Abstract:Plant-based foods generally refer to food made from plant materials. There is much room for the growth of plant-based foods in the era of great health. Lactic acid bacteria (LAB) fermentation technology has great potentials in the development of diversified plant-based foods, which can achieve the diversification of flavor and health of plant-based foods. Thus, LAB-fermented plant-based foods industry is very promising in the future. This review summarizes the types of LAB-fermented plant-based foods, the relevant basic theories, key technologies as well as the industrialization status at home and abroad, and briefly discusses the main development trend of LAB-fermented plant-based food industry from the aspects of basic theory, key technology, and product a development. The aim of this review is to provide reference for the research and development of new LAB fermented plant-based food products.

Abstract:Umami and umami-enhancing peptides are the key components of novel umami flavorings. They have advantages of naturalness, higher nutritional value, and better umami taste over glutamate. There are a wide variety of umami and umami-enhancing peptides and these peptides can, as precursors, directly affect the flavor characteristics of food by participating in relevant reactions. The number of reported umami and umami-enhancing peptides is 208 and 60, respectively. For umami peptides, their amino acid composition and spatial structure are the most two important factors affecting the umami intensity, while the structure-activity relationships of umami-enhancing peptides are more complicated, which needs to be further studied. Meanwhile, umami and umami-enhancing peptides are active reactants of many reactions (enzymatic and non-enzymatic), generating the derivatives having better umami taste or umami-enhancing ability under certain conditions. In this review, the structural characteristics of umami and umami-enhancing peptides were systematically studied and their relevant reactions, as well as the flavor features of the expected products, were discussed based on different processing methods. Furthermore, some problems with the study and possible solutions are summarized to support the scientific research about umami and the development of the condiment industry.

Abstract:In processing, storage and transportation of probiotics, there is a technical bottleneck of easy attenuation of bacterial activity. Electro-fluid processing technology is a new non-thermal packaging technology, which has little damage to cell activity and has great application potential in the production of probiotics. Based on principle of electric fluid processing in this paper, the author discusses the electrostatic spinning and electrostatic spray technology in the application status of active probiotic encapsulation, including electric fluid processing technology principle, equipment, process parameters and packaging materials, which could provide new ideas and references for the study of probiotics processing, in order to realize highly active probiotics preparation production.

Abstract:Mitochondria are important places where citric acid cycle, glyoxylate cycle and respiratory chain reactions occur, and they also the indispensable organelles of eukaryotes. The exchange of substances between mitochondria and cytoplasm directly affects the catabolism and anabolism of cells, while the inner mitochondrial membrane is highly selective and impermeable. Therefore, the exchange of substances needs to be assisted by substrate channels or carrier proteins on the mitochondrial membrane. This review summarizes the mitochondrial carrier and metabolic substrate channels in the exchange of metabolites between mitochondria and cytoplasm and other organelles, including carbon metabolites mitochondrial carrier proteins, NAD(P)H and NAD(P)⁺ metabolites mitochondrial substrates channel, cofactor carrier protein, amino acid carrier protein, and several other mitochondrial carrier and substrate channels that have been identified. At the same time, the application of mitochondrial membrane carrier protein engineering in microbial metabolic transformation is summarized as well. In addition, the elucidation of metabolite transport mechanisms across organelle membranes in this review will pave the way for mitochondrial carrier protein engineering in designing new metabolic pathways and remodeling intracellular metabolic networks, which deepens our understanding of intracellular metabolism and makes us better design the microbial cell factories.

Abstract:The interactions of starch, lipids and proteins during thermal processing can significantly affect the flavor, taste, texture, nutritional properties and shelf-life of food products, which has received extensive attention in recent years. Understanding the mechanisms underlying the interactions between starch and other food components is of high significance for quality control in food processing. Molecular dynamics (MD) simulations, as an important theoretical computational analysis method, play a critical role in gaining insights into the interactions between starch and other components, which has drawn much attention in recent years. After brief description of the formation and structure of starch-lipid complex and starch-lipid-protein complex, this review article comprehensively summarizes the latest research about the basic theory, definition and operation procedures of MD simulations and their applications in investigating the interactions among starch, lipid and protein, and provides future directions in this area.

Abstract:As an emerging tool for gene editing and regulation, CRISPR system is characterized by its high specificity, sensitivity and flexibility. In addition to its important role in gene editing and modification, it also has a promising prospect in infectious disease diagnosis, environmental monitoring and food safety. With the intensive research of CRISPR/Cas system, a variety of simple and sensitive biosensing platforms have been established through its high specificity in identifying target sequences and trans-cleavage capabilities. The shortcomings of traditional methods in terms of operation, sensitivity, specificity and detection cycle have been addressed. In this review, we will focus on the features and mechanisms of the most widely used class 2 CRISPR/Cas systems and summarize CRISPR/Cas based biosensing strategies and future directions for nucleic acids, proteins and small molecules.

Abstract:Matrix reference materials for food safety detection are the combination of target analysis and food matrix, which is consistent with the real test sample, and can ensure the accuracy and effectiveness of the test result. In this paper, the development and classification of food matrix reference materials, its development status, current problems and the latest trends at home and abroad, were comprehensively described, which could provide a reference for the preparation and development of matrix reference materials of food safety detection.

Abstract:Marine fish are rich in nutrients and high in water content, and are prone to spoilage in the cold chain logistics. Therefore, understanding the spoilage mechanism of marine fish in cold chain logistics, and then carrying out targeted preservation of marine fish products, greatly improve the quality of marine fish products in cold chain. This review discusses the mechanisms of autolytic spoilage, oxidative spoilage and microbial spoilage in the cold chain logistics of marine fish, and focuses on the research progress of the preservation technology for controlling microbial spoilage. The surface microbial of marine fish can be effectively reduced by the ozone water, electrolyzed water, low temperature plasma, irradiation sterilization, high hydrostatic pressure, photodynamic sterilization technology and other bacteria-reducing technologies. Then the low temperature control, modified atmosphere packaging and active packaging technologies are used to control the microbial growth, protein and lipid oxidation of marine fish in the cold chain logistics, which could maintain the freshness quality of marine fish. These findings can provide a reference for the further development of preservation technology applied to the marine fish in the cold chain logistics.

Abstract:The output of fresh food is very large, however, fresh food was prone to be contaminated by microorganisms during storage and transportation, which would lead to spoilage and cause food safety risks and economic losses. Thermal sterilization is a commonly used sterilization method, but it would have negative effect on the flavor, color and nutrition of food, moreover, it is not suitable for heat-sensitive food materials. Non-thermal sterilization methods could to some extent make up for this deficiency. Photodynamic sterilization, one of non-thermal sterilization method, has been carried out in the preservation research area of fresh food for a while. This paper reviews the sterilization mechanism of photodynamic sterilization technology, summarizes its killing effect and mechanism on different microorganisms, and introduces their application and impact on the quality of fresh food, such as aquatic products, fruit and vegetables, dairy, and meat. This review would provide meaningful references to the preservation and safety control of fresh food.

Abstract:Quercetin is a kind of important citrus flavonoid with antibacterial, anti-inflammatory and antioxidant activities, but with poor water solubility and lipid solubility. It has been proved that the metabolic stability and bioavailability of quercetin can be improved by methylation, and microbial transformation method is a good method to obtain methylated quercetin. In this study, 11 flavonoid O-methyltransferase(FOMT) from different sources were screened and classified according to methylation sites, and then the corresponding Escherichia coli engineering bacteria were constructed. Four mono O-methylated quercetin（tamarixetin, rhamnetin, isorhamnetin and 3-O-methylquercetin）were synthesized by fermentation with quercetin as substrate. The highest yields were 31.17, 11.17, 8.90, 52.95 mg/L, respectively. Then, the co-culture system of E.coli was constructed, and the whole cell catalyst containing MpOMT4 and OsNOMT was added step by step. By adjusting the proportion and biomass of the two bacteria in the system, it was finally determined that when the dry weight of cell was 24 g/L and the ratio of cell 1 and cell 2 was 1∶2, and the highest yields of 4′, 7-dimethoxyquercetin was 21.56 mg/L.

Abstract:To improve the hydrolysis efficiency toward konjac powder, the mannanase from Rhizomucor miehei was successfully modified through directed evolution. After two rounds of screening, a mutant (RmMan5AM2) with improved catalytic efficiency was obtained. The optimal pH of the mutant was pH 7.0, and its optimal temperature was 65 ℃, which was increased by 10 ℃ compared with RmMan5A. RmMan5AM2 inherited the high specific activity of RmMan5A. Its specific activity toward locust bean gum was 10 371.4 U/mg. At the optimal condition, the catalytic efficiencies of the mutant toward locust bean gum, konjac powder, and guar gum were improved by 37.4%, 28.9% and 34.4%, respectively. RmMan5AM2 was further expressed in Pichia pastoris for high cell density fermentation. After 156 h, the expression level of the mutant was up to 176 000 U/mL, which is the highest expression level of mannanases as reported so far. The mutant was then used to hydrolyze konjac powder for manno-oligosaccharides production. The products were mainly manno-oligosaccharides with a degree of polymerization of 2~6(relative peak area>85%), and the total yield was 88.5%. RmMan5AM2 showed excellent enzymatic properties, and its hydrolysis efficiency toward konjac powder was significant improved. Thus, the mannanase has great potential in manno- oligosaccharide production.

Abstract:This study explored the protective effects of royal jelly (RJ) and its major protein and lipid fractions on the D-galactose (D-gal) induced aging mice. In the experiment, the crude protein fractions, functional protein and lipid fractions were extracted and separated from royal jelly by dialysis, ultrafiltration and organic solvents, respectively. The aging mice model was established by intraperitoneal injection of 100 mg/kg D-gal per day for 7 weeks. The improved precision rate of mice in the T-maze and the reduction of liver organ index in mice intervened by royal jelly proved its beneficial functions on the aging-associated impairments of cognition and memory. Moreover, intervention of functional lipid fractions and functional protein fractions under high dose could significantly improve the accuracy of mice in T-maze and relief the liver enlargement. Therefore, both the functional protein and lipid fractions of royal jelly performed desirable anti-aging effects, and the mechanism may be related to the improvement of memory capacities.