25 May 2020, Volume 46 Issue 10
    

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  • YI Zhi, DING Jieqiong, WANG Hongchao, LU Wenwei, ZHAO Jianxin, CHEN Wei, ZHANG Hao
    Food and Fermentation Industries. 2020, 46(10): 1-7. https://doi.org/10.13995/j.cnki.11-1802/ts.023385
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    In this study, biological characteristics and genetic diversity of nine strains of Clostridium butyricum, previously isolated from 150 healthy human stool samples, were studied. The analyses included the study of strain-specific and homologous genes, phylogenetic evolution, carbon source utilization, antibiotic resistance and simulated gastrointestinal fluid tolerance. Non-targeted pan-genomic analysis showed that the number of strain-specific genes in C. butyricum was 4-1 501 genes/strain, accounting for 6% to 29% of the total genes. The profiles of carbohydrate utilization and antibiotic resistance genes exhibited strain-specific characteristics. The genome sizes of the strains isolated from the same sample ranged from 4.48 Mb to 4.65 Mb, whereas the number of genes ranged from 4006 to 4203. These results indicated a significant strain level genomic diversity in C. butyricum. Phylogenetic analysis found that there was no significant correlation between strains clustering and their origin. Carbon utilization experiments showed that these C. butyricum strains were able to use mannose, cellobiose, and fructooligosaccharides, whereas, they failed to utilize inulin, erythritol, and rhamnose, and these findings were consistent with the results of functional gene analysis. The strains showed high resistance towards aminoglycosides, which confirmed the functional role of antibiotic resistance genes. These nine strains were generally non-resistant to other antibiotics, and there was a mismatch between the genotype and phenotype. Simulated gastrointestinal fluid experiments showed that the spore formation could significantly improve the acid and bile salt resistance. The above studies at the gene level including physiological characteristics of C. butyricum strains could lay the foundation for the screening and application of its excellent strains.
  • MAO Zhiyi, TAN Xinyuan, CAO Rong, ZHANG Xiaojuan, FU Jing, XU Jianguo, XU Guoqiang, ZHANG Xiaomei, XU Zhenghong
    Food and Fermentation Industries. 2020, 46(10): 8-13. https://doi.org/10.13995/j.cnki.11-1802/ts.023219
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    Adenosylmethionine (SAM) plays a vital role in the organisms’ metabolic activity as an important intermediate metabolite and has been widely used in pharmaceutical industry involving the therapies for liver, nervous systems, osteoarthritis and so on. Thus, production of SAM by enzyme transformation process exhibits potential industrial prospects. Codon optimization of the adenosylmethionine synthase gene sam2 derived from S. cerevisiae BY4741 was performed, and the gene was ligated to pET-28a(+) and pET-3b(+), resulting in recombinant plasmids pET-28a(+)-sam2 and pET-3b(+)-sam2, respectively, and was heterologous expressed in E. coli BL21(DE3) and E. coli Rosseta (DE3) respectively. Results showed that the recombinant strain E. coli BL21/ pET28a(+)-sam2 exhibited higher enzymatic activity up to 0.184 U/mL. Thus, the recombinant strain E. coli BL21/ pET-28a(+)-sam2 was chosen for the optimization of fermentation condition to further improve the enzymatic activity. Under optimal conditions, the enzyme activity of the recombinant adenosylmethionine synthase reached 0.245 U/mL, which was 34% higher than that before optimization.
  • YUAN Huijun, GAO Ze, WANG Juanjuan, BAO Jingting, FENG Zaiping
    Food and Fermentation Industries. 2020, 46(10): 14-18. https://doi.org/10.13995/j.cnki.11-1802/ts.023403
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    Aldehyde decarbonylase is a class of enzymes participate in plant alkane biosynthesis. In order to breed new varieties for fruits drying process, ECERIFERUM1 (CER1), an aldehyde decarbonylase coding gene was subjected into an RNA interference (RNAi) assay in xerophytic plant Lycium barbarum ssp. Bianguo. The segment between the 1,469 bp to 1,840 bp of LbCER1 coding aldehyde decarbonylase region in Lycium barbarum ssp. Bianguo was chosen as the optimal target of RNAi. An intermediate vector, pKANNIBAL-LbCER1(+)-PDK intron-LbCER1(-), was used to achieve the proper hairpin structure required for RNAi assay. The final hairpin sequence containing reverse complementary fragments of the chosen LbCER1 sequence flanking the PDK intron was inserted into the vector pART27. In addition, the final vector, pART27-LbCER1(+)-PDK intron-LbCER1(-), was chemically transformed into Agrobacterium tumefaciens GV3101. Restriction enzyme digestion and PCR methods were employed to screen positive intermediate and final vectors. The result showed that A. tumefaciens containing pART27-LbCER1(+)-PDK intron-LbCER1(-) was achieved. Hence, using this method to generate plasmids was correct, which laid the foundation for obtaining new varieties for dry processing through bioengineering of LbCER1- RNAi plants.
  • WANG Qiang, XIE Yuejie, LI Yuanyuan, WEI Huaheng, HE Zhifei, LI Hongjun
    Food and Fermentation Industries. 2020, 46(10): 19-26. https://doi.org/10.13995/j.cnki.11-1802/ts.023618
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    In this study, 2-monoacyl glycerolrich in 2D-MAG was synthesized from algal oil by ethanol, and the types of lipase, the molar ratio of algal oil to ethanol, reaction time, reaction temperature and utilization times of lipase were studied. The results showed that n-3 PUFA (62.26%) was the most abundant fatty acid of sn-2 in algal oil, and it was an ideal raw material for the synthesis of the sn-2 long-chain structural lipid 2D-MAG.The catalytic activity of lipozyme RM IM >Novozym 435 >lipozyme TL IM >Newlase F > Lipase AK > Lipase AY was in the order of high to low. Lipozyme RM IM was used to catalyze the alcoholysis of alga oil under the conditions of molar ratio of alga oil/ethanol of 1∶40, enzyme addition of 10%, reaction time of 3h and reaction temperature of 35 ℃, which was more conducive to the accumulation of 2D-MAG synthesis products. Under these conditions, the yield of 2D-MAG was 45.36%. After the 6th repetition of Lipozyme RM IM lipase, the content of 2D-MAG was significantly lower than that of the previous five times (P<0.05), indicating that although the overall catalysis of Lipozyme RM IM lipase was stable, its catalytic activity significantly weakened with the increase of repeated use. The results will provide references for the preparation and modification of functional structural lipids of related sn-2 long-chain polyunsaturated fatty acids.
  • LI Xuepeng, LIN Boyan, WANG Jinxiang, ZHOU Mingyan, ZHU Wenhui, YI Shumin, LI Jianrong, LIN Hong, MOU Weili, GUO Xiaohua
    Food and Fermentation Industries. 2020, 46(10): 27-34. https://doi.org/10.13995/j.cnki.11-1802/ts.023743
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    Myofibrillar protein from grass carp (Ctenopharyngodonidellus)was first oxidized by different concentrations of hydroxyl radicals (·OH) generated by FeCl3-VC-H2O2 system, and the effect of ·OH oxidation on the thermal aggregation behavior during the heating process was investigated by the measurements of protein thermal stability, surface hydrophobicity, Zeta potential values, endogenous fluorescence, turbidity, particle size and topographical features. The results showed that low-concentration of ·OH oxidation (generated by 0.1-1 mmol/L H2O2) was helpful to improve the thermal stability, while high-concentration of ·OH oxidation (generated by 10 mmol/L H2O2) could reduce the protein thermal stability. The surface hydrophobicity, Zeta potential values, and turbidity of myofibrillar protein in all groups were generally increased first and then decreased with the increase of temperature, while the endogenous fluorescence intensity and the surface hydrophobicity of the 10 mmol/L H2O2treated group decreased. The particle size of control group and the low-concentration of ·OH oxidation groups became larger with the increasing temperature, while the particle size of the 10 mmol/L H2O2treated group decreased after reaching a maximum at 70 ℃. The result of atomic for cemicroscope demonstrated that compared with the non-oxidized group, the aggregated particles formed by the oxidized myofibrillar protein were larger and fewer in number, and the distribution uniformity and shape regularity became worse. The results of this study indicated that low-concentration of ·OH oxidation was beneficial to the thermal aggregation of myofibrillar protein, while high-concentration ·OH oxidation was not favorable to the formation of soluble thermal aggregates. Meanwhile, ·OH oxidation changes the thermal aggregation mode and behavior of myofibrillar protein, which in turn affects the morphological characteristics of its thermal aggregates.
  • JIAO Ting, ZHU Huiyue, SI Qian, XU Mengshu, SUN Shanshan, MA Fangli, WANG Gang, ZHAO Jianxin, ZHANG Hao, CHEN Wei
    Food and Fermentation Industries. 2020, 46(10): 35-43. https://doi.org/10.13995/j.cnki.11-1802/ts.023271
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    In order to investigate the effects of different lactic acid bacteria (LAB) on the progression of non-alcoholic fatty liver disease (NAFLD) in mice which was induced by a high-fat and high-cholesterol diet (HFHCD), 4-week-old C57BL/6J mice were fed with HFHCD while administrated different LAB for 23 weeks. At the end of experiment, the blood lipid, blood glucose, liver inflammation, liver damage, fecal short-chain fatty acids (SCFAs), and gut microbiota were evaluated. It was showed that LAB supplementation prevented abnormal weight gain and liver damage induced by HFHCD, while showing different effects on the blood lipid and blood glucose regulation. Among all the strains, Lactobacillus reuteri CCFM8631 showed the highest capacity in alleviation of NAFLD. Furthermore, at the end of the treatment, the fecal SCFAs content and the abundance of Bifidobacterium, Lactobacillus, and Desulfovibrio significantly increased, whilst the abundance of Mucispirillum, Turicibacter, SMB53, and Allobaculum were significantly reduced. Correlation analysis between intestinal and liver pathological indicators showed that regulation on the SCFAs and gut microbiota was significantly associated with NAFLD alleviation. Therefore, the regulation on the SCFAs and gut microbiota by Lactobacillus reuteri CCFM8631 may be an important way for it to relieve NAFLD. This study provides a reference for the preparation of probiotic products in NAFLD prevention. This study provides a new option for the prevention and treatment of NAFLD. Also, it provides a reference for the development of probiotic preparations for NAFLD.
  • ZHENG Yuxing, ZHU Huiyue, JIAO Ting, YANG Shurong, LIU Qian, WANG Gang, ZHAO Jianxing, ZHANG Hao, CHEN Wei
    Food and Fermentation Industries. 2020, 46(10): 44-52. https://doi.org/10.13995/j.cnki.11-1802/ts.023285
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    In this study, DSS-induced colitis mice were used to investigate the effects of two Lactobacillus rhamnosus strains on disease and their potential mechanisms. C57BL/6J mice with colitis induced by 25 g/L DSS were administered with L. rhamnosus strains for 28 d. The results showed that L. rhamnosus FZJTZ46L6 alleviated DSS-induced colitis significantly and more effectively than that by FNMGEL5-1. L. rhamnosus FZJTZ46L6 alleviated the body weight loss caused by DSS, improved stool consistency and relieved bloody stool, and significantly improved the colonic mucosal damage in mice. Although FNMGEL5-1 alleviated the symptoms of diseases caused by DSS, it showed no effect on colonic inflammation and pathological damage. In addition, compared with the model group, L. rhamnosus FZJTZ46L6 significantly increased the transcription level of tight junction proteins in colon and reduced pro-inflammatory cytokines such as TNF-α、IL-1β、IL-6 and IFN-γ in colon. Besides, the content of short-chain fatty acids in the feces of mice was also increased significantly. The abundance of genera Coprococcus, the propionate and butyrate-producing bacteria, were elevated together with the diversity of gut microbiota.
  • WANG Hao, LI Haitao
    Food and Fermentation Industries. 2020, 46(10): 53-59. https://doi.org/10.13995/j.cnki.11-1802/ts.023474
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    The objective of this study was to evaluate the effect of mannose on colorectal tumorigenesis and proliferation, and explain the mechanism. Establishing a mouse model of primary colorectal tumors showed that daily administration of mannose could significantly attenuate colitis-associated colorectal tumorigenesis in mice. Moreover, mannose also suppressed the growth of colon cancer cells HCT116 and HT29 in cell experiments. With mannose concentration of 25 mmol/L, the glucose comsumption of these two cell lines reduced to (68.40±3.43)% and (58.78±1.27)% after 48 hours, respectively. Western blotting showed that mannose could down-regulate the expression of glucose transporter protein GLUT1 in both cell lines and mice. Taken together, we suggested that mannose could disturb the glucose uptake and suppress the proliferation of colon cancer cells in vitro, and attenuate tumorigenesis in mice, which was related to the down-`regulation of GLUT1.
  • WEI Wenli, MIYAO Shigeo, WU Zhengyun, ZHANG Wenxue
    Food and Fermentation Industries. 2020, 46(10): 60-65. https://doi.org/10.13995/j.cnki.11-1802/ts.023497
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    In this study, meta-transcriptomics technology was used to analyze the active microbial community structure during industrial cowpea pickle fermentation and functional gene annotation was performed as well. The results showed that Lactobacillus, Starmerella, Pediococcus, Weissella, Millerozyma and Sugiyamaella were the main active microbial genera in industrial cowpea pickle fermentation process. Among them, Lactobacillus predominated the initial and middle stages of fermentation, followed by gradually decrease of its relative abundance and the increase of Starmerella along with the fermentation. Starmerella became the absolutely dominant active genus in the later stage of fermentation. In the aspect of KEGG function annotation, overall, the highest amount of gene expression was related to metabolism in the fermentation process, mainly the carbohydrate metabolism. This study revealed the composition of the active microflora that really played roles in the fermentation process of industrial cowpea pickle, which provided a theoretical basis for the analysis of the fermentation mechanism and the control of the fermentation process.
  • HU Xiaolong, WANG Kangli, YU Miao, TIAN Ruijie, ZHANG Zhigang, WANG Yongliang, ZHAO Dong, HE Peixin, WEI Tao
    Food and Fermentation Industries. 2020, 46(10): 66-73. https://doi.org/10.13995/j.cnki.11-1802/ts.023321
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    In this study, high-throughput sequencing technology was used to analysis the microbial community succession and its spatial distribution on the upper-, middle- and lower-layer in the fermented grains of Jiahu Liquor Group Co., Ltd. The results showed that changes in α-and β-diversity of microbial communities in the fermented grains collected from different layers were similar. According to the result of β-diversity analysis, the entire fermentation process could be divided into early (0-7 d), middle (7-15 d) and late (15-60 d) stage, among which the species diversity and richness in the early stage were significantly higher than those in the late stages (P<0.05), and the genus Lactobacillus was the absolute dominant microorganism in the middle and late stage. The statistical significance of differences of α-diversity and composition at the phylum level of microbial communities in each layer was associated with the fermentation time. Generally, there was no significant difference in the α- and β-diversity of the microbial communities in the fermented grains at different layers with the same fermented time, in other words, fermented grains in each layer could not effectively cluster into one group (UPGMA and PCA analysis). This study could enrich the contents of the microbial community succession and spatial distribution of strong-flavor fermented grains in China, and provide data reference for further exploring the mechanism of the influence of spatial location on the microbial community of fermented grains, as well as provide ideas and methods for the study of the microbial community spatial heterogeneity in the Baijiu brewing environment.
  • LI Yuanyuan, LUO Bixia, ZHANG Lanlan, YAO Yalin, GUO Yan, HUANG Zhiguo, REN Zhiqiang
    Food and Fermentation Industries. 2020, 46(10): 74-79. https://doi.org/10.13995/j.cnki.11-1802/ts.022535
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    Daqu plays a key role in the production of Baijiu. To improve the quality of Baijiu, the physicochemical properties and volatile ingredients of Daqu made from different grains (rice, glutinous rice, corn, wheat and sorghum) were characterized. The high-throughput sequencing technology was employed to analyze the structure of microbial community. The correlation analysis between microbial community structure and physicochemical properties of Daqu was performed using SPSS 20.0. The results showed that the Daqu made from rice had the highest saccharification capacity (180.9 U/g) and fermentation capacity (0.86 g/(g·36 h)). Daqu made from wheat, had the highest esterification capacity of 26.4 mg/ (g·100 h), which was significantly higher than those of the others (P <0.05)). Ten ester compounds were found in the Daqu made from rice and eight aromatic compounds in the Daqu made from wheat, accounted for the most flavor compounds in different Daqu respectively. The dominant bacterial genera were Thermoascus and Bacillus in all kinds of Daqu. The results of correlation analysis suggested that the saccharification and fermentation capacity correlated with the Thermoascus, and the esterification capacity correlated with the Bacillus. Overall, the Daqu made from rice showed better properties than others.
  • DOU Jiayu, LIANG Qi, ZHANG Yan
    Food and Fermentation Industries. 2020, 46(10): 80-86. https://doi.org/10.13995/j.cnki.11-1802/ts.023301
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    The hard cheese has a long ripening period. The protein degrades to form a certain amount of water-soluble polypeptide, some of the small molecule polypeptides have antioxidant activity. In this study, the relationship between ripening time and antioxidant activity of water-soluble peptide was explored, skim yak milk was used as raw material to prepare hard cheese. The physicochemical index, antioxidant activity and microorganism quantity were determined during 0-6 months maturation. The results showed that regarding the antioxidant activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate, O-2· scavenging rate and OH· scavenging rate reached the peak value after 4 months, which were 52.39%, 63.27% and 49.54% respectively. The increase after one month were 71.43%, 62.20% and 104.39% respectively. The reducing power increased with a value of 24.50% after 2 months. During the 6-month ripening period, the number of microbes showed a downward trend. The total number of lactic acid bacteria and aerobic bacteria decreased by 9.89% and 8.00% after 4 month of maturity. The correlation analysis was performed on each indicator. The results showed that the ripening time affected the antioxidant activity of the water-soluble polypeptide and the bacterial count in cheese; the bacterial count in cheese ripening process affected the concentration of the water-soluble polypeptide and the antioxidant activity.
  • YANG Xi, CHENG Qun, LIU Jiang, CHEN Qiong, WANG Zhenxing, ZHANG Xuechun, SUN Jian
    Food and Fermentation Industries. 2020, 46(10): 87-91. https://doi.org/10.13995/j.cnki.11-1802/ts.023609
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    To explore the effect of the treatment with the lipid free radical on the functional properties of peanut proteins during food production, the hydroxyl radicals generating system (Fe/H2O2/Ascorbate) and peroxy radicals generating system (2,2'-azobis (2-amidinopropane) dihydrochloride, AAPH) were established to oxidize the peanut proteins, respectively. The functional properties (carbonyl content, solubility, emulsifying and foaming properties) of oxidized peanut proteins were further studied. The results showed that increase of radical concentration in 2 systems raised the carbonyl derivatives of peanut protein 1.42 times and 1.66 times, and the solubility decreased by 43.06% and 49.62%, respectively. Fluorescence analysis revealed a blue shift of maximum absorption wavelength, and the fluorescence intensity decreased by 33.01% and 28.02%, respectively. In addition, the emulsifying ability decreased by 63.91% and 28.91%, respectively, while emulsifying stability decreased by 46.79% and 33.08%, respectively. With the increase of free radical concentration, foamability and foaming stability first increased and then decreased. The highest foaming stability was obtained at hydroxyl radical concentration of 5 mmol/L and peroxy radical concentration of 0.5 mmol/L, respectively. In conclusion, these results imply that the functional properties of peanut proteins are greatly affected by the lipid free radicals, and could be regulated by appropriate oxidation.
  • WANG Kaituo, LEI Changyi, WEI Panpan, LIU Qun, LI Chunhong, JIANG Yongbo
    Food and Fermentation Industries. 2020, 46(10): 92-99. https://doi.org/10.13995/j.cnki.11-1802/ts.023563
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    The present study attempted to characterize the involvement of exogenous spermidine (Spd) in the maintenance of quality attributes in postharvest peaches, and further analyze the involved mechanism regarding the interrelationship between polyamines synthesis and ethylene release. The selected peaches were immersed in Spd solutions at different concentrations (0, 0.5, 1 and 2 mmol/L) for 10 min at 20 ℃ respectively, after which the peaches were stored at 20 ℃ for eight days. The quality and physiology parameters, contents of ethylene and polyamines and expression levels of relevant genes were measured at two-day intervals during storage. The results showed that the 1 mmol/L Spd treatment could more significantly decrease the decay incidence, maintain the higher TSS and TA contents as well as enhance the accumulations of total phenol, flavonoids and anthocyanins compared with the either Spd treatment at the concentration of 0.5 or 2 mmol/L. Meanwhile, the 1 mmol/L Spd treatment also remarkably delayed the increase on the MDA content, relative electric conductivity and level of reactive oxygen radicals (ROS) in peaches. In addition, the Spd treatment effectively up-regulated the transcription level of PpSAMDC, PpSPDS, PpADC and down-regulated the levels of PpACS1 and PpACO1 in peaches, contributing to the increase on the polyamines content and the decrease on the ethylene release and ratios of E/Spd and E/Spm over the storage period. These results indicated that reverse suppression of ethylene synthesis and its related genes could be attributed to the promoted expression of genes involved in polyamines metabolism and the polyamines accumulation, which finally delayed the process of membrane-lipid peroxidation and maintain the better quality in peaches.
  • TIAN Wenhui, LI Ruofan, JIANG Kun, SUN Liping, SUN Yun
    Food and Fermentation Industries. 2020, 46(10): 100-108. https://doi.org/10.13995/j.cnki.11-1802/ts.022994
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    The extraction conditions of red pigments from Russula vinosa in Yunnan province were optimized by orthogonal test. The stability and antioxidant activities of the pigment extracts were evaluated, and the main components were analyzed and identified by UPLC-Q-Orbitrap-MS system. The results showed that the optimum extraction conditions were ethanol concentration of 40%, solid to liquid ratio of 1∶90(g∶mL), and the 5 cycles of “ultrasonic treatment for 5 min,stand for 5 min,vortex oscillation for 30 s”. The pigment extracts exhibited good stability under certain heating conditions, and different pH ranges, with ultraviolet light irradiation, metal ions and food additives. The pigment extracts showed scavenging abilities on DPPH·, ABTS+· and ·OH, reducing effect on Fe3+, and inhibiting activity on lipid peroxidation. According to the MS analysis, 31 components were identified from the pigment extracts, including 9 organic acids, 1 polyol, 1 polysaccharide, 1 vitamin and 9 anthocyanins. The red pigment of R. vinosa was identified as water-soluble anthocyanins.
  • WEI Zheng, HE Yan, HAO Qilin, HUANG Xianzhi, DING Xiaowen, CHEN Mei, CHENG Hong
    Food and Fermentation Industries. 2020, 46(10): 109-117. https://doi.org/10.13995/j.cnki.11-1802/ts.023255
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    This study aims to investigate the antioxidant effects of tea polysaccharides after simulated gastrointestinal digestion and to provide a basis for the development of functional foods and animal experiments in the later period. Changes of DPPH · clearance, FRAP value, ORAC value, β-carotene fading inhibition rate, protein carbonyl content and DNA protection potential were detected after tea polysaccharides were digested for a certain period. Results showed that 0.1 mg/mL and 5 mg/mL tea polysaccharides were digested in simulated gastric fluid for 2 h. In respectively, the DPPH· clearance was (34.21±2.72)%, (92.80±0.35)%; the FRAP values were (135.89±3.15) μg/mL, (1 035.89±34.36) μg/mL; ORAC values reached (6.20±0.087) μmol/L, (8.58±0.15) μmol/L; β-carotene fading inhibition rates reached (71.73±0.48)%, (90.88±1.41)%; the protein carbonyl content was (0.126±0.003) μmol/mL, (0.054±0.002) μmol/mL; the brightness of DNA bands gradually increased. 1 mg/mL tea polysaccharide digested by intestine for 5 h after digested by stomach , its DPPH · clearance was only (6.06±0.21)%; FRAP value was (199.33±4.93) μg/mL; ORAC value was (7.45±0.15) μmol/L; β-carotene fading inhibition rate was (96.11±0.16)%; protein carbonyl content was (0.067±0.002) μmol/mL; the brightness of DNA band remained constant, but the time of digestion had no significant effect on the above results. Therefore, tea polysaccharide had an obvious antioxidative effect after simulated gastrointestinal digestion. The higher the concentration, the stronger the antioxidant capacity.
  • MENG Guangyan, CHEN Xuefeng, LIU Huan, CAI Guoqiang, ZHAO Yuanyuan, DANG Yue, ZHU Rongjing, SANG Cong
    Food and Fermentation Industries. 2020, 46(10): 118-123. https://doi.org/10.13995/j.cnki.11-1802/ts.022998
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    In previous experiments, high-throughput transcriptome sequencing was used to analyze the differentially expressed genes in Nostoc flagelliforme under salt stress of different concentrations. The results showed that the transcription level of potassium channel protein TrkA-N was significantly down-regulated at 0.3 mol /L salt concentration compared with that of the control group (without salt). In order to further study this gene and its coding protein, the TrkA-N sequence encoding the potassium channel protein was cloned by molecular biology methods using the genome of Nostoc flagelliforme as the template, and the nucleic acid sequence with a length of 696 bp was successfully obtained. By analyzing the biological information of the protein encoded by the nucleic acid sequence, the following results were obtained: the average molecular weight of potassium ion channel protein TrkA-N was 31.41 kDa, and the theoretical isoelectric point was 5.82. This protein did not contain transmembrane region and was a hydrophilic protein. There were 10 Ser residues, 6 Thr residues and 2 Tyr residues in the amino acid sequence of this protein, and the secondary structure of this protein was mainly α-helix and β-sheet. The TrkA-N coding gene was cloned into pET28a and transformed into E. coli BL21(DE3) for expression. The optimal expression condition was when OD600 reached 0.8 after 10 h of cultivation, adding 1 mmol/L of IPTG and induced for 20 h. Finally, the 31.41 kDa protein was successfully expressed in E. coli. This study provides theoretical basis to further clarify the mechanism of response to salt stress.
  • ZHENG Yanyan, ZHAO Lihui, WANG Yubin, MA Yue, ZHAO Xiaoyan
    Food and Fermentation Industries. 2020, 46(10): 124-131. https://doi.org/10.13995/j.cnki.11-1802/ts.023148
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    The postharvest diseases accounted for 20%-30% of the total loss of Hami melon, resulting in huge economic losses. The objective of this study is to investigate the physiological changes of Hami melon and to clarify the decay mechanism caused by Alternaria alternata and Trichothecium roseum. The propagation of pathogenic fungi and cell wall structure of melon were observed by scanning electron microscope (SEM). The disease symptoms, the activity of cell wall degradation enzyme, as well as the quality changes caused by cell wall degradation were discussed. The results showed that compared with different inoculation methods, the inoculation on holes exhibited the most serious spoilage, showed disease symptom after 1 d, and the disease incidence reached 100% on the 4th day. Comparing the two pathogenic fungus inoculated groups, the lesion area of melon infected by T. roseum expanded faster than that of A. alternata. SEM observation showed that during storage, the cell wall structure of the control group was complete, and fungi grew on the surface on the 7th day, but did not cause the degradation of the cell structure. In the group inoculated with A. alternata and T. roseum, the cells were covered with fungus and the cell wall collapsed on the 3rd day, and the tissue ruptured in the T. roseum group on the 7th day. The activities of β-galactosidase, polygalacturonase, carboxymethyl cellulase and β-glucuronidase in Hami melon pericarp after inoculation increased slowly. The enzyme activity in the inoculated group (1.28-1.85 times of the control group) was significantly higher than that in the control group. The respiration rate, weightlessness rate and relative conductivity of Hami melon inoculated with spoilage fungus were higher than those in the control group, but the hardness was lower than that of the control group. These results provide a theoretical basis for the infection process of pathogenic fungus and the disease control of melon.
  • LI Ningning, ZHANG Bo, NIU Jianming, SHI Xiao, MA Tengzhen, HAN Shunyu
    Food and Fermentation Industries. 2020, 46(10): 132-140. https://doi.org/10.13995/j.cnki.11-1802/ts.023059
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    In this study, the pre-fermentative addition of 150 mg/L of caffeic acid and rosmarinic acid in Cabernet Sauvignon red winemaking was performed. The influence of phenolic compounds addition on wine color parameters and aroma components was monitored after 6 months of aging using UPLC-MS and GC-MS technologies. The results showed that the L* value of the treated samples was decreased by 0.9-1.5 a.u. and the a* value was increased by 1.0-1.3 a.u.. Among them, the rosmarinic acid treatment had a better effect. Meanwhile, the results showed that the mean total anthocyanin and total phenol concentrations of the treated samples increased significantly by about 70 and 580 mg/L, respectively. The results of UHPLC-MS showed that although there was no difference in the types of anthocyanins in the tested samples, the addition of phenolic compounds could significantly improve their content, especially the type of acylated anthocyanins after rosmarinic acid treatment. The analysis of aroma components showed that caffeic acid treatment increased the content of esters, acids and terpenes in wine, while rosmarinic acid treatment increased the content of esters and decreased the concentration of other types of aroma components.
  • LI Yaling, SHI Ling, LIU Jia, LI Ling, MA Xue, ZHU Xuan, CUI Kuanbo
    Food and Fermentation Industries. 2020, 46(10): 141-146. https://doi.org/10.13995/j.cnki.11-1802/ts.022901
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    Xinjiang “Xiaobai” Apricot fruits were used as experimental material, the effects of different out-store modes on the shelf-life quality of apricot fruits after 49 days of near freezing temperature storage were studied. Physiological indexes and sensory qualities of fruit were measured daily during shelf-life. Results showed that: compared with direct out-storage (CK), both low-temperature chain out-storage (A) and slow-temperature increasing out-storage (B) could maintain high fruit firmness and soluble solid content (SSC), and effectively delay the decrease of titritable acidity (TA), ascorbic acid (VC) content and fruit color change (L*, a*, b*). Besides, the fruit commodity rate and sensory evaluation also maintained a high level. Compared to group CK and B, A had better parameters of experiment. Specifically, the shelf-life under the experiment of A could be extended longer than CK and B, and the sensory evaluation was significantly higher than group B. The results illustrated that the quality during shelf-life of apricot fruits treated with low-temperature chain out-store(A) is the best among the three experimental groups.
  • GAO Congcong, LIU Yunfei, DONG Chenghu, YU Jinze, LI Shuhai, ZHU Zhiqiang, GUAN Junfeng, LIN Qi, CHEN Cunkun
    Food and Fermentation Industries. 2020, 46(10): 147-151. https://doi.org/10.13995/j.cnki.11-1802/ts.023061
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    This study aims to explore the effect of new preservatives on the quality of Shine Muscatgrape and to select the best combination of preservatives. The effects of a new precise sulfur control preservative on the storage quality of Shine Muscat grape were studied under (0±0.5) ℃ storage condition. Results indicated that a new precision control sulfur antiskating agent could effectively maintain the luster of the grape storage period, delay soluble solids, total soluble solid (TSS) and titratable acid, total acid (TA) and decrease in reducing sugar content, thus to better keep grape appearance and flavor. Additionally, it could maintain the grape flesh hardness at a higher level and well inhibit the activity of polyphenol oxidase (PPO), maintain high catalase (CAT) activity, delay senility and increase the storage time. In conclusion, T1 (5 packets of precise pore preservative) is the best preservative for Shine Muscat grape.
  • WU Shida, ZHANG Yubin, TAI Jingjing, WEI Hongyan, LEI Yun, YU Qunli
    Food and Fermentation Industries. 2020, 46(10): 152-158. https://doi.org/10.13995/j.cnki.11-1802/ts.022706
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    The paper aims to study the impact of different packaging materials on the color of Tibetan mutton after calcium lactate injection. The hind leg meat of Euler Tibetan sheep was used as the experimental material in this experiment, by injecting 0.3% calcium lactate, PLA/PBAT degradable film and PA / PE film were used to pack the chilled Tibetan mutton (non packed meat as the control group) to measure the related index of its color. The results showed that the relative content of OMB in PLA/PBAT packaging film was higher than that in PA/PE film during cold storage. The activity of MMBR, LDH and NADH decreased with the increase of cold storage time, and the decrease rate of PLA/PBAT packaging group was lower than that of PA/PE packaging group and control group. With the prolongation of cooling time, the decrease rate of mitochondrial membrane potential and permeability in PLA/PBAT group was significantly lower than that in PA/PE group and control group. Through comprehensive evaluation, PLA/PBAT packaging film can effectively reduce the accumulation of MMB, delay the damage rate of mitochondrial physiological structure, and has the most apparent effect on stabilizing and maintaining meat color. This study provides a reference for the storage of Tibetan mutton.
  • ZHANG Jingjing, PENG Jian, YI Jianyong, BI Jinfeng, LYU Jian, HOU Chunhui, LIU Jianing
    Food and Fermentation Industries. 2020, 46(10): 159-165. https://doi.org/10.13995/j.cnki.11-1802/ts.023569
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    To investigate the effects of osmotic temperature on the texture and microstructural properties of instant controlled pressure drop (DIC) dried carrot chips, three osmotic temperatures 25, 50 and 100 °C were applied to immerse the carrot samples. Volume ratio, texture, microstructural and sensory properties of the carrot chips were measured. The results exhibited that the expanded volume of the DIC-dried samples was highly dependent on the solute gain (R2 = 0.957 3), and all of the selected osmotic conditions could be used to produce high-quality carrot chips with high volume ratio (≥0.72), appropriate hardness (4 521-4 729 g) and crispness (1.20-2.06 mm ). The microstructural characteristics were affected by osmotic temperature significantly, and the broadest range of pore wall thickness and pore size diameter were obtained at 100 ℃ and reached 18-558 μm and 18-1 926 μm, respectively. Furthermore, osmotic temperature significantly affected the sensory indicators (P<0.05), 100 ℃ osmotic samples obtained the highest color score, while the 25 °C osmotic samples obtained the strongest flavor and texture score. The present study supplied theoretical and technical support for porous carrot chips producion.
  • ZHANG Jianhua, XIA Yangyi
    Food and Fermentation Industries. 2020, 46(10): 166-172. https://doi.org/10.13995/j.cnki.11-1802/ts.023035
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    This experiment aims to study the effect of HL-low sodium salt on the gel properties of goose muscle fibrillin in Fenton oxidation system. Goose meat myofibrillar protein (MP) was used as the raw material, and 0.1%, 1%, and 3.5% NaCl added groups were used as controls, and 0.1%, 1%, 1.5%, 2.5%, and 3.5% HL-low sodium salt treatment group on the gel strength, gel cooking loss rate, gel water retention, gel chemical force and gel rheology of MP after oxidized by Fenton oxidation system for 24 h, 48 h and 72 h. The study found that with the extension of the oxidation cycle, the content of ionic bonds, hydrogen bonds, and disulfide bonds in MP gels decreased significantly (P<0.05), while hydrophobic interactions increased significantly (P<0.05). At the same time, the elastic modulus, gel strength and gel water retention of the MP gel were significantly reduced (P<0.05), and the gel cooking loss rate was significantly increased (P<0.05). In the same oxidation cycle, with the increase of NaCl and HL-low sodium salt, the content of hydrogen bonds, hydrophobic interactions, and disulfide bonds in MP gels is increasing, while the content of ionic bonds is decreasing. At the same time, the elastic modulus, gel strength and water retention of the MP gel were significantly increased (P<0.05), and the cooking loss rate of the gel was significantly reduced (P<0.05). When the addition ratio of HL-low sodium salt reaches 2.5%, the gel properties of MP and the gel properties of 3.5% NaCl treatment group are not significantly different or some properties are significantly better than the gel properties of 3.5% NaCl treatment group. This test provides a reference for the future research of HL-low sodium salt for myofibrillar protein.
  • XIE Jinming, ZHAO Xiufang, YUAN Jianglan, KANG Xu
    Food and Fermentation Industries. 2020, 46(10): 173-178. https://doi.org/10.13995/j.cnki.11-1802/ts.023075
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    In order to obtain acetic acid bacteria strains with high acid production and exceptional condition tolerance, three strains of acetic acid bacteria JM1, JM2 and JM3 were selected from Shaanxi Folk Vinegar Pei through preliminary and secondary screening. The acid-producing and fermentation characteristics of these selected strains were tested using AS1.41 as the control. The results showed that JM2 had a significantly higher acid-producing ability than the control (P<0.05), and the tolerance to temperature, ethanol, acetic acid and salt was relatively strong. It could resist to φ(ethanol) 9% (30 ℃, 180 r/min), φ(acetic acid) 3% and 16.0 g/L salt (30 ℃, φ(ethanol) 3.6%, 180 r/min), and had a strong acid-producing ability in the temperature range of 26-37 °C. Through the homologous sequence analysis of 16S rDNA, the strain JM2 was identified as Acetobacter tropicalis. JM2 is a superior strain of acetic acid bacteria with strong acid production ability and good tolerance, which has potential industrial application prospects.
  • WANG Xiaoping, HUANG Yongguang, ZHOU Wenmei
    Food and Fermentation Industries. 2020, 46(10): 179-184. https://doi.org/10.13995/j.cnki.11-1802/ts.023220
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    Twenty three strains of high temperature resistant bacteria were obtained from Maotai-flavor Daqu using the strategy of flavor orientation and structural sensory module of Maotai-flavor liquor. Through the sensory analysis at the end of solid and liquid fermentation, three strains producing typical Maotai-flavor were obtained. The strains were identified as Bacillus licheniformis by morphology and molecular biology. Through the temperature conditions optimization of liquid fermentation and comparative analysis of sensory smell, the temperature conditions were determined as follows: 37 ℃→50 ℃→55 ℃→60 ℃→65 ℃ temperature gradient fermentation for 10 d, each temperature fermented for 2 d at 150 r/min. Under this condition, the culture produced the strongest Maotai-flavor. This research provides a theoretical reference for microbial screening and flavor formation mechanism study in Maotai-flavor liquor brewing process.
  • FU Qi, LIN Junjie, ZHUANG Zhixia, HUANG Huabin, SUN Enxian, GAN Meiyu, XIAO Yujuan
    Food and Fermentation Industries. 2020, 46(10): 185-190. https://doi.org/10.13995/j.cnki.11-1802/ts.023581
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    A marine protease-producing fungal strain was screened from the local sea sediments in Xiamen. The morphology of this fungal strain was observed by scanning electron microscopy, and it was identified as Parengyodontium album HX2019006 by extracting the ITS sequence and comparing it in Genbank with the subsequent generation of the phylogenetic tree. This strain was capable of producing protease in seawater-based culture. We performed a single-factor optimization of the culture medium components and fermentation conditions to achieve an increase in protease yield. Three levels of maltose concentration, peptone concentration, and culture time were selected for the response surface methodology (RSM) optimization. Under the optimized culture medium and fermentation conditions, the protease activity in the fermentation broth was 71.1 U/mL, which was 125.7% higher than that under the initial conditions.
  • FENG Tingting, PENG Qian, WANG Yang, YE Yang
    Food and Fermentation Industries. 2020, 46(10): 191-196. https://doi.org/10.13995/j.cnki.11-1802/ts.022026
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    To avoid metal salt, which is contained in the preserved eggs endangering human body health and improve the production efficiency of preserved eggs, eggs without any metal salt were pickled in the traditional pickling method and adjusting the alkali method for NaOH concentration of 5%, 5.5%, 6%. The sensory evaluation, pH, free alkalinity, structure properties were studied in this paper. The results showed that non heavy metal salt-preserved eggs pickled with traditional methods had severely alkali injured on 16 d. However, the free alkalinity of metal-free preserved eggs pickled by cascade alkali adjustment decreased by 74, 79 and 77 mg/100g, respectively; and that of yolk decreased by 60 mg/100g, 69 mg/100g and 67 mg/100g, respectively. The L* value reached 25.97, a* value reached 25.1, and the color was dark red. Hardness reached 139.828 g and the elasticity reached 0.92, which is in full compliance with the quality of traditional preserved egg quality. The method of alkali adjusting in stages not only avoids the alkali injury successfully, but also shortens the production cycle of preserved eggs without heavy metal. The specific condition of preserved eggs without heavy metal is: pickled 25 ℃ , concentration of NaOH is 5.5%, concentration of black tea is 2%, change the concentration of NaOH to 0.3% when it has been pickled 11 d, then marinate until ripe 24 days.
  • GE Xinyu, LIU Yongfeng, GU Minghui, ZHANG Xueru
    Food and Fermentation Industries. 2020, 46(10): 197-202. https://doi.org/10.13995/j.cnki.11-1802/ts.023645
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    In this study, four types of tea were used to steam beef. Through sensory evaluation of processed beef, texture characteristics, moisture content, color, lipid oxidation, reduction ability, total antioxidant activity and other indicators were measured to comprehensively evaluate the quality of beef after tea treatment. The results showed that in terms of sensory evaluation, the beef treated with black tea had the best taste and flavor and the highest score. The moisture content of beef treated with green tea, dark tea and black tea decreased by 3.61%, 7.23% and 7.06% (P<0.05). After green tea, dark tea and black tea treatment, the hardness, chewiness and restoring force of beef increased significantly by 25.81%-45.57%, 41.60%-68.38% and 13.78%-26.57% (P<0.05). The cohesion of the dark tea treatment group increased significantly by 12.23% (P<0.05). The elasticity of beef after tea treatment was not significant (P>0.05). The L* value of beef treated with green tea and black tea decreased significantly by 9.61% and 12.26% compared with the control group (P<0.05), the a* and b* values of beef treated with black tea increased significantly by 102.07% and 15.75% (P<0.05), and the b* value of beef treated with scented tea decreased significantly by 23.06% (P<0.05). The degree of lipid oxidation of beef after tea treatment was significantly reduced by 29.16%-66.87% (P<0.05), and the inhibition effect was the best after scented tea treatment. The reducing capacity and total antioxidant activity of beef were significantly increased by 4.50-8.43 times and 2.73-4.24 times after tea treatment (P<0.05), with the most obvious effect of dark tea. It can be seen that all the four tea treatment groups can improve the physical and chemical properties of beef, as well as the reducing ability and total antioxidant activity of beef, among which the black tea treatment group has the best color and flavor, which is suitable for the preparation of beef products.
  • WANG Hui, LEI Zunguo, WANG Mei, CHEN Zhongai, TANG Jianbo, LIU Min, LIU Jia
    Food and Fermentation Industries. 2020, 46(10): 203-208. https://doi.org/10.13995/j.cnki.11-1802/ts.022025
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    To screen the best packaging methods and storage environments of dehydrated potato chips, the effects of different packaging methods and storage environments on quality of dehydrated potato chips were studied. The preservation effects of bulk bag, ziplock bag, kraft paper, foil bag, woven bag, plastic box, carton, vacuum packaging, nitrogen filling packaging, high temperature and humidity, refrigeration and frozen storage were compared. Moisture content, chroma-differentiation, firmness, crushing force and a total number of bacterial colonies were determined as indexes. The results showed that vacuum packaging and nitrogen filling packaging had the best preserve effect on the moisture content, chroma-differentiation, firmness crushing force of dehydrated potato chips, total number of bacterial colonies after storage for one year were basically the same as that at the beginning of storage. The dehydrated potato chips can be protected better under refrigeration and frozen storage conditions. Hence, vacuum or nitrogen filling packaging combined with refrigeration is the best way to preserve the dehydrated potato chips for a long time.
  • LI Tianyi, SUN Bo, XIE Shuangyu, LIU Kai, LI Zhi
    Food and Fermentation Industries. 2020, 46(10): 209-214. https://doi.org/10.13995/j.cnki.11-1802/ts.022674
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    In this paper, the sensory score, amino acid nitrogen, total acid, total ester and aerobic plate count of northeast farmhouse sauce stored at 4, 25 and 37 ℃ were analyzed to study its quality change. The results showed that, under different storage conditions, the sensory score gradually decreased with time, the content of amino acid nitrogen, total acid, total ester and aerobic plate count gradually increased. The sensory score and other indicators were analyzed by Pearson correlation, and the aerobic plate count as key indicator. We established a mathematical model that correlated the total number of colonies with storage time and storage temperature to predict the shelf life of northeast farmhouse sauce. The predicted data were compared and verified by the measured value of shelf life. By calculation, the predicted shelf life of northeast farmhouse sauce under the storage conditions of 4, 25, and 37 ℃ were 243, 130, 101 d, respectively. The relative error was less than 10%, indicating that the mathematical model constructed could accurately predict the shelf life of the product.
  • WANG Juan, MA Xiaoyan, WANG Tong, ZHU Yunsheng, ZHANG Haihong
    Food and Fermentation Industries. 2020, 46(10): 215-221. https://doi.org/10.13995/j.cnki.11-1802/ts.023351
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    In order to optimize the storage and preservation conditions of fresh daylily and prolong the shelf life of fresh daylily, this experiment used fresh daylily as raw material, and adopted vacuum pre-cooling and cold storage pre-cooling respectively to pre-cool the daylily, and used non-pre-cooling as control to study the effect of different pre-cooling methods on quality of fresh daylily during storage. The weight loss rate, sensory quality, respiration intensity, total soluble solid (TSS), peroxidase(POD) and superoxide dismutase(SOD) of fresh daylily were compared under different treatments, and the shelf life of fresh daylily was predicted. The results showed that vacuum pre-cooling was more effective in prolonging the shelf life of fresh daylily. Compared with cold storage pre-cooling and control group, vacuum pre-cooling can effectively reduce the respiratory intensity of daylily (P<0.05), delay the deterioration of sensory quality and nutrition loss such as vitamin C(P<0.05) and soluble solids (P<0.05) during storage, and maintain the higher activity of POD and SOD (P<0.05). The predicted shelf life of daylily precooled by vacuum pre-cooling was 23 days, which was four days more than pre-cooling method of cold storage and nine days more than control group. The research results provide a theoretical basis for optimizing the storage and preservation methods of fresh daylily.
  • WANG Jilian
    Food and Fermentation Industries. 2020, 46(10): 222-226. https://doi.org/10.13995/j.cnki.11-1802/ts.023331
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    Gliadin and arabic gum nanoparticles loaded with phloretin were prepared with gliadin as carrier and arabic gum as stabilizer, so as to stabilize phloretin and exert its efficacy. The effects of the concentration of gliadin, the ratio of the ethanol to water, pH and the concentration of salt on the stability of nanoparticles were investigated. High content tocopherol (phloretin) -AG nanoparticle was also prepared. The results showed that the best conditions were as follows: 5% of Gliadin, 1∶50 ratio of ethanol∶water, Gliadin∶AG=1∶2, at pH 4-9, less than 20 mmol /L of salt concentration. Under these conditions, the Gliadin -AG nanoparticles were very stable. When the ratio of Gliadin -AG nanoparticles to phloretin was 1∶5, the encapsulation efficiency was more than 88.9%, and the particle size, PDI, zeta-potential of the nanoparticles were all stable. The stability of compound nanoparticle of AG and Gliadin, as well as the tolerance of acid, alkali and salt all improved the encapsulation efficiency of phloretin.
  • XU Zhewei, CHEN Kun, HU Changying
    Food and Fermentation Industries. 2020, 46(10): 227-232. https://doi.org/10.13995/j.cnki.11-1802/ts.023547
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    A broad-spectrum quantitative detection method of Gram-positive bacteria was realized based on the competitive binding of Gram-positive bacteria and gold nanoparticles (GNPs) to lysozyme (LZM). LZM and GNPs were incubated under the optimized condition of 15 min, pH 8.0 and room temperature. The Gram-positive bacteria were quantitatively detected by ultraviolet-visible (UV-Vis) spectrum and laser light scattering (DLS). Compared with the UV-Vis spectrum, DLS showed higher sensitivity to particle size changes, and the addition of 0.14 mg/mL LZM solution could be reduced from 40 μL in UV-Vis method to 20 μL in DLS method when the signal intensity reached an acceptable range. Therefore, the limit of quantitation reduced from 1.26×107 CFU/mL to 6.87×105 CFU/mL. Compared with the Gram-negative bacteria, both quantitative methods showed good selectivity for Gram-positive bacteria, and both methods could realize the quantitative bacterial detection in real sample with the average recoveries of 83.0%-87.0% with the relative standard deviation of 2.4%-3.1%. The DLS quantification also showed higher sensitivity. Compared with the UV-Vis method, DLS showed the superiority in this competitive binding detection system, which could improve the sensitivity of detection.
  • LI Ting, TIAN Jiale, LIU Yang, LI Jiawen, QIAO Shaoting, DAN Tong, SUN Tiansong
    Food and Fermentation Industries. 2020, 46(10): 233-241. https://doi.org/10.13995/j.cnki.11-1802/ts.023457
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    To evaluate the potential of superior flavor production by starter strains in fermented milk, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus were used in combination as experimental strains for fermentation. Solid phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) were used to analyze the aroma profile in the commercial starter JD and the consortium fermented milk. The SPME-GC-MS results showed that a total of 116 volatile flavor compounds were identified in the fermented milk. The identified compounds were constituted of 17 acids, 11 aldehyde, 17 ketones, 15 alcohols, 11 esters, 30 alkanes, and 15 nitrogen compounds. The results of odor activity values (OAV) indicated that 6 kinds of key flavor compounds (OAV≥1) were found in the fermented milk, including 3-methylbutyraldehyde, benzaldehyde, n-nonanal, diacetyl, acetoin, and 2-nonanone. Moreover, other compounds such as caprylic acid, acetaldehyde, 3-hydroxybutyraldehyde, heptaldehyde, decanal, and 2-heptanone played a modificatory role in the overall flavor of the fermented milk (0.1≤OAV<1). These compounds had significant higher concentration, which conferred a superior flavor to the fermented milk. Principal component analysis and linear discriminant analysis revealed that A6 compound group had good aroma-producing characteristics. During fermentation, flavor was positively related to acid compounds, ketone compounds, alcohol compounds, nitrogen compounds and alkanes.
  • LI Tanping, LOU Xiaoming, LI Aiyang
    Food and Fermentation Industries. 2020, 46(10): 242-247. https://doi.org/10.13995/j.cnki.11-1802/ts.023512
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    Based on inductively coupled plasma tandem mass spectrometry (ICP-MS/MS), the interference-free determination of 10 harmful metal elements in perlite was established. After microwave digestion of the perlite sample with a mixed solvent HNO3+HCl+HF, the harmful metal elements Be, Cr, Co, Ni, As, Cd, Sn, Sb, Hg, and Pb were determined by ICP-MS/MS. In the MS/MS mode, NH3/He and O2 were selected as the reaction gases. The NH3/He and O2 mass shift method were used to eliminate the spectral interference during the determination of Cr, Co, Ni, As, and Cd. NH3/He on-mass method was used to eliminate the spectral interference during Cd measurement. The accuracy of the method proposed was evaluated by analysis of national standard reference material rock (GBW07106). In the linear range of 0-50 μg/L, the linear correlation coefficient of the analysis element was ≥ 0.999 6; Limit of detection (LOD) for analytes ranged from 0.52 to 7.36 ng/L, and the method detection limit (MDL) ranged from 0.26 to 3.68 ng/g; At a 95% confidence level, no significant differences were found between the results obtained via ICP-MS/MS and the certified values. The relative standard deviation (RSD) was ≤ 6.02%. The newly developed method has a good linear relationship, low LOD, high accuracy and excellent precision. It could be used for the determination of 10 harmful metal elements in food filter aid perlite.
  • ZHOU Qi, YI Xin, OUYANG Zhu, LI Guijie, ZHU Xiajian, FAN Jiaying, LI Zeling, TAN Anqun, HUANG Linhua, WANG Hua
    Food and Fermentation Industries. 2020, 46(10): 248-254. https://doi.org/10.13995/j.cnki.11-1802/ts.023501
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    A total of 18 satsumas were extracted from the especial-early, early, medium and late-ripening varieties. The aroma components of juice were qualitatively and quantitatively analyzed by using headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and principal component analysis (PCA) was used to compare and distinguish. Results showed that a total of 60 aroma components were detected in 18 kinds of satsuma juice, and 29 characteristic aroma was determined according to the odor activity value (OAV), among which the number and content of aroma component in 2003-4 Wenzhoumigan were the highest. The analysis showed that allo-ocimene, trans-2-hexenal, L-carvone, dodecanal, perilla aldehyde, β-citronellol and thyme camphor are characteristic components of a few varieties. The distribution of characteristic aroma components in different kinds of satsuma is characteristic, which can be amplified by principal component analysis. Hence, 2003-4 Wenzhoumigan and Ninghong 73-19 Wenzhoumigan have better aroma compositions than other varieties, but the quality of their juice is also influenced by factors such as producing area,cultivation and weather.
  • ZHENG Yue, YANG Wensheng, ZHANG Yuhui, LIU Dengyong
    Food and Fermentation Industries. 2020, 46(10): 255-263. https://doi.org/10.13995/j.cnki.11-1802/ts.023179
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    “Yangguang-pork” is a kind of pork produced by adopting animal welfare pig house breeding mode (high quality non-drug feed, high quality pig breed, welfare management and slaughter). This study compared and analyzed the differences in flavor of dorsal longest muscle of “Yangguang-pork” and ordinary chilled pork cooked by steaming, boiling, roasting and microwaving. The results showed that the sensory taste and smell of “Yangguang-pork” were about 1.3 points higher than that of ordinary pork and the degree of lipid oxidation were higher than that of ordinary pork except for the boiled sample, and the highest value of lipid oxidation in roasted “Yangguang-pork” sample was 6.55 mgMDA/kg. After processing, the relative contents of saturated fatty acids were lower than that of ordinary pork and the differences were significant (P<0.05). It was found that “Yangguang-pork” was healthier and more suitable for processing compared with ordinary pork. A total of 42 volatile flavor compounds were detected by four processing methods, with the highest proportion of aldehydes (59.25%-76.90%), among which the boiled “Yangguang-pork” sample had the highest proportion of aldehydes (76.9%). To summarize, “Yangguang-pork” has improved the flavor of pork through large-scale and scientific breeding, and is healthier and more delicious after processing by the four methods. This study provides consumers with data reports and theoretical references on the flavor differences of pork produced by different breeding methods and processed by different methods.
  • HE Hongju, WANG Wei, WANG Yangyang, MA Hanjun, CHEN Fusheng, ZHU Mingming, ZHAO Shengming, KANG Zhuangli
    Food and Fermentation Industries. 2020, 46(10): 264-270. https://doi.org/10.13995/j.cnki.11-1802/ts.023489
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    The aim of this study was to detect acid value of pork stored at 0-4 ℃ by using near infrared (NIR) hyperspectral technique (900-1 700 nm) in a rapid and nondestructive way. The hyperspectral images of pork samples were collected, and the reflectance spectral information within the region of interest of the images was extracted. Then eight methods including moving average smoothing (MAS), Savitzky Golay convolution smoothing (SGCS), median filtering smoothing (MFS), Gaussian filter smoothing (GFS), normalization correction (NC), multiplicative scatter correction (MSC), baseline correction (BC) and standard normal variate (SNV) were applied to preprocess the raw extracted spectra. Partial least squares (PLS) algorithm was used to establish the model for predicting the acid value of pork. The results showed that the full-band PLS models based on the raw spectra and BC spectra had better performance in prediction of acid value, with rP of 0.824, RMSEP of 0.594 mg/g in RAW-PLS model and rP of 0.825, RMSEP of 0.587 mg/g in BC-PLS model. Regression coefficient method (RC) and successive projections algorithm (SPA) were used to select the optimal wavelengths for PLS model optimization. The results showed that the RAW-RC-PLS model built with 28 optimal wavelengths selected from raw spectra by RC method had best prediction performance, resulting in rP of 0.846 and RMSEP of 0.569 mg/g. The whole study indicated that it is potential to realize the rapid and nondestructive detection of acid value of pork by NIR hyperspectral imaging technology.
  • ZHAO Yanyan, WANG Shuyan, ZHAO Linlin, ZHAO Lu, ZHOU Wei, CUI Zhenkun, ZHANG Hao, WANG Miaoyan, WANG Shuxian, ZHAO Shengming
    Food and Fermentation Industries. 2020, 46(10): 271-277. https://doi.org/10.13995/j.cnki.11-1802/ts.023146
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    Using the genome of Bacillus cereus ATCC 14579 as a template, the specific target of Bacillus cereus was screened by bioinformatics and comparative genomics analysis and three specific genes of Bacillus cereus were identified by PCR protocol. Then, these three specific genes were used for molecular biological detection of Bacillus cereus in food. The primers were evaluated by its specificity, sensitivity, anti-interference capability and artificial contamination. The results showed that three screened primers had better specificity and there was no specific band in non-Bacillus cereus. The primer gFA2 based on 公式had the best sensitivity which reached 359.5 fg/μL. The anti-interference results showed that in the presence of natural background flora enriched from beef (5.28×107 CFU/mL) and pork(7.75×106 CFU/mL)samples, the minimum detection limit of Bacillus cereus was 3.74 × 103 CFU/mL. After 10 h enrichment cultivation of Bacillus cereus, the detection limits of three primers to artificially contaminated beef and pork samples were 4.62 CFU/g and 8.38 CFU/g, respectively. In conclusion, the specific gene screened in this study and the PCR assay could be widely used for rapidly detection of Bacillus cereus in food safety validation.
  • HAO Qilin, CHEN Mei, HE Yan, CHENG Hong, WEI Zheng, HUANG Xianzhi, DING Xiaowen, ZHANG Xialan, TU Ximao, YANG Fengjiao
    Food and Fermentation Industries. 2020, 46(10): 278-283. https://doi.org/10.13995/j.cnki.11-1802/ts.023350
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    The purpose of this study was to investigate and evaluate the quality of green tea in X district of Chongqing. 41 samples of green tea in X district were extracted to determine the contents of 13 main evaluation indexes such as polyphenols and theanine, and the main quality characteristics of green tea in X district were evaluated by principal component analysis and cluster analysis. The results showed that there were differences in different indexes of green tea samples in X district. Five comprehensive evaluation indexes were extracted by principal component analysis, and the cumulative contribution rate reached 75.701%. According to the cluster analysis, 41 samples of green tea were grouped into four categories. There were some differences in the quality characteristics of each type of green tea, and the results were consistent with the principal component analysis. In conclusion, the best quality of green tea was selected from X district was number 30, 31 and 28.
  • ZHU Shichen, CHU Yushan, KE Zhigang, GU Saiqi, LYU Fei, DING Yuting, ZHOU Xuxia
    Food and Fermentation Industries. 2020, 46(10): 284-289. https://doi.org/10.13995/j.cnki.11-1802/ts.023154
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    Salt-cured fish is one of the traditional pickled aquatic products of China, which plays an important role in the food culture of South China. High-quality salted fish with a unique flavor and taste is very popular among consumers. However, the normal-temperature transportation of salt-cured fish makes it more prone to biochemical reactions, including hydrolysis and oxidation of lipids and proteins, amino acid decarboxylation and nitrate reduction, which affect the quality and safety of salt-cured fish during storage. The elucidation of the quality change and its internal mechanism of salt-cured fish during storage, and various methods (i.e., optimization of processing, quality control and packaging technologies) aiming to improve the quality and safety have gained more and more attention. To provide some guidelines for the high-quality storage of salt-cured fish, this paper reviewed the quality changes and corresponding mechanism of salt-cured fish during storage, and also made a further summary of the quality control technologies developed in recent years.
  • LYU Ying, XIE Jing
    Food and Fermentation Industries. 2020, 46(10): 290-295. https://doi.org/10.13995/j.cnki.11-1802/ts.023483
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    Aquatic products have a high value of nutrition and good flavor. Nevertheless, due to their organizational characteristics, aquatic products are prone to spoilage and deterioration at room temperature, so they need cold chain circulation. However, temperature fluctuation often occurs in current cold chain processes, which accelerates the deterioration of aquatic product quality. A series of adverse effects of temperature fluctuations on aquatic product quality were summarized, including poor texture, poor appearance, protein and lipid oxidation, and accelerated microbial growth, which significantly shortened shelf life. Some methods to maintain the quality of frozen storage aquatic products, such as adding some sugars, salting at an appropriate concentration, and vacuum packaging were summarized. The future research on how to avoid the adverse effects of temperature fluctuations on the quality of aquatic products in the cold chain break on the quality of aquatic products was proposed.
  • TANG Huali, GAO Tao, WANG Zhaodan, LUO Zhenyu, LUO Huangyang
    Food and Fermentation Industries. 2020, 46(10): 296-302. https://doi.org/10.13995/j.cnki.11-1802/ts.023229
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    With the increasing mis-lableing in aquatic product in recent years and the difficulty of identifying origins for ordinary consumers based on the appearance of aquatic products, this paper discusses the progress of stable isotope methods in the traceability of aquatic products. Through the analysis of the literature applied in the traceability of a single stable isotope technology in aquatic products, it is concluded that (a) in single stable isotope traceability, the number of origins, the number of samples, the species category and other factors will affect the correct rate of traceability of origin; and (b)there are certain difficulties in the traceability of single stable isotope traceability in organic culture and wild aquatic products; (c) also, the traceability effect of compound-specific isotope analysis (CSIA) in different seasons is influenced by species; (d) stable isotope binding and other traceability techniques could significantly improve the traceability of aquatic products, the identification of production methods, the correct rate of species identification.
  • XUE Shan, JIANG Wenhui, LI Bianhua
    Food and Fermentation Industries. 2020, 46(10): 303-308. https://doi.org/10.13995/j.cnki.11-1802/ts.022903
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    Under the tide of new engineering, the construction and reform of compulsory courses for food science has become the general trend. The “Food Safety and Hygiene” took “gold course” as the standard, which characterized as "high order, high innovation and high challenge", to keep going on perfecting the teaching contents, improving teaching meaning, and simplifying course characteristic. It was aimed at building “four-stage” teaching mode: before class, in class, after class and teaching reflection. Meanwhile, it summarized the practice methods and experiences in the process of the curriculum reform, and put forward the “gold course” construction idea, so as to provide impetus for constructing the reform of training mode for new engineering food professionals, and provide high-quality and shareable learning resources for the cultivation of application-oriented talents in food specialty.