Abstract:As an emerging non-thermal food processing technology, cold plasma (CP) technology has been widely applied in food preservation and improvement of food quality due to its high efficiency, greenness and lack of chemical residues. CP technology can inhibit the growth of spoilage microorganisms, and degrade allergens and toxins in food. At the same time, the technology may also have both positive and negative impacts on the nutritional composition of food. Studying the application conditions of CP technology and the synergistic effect between CP and food processing conditions can help promote the rational application in the food industry. Based on an introduction to the generation methods of CP, the applications of CP technology in the field of food safety and its effects on nutritional components are elaborated, providing a reference for the precise application of CP technology in the food industry.

Abstract:Sour soup is a distinctive food in Guizhou Province, which is fermented mainly with tomatoes, chili peppers or rice as the primary raw materials. Sour soup possesses the functions of flavor adjustment, aroma enhancement and food texture improvement, and is frequently utilized as a condiment or the base material for hot pot. The production of sour soup is dominated by natural fermentation, where the microorganisms mainly originate from those carried on the surface of the raw materials. During the fermentation process, variations in oxygen, pH and nutrients will influence the dominant microbial flora. The growth and metabolic activities of the dominant microbial flora transform or synthesize the flavor substances of sour soup. The author has reviewed the current relevant research on the microorganisms in sour soup and their connection with flavor substances, elucidating the changes of microorganisms during the sour soup fermentation process and their impact on flavor, with the aim of providing references for the research and application of microorganisms and flavors in sour soup.

Abstract:As a valuable by-product after oil extraction, oilseed-based cake meal has a huge annual output in China and is a high-quality source of plant protein. However, conventional methods for extracting protein from cake meal often have problems such as long extraction time, high consumption of organic solvents, and low extraction rates, which greatly limit the application of such protein in the food industry. Therefore, developing efficient, rapid, and safe protein extraction methods and fully exploiting the protein resources in cake meal are the main tasks at present. The author reviews the extraction methods, functional properties, and food applications of the protein in oilseed-based cake meal, aiming to provide theoretical support and practical guidance for the high-value development and utilization of by-products in the grain and oil processing industry.

Abstract:[Objective] This study aims to construct hydrogel scaffolds with both excellent mechanical properties and cell suitability for preparing high-quality structured cultured meat. [Method] Three biogenic protein gel materials (gelatin, collagen, and fibrinogen) and three polysaccharide gel materials (sodium alginate, chitosan, and gellan gum) were selected to construct single network (SN) hydrogels and double network (DN) hydrogels by cross-linking a single material or two materials of different categories. The physical properties (hardness, elasticity, and degradation rate) of the prepared hydrogels were characterized. Moreover, the biological properties of the prepared hydrogels were characterized in terms of cell adhesion, proliferation, and differentiation rates on the hydrogel surface. The scaffold function of the prepared hydrogels was then verified by three-dimensional culture of muscle stem cells. [Result] DN hydrogels demonstrated high hardness, high elasticity, and slow biodegradation, with the physical properties superior to those of SN hydrogels. In DN hydrogels, the addition of sodium alginate impeded the adhesion, proliferation, and differentiation of cells, and thus the biocompatibility of DN hydrogels with sodium alginate as the first network material was the lowest. DN hydrogels with chitosan as the first network material had high biocompatibility. In particular, the DN hydrogels with collagen and chitosan promoted the three-dimensional proliferation and differentiation of muscle stem cells, in which the cells showed the highest spreading and proliferation rates, as well as the highest expression of myosin heavy chain. [Conclusion] The material suitable for three-dimensional culture of porcine muscle stem cells are selected for the preparation of DN hydrogels based on high cell compatibility. The DN hydrogels with collagen and chitosan can be used as a scaffold material for preparing high-quality structured cultured meat.

Abstract:[Objective] The study aims to investigate the alleviating effect of Lactobacillus plantarum (L. plantarum) CCFM8661 on constipation in mice. [Method] One hundred mice were allocated into five groups (control, model, and low-, medium-, and high-dose groups) and administrated with corresponding agents by gavage for 14 d. On the last day, the mouse model of constipation was established by gavage of loperamide hydrochloride. The degree of constipation alleviation by L. plantarum CCFM8661 was evaluated through the determination of the defecation situation, short-chain fatty acids (SCFAs), and intestinal flora of mice. [Result] L. plantarum CCFM8661 effectively alleviated the symptoms of constipation in a dose-dependent manner. [Conclusion] L. plantarum CCFM8661 may relieve constipation via multi-level regulation. On the one hand, it improves the intestinal function by regulating the levels of neurotransmitters and the expression of inflammatory factors; on the other hand, it inhibits the growth of pathogenic bacteria by increasing the molar mass concentrations of SCFAs (acetic acid, propionic acid, and butyric acid) and decreasing the intestinal pH while reshaping the intestinal flora balance. The analysis of KEGG pathways further reveals that these effects may be closely related to biological processes such as glucose metabolism, amino acid metabolism, as well as the synthesis, transport, and cycling of a variety of substances, which synergistically exert their multi-pathway regulatory effects to alleviate constipation. This study further demonstrates the potential of L. plantarum CCFM8661 in alleviating constipation and provides a reference for the application of this strain.

Abstract:[Objective] This study aims to understand the succession and metabolic characteristics of Lentibacillus daqui (L.daqui) in fermented grains during stacking fermentation.[Method] The bacterial community structure in fermented grains during stacking fermentation was analyzed by amplicon sequencing. The effects of raw materials, oxygen content, and culture temperature on the biomass, enzyme production, and aroma production of L. daqui ZS110521T were evaluated by the pure culture solid-state fermentation method. [Result] L. daqui ZS110521T was the dominant genus (relative abundance>10%) in the bacterial community in the early stage (0~60 h) of stacking fermentation. The results of pure culture showed that L. daqui ZS110521T had higher biomass and enzyme activity in the wheat medium, while more pyrazines were accumulated in the sorghum-wheat (mass ratio of 1? ∶ 1) mixed medium. Under aerobic conditions, the enzyme activity and pyrazine content of the strain was higher. The gene copies reached the highest when the strain was cultured at 37~45 ℃ for 36 h, and the enzyme activity was the strongest when the strain was cultured at 45~55 ℃. When the strain was cultured at 65 ℃ for 120 h, 2,5-dimethylpyrazine, 2,4-di-tert-butylphenol, benzaldehyde, nonanal, and acetoin were mainly accumulated. [Conclusion] This study provided a scientific basis for clarifying the enzyme production and aroma production functions of L. daqui ZS110521T in stacking fermentation.

Abstract:[Objective] This study aims to elucidate the interactions between Lactobacillus crispatus CCFM1298 and Lactobacillus gasseri CCFM1201 in a co-culture system, thereby providing a theoretical basis for the development of multi-strain probiotic preparations. [Method] By the design of selective counting medium, the viable cell counts of the two probiotic strains in the co-culture system were monitored, and the interactions of the two strains were elucidated based on the results. [Result] Adjusting the osmotic pressure of the medium to 1 600 mOsmol/kg enabled effective isolation and accurate counting of the two probiotic strains in the co-culture system. Regardless of the initial inoculation ratio, after co-culture in the MRS broth, Lactobacillus gasseri CCFM1201 always emerged as the dominant strain, which was attributed to its shorter generation time than that of Lactobacillus crispatus CCFM1298 (P<0.01). The experiment aiming to balance the generation time showed that fructooligosaccharides effectively alleviated the competition for nutrient niches between the two strains, thereby preventing imbalanced growth. [Conclusion] The study preliminarily reveals the interaction between the two probiotic strains and the method to effectively mitigate the imbalanced growth. The findings provide new strategies for the rational design and functional optimization of subsequent multi-strain probiotic preparations.

Abstract:[Objective] The aim of this study is to explore whether glycosylation affects the binding of the carbohydrate-binding module (CBM) to cellulose and lignin or not.[Method] Four CBM glycoforms CBM000, CBM010, CBM002, and CBM122 were prepared by chemical synthesis at three glycosylation sites Thr1, Ser3, and Ser14. Their binding abilities to cellulose and lignin at 4, 35, 45, 60, and 70 ℃ were compared. [Result] Glycosylation had different effects on the binding of CBM to cellulose and lignin at different temperatures. CBM000, CBM010, CBM002 and CBM122 have better selectivity for binding to cellulose at 45 ℃, 4 ℃/45 ℃, 60 ℃, and 45 ℃, respectively. [Conclusion] Rising the temperature can improve the substrate-binding selectivity of CBM. Glycosylation enhances the substrate-binding ability of CBM at high temperatures.

Abstract:[Objective] Alkyl gallates can interact with phospholipids to form phospholipid complexes of alkyl gallates. This study aims to investigate the sustained release of gallic acid by such phospholipid complexes. [Method] A thin-film dispersion method was employed to prepare phospholipid complexes of alkyl gallates with different acyl chain lengths. The gastrointestinal digestion and absorption characteristics of these phospholipid complexes were studied based on a rat model of everted gut sac and high-performance liquid chromatography-ultraviolet (HPLC-UV) detection. [Result] Alkyl gallates were gradually released from their phospholipid complexes (Step 1) and hydrolyzed by intestinal lipase to produce free gallic acid (Step 2). In addition, both gallic acid and short-chain alkyl gallates (methyl gallate, ethyl gallate, propyl gallate, and butyl gallate) can cross the small intestinal mucosa, and the short-chain alkyl gallates that cross the membrane were further hydrolyzed to produce free gallic acid (Step 2). As the acyl chain length increased, the hydrolysis rate constant showed a trend of first increasing (methyl gallate: 1.081×10^-5 min^-1; ethyl gallate: 1.768×10^-5 min^-1; propyl gallate: 2.193×10^-5 min^-1; butyl gallate: 2.520×10^-5 min^-1; octyl gallate: 2.901 × 10^-5 min^-1) and then decreasing (octyl gallate: 2.901×10^-5 min^-1; dodecyl gallate: 2.048×10^-5 min^-1; tetradecyl gallate: 1.136×10^-5 min^-1; hexadecyl gallate: 0.689×10^-5 min^-1; stearyl gallate: 0.409×10^-5 min^-1). [Conclusion] Therefore, by adjusting the acyl chain length of alkyl gallates, a two-step controllable sustained release of gallic acid by phospholipid complexes of alkyl gallates can be effectively achieved.

Abstract:[Objective] This study aims to investigate the effects of adding sucrose to plant-based beverages containing milk on the structure and properties of milk proteins, as well as the binding of proteins to small molecules in plants. [Method]Molecular dynamics simulation was conducted for the binding patterns between β-lactoglobulin and anthocyanins and the protein structure changes under different sucrose concentrations (0, 0.25, 0.50, 0.75, and 1.00 mol/L). [Result] Anthocyanins mainly bound to the hydrophobic cavity of β-lactoglobulin. With the optimal binding conformation as the starting structure, GROMACS was used for the molecular dynamics simulation at 150 ns. The results showed that the structure of β-lactoglobulin in the sucrose solution was more stable, with milder fluctuations of amino acid residues. The increase in the number of α helixes significantly increased the hydrogen bonds between proteins, which was accompanied by the decrease in the number of β folds. The binding free energy between β-lactoglobulin and anthocyanins did not change much in 0.25 and 0.50 mol/L sucrose environments, but significantly increased in the 0.75 mol/L sucrose solution and significantly decreased in the 1.00 mol/L sucrose solution compared with the control group. The differences in binding free energy were mainly caused by changes in van der Waals forces and hydrogen bonding. [Conclusion] The changes in sucrose concentration would cause the differences of the binding position and binding mechanisms of anthocyanins on the β-lactoglobulin surface.

Abstract:[Objective] The application of γ-aminobutyric acid (GABA) in food has become increasingly popular in recent years. The effects of high-loading GABA on the rheological and textural properties and the quality of tapioca pearls were studied. [Method]Rheometry, low-field nuclear magnetic resonance, field emission scanning electron microscopy were employed to study the effects of GABA on the rheological properties, moisture distribution, and microstructure of tapioca pearls, respectively. A rapid viscosity analyzer was used to examine the gelatinization properties of tapioca pearls with the addition of GABA at different mass fractions. The quality of cooked tapioca pearls was measured by a texture analyzer combined with sensory evaluation. [Result]GABA decreased the elastic modulus (G') and viscous modulus (G") of tapioca pearls. The proportion of peak area of free water, bound water, and adsorbed water in the tapioca pearls added with mass fraction 14% GABA (calculated by the mass of all powder) were (33.38±0.23)%, (6.46±0.02)%, and (60.16±0.25)%, respectively. Compared with the mixed powder without GABA, the mixed powder with the addition of GABA (mass fraction is 14%) showed the gelatinization peak viscosity and final viscosity decreases of 32.87% and 36.19%, respectively. The tapioca pearls with 10% GABA got the highest sensory score and had the best taste. [Conclusion] The addition of GABA could weaken the network structure to reduce the water holding properties, viscoelasticity, and hardness, thus affecting the quality of tapioca pearls.

Abstract:[Objective] This study aims to develop an effective sterilization method for fresh-cut coriander. [Method]Acetic acid and sodium chloride were used as sanitizers. Single-factor experiments were first conducted, followed by the orthogonal experiment based on the results of single-factor experiments. After storage at 4 ℃ for 2 days, the aerobic plate count, chlorophyll mass fraction, hardness, color, flavor substances, and sensory quality were determined. [Result]The treatment with 1 g/L acetic acid and 3 g/L sodium chloride for 5 min achieved the best sterilization effect. Under refrigerated storage (at 4 ℃), coriander treated with this compound sanitizer maintained a shelf life of 7 days, with a sensory score of 7.72 and a total bacterial count of 5.86. This treatment extended the shelf life by 2 days compared with the treatment using 150 mg/L chlorine dioxide or 200 mg/L sodium hypochlorite. [Conclusion]The compound sanitizer composed of 1 g/L acetic acid and 3 g/L sodium chloride is an effective and safe alternative for sterilizing fresh-cut coriander. This method not only improves the quality and prolongs the shelf life of coriander but also reduces water consumption and production costs, providing a theoretical foundation for commercial application.

Abstract:[Objective] The aim of the study is to explore a digital blending method based on spectral information, thereby improving the efficiency of black tea blending and ensuring the stability of the finished tea quality. [Method]'Ying Hong No. 9' black tea was taken as the research subject. Partial least squares regression was employed to compare the effects of different spectral preprocessing methods and feature wavelength selection algorithms on prediction model performance. Quantitative prediction models for the mass fraction of tea polyphenols, the mass fraction of free amino acids, and the mass of water-soluble extractives, as well as the taste scores, were established accordingly. Furthermore, a multi-objective optimization algorithm was employed to transform the tea blending process into a mathematical model that balanced both quality and cost considerations. The NSGA-Ⅱ (non-dominated sorting genetic algorithm Ⅱ) was utilized for global optimization of blending recipes, with manual sensory evaluation conducted to validate the results. [Result] The prediction models for the mass fraction of tea polyphenols, the mass fraction of free amino acids, and the mass of water-soluble extractives, as well as the taste scores, achieved determination coefficients of 0.890, 0.810, 0.802, and 0.863, respectively, in their predictive sets, all outperforming the full-spectrum prediction results. The optimized blending recipe derived from digital blending strategy optimization not only met sensory evaluation standards but also reduced blending costs by 28.5%. [Conclusion]The combination of near-infrared spectroscopy and the multi-objective optimization algorithm enables digitization of the whole process from sensory evaluation to tea blending. Near-infrared spectroscopy effectively captures chemical information related to key flavor compounds and taste quality of black tea. The multi-objective optimization algorithm, together with near-infrared spectroscopy, enables rapid development of optimal recipes, serving as an effective auxiliary method in the tea blending process. The findings hold significant theoretical and practical value in advancing intelligent upgrading in the tea industry.

Abstract:[Objective] This study aims to compare the flavor substances in Maotai-flavor Daqu samples with different sensory characteristics, explore their correlations with free amino acids and bacterial community composition, and preliminarily analyze the reasons for the flavor formation of Maotai-flavor Daqu. [Method]The flavor substances, free amino acids, and bacterial community composition in Maotai-flavor Daqu samples with different sensory characteristics were analyzed by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry and quantitative analysis of multi-components by a single marker (UPLC-HRMS-QAMS), and high-throughput sequencing, respectively. The effects of different free amino acids and bacterial community composition on the flavor of Maotai-flavor Daqu were analyzed. [Result]A total of 75 flavor substances and 14 free amino acids were identified in Maotai-flavor Daqu, of which the flavor substances were mainly pyrazines, alcohols, esters, acids, and aldehydes. Yellow and black Daqu had similar flavor substances, with greater differences from white Daqu. The mass fraction of free amino acids ranged from 3.76 to 9.22 mg/g, with bitter amino acids being dominant, and the mass fraction of free amino acids in Qupi was higher than that in Quxin. The correlation analysis showed that multiple free amino acids such as lysine, tyrosine, tryptophan, and citrulline were closely related to the metabolism and synthesis of pyrazines, esters, acids, and aldehydes. Kroppenstedtia was the characteristic bacterial genus of yellow Qupi (YP) samples, and it was closely related to the metabolism and synthesis of esters such as ethyl lactate and ethyl phenylacetate. Pseudomonas was the characteristic bacterial genus of yellow Quxin (YX), black Qupi (BP), and black Quxin (BX) samples, and it had significantly positive correlations with aldehydes such as 5-methyl-2-phenyl-2-hexenal, benzaldehyde, and 2-phenyl-2-butenal. The main bacterial genera of white Qupi (WP) and white Quxin (WX) samples were Blastococcus and Scopulibacillus, respectively, which had significantly negative correlations with ethyl lactate, 2-phenyl-2-butenal, and 5-methyl-2-phenyl-2-hexenal. [Conclusion]The flavor substances vary in Maotai-flavor Daqu samples with different sensory characteristics, and the investigation in this field could further reveal the formation mechanism of Maotai-flavor Daqu.

Abstract:[Objective] A liquid chromatography-tandem mass spectrometry method was developed for rapid determination of 3 isothiazolinone residues in milk powder. [Method]Each sample was extracted twice with acetonitrile, and the extract was purified and enriched by Waters Prime HLB. The eluate was separated on a Waters BEH HILIC column (2.1 mm×100 mm×1.7 μm) and determined by quadrupole-MS/MS, and an isotopic internal standard method was employed for quantitation. [Result] The 3 isothiazolinones showed with good linearity (r≥0.995) within the range from 2.5 μg/kg to 250.0 μg/kg. The limits of detection (LOD) and the limits of qualification (LOQ) for the 3 isothiazolinones were 4 μg/kg and 10 μg/kg, respectively. The spiked recovery tests at three levels were conducted for the samples, and the spiked recoveries of the 3 isothiazolinones varied between 80.5% and 94.3%. The intra-batch and inter-batch coefficients of variation were 3.52%~10.95% and 6.64%~9.67%, respectively. [Conclusion]This method, with simple operation, short analysis time, high sensitivity, high accuracy, and high precision, is suitable for the determination of 3 isothiazolinone residues in milk powder.

Abstract:[Objective] This study aims to establish a pre-treatment method with only one time of operation for simultaneous and rapid detection of seven veterinary drug residues in pork. [Method]Seven veterinary drugs (dexamethasone, chloramphenicol, thiamphenicol, florfenicol, sulfamethazine, metronidazole, and tylosin) in pork were studied. A unified pre-treatment method was established after integration, optimization, and testing based on colloidal gold immunochromatographic assay products from major rapid detection brands for veterinary drugs in China. The performance indicators including limit of detection, sensitivity, false positive rate, and false negative rate of the established method were investigated. The colloidal gold immunochromatographic assay products from other manufacturers in the market were used to verify the universality of the established method. [Result]The optimal extraction system was saturated sodium chloride solution-ethyl acetate. The preferred purification method was n-hexane degreasing. Phosphate buffered saline (pH 7.2, 0.02 mol/L) containing 3% (volume fraction) methanol was selected as the solution for drug reconstitution. The limits of detection of the seven veterinary drugs in pork were determined as follows: 1.0 μg/kg for dexamethasone, 0.10 μg/kg for chloramphenicol, 50 μg/kg for thiamphenicol, 300 μg/kg for flurfenicol, 100 μg/kg for sulfamethazine, 0.50 μg/kg for metronidazole, and 100 μg/kg for tylosin. The sensitivity, false positive rate, and false negative rate of the established method was 96%, 6%, and 4%, respectively. [Conclusion] The detection results of this method were highly consistent with the reference methods. And this method can be used for colloidal gold immunochromatographic assay products for rapid detection from other manufacturers. This method, with high accuracy, rapid detection, simple operation, high efficiency, and a low cost, can meet the needs of on-site and large-scale screening of multiple veterinary drug residues in pork.

Abstract:[Objective] The study evaluated the measurement uncertainties of Bacillus cereus (B. cereus) in milk powder samples to analyze the factors influencing the measurement of B. cereus. [Method]According to the evaluation procedure in JJF 1059.1—2012, the uncertainties of the plate counting results for B. cereus in infant formula milk powder were evaluated through the following five steps: identifying uncertainty sources, establishing the measurement model, assessing standard uncertainties, calculating the combined standard uncertainties, and determining the expanded uncertainties. Contributions from each uncertainty component were analyzed, and corresponding measures were suggested to enhance the accuracy of the measurement results. [Result]At a confidence level of 95% and with 9 degrees of freedom (ν), the k value was determined to be 2.26, and the expanded uncertainty (U₉₅) was 0.20. The findings indicated that the largest source of uncertainties during the counting process for B. cereus arose from repeated measurements, followed by the uncertainty introduced by growth rate in culture media. [Conclusion]The study lays a foundation for the quality control of B. cereus and provides technical guidance for improving the evaluation of uncertainties in the microbiological field.