant changes in flavor scores, while color ratings were significantly higher than those from single E-beam treatments. Additionally, the patties retained a desirable red hue and exhibited higher umami response values after cooking. This study provide a reference for quality control in irradiated beef patties.

Abstract:To fully understand the differences in indicators among various quality levels of jiang-flavour Baijiu, 4 grades of jiang-flavour Baijiu were studied. Using gas chromatography technology combined with sensory evaluation, 64 flavor compounds in sauce-flavored liquor were quantitatively analyzed. By integrating odor activity value (OAV) and chemical metrology, key differentiating compounds were identified. The results showed that the Baijiu samples were ranked by total flavor compound content in the order of B>A>C>D. The A-grade and B-grade Baijiu samples generally contained more flavor compounds than the C-grade and D-grade Baijiu samples. However, the D-grade Baijiu sample contained a higher total amount of aromatic compounds compared to the other three grades. Key differentiating compounds, such as ethyl valerate, valeric acid, ethyl butyrate, butyric acid, and phenylacetaldehyde, were identified through OAV calculations. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to build models for 4 different grades of jiang-flavour Baijiu, achieving a classification accuracy of 97.4% and effectively distinguishing the 4 grades of jiang-flavour Baijiu. Additionally, 27 key differentiating compounds were selected using variable importance in projection (VIP) analysis. A cluster heatmap was generated according to these 27 compounds, and OAV analysis further validated the effectiveness of the VIP selection.

Abstract:In order to reduce the quality deterioration of perch fillets during freezing, the effects of air freezing (groups AF-7, AF-20, AF-40, AF-60), immersion freezing (groups IF-20, IF-40), and liquid nitrogen freezing on the quality of perch fillets were discussed. Quality-related indicators including ice crystal structure, microstructure, texture, thawing loss, moisture distribution, total volatile base nitrogen (TVB-N), K-value, and others were analyzed for samples subjected to different freezing methods. The results showed that as the freezing rate increased, the hardness and elasticity showed an upward trend, while the ice crystal equivalent diameter, TVB-N, and K-value tended to decrease. Although quality deterioration was observed across different treatment groups, the liquid nitrogen freezing group and the IF-40 group effectively preserved the quality characteristics of perch fillets, with the liquid nitrogen freezing group most closely resembling the fresh sample group. Under the same freezing temperature, immersion freezing achieved a faster freezing rate than air freezing, effectively inhibiting ice crystal growth and reducing changes in texture, TVB-N, and K-value. In comparison, liquid nitrogen freezing proved most effective in alleviating quality deterioration of perch fillets during freezing.

Abstract:To rapidly identify safe and effective natural inhibitor of pancreatic lipase (PL), the author utilized molecular docking, spectrophotometry, the orthogonal t-value method, and fluorescence quenching experiments to investigate the interaction between PL and the inhibitors by analyzing PL's conformation, activity, kinetics, and thermodynamics. Results showed that of the 31 screened compounds, 28 exhibited more than 50% inhibition of PL activity, with 11 compounds demonstrating half-maximal inhibitory concentrations (IC₅₀) below 100 μg/mL. Notably, (-)-epigallocatechin gallate (EGCG) and coenzyme Q9 (CoQ9) displayed IC₅₀ values lower than that of orlistat. The author designed compound formula, comprising luteolin, myricetin, quercetin, isoquercetin, and naringin, achieved an inhibition rate of (98.79±2.46)% at a concentration of 0.5 mg/mL and a volume ratio of 15∶6∶17∶5, surpassing the efficacy of individual components. The five substances in the formulation spontaneously bind to PL, leading to the quenching of its intrinsic fluorescence through static quenching. Non-covalent interactions, including hydrophobic interactions, hydrogen bonds, ionic bonds, and π-π stacking, are observed between these substances and PL. This study provides multiple promising candidates for PL inhibitors.