Abstract:As one of the most popular drinks in the world, wine's organoleptic properties (such as smell, taste and color) largely depend on the aging technology. Oak barrel is a commonly used method for aging red wines, but it has a long aging cycle, high labor and material consumption, and limited production. Thus, it is urgent to find an alternative to oak barrel. This article explores the principle of oak barrel aging, and compared the principle, advantages and disadvantages and feasibility of different new methods to aging wine. At the same time, the feasibility of seeking alternative materials for oak barrel in the future is prospected based on the national conditions in China, which provides theoretical support for the combination of emerging technologies and wine industry.

Abstract:Kidney bean is an important legume in China and is also plant-based resource with highly edible and medicinal value. Kidney bean proteins are complete proteins, which are rich in functional glycoprotein with hypoglycemic or immune activity. Kidney bean also contains abundant polysaccharides with intestinal physiological regulation and other functions. In recent years, the development of kidney bean-based diet foods has attracted much attention, and the rise of plant-based diet style has aroused intensive researches on this valuable bean resource conducted by domestic and foreign scholars. The structural characteristics, substance compositions, physiological functions and processing properties of macromolecular components in the different varieties of kidney beans were introduced. The interactions and functional characteristics of macromolecules in kidney beans were also summarized to provide the theoretical basis for the study of health regulatory mechanism of kidney bean macromolecules and to provide references for the development of novel nutritional and healthy foods.

Abstract:Drying is a common procedure frequently used to process starchy raw materials and their products. The pretreatment of starchy raw materials such as roots, tubers, and grains by drying is not only convenient for safe preservation and subsequent processing, but also significantly promotes the yield of starch extraction and the processing suitability of starch. Drying is a necessary procedure in the production of starchy foods such as starch noodles, vermicelli, shrimp crackers, and so on, playing a decisive role in the quality of starchy products. Drying is a complex process involving moisture transfer, heat transfer and other accompanying physicochemical changes (i.e., recrystallization of starch molecular chains, interactions between starch and other coexisting components), which makes the drying process is more empirical than scientific in industrial production. Therefore, we comprehensively summarized and analyzed the effects and rules of drying on the characteristics of starch in raw materials and the quality of starchy products, providing references in improving the processing suitability of starchy raw materials and the quality of dried starchy foods through the selection of drying modes and conditions.

Abstract:In order to reduce the production process of collagen casing film, and to improve the quality of packaging materials in food industry, the effect of glutaraldehyde addition sequence on the quality of collagen casing film was investigated. The tensile strength, elongation at break, thermal shrinkage, swelling rate, color and denaturation temperature were studied through three addition treatments, i.e., during the process of collagen paste making, after paste making, and after film forming, respectively. Results showed that glutaraldehyde could improve the mechanical properties and surface hydrophobicity, and decrease the swelling rate and thermal shrinkage rate of collagen casing films under any treatments. The results of FTIR and DSC showed that the films crosslinked with glutaraldehyde after film formation had the highest crosslinking efficiency and thermal stability, and the most significant improvement in film properties. Furthermore, with the increase of glutaraldehyde content, the color of casing film gradually changed yellow. However, when the content of glutaraldehyde was over 100 mg/L, there was no further significant improvements on the quality of casing films by the crosslinking of glutaraldehyde.

Abstract:In this study, the silicon carbon quantum dots (SiCDs) with a specific response to acetamiprid pesticides were modified and prepared, which were then used as the fluorescence probe to develop a highly sensitive molecularly imprintied fluorescence sensor (SiCDs@MIPs) to rapidly detect the acetamiprid pesticides. The effects of the ratio of template to functional monomer, the amount of cross-linking agent, and the amount of SiCDs on the detection sensitivity of SiCDs@MIPs were further investigated. The results showed that the optimal preparation conditions of SiCDs@MIPs were as follows: the ratio of template to functional monomer was 1∶4, the amount of cross-linking agent was 25 μL, and the embedding amount of SiCDs was 10 mg. Under the optimal detection conditions, the detection limit of SiCDs@MIPs toward acetamiprid was 0.086 μmol/L within the linear range of 0.045 to 0.450 μmol/L, the correlation coefficient was 0.989, and the detection time was only 25 minutes. When SiCDs@MIPs was further applied to determine the acetamiprid pesticide residues in Chinese cabbage, tomato and wax gourd, the recoveries ranged from 73.0% to 109.0%. The proposed method provided a new strategy for the determination of acetamiprid pesticide residues in vegetables.

Abstract:The proliferation culture medium of Lactobacillus fermentum SS-31 which was isolated from the fermentation broth of sour bamboo shoots in Liuzhou, Guangxi, with excellent probiotic properties, was optimized and its high-density fermentation conditions were explored. The composition of fermentation and proliferation medium as well as the culture conditions were optimized using the viable bacteria number of Lactobacillus fermentum SS-31 as the main reference index through single factor experiment, response surface optimization and other experimental methods. The final composition of Lactobacillus fermentum SS-31 medium was optimized with maltose of 16.20 g/L, yeast extract of 20.16 g/L, dipotassium hydrogen phosphate of 9.33 g/L, manganese sulfate of 0.50 g/L, magnesium sulfate of 1.00 g/L, and Tween of 1.00 g/L. The optimal fermentation conditions were set as 3% of inoculum size of SS-31, pH 6.8 of initial pH value with ammonia added to maintain the pH of fermentation broth, under which the viable count of Lactobacillus fermentum SS-31 reached 1.19×10¹⁰ CFU/mL cultured at 37 ℃ for 24 h, laying a foundation for its industrial production.

Abstract:Myofibrillar protein emulsion microgels is a kind of discrete spherical particles formed by the aggregation of denatured proteins on the emulsion droplets when the myofibrillar protein emulsion is heated and sheared at the same time. In this investigation, the effects of pH on the rheological properties of myofibrillar protein emulsion microgels were studied by measuring the rheological behavior and microstructure of microgels prepared under different pH conditions. Results showed that the particle size of myofibrillar emulsion microgels under strong acid condition and near its isoelectric point was significantly larger than that of other pH ranges. The emulsion microgels under different pH were all non-Newtonian fluids with the pseudoplastic fluid characteristics, and pH condition would not change the fluid type of emulsion microgels. The viscosity first decreased and then increased with the increase of pH value. At pH 6, myofibrillar emulsion microgels showed the highest viscoelasticity at low frequency sweep with the optimum thixotropy. In the shear resilience test, the structure of microgel particles was damaged to a certain extent, while the optimal recovery was achieved at pH 5.

Abstract:To explore a new method for the combined preparation of wheat protein peptide and wheat starch, the effects of different treatment conditions on the preparation of wheat peptides by two proteases under the non-gelatinization state of raw flour were studied using the purity and yield of peptides, degree of hydrolysis, and reducing sugar content as evaluation indexes. The results showed that the peptides were higher in protein purity and lower in reduced sugar content when the enzyme was added after soaking, while their yields had insignificant difference. The optimum soaking was carried out under 50 ℃ for 2.5 h. Under the optimal condition, the protein purity of wheat peptides, protein yield, hydrolysis degree and reducing sugar content obtained by the neutral protease were 27%, 75%, 17.6%, and 5.9%, respectively, while those obtained by the alkaline protease hydrolysis were 25%, 85%, 23.7%, and 9%, respectively. The enzyme was recommended to add after soaking during the pretreatment process. Moreover, different protease could be selected according to the demand, but the higher content of amylase in alkaline protease would produce relatively more starch sugar.

Abstract:The effects of Lentinus edodes after fermentation by lactic acid bacteria on the structure and diversity of gut microbiota were studied by gavage test and 16S rRNA high-throughput sequencing in mice, and the flavored ready-to-eat products were studied and developed. The results showed that medium dose (10 g/kg, calculated by the mouse body weight) of fermented L. edodes changed the species diversity of gut microbiota in mice. The number of endemic and rare species increased, the individual differences decreased, and the species distribution was more uniform. Fermented L. edodes could increase the relative abundance of beneficial bacteria in varied degrees, including Muribaculaceae, Lactobacillus, Dubosiella, Lachnospiraceae, and reduce the relative abundance of Helicobacter, Mycoplasma and other pathogenic bacteria in the intestinal tract of mice, and thus the intestinal health could be improved. Through single factor and response surface optimization tests, the best formula of flavored ready-to-eat product prepared through lactic acid bacteria fermented L. edodes was set with fermented L. edodes block of 81.5%, sweet bean paste of 1.0%, broad bean paste of 1.5%, white granulated sugar of 6.0%, rattan pepper oil of 3.0%, sesame of 2.0%, chili oil of 4.0%, and ginger juice of 1.0% (mass ratio). This study could provide a useful reference for the application of lactic acid bacteria fermentation technology in the value-added processing of L. edodes.

Abstract:To reveal the relationship between the dominant microbial communities on tobacco leaf surface and the quality of tobacco, the structure of microbial community in tobacco with different qualities was analyzed by high-throughput sequencing technique, and the volatile aroma compounds were detected by solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC/MS), and the dominant microbial species related to the formation of volatile aroma components in tobacco were analyzed by calculating Pearson correlation coefficient. The results showed that the dominant bacteria in tobacco were Variovorax, Spingomonas, and Bacillus, while the dominant fungi were Sampaiozyma, Aspergillus, and Cladosporium. The bacterial communities were related to the difference of tobacco leaf qualities, and the relative abundance of Variovorax, Spingomonas, and Rhodococcus was up-regulated in the high-grade and middle-grade tobacco leaves. However, the fungal communities were related to the geographic location differences of tobacco leaves. The contents of volatile compounds were higher in high-grade and middle-grade tobacco, such as furfural and 5-methyl-2-furancarboxaldehyde of caramel aroma, and sweet milk-flavored vanillin. There was more α-nicotine producing irritating smoke in the low-grade tobacco. Combined with the correlation analysis, a positive correlation was found between bacterial species and various volatile aroma compounds in tobacco leaves, and Rhodococcus, Variovorax and Bacillus were the main flavor-associated bacteria in tobacco. The results showed that the dominant microbiota in tobacco played a critical role in promoting the formation of tobacco aromatic quality, which could provide a theoretical reference for the realization of tobacco quality improvement and damage reduction, as well as the targeted regulation of flavor based on the microbial technology.

Abstract:In order to understand both effects of combustion temperature of cigarettes on the formation of main volatile components in cigarette smoke and the relationship between the volatile compounds formation in cigarette smoke and tobacco precursors, the effects of sequential pyrolytic temperatures on the formation of volatile components were simulated and investigated using the multi-step pyrolysis technology coupled with gas chromatography-mass spectrometry (GC-MS). The results showed that 1) the multi-step pyrolysis technology could be used to well-study the effect of pyrolysis temperature on the volatile and semi-volatile substances released from tobacco during pyrolysis to reveal the relationship between the released substances and temperature. 2) During the combustion of cigarette, the free flavoring substances distillated and released under 250 ℃ with less volatile substances released, which were mainly free nicotine, nicotyrine and neophytadiene. The tobacco cracked within 300~600 ℃, and many volatile and semi-volatile substances were formed when the precursors, i.e., carbohydrates, amino acids, pigments, pigment esters with long-chain fatty acids, acyclic isoprenoids and cembrenoids, cracked at 300~500 ℃. Protein degraded and formed a large amount of nitrogen containing heterocyclic compounds at 600 ℃. The carbonization and combustion of tobacco occurred within 700~900 ℃, mainly producing simple gases such as carbon dioxide and carbon monoxide. 3) Compared with pyrolysis, the proportion of volatile and semi-volatile compounds distilled from cigarette itself was very small (about 5.74%), while the volatile components formed by pyrolysis under high temperature (300 ℃ or above) might determine the aroma style characteristics of cigarettes.