Abstract:Based on a comparative analysis of challenges faced by traditional meat production and the environmental impacts of cultivated meat, it is indicated that the cultivated meat is an advanced form of meat production in the production technology, development concept and future significance. The comparative analysis of different LCA of cultivated meat suggests various environment factors affecting of cultivated meat production, including raw material source, cell growth density and so on. Compared with the traditional meat production, the process of cultivated meat production could take up less land area and consume almost negligible fresh water resources, showing significant advantages in greenhouse gas emission. It can also be concluded from this study that there is still much room for improvement in reducing the impact of cultivated meat life cycle on the environment. It is necessary to further reduce its environmental impact by developing specific processes suitable for industrial production and tackling a series of basic scientific and technological problems, so as to meet the requirements of human civilization for sustainable development. However, the industrialized production technology of cultivated meat has not been established so far, and the specific parameters of cell proliferation, differentiation and quality control of cultivated meat have not yet been defined, resulting in great differences among different LCA. In order to promote the development of cultivated meat industrialization, it is necessary to determine the industrialized production technology of cultivated meat as soon as possible. According to the basic level of Chinese equipment reagent industry, the LCA of cultivated meat in line with the current situation of Chinese technological development should be counted, which could provide the theoretical basis for formulating the development policies of relevant cultivated meat industrialization in China in the future.

Abstract:The serious impact of the improper use of antibiotics in food-related fields such as animal husbandry and fishery on the environment and human body has attracted widespread attention of many researchers. In this study, a magnetic beads-kanamycin complex was prepared, and a simple, rapid and sensitive competitive colorimetric aptamer sensing strategy was developed by competing for the aptamer in the system between kanamycin on the surface of magnetic beads and kanamycin in the sample. The synthesis of magnetic beads-kanamycin and the biological recognition between the aptamer and the target were characterized by scanning electron microscope and ultraviolet-visible spectrophotometer. The successful synthesis and recognition provide a strong guarantee for the sensing strategy construction. The sensor has good colorimetric performance in the detection range of kanamycin molar concentration of 0.05~500 nmol/L, and the limit of detection is 0.21 nmol/L. In addition, by comparing with other aminoglycoside antibiotics detection experiment, it could be concluded that the sensor has a good selectivity to kanamycin. In short, the colorimetric aptasensor is easy to operate without large-scale instruments, providing a good idea for the rapid detection of other antibiotics and other chemical contaminants affecting food safety.

Abstract:This research aimed to explore the dynamic changes of aroma compounds composition and mass fraction of coffee brews at different stages of extraction process. The roasted Guatemalan coffee beans were selected to prepare coffee brews under a continuous constant pressure 900 kPa extraction. The HS-SPME-GC/MS method was used to study the mass fraction of aroma compounds in coffee brews. The results showed that the constant pressure extraction process of key volatile aroma compounds conformed to the Power Law equation, and the polarity was the key factor that determined the dynamic extraction rate. In the initial stage of extraction, the extraction rate constant of strong polarity substances such as 2-methylpyrazine was 7 to 35 times that of β-damascone with weak polarity. At the end of extraction, the total mass fraction of weak polarity substances increased from 20% to 30%, and the aroma balance changed. During the continuous extraction process, the odor activity value of key compounds in light and medium roasted coffee decreased faster than that in dark roasted coffee. Based on the experimental data, combined with and concerned about the Golden cup extraction regulations formulated by the Specialty Coffee Association, the study proposed that in order to obtain a cup of coffee with a better balance of taste and aroma, the cup extraction could be controlled to 30~40 g of 17 g coffee powder for light and medium roasted coffee, and 40~50 g of 17 g coffee powder for dark roasted coffee.

Abstract:In order to further explore the protein changes of mutton during freezing-thawing process, differential scanning calorimetry (DSC) was used to study the changes of Xinjiang mutton under four freeze-thaw procedures, including non-freezing-thawing (NFT), one cycle of freezing-thawing at -20 ℃(TFT1), two cycles of freezing-thawing at -20 ℃ (TFT2) , and one cycle of freezing-thawing at -80 ℃(EFT1). The effects of the freezing-thawing cycles, minimum freezing-thawing temperature and duration of sample preparation and measurement on the DSC enthalpy curve were analyzed. The results showed that the temperature of protein denaturation shifted after freezing-thawing process. Compared with the NFT group, the peak enthalpy of myosin in TFT1 and EFT1 groups decreased by 57.0% and 89.6% (P<0.05), respectively, and the heat absorption peak enthalpy of actin in TFT1, TFT2 and EFT1 groups decreased by 47.0%, 68.8% and 59.6% (P<0.05), respectively. The heat absorption peak enthalpy of rapid moisture transpiration in TFT1 and TFT2 groups increased by 1.3% (P<0.05) and decreased by 11.9% (P<0.05), respectively, while that of EFT1 group increased by 15.6% (P<0.05). In PCA analysis, there was a significant negative correlation between the duration from sample preparation to measurement and the thermal absorption peak enthalpy of actin, while sample weight had no obvious effect on other indexes. The results showed that the increase of freezing-thawing cycles increased the denaturation degree of myosin and actin, showing a more significant effect on myosin. Under the same cooling rate, the decrease of minimum freezing-thawing temperature could aggravate the denaturation of protein, but the moisture loss during the cycle could be reduced. There was a positive correlation between the duration between sample preparation and measurement and the degree of actin degeneration.

Abstract:Taste value and textural properties are important indicators to evaluate the edible qualities of cooked rice. This research aimed to explore the relationship between the taste value, texture characteristics and physicochemical properties of different rice varieties with the starch structure. Twelve rice varieties were selected to determine their taste values, textural properties, physicochemical properties and starch structural properties, and their internal correlation was analyzed. These results presented that amylose content (mass fraction) positively correlated with hardness of cooked rice (P<0.01), while had highly significant negative correlation with cohesiveness of cooked rice (P<0.01). There was a significant correlation among the taste value, textural properties, gelatinization and thermal properties of rice starch, while there was insignificant correlation with the crystallization properties and the surface order degree of rice starch granule. These results indicated that the taste value, hardness, cohesiveness and resilience of cooked rice were determined by the gelatinization properties of rice starch. This research could provide a theoretical basis for the high-quality rice cultivation and suitable processing of rice.

Abstract:This study explored the differences of meat quality characteristics and processing suitability of different parts of Bactrian camel to provide a theoretical basis for the fine processing of Bactrian camel meat. The edible quality was investigated and the nutritional components and texture characteristics were analyzed from seven parts of the 8-year-old Alxa Bactrian camel, including tenderloin, sirloin, brisket, plate and flank, round, hindleg and shank. The results showed that the tenderloin had the smallest color difference with bright color and moderate water retention. The sirloin had the higher fat content (6.50%) with better tenderness and poor water retention due to the lower water content (66.11%). The brisket had the lowest hardness with good elasticity and tenderness, containing the richest and most complete varieties of amino acids and fatty acids. The plate and flank had the higher fat content (9.03%) and good water retention. The round has the worst hardness, cooked meat rate and cohesion. The hindleg had the higher protein content (21.27%) and lower fat content (0.33%). The shank had the higher moisture content (mass ratio of 75.27%) and largest water holding rate (0.89%) with less fatty acids varieties. The results showed that the meat quality characteristics of different parts of Alxa Bactrian camel was varied, and each part had its appropriate processing methods.

Abstract:The metabolites of Huang Guanyin oolong tea produced in Yunxiao and Wuyishan were analyzed by widely targeted metabolomics and sensory evaluation to investigate the quality differences of Huang Guanyin oolong tea from different areas. The results showed that a total of 820 metabolites from 11 classes were identified in Huang Guanyin oolong tea from the two areas. The different metabolic components identified from the first-grade oolong tea were 63, and 120 for the second-grade oolong tea, accounting for 7.68% and 14.63% of the total metabolites, respectively. The KEGG metabolic pathway analysis showed that three highest enrichment pathways of the first-grade Huang Guanyin oolong teas from two areas were related to the flavonoid differential metabolites, and two highest enrichment pathways of the second-grade Huang Guanyin oolong teas from two areas were related to the differential metabolites of amino acids and their derivatives. According to the comparison of flavor components in Huang Guanyin oolong teas from different areas, the content of differential metabolites including quercetin-3-O-sambubioside, kaempferol-3-O-rhamnoside, apigenin-7-O-rutinoside, L-proline, L-asparagine and γ-aminobutyric acid in the first-grade Huang Guanyin oolong tea from two areas were extremely significant, and the content difference of metabolites including L-asparagine, L-glutamic and γ-aminobutyric acid in the second-grade Huang Guanyin oolong tea from two areas were extremely significant. In this study, the differential metabolites associated with the quality of Yunxiao and Wuyi Huang Guanyin oolong teas were screened out based on the widely targeted metabolomics analysis, providing a reference for elucidating the quality characteristics of Huang Guanyin oolong teas from the two areas.

Abstract:In order to realize the rapid detection of volatile flavor substances in oolong tea samples from different producing areas, the gas chromatography-ion mobility (GC-IMS) technique combined with the stoichiometry was employed to study the volatile compounds in 29 samples of oolong tea from 4 different origins. The IMS maps of oolong tea samples from different origins showed significant differences in volatile substances. The citrus limonene content was the highest in the oolong tea from Guangdong Province, and the contents of heptanal, hexanal and 3-octanone with characteristic components of herbaceous aroma in the oolong tea from southern Fujian were obviously higher than those of oolong tea from other producing areas. The oolong tea from Taiwan Province had more fruit aroma characteristic components, such as 2-hexanone, propionic acid, γ-butyllactone, n-hexanal and so on. The oolong tea from northern Fujian had more baked fragrance like trans-2,4-heptyl diene aldehyde, p-ethyl phenol and 5-methyl furfural. The peak strength of 43 kinds of volatile compounds screened by the differential spectrum method were set as the variables, and dimension reduction was done by the principal component analysis (PCA), which could distinguish oolong tea from different producing areas. The contribution of PC1 and PC2 were 54.2% and 19.4%, respectively, and the cumulative contribution rate was 73.6%. The results of partial least squares discriminant analysis (PLS-DA) showed that the contribution rate of PC1 and PC2 were 54.2% and 19.3%, respectively, and the cumulative contribution rate was 73.5%, which had good distinguishing effect on the oolong tea from different producing areas. The linear discriminant analysis (LDA) could effectively distinguish oolong tea from different producing areas with the discriminant rate of 100%. The experiment showed that GC-IMS technology could be effectively applied to detect the volatile substances in oolong tea and rapidly identify their origin.

Abstract:In order to explore the effect of norisoprenoids produced after carotenoids degradation on the characteristic aroma of wolfberry wine, a strain of Kurthia sp. which could degrade carotenoids was used. Kurthia sp. was inoculated in the wolfberry residue, and the industrial Saccharomyces cerevisiae was inoculated in the wolfberry juice, separately. They were mixed after fermentation. Kurthia sp. enzyme was inoculated in the wolfberry juice and assisted by the fermentation of industrial Saccharomyces cerevisiae to get the autoclaved wolfberry dregs. The wolfberry residue sterilized by high pressure was added into the wolfberry juice, and then fermented by inoculation with the industrial Saccharomyces cerevisiae. The wolfberry wine brewed by traditional fermentation process was used as the control. The aroma components of wolfberry wine were detected and analyzed using headspace solid phase micro-extraction and gas chromatography-mass spectrometry (GC-MS). And the influence of three carotenoid degradation methods to the aroma of wolfberry wine was evaluated by the sensory scoring method. The results showed that the aroma and taste of wolfberry wine in the Kurthia sp. enzyme preparation-assisted fermentation group were the best, and the best clarity after autoclaving was found in the group of fermentation after high pressure sterilization. Therefore, in the brewing process of wolfberry wine, the wolfberry juice could be degraded by the enzyme from Kurthia sp., and the wolfberry residue could be appropriately prepared with high pressure sterilization before fermentation, which could improve the brewing process and enhance the aroma of wolfberry wine.

Abstract:The effect of ethephon solution on the content of free amino acids in fresh tea leaves during withering was studied. A control group, a liquid-applied ethylene group and an ethylene inhibition group were set using the cultivar 'Qiancha 1' self-cultivated in Guizhou Province as the test material. o-phthalaldehyde (OPA) and fluorenylmethyl chloroformate (FMOC) methods were used for online derivatization and detection of free amino acids through high-performance liquid chromatography. The results showed that the content of umami and refreshing amino acids decreased, while the content of sweet and bitter amino acids increased with the prolongation of withering. The contents of three kinds of flavor amino acids had different responses to liquid-applied ethylene treatment during withering. The contents of umami amino acids were up-regulated by ethylene during withering, and the difference was significant at 4 h and 8 h. There was insignificant difference in the content of sweet amino acids among all the treatments. The bitter amino acids had no significant change at 4 h and 8 h during withering, but decreased with insignificant difference at 12, 20, 24 h. Theanine was the dominant umami flavor, and the contents of theanine, aspartic acid and glutamic acid were up-regulated by ethylene, except that there was no significant difference in glutamic acid content among all the treatments at 4 h. The contents of serine and proline in sweet amino acids were not regulated by ethylene, while the content of glycine was up-regulated by ethylene. And the content of alanine was incompletely regulated by ethylene. The contents of histidine, tyrosine, valine, isoleucine and leucine in bitter amino acids were up-regulated by ethylene. Therefore, the application of ethephon solution during withering could significantly increase the content of partial free amino acids.

Abstract:A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established for the simultaneous determination of cyazofamid and its major metabolite 4-chloro-5-(4-methylphenyl )-1H-imidazol-2-nitrile (CCIM) to evaluate their safety in fruits. The sample was extracted with acetonitrile containing 1.0% acetate acid and purified with octadecylsilane bonded phase (C₁₈) powder and Florisil powder. Then the UPLC separation of sample was performed on Capcell PAK C18 column (150 mm×2.0 mm, 5 μm) and determined with multiple reaction monitoring mode (MRM) through HPLC-MS/MS. The results showed good linear relationships between the peak areas and the mass concentrations for both cyazofamid and CCIM in the range of 0.001~0.040 μg/mL (R≥0.999 3). When the spiked levels were between 0.004~0.080 mg/kg, the recoveries of cyazofamid and CCIM were in the range of 80.71%~103.27% and 76.62%~100.20%, respectively, and the relative standard deviations were between 4.14%~11.15% and 3.24%~11.16%, respectively. The LODs and LOQs of cyazofamid and CCIM in fruits were between 0.001 5~0.003 8 mg/kg and 0.003 0~0.007 9 mg/kg, respectively. The method was simple, rapid, high sensitivity and accurate, which could satisfy the rapid qualitative and quantitative detection of cyazofamid and CCIM residues in fruit samples.

Abstract:Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was used to analyze the volatile flavor substances of dried raw dark tea treated with bake drying and sun drying. The results showed that 65 volatile substances were identified in the two drying methods, including 23 aldehydes, 13 esters, 11 alcohols, 10 ketones, 3 heteroxides, 2 hydrocarbons, 2 pyrazines and 1 acid. The HS-GC-IMS fingerprint spectrum visually displayed the differences of volatile flavor between the bake-dried and sun-dried raw dark tea samples. Similarity and principal component analysis showed that each group of samples had their own specific volatile flavor substances, and sun-dried raw dark tea would release more characteristic volatile substances. The similarity between the two drying methods was low, and the raw dark tea dried by different methods were significantly distinguished. This study could provide a theoretical basis for the processing and flavor quality control of raw dark tea.