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LI Bin, BAO Yiwen, LI Jiaxin, HONG Wanqi, XIAO Yahua, SI Xu, WANG Liang, HE Ying
2024,42(4):1-10, DOI: 10.12301/spxb202400315
Abstract:
Blueberry, known as the “king of berries”, is loved by consumers because of their high nutritional value. With the rapid development of blueberry processing industry, the by-products resources generated during the processing are becoming increasingly abundant. Comprehensively improving the utilization rate of by-product resources is an important way to practice the national “grain conservation and loss reduction” strategy. Application status of blueberry processing by-products in terms of efficacy component extraction, functional activity application, biomass conversion, and intelligent food packaging was summarized. Main problems restricting the overall development of the blueberry processing by-products industry were discussed, including low level of development and utilization of by-products, incomplete extraction technology for high retention of functional components, insufficient steady-state technology for processing activity of functional extracts, and a relatively single type of high value-added functional products in the market. In view of the existing problems, it was proposed that the key measures to effectively improving the utilization of blueberry by-product resources was to tackle the high steady-state technology of active ingredients in by-products, deeply explore precise nutritional benefits of active ingredients, develop diversified and personalized functional products, and construct complete processing standards and quality assurance systems. Current situation and existing problems of resource utilization of blueberry processing by-products were systematically summarized, and rational suggestions and future development trends were proposed, aiming to provide reference for the high-value utilization and high-quality development of blueberry processing by-products.
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LI Shugang, HUO Jiaying, ZHOU Qi, WANG Ping, LU Chaoqun, YU Xiongwei
2024,42(4):11-21, DOI: 10.12301/spxb202300528
Abstract:
Walnut oil is a good highly processed product of walnut resources in China. As is well known, both the volatile flavor and the biological activity presentation of walnut oil are influenced by its raw material properties, processing methods, and storage and transportation conditions. The core is the significant changes in the internal substance composition. To some extent, the volatile flavor changes of walnut oil are important dominant indicators to evaluate its biological activity. Based on objectively evaluating the main volatile flavor characteristics of walnut oil, the composition of flavor substances in walnut oil was analyzed. Aldehydes, ketones, alcohols, heterocycles, acids, and esters are the key components that give walnut oil a unique flavor. Furthermore, the main biological activities, including anti-inflammatory, antioxidant, anti-tumor, lipid-lowering, hypoglycemic, and immune regulation of walnut oil were introduced. Additionally, the effects of factors such as walnut variety and origin, harvesting period, processing technology, and storage conditions on the flavor compounds and bioactive substances composition of walnut oil were analyzed. Finally, the internal relationship between the volatile flavor of walnut oil and the changes in its biological activity was emphasized. This relationship is not only reflected in the volatile flavor components with biological activity, but also in oxidative products, which indirectly reflect the changes in the biological activity of walnut oil. This paper aimed to analyze the scientific connotation of the correlation between nutrition and flavor of walnut oil, and provide theoretical guidance for the quality control and high-value development and utilization of walnut oil.
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LIU Ye, SU Kai, XU Ying, DAI Yixin, BI Shuang
2024,42(4):22-30, DOI: 10.12301/spxb202300357
Abstract:
Walnuts are a source of high-quality vegetable oil and have a high lipid content and favorable fatty acid composition (a ratio of linolenic to linoleic acid approaching 1∶4). Walnut oil is rich in nutritional substance and has high edible and nutritional value, and plays an important role in regulating blood lipids, antioxidation, and enhancing immunity The commercial procedures for walnut oil production commercial using the traditional pressing methods of hot-pressed and cold-pressed were reviewed, and the key aroma compounds of walnut oil based on various flavor extraction methods were summarized. The current oil flavor enhancement technologies from the aspect of raw material pretreatment, leaching and enzymatic hydrolysis were reviewed in response to the bottleneck issue of weak flavor in cold-pressed walnut oil. The pathways of lipid oxidation and Maillard reaction and the mechanism of aroma enhancement at the molecular level were expounded. This study provides new ideas and new approaches for improving the flavor quality, in order to obtain the cold-pressed walnut oil with better flavor quality, and helps the development of cold-pressed walnut oil industry.
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LIU Ya, LIU Shuangping, LIU Tiantian, XIE Ling, MAO Jian
2024,42(4):31-44, DOI: 10.12301/spxb202400190
Abstract:
Fusel alcohols and esters are the key compounds affecting the quality of Huangjiu. Searching for excellent fermentative yeast strains and developing a fermentation process with low fusel alcohol production and high ester production have important theoretical value and application prospects. The Saccharomyces cerevisiae jiangnan1# was used as the starting strain, a mutation strain named YAR28 was screened through UV mutagenesis and atmospheric pressure room temperature plasma mutagenesis techniques, and the mass concentration of fusel alcohols and esters in laboratory-simulated fermented Huangjiu was used as the evaluation index. YAR28 was then subjected to spore purification screening, resulting in Saccharomyces cerevisiae with superior alcohol ester ratio production, named Saccharomyces cerevisiae Y28-23. It was cultured continuously for 5 generations to verify stability, showing no significant difference in alcohol production (P>0.05) but a 21.41% reduction in fusel alcohol mass concentration [(378.16±28.76)mg/L] compared to the starting strain and a 35.57% increase in ester concentration [(152.86±19.73)mg/L]. Saccharomyces cerevisiae Y28-23 was co-fermented with 52 non-Saccharomyces yeasts with potential ester production capabilities, and based on the evaluation index of low fusel alcohol and high ester production, the Wickerhamomyces anomalus Y34 was identified as the superior non-Saccharomyces yeast. Further optimization of the co-fermentation conditions between Saccharomyces cerevisiae Y28-23 and Wickerhamomyces anomalus Y34 revealed that co-fermenting Huangjiu with a 1∶10 addition ratio at a temperature of 20℃ during the main fermentation stage yielded optimal results for the alcohol ester ratio in Huangjiu, with a fusel alcohol concentration of (281.20±5.73)mg/L and an ester concentration of (240.02±2.47)mg/L. Compared to single-strain fermentation, the fusel alcohol mass concentration in Huangjiu decreased by 25.63%, while the ester mass concentration increased by 57.13%. Finally, based on metabolomics analysis, multiple differential metabolites and metabolic pathways closely related to substrate utilization and flavor formation during Huangjiu fermentation were obtained, elucidating the metabolic regulation of Wickerhamomyces anomalus Y34 on Saccharomyces cerevisiae Y28-23 during Huangjiu co-fermentation. This research could provide technical support for using fermentation strains to control alcohol ester content in Huangjiu brewing, and it was of reference value for the development and utilization of Huangjiu fermentation strain resources and the improvement of Huangjiu quality.
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GENG Xiaojie, CHEN Erbao, MA Zhiying, WANG Xinlei, WANG Bowen, ZHENG Fuping, SUN Jinyuan, ZHANG Yuhang, LI Zexia
2024,42(4):45-60, DOI: 10.12301/spxb202400133
Abstract:
Metabolites during Baijiu fermentation process are closely related to its unique style characteristics. Characteristics and succession of metabolites for Laobaigan Baijiu during its fermentation process have not been comprehensively analyzed. The metabolites of fermented grains during the fermentation process of Laobaigan Baijiu were identified by ultra-high performance liquid chromatography-tandem mass spectrometer. The differential metabolites were screened by principal component analysis and significant difference analysis, and then the possible metabolic pathways of these differential metabolites were annotated by KEGG database. Results showed that 2157 metabolites were detected in 9 samples of fermented grains with different fermentation time, of which 172 were extremely significant different metabolites (VIP>2, P＜0.01, |log2(FC)|>0.1). In different stages of fermentation, the expression levels of various metabolites were different. In the early stage of fermentation (0-8d), there were the most differential metabolites, with 128 extremely significant differential metabolites(P<0.01). The metabolism of amino acids, peptides and their analogs, lipids, heterocyclic compounds, carbohydrates, and carbohydrate conjugates was significantly up-regulated. In the middle stage (8-17d), there were 22 metabolites with extremely significant differences(P<0.01). The metabolism of amino acids, peptides and their analogs was significantly up-regulated (8-14d), and lipids metabolism was up-regulated first and then down-regulated, while flavonoids metabolism was down-regulated first and then up-regulated. In the later stage (17-36d), there were 33 metabolites with extremely significant differences, and the metabolism of amino acids, peptides and their analogs, and lipids was up-regulated first and then down-regulated. In addition, 104 metabolic pathways were annotated by KEGG database, and the metabolic network diagram was depicted accordingly. In different stages of fermentation, some metabolic pathways such as carbohydrate metabolism, lipid metabolism, flavonoid metabolism, and amino acid metabolism became more active mainly in the early stage of fermentation(P＜0.05), flavonoid metabolism was more active in the middle stage of fermentation(P＜0.05), lipid metabolism and amino acid metabolism were more vigorous in the late stage of fermentation(P＜0.05). Eighteen metabolites, such as serine, glutamine, and aspartate semialdehyde, showed significant differences in several fermentation stages, and they annotated galactose metabolism, glycine, serine and threonine metabolism, arginine and proline metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and glycerophosphate metabolism, which may be the potential pathways to produce flavor compounds. Based on metabonomics technology, the characteristics and succession of metabolites during the fermentation process of Laobaigan Baijiu were revealed, which could provide a theoretical basis for analyzing the flavor metabolism mechanism during the fermentation process of Laobaigan Baijiu.
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SUN Wenjing, CHEN Jiansheng, SHU Chao, ZHU Jiaqi, ZHANG Junxiang
2024,42(4):61-74, DOI: 10.12301/spxb202400149
Abstract:
In order to investigate the acid-enhancing effect of commercial Kluyveromyces and its effect on wine quality, Cabernet Sauvignon grapes from the eastern foot of Helan Mountain were used as raw materials. Three commercial Kluyveromyces strains were selected, two Lachancea thermotolerans strains (1 strain with trade name Excellence X-FRESH, referred to as “Excellence X”, and 1 strain with trade name ZYMAFLORE OMEGALT, referred to as “ZO”) and 1 Kluyveromyces thermotolerans strain (trade name CVE-7, referred to as “CVE-7”). They were subjected to sequential fermentation experiments with Saccharomyces cerevisiae (trade name Excellence XR, referred to as “XR”) at a 10∶1 inoculation amount.The effects of three strains of Kluyveromyces on organic acid content, basic physical and chemical indexes, aroma composition and sensory characteristics of wine were analyzed. The results showed that the Excellent X wine sample and CVE-7 wine sample had significant acid-enhancing effect, especially with an increase in the mass concentration of lactic acid. The basic physical and chemical indexes of all wines inoculated with Kluyveromyces met the requirements of GB/T 15037—2006. The purplish red tone of the Excellent X wine sample and the CVE-7 wine sample was significantly improved (P<0.05). Compared with the control group using only Saccharomyces cerevisiae, the aroma compounds in the wine samples prepared by mixed fermentation were more abundant and the mass concentration was higher, especially the total mass concentrations of ethyl lactate, higher alcohols and fatty acids were significantly increased (P<0.05). The principal component analysis of aroma active compounds with OAV greater than 1 showed that the Excellent X wine sample had richer esters, higher alcohols and fatty acids. CVE-7 wine sample increased the mass concentration of decanal, 2,3-butanedione, isoamyl caproate and other compounds. The ZO wine samples were rich in esters and had a high concentration of isoamyl alcohol.The results of subjective evaluation showed that the scores of Excellent X wine samples and CVE-7 wine samples were higher, followed by ZO wine samples, and the lowest was the control group without mixed fermentation. The results showed that the three commercial Kluyveromyces strains had positive effects on the quality of Cabernet Sauvignonwine in the eastern foot of Helan Mountain. In particular, the acid-enhancing effects of Excellence X and CVE-7 were good, and they could be used as acid-enhancing strains for low-acid Cabernet Sauvignon raw materials in the eastern foot of Helan Mountain. It was hoped that the research could provide reference for the acid-enhancing brewing technology of Cabernet Sauvignon wine and provide theoretical basis for the improvement of wine quality.
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DENG Jie, ZHANG Man, ZHOU Jie, YE Guangbin, HUANG Dan, LUO Huibo
2024,42(4):75-85, DOI: 10.12301/spxb202300482
Abstract:
The medium-high temperature Daqu (ZGW) and medium temperature Daqu(ZW)are mainly used for fermentation starter for strong flavor Baijiu. In the early days, ZW was used in the production of strong flavor Baijiu. At present, most of the production of strong flavor Baijiu has turned to ZGW. However, due to the lack of in-depth understanding of the differences in flavor and mechanism of strong flavor Baijiu brewed by 2 types of Daqu, choosing ZGW or ZW has become an urgent problem for the industry. In order to regulate and control the fermentation process to obtain better quality strong flavor Baijiu, the physicochemical indexes, enzyme activity indexes and microbial community structure of 2 types of Daqu were analyzed, and the influence path and function of different microorganisms on the flavor formation of strong flavor Baijiu were deeply explored. The results showed that acidity and protease activity in ZGW were significantly higher than ZW samples(P<0.05), whereas saccharification power, liquefaction power and fermentation power in ZW were significantly higher than ZGW(P<0.05), and there were no significant differences in water, starch and reducing sugar content between the 2 types of Daqu. 20 Dominant fungal species and 20 dominant bacterial species were detected in 2 types of Daqu. According to the identification of fungal species, the main dominant fungal species of ZGW were Thermoascus aurantiacus (24.64%), Dipodascus geotrichum (13.39%), Wickerhamomyces anomalus (8.04%). The main dominant fungal species of ZW were Candida tropicalis (40.00%), Kodamaea ohmeri (12.80%), Trichosporon coremiiforme (10.98%). For bacterial species, the main dominant bacterial species of ZGW were Acinetobacter johnsonii XBB1 (32.49%), Lactobacillus sakie (16.80%), Pseudomonas putida (10.68%). The main dominant bacterial species of ZW were Lactobacillus sakie (39.32%), Acinetobacter johnsonii XBB1 (18.45%), Enterococcus faecium (13.00%). Moreover, 23 differential species were found in 2 types of Daqu,including 14 species of fungi and 9 species of bacteria. According to microbial function prediction, there were abundant enzymes about carbon and nitrogen metabolism in 2 types of Daqu. The abundance of saccharify and fermentation enzymes in ZW was higher than ZGW, indicating the potential ethanol production ability of ZW was stronger than ZGW. The abundance of enzymes related to acid production and nitrogen metabolism in ZGW was higher than ZW, indicating the potential ability of acid production and nitrogen flavor compounds in ZGW was stronger than that in ZW. Through analysis of physicochemical parameters,enzyme activity, microbial community structure and metabolic function of 2 types of Daqu, the differences between 2 types of Daqu were further understood, to provide theoretical basis and technical guidance for strong flavor Baijiu production.
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XU Yuhan, KONG Yu, YANG Benxu, WANG Jianfeng, WU Shufen
2024,42(4):86-100, DOI: 10.12301/spxb202300374
Abstract:
i>Monascus yellow pigments are common natural food pigments with various physiological effects, but their poor water solubility and sensitivity to light, heat, and pH, which limit their wide application in food field. Water-soluble flaxseed protein (FPW) was used as a carrier to prepare the complex between FPW amd Monascus yellow pigments. The interaction hehavior between two types of Monascus yellow pigments (Monascin, MS and Ankaflavin, AK) and FPW was studied using combined spectral method. The dispersion and stability changes of pigments combined with FPW and Monascus pigments (Mps) which riched in Monascus yellow pigments in aqueous solution were investigated. Fluorescence spectroscopic analysis indicated that both MS and AK bound to FPW in the static quenching mode, and there was only one binding site. The binding constant of FPW-AK system was larger than that of FPW-MS system. The results of thermodynamic parameters demonstrated that the main forces maintaining FPW-MS system were hydrogen bond and van der Waals force, while those maintaining FPW-AK system were hydrogen bond and electrostatic attraction. Synchronous fluorescence spectrum and three-dimensional fluorescence spectrum showed that the addition of MS or AK changed the microenvironment of the amino acid residues of FPW, resulting in the conformational change of FPW. Analysis of UV-Vis and infrared spectroscopy further indicated that the secondary structure of FPW was changed after the addition of MS and AK. In addition, the combination of FPW and Mps could improve the dispersibility of Mps in water. After forming complexes with different concentrations of FPW, the retention rates of FPW-Mps were increased by 9.53%, 16.92%, and 31.37% compared to free Mps at a temperature of 25℃, a light intensity of 3900Lux, and a light duration of 72h. At temperatures of 4,25, and 50℃, and under light avoidance conditions, the retention rates of FPW-Mps increased by 25.65%, 22.04%, and 25.98% compared to free Mps. At a temperature of 25℃, pH values of 3,5, 7,9, and 11, and under light avoidance conditions, the retention rates of FPW-Mps increased by 10.27%, 12.96%, 12.06%, 17.82%, and 7.27% compared to free Mps, respectively. After composite with FPW, the retention rates of Mps increased under different illumination time, temperatures, and pH conditions, indicating that FPW could improve the photostability, thermal stability, and acid-base stability of Mps. This study aimed to provide new ideas for the stability study of Monascus yellow pigments.
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LIU Jinjie, MA Mengyao, XIE Yanli, YANG Yuhui, SUN Shumin, MA Weibin, LI Qian
2024,42(4):101-113, DOI: 10.12301/spxb202300496
Abstract:
The main forms of cyanidin-3-O-glucoside (C3G) in various pH environments are different,leading to differences in its antioxidant capacity. Black bean protein,a common dietary protein, has the potential to serve as a carrier for unstable bioactive compounds. Understanding the interaction mechanism between black bean protein and C3G is beneficial for their application in food systems. Interactions between β-conglycinin(7S)and glycinin(11S)soybean proteins with C3G and their effects on the oxidative stability and antioxidant capacity of C3G at pH 2.0,5.0,and 7.0 were investigated using various spectroscopic analyses and molecular docking experiments. The results showed that binding of C3G with 7S and 11S at pH 2.0 and 5.0 not only reduced the hydrophobic environment around Tyr residues and increased polarity,but also increased α-helical content and decreased β-sheet content in both 7S and 11S. At pH 7.0,the presence of C3G led to an increase in both α-helical and β-sheet content in 7S and 11S except for β-turns. Furthermore,the binding of C3G with 7S and 11S was an exothermic process,and at different pH conditions,hydrogen bonding and van der Waals forces were the main driving forces for the interaction between C3G with 7S and 11S,resulting in static fluorescence quenching of 7S and 11S. Both 7S and 11S exhibited the highest affinity for C3G at pH 7.0. Molecular docking revealed that GLU229,ARG356,and PRO101 residues on 7S,and ARG161,VAL162,ILE171,and THR176 residues on 11S played key roles in the binding with C3G. Moreover,the binding of 7S and 11S with C3G significantly enhanced the oxidative stability and antioxidant capacity of C3G at different pH conditions.
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LIU Xiuyu, LI Li, LI Wangqiang, DING Wentao, LIU Huanhuan, LI Zhenjing, LU Laifeng, GUO Qingbin, WANG Changlu
2024,42(4):114-124, DOI: 10.12301/spxb202300223
Abstract:
Mycotoxin present a significant risk to the safety of food, while pamamycin exhibits promising biological antibacterial properties against pathogenic fungi. In order to enhance the production of pamamycin, the differences in growth and metabolism, intracellular metabolites, and metabolic pathways of Streptomyces alboflavus TD-1 in two distinct fermentation media, one containing 1,2-propanediol and the other without it were studied based on metabolomics analysis method. The alterations in metabolite levels were examined in conjunction with the interplay between significantly different metabolite content changes and metabolic pathways to elucidate the underlying mechanism responsible for the high-yield biosynthesis of pamamycin. The findings of this study indicated that the addition of 1,2-propanediol increased the production of pamamycin by Streptomyces alboflavus TD-1. Through the utilization of gas chromatography-mass spectrometry, a total of 27 intracellular metabolites were identified as significantly different, and these metabolites were found to be closely associated with the biosynthesis of pamamycin. These metabolites were primarily involved in central carbon metabolism, amino acid metabolism, and fatty acid metabolism pathways. Furthermore, by employing a verification strategy of adding significant different precursors, the supplementation of glutamic acid resulted in a 102.33% increase in pamamycin yield. The supplementation of significantly different precursors, based on analysis of metabolomics, proved to be an effective approach for enhancing the yield of pamamycin. The objective of this study was to mitigate the adverse effects of Aspergillus flavus and aflatoxins contamination on grain processing foods, while also to ensure food safety from the source.
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HUANG Huiqin, XU Youqiang, LI Weiwei, ZHANG Chengnan, LI Xiuting
2024,42(4):125-134, DOI: 10.12301/spxb202300143
Abstract:
Phthalate esters (PAEs) show physiological toxicity, and the key to reduce toxicity lies in the complete cleavage of side chain ester bonds. Amidohydrolase RhoⅡ is a hydrolytic enzyme acting on ester bond of monoalkyl phthalate esters, but cannot hydrolyze PAEs. RhoⅡ was modified by computer simulation and site-directed mutation to achieve the purpose of PAEs hydrolysis. Results of the molecular docking between RhoⅡ and monobutyl phthalate (MBP) showed that RhoⅡ stabilized the carboxyl group of MBP with R-groups of Lys200 and Arg185, and both monomers of MBP and RhoⅡ formed hydrogen bond interactions. The site-directed mutation indicated that Asp39, Lys127 and Cys160 formed the catalytic triplet of RhoⅡ, which as the active center positioned in the hydrophobic cavity of the enzymes. Additionally, the mutant enzyme F44N was obtained through site-directed mutation and could hydrolyze PAEs, which significantly improved the enzymatic hydrolysis efficiency toward dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP) compared with the original enzyme. After phenylalanine mutated to asparagine, the steric hindrance effect of the enzyme on the substrate was significantly weakened, and the substrate binding cavity of the enzyme increased. DBP and DIBP could bind to the catalytic pocket of the enzyme to achieve ester bond cleavage. The catalytic mechanism was speculated based on molecular docking and mutation. The mutation might affect the substrate binding cavity, and the mutant enzyme could not effectively bind to the monoalkyl phthalate esters. This work performed sequence and structure analysis of RhoⅡ, and verified the catalyzed triplet. By finding the catalytic activity center of RhoⅡ and mutating the key site, the substrate specificity of RhoⅡ was changed. This study hoped that the enzyme resources related to enzymatic catalytic hydrolysis of PAEs could be expanded and promoted the application of related hydrolases.
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WANG Liping, WU Junyi, WANG Ying, QIN Min, CHEN Qianru, CHEN Tiejun
2024,42(4):135-144, DOI: 10.12301/spxb202300442
Abstract:
In order to find and explore new enzymes for degrading fucoidan, a strain of marine Flavobacterium sp. RC2-3 which can degrade fucoidan was screened from kelp as the research object, and its whole genome was sequenced. By comparing with the amino acid sequence of fucoidanase reported, transcriptomic analysis and real-time fluorescence quantitative PCR verification, a possible fucoidanase gene was discovered and named Fcn1. The full length of Fcn1 gene is 1221bp, encoding 406 amino acids, and the molecular weight of the protein is about 46.8kDa. By primer design and PCR amplification, the Fcn1 gene was cloned, and the heterologous expression vector Fcn1-pET-28a (+) was further constructed, and it was successfully induced and expressed in E.coli BL21(DE3) expression host.The recombinant enzyme Fcn1 was separated and purified by a nickel column with His tag. The specific enzyme activity of the purified enzyme in hydrolyzing fucoidan was 332U/mg determined by potassium ferricyanide method, and the purification multiple was 2.25. Enzymatic property study showed that the optimal reaction temperature of Fcn1 was 50℃, the optimal reaction pH was 8.0, and the stability of Fcn1 was better at 20-30℃ and pH 7.0-8.0. Combined with the results of enzymatic properties, the optimum reaction conditions were determined to be 30℃ at pH 8.0, and the kinetic parameters of enzymatic hydrolysis of fucoidanase were determined, with Km of 1.17mg/mL, Vmax of 10.53g·L-1·min-1. The enzyme has high activity in degrading fucoidan, and has great application potential in the development and utilization of fucoidan resources.
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LI Qinghuan, XIN Weishan, LI Jiajia, LIU Yongxia, LIU Yichang, ZHANG Zhong
2024,42(4):145-155, DOI: 10.12301/spxb202300477
Abstract:
The protective effect of D-fructose on spores of Bacillus subtilis treated by high-pressure thermal sterilization (HPTS) was studied. The treatment pressure of HPTS was 200 and 600MPa, the treatment temperatures were 25,65, and 75℃, the treatment time was 20min, and the mass fractions of D-fructose were 0,15%, 30%, 60%. At these conditions, flow cytometry was used to detect the damage of spore inner membrane before and after treatment, and Fourier infrared spectroscopy was used to analyze spore protein and inner membrane lipids before and after treatment to reveal the changes in protein structure and inner membrane lipid phase. After HPTS treatment, the permeability of spore inner membrane increased and the integrity of spore inner membrane was damaged. However, with the increase of D-fructose mass fraction, the phase state of spore inner membrane lipids gradually changed from liquid crystal state to gel state, stability of inner membrane increased, permeability decreased, integrity improved, and the content of ordered secondary structure of spore protein increased. When D-fructose was not added, after treatment at 600MPa and 75℃ for 20min, the 5.31 lg(CFU/mL) spores died,and the OD600 of spore suspension decreased to 0.41, the leakage rate of 2,6-pyridinedicarboxylic acid (DPA) reached 93.56%, the proportion of spores with inner membrane damage reached 80.95%, and the content of α-helix and β-fold structures in spore proteins decreased to 16% and 17%, respectively. When the mass fraction of D-fructose increased to 60%, the number of viable spores increased by 1.69 lg(CFU/mL) under the same HPTS treatment conditions, the OD600 of spore suspension increased by 0.09, the proportion of spores with inner membrane damage decreased by 20.74%, and the contents of α-helix and β-fold structures of spore proteins increased to 25% and 28%, respectively. D-fructose protected the spore structure and key substances in spores during HPTS treatment, and this protective effect was positively correlated with the mass fraction of D-fructose.
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ZHUANG Shuai, LIANG Shijie, XIONG Xin, LUO Yongkang
2024,42(4):156-163, DOI: 10.12301/spxb202300426
Abstract:
Grass carp are perishable due to the growth of microorganisms during storage, which restricts the development of its processing industry to some extent. Microbial interactions are important factors affecting food spoilage. In order to explore the roles of microbial interactions in the deterioration of grass carp quality, Pseudomonas putida (P. putida) and Shewanella putrefaciens (S. putrefaciens) were co-inoculated into grass carp flesh and arginine solutions. The effects of the interactions between P. putida and S. putrefaciens on their growth and spoilage potentials were evaluated by detecting total viable counts, soluble peptides, free ammonia, and putrescine changes in co-inoculated fish flesh and the putrescine production in the co-inoculated arginine solutions. Results showed that P. putida had potent activity in producing siderophores and inhibited the growth of S. putrefaciens in fish flesh by competing for ferric irons. The interactions between P. putida and S. putrefaciens increased the ammonia content of fish flesh in the first 11d of storage and facilitated the putrescine production in the first 8d of storage, but had no promoting effect on the production of soluble peptides. After 11d of storage, P. putida and S. putrefaciens did not promote the production of free ammonia and putrescine through interaction effects due to the inhibition of S. putrefaciens growth. P. putida was able to enhance the putrescine-producing activity of S. putrefaciens by providing arginine-degrading products through the arginine deiminase pathway. Overall, P. putida and S. putrefaciens facilitated the quality deterioration of grass carp during storage (0-11d) through microbial interactions like metabiosis. S. putrefaciens played a primary role in grass carp spoilage and the interactions with P. putida. More attention should be paid to the control research of S. putrefaciens in the development of fish preservation techniques.
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XUE Zixi, WANG Shengnan, YANG Hui, LIU He, HE Yutang, YANG Lina, LIU Jun
2024,42(4):164-172, DOI: 10.12301/spxb202300311
Abstract:
Emulsion gels can be used to replace part of the fat, reducing the amount of saturated fatty acids in foods such as mayonnaise, as delivery vehicle for active bioactive substances. The emulsion gels were prepared by heat-treated soy protein isolate (SPI) and soybean hull polysaccharide (SHP). The effects of different SHP contents (0,0.15%, 0.30%, 0.45%, 0.60%) on the structure, rheological properties, gelation properties and emulsion stability of the emulsion gels were investigated using rheometer, Fourier transform infrared spectrometer, X-ray diffraction, scanning electron microscopy and texture analyzer. The results showed that the microstructure of the emulsion gel become denser and the storage stability, G′ value, G″ value and the relative recovery of the emulsion gels increased as the additive amount of SHP increased. The apparent viscosity of the emulsion gels also increased with the increase of SHP addition and reached maximum at 0.45% SHP. The existence of intermolecular interactions and hydrogen bonding between SHP and SPI was founded by infrared spectroscopy and scanning electron microscopy. It was confirmed by 7d storage experiments that the storage stability of the emulsion gel was enhanced with the increase of SHP addition, and the best stability of the emulsion gel was achieved when the SHP addition was 0.45%. This study aimed to provide the theoretical basis for the development and application of SHP in food emulsion gels.
Volume 42,2024 Issue 4
Special Edition
青年视点
Special Studies
Foundational Research
Applied Technology
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Current Situation of China
Abstract:
The two pillars on which the development of China"s wine industry had long relied were quality and culture. Quality and culture have jointly shaped the core competitiveness of China"s liquor industry. On the whole, China"s liquor industry is in a stage of high-quality development. The overall output and sales revenue of the industry have maintained steady growth, showing strong market demand. At the same time, product innovation is active, and different liquors such as liquor, beer and wine have increased to varying degrees, reflecting the innovation power of the industry. As well as the inadequate popularization of health concepts and consumption concepts, etc. These problems need the joint efforts of the industry to solve them. From the perspective of cultural inheritance, Chinese wine culture includes three levels: consumption culture, brewing culture and wine culture. Consumption culture embodies the romanticism and realism characteristics of Chinese people. Brewing culture emphasizes the concept of ‘culture + quality = Chinese wine’ and pays attention to the combination of tradition and innovation. Wine culture highlights the uniqueness and unrepeatability of Chinese traditional wine, especially the time value. In the future, the development direction of China"s wine industry includes: relying on scientific and technological innovation to promote industrial upgrading, meeting the changing trend of the consumer market, improving product quality and perfecting the standard system, attaching importance to culture and brand building, and paying attention to environmental protection and sustainable development. In short, China"s wine industry is developing in a higher quality and more competitive direction, making due contributions to promoting the high-quality development of the national economy.
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Efficient Breeding of Cyclic Lipopeptide Producing Bacillus velezensis G-1 by Mutagenesis and Its Antibacterial Efficacy Against Alternaria alternata
Abstract:
In order to improve the cyclic lipopeptide production and reduce the production cost of cyclic lipopeptide producer Bacillus velezensis G-1, this study used Alternaria alternata as the target, cheap rapeseed meal as the nitrogen source, and antifungal activity as the evaluation index. The effects on the synthesis of cyclic lipopeptides in B.velezensis G-1 was studied by single and compound mutagenic manner of ultraviolet, microwave, ARTP(atmospheric room temperature plasma), NTG (nitroso guanidine), DES (diethyl sulfate) and EMS (ethyl methylsulfonate) mutagenesis. It aims to establish an efficient mutagenesis method for high-yield B.velezensis G-1 cyclic lipopeptide mutants and to select high-yield strain with rapeseed meal as nitrogen source. The results showed that the forward mutation rate of chemical mutagenesis was significantly higher than that of physical mutagenesis in six kings of single mutagenic manner. The forward mutation rate of chemical mutagenesis was higher for NTG and EMS, 59.97% and 59.40%, respectively. In physical mutagenesis, ARTP mutagenesis has a higher forward mutation rate of 31.37%. The combined treatment of NTG 150 μg/mL, EMS 0.6 mol/L, and ARTP 160 s was a better mutagenesis scheme than any kinds of single mutagenesis. A high-yield cyclic lipopeptide mutant selected from the compound mutagenic strain could increase the production of cyclic lipopeptide by 2.33 times. The antifungal activity in vitro and living life increased by 52.20% and 96.55%, respectively. In this study, the three-level composite mutagenesis method of NTG+EMS+ARTP could successfully obtain the B.velezensis G-1 mutant with high-yield cyclic lipopeptide, and further selected mutants with high-yield cyclic lipopeptide by rapeseed meal. It lays a theoretical foundation for the industrial application of the mutant and its cyclic lipopeptides in the prevention of A. alternata infection after fruit and vegetable harvest.
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Studies on Immobilization of β-Galactosidase and Synthesis of Galacto-Oligosaccharide
LI Zhi-hui, LAI Tian-tian, ZHANG Min, HAO Rui-min, YAO Meng-ke, ZHAO Hua, YANG Zhen-nai
Abstract:
Chitosan, sodium alginate, sodium alginate/gelatin, sodium alginate/carboxymethyl cellulose were used as immobilized carrier materials to investigate the immobilization methods of β-galactosidase, and the synthesis of galacto-oligosaccharide (GOS) by the immobilized enzyme was studied. The results showed that the obtained suitable immobilization carrier was chitosan, and the optimal immobilization conditions were deter mined as follows: chitosan mass concentration 0.03 g/mL, standing time 2 h, glutaraldehyde volume fraction 2%, crosslinking time 3 h, adsorption time 12 h, immobilization temperature 60 ℃, enzyme dosage 0.4 mg/g chitosan microspheres. Compared with the free enzyme, the immobilized enzyme""s stability against acid, alkali and heat was significantly improved. Chitosan immobilized β-galactosidase was further used to synthesize GOS, and the optimal reaction conditions were deter mined: amount of enzyme 2 U/ mL, pH 6.0, 50 ℃, initial lactose mass concentration 500 g/L, and reaction time 14 h. Under these conditions, the GOS yield reached 52.61%, which was higher than those reported. And the content of GOS with DP ≥ 3 in the GOS product was 37.07%. After repeated use of the immobilized enzyme for five times, the GOS production activity remained 97.21% . The chitosan-immobilized β-galactosidase obtained from the study has a promising application in the field of GOS synthesis.
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Screening Antimicrobial Peptides from Metagenomes Based on Deep Learning and Molecular Simulation
TIAN Yuan, HAN Aiping, XU Chunming
Abstract:
Antimicrobial peptides are a type of peptide capable of exerting antibacterial functions by interacting with bacterial cell membranes or intracellular biomolecules, thereby disrupting bacterial physiological processes and ultimately leading to bacterial death. Given the challenges posed to food safety and quality, the development of novel food antimicrobials to enhance food safety has become a key direction in current food science research. A novel deep learning model was constructed to screen for antimicrobial peptides from soil metagenomic data, with the screened peptides being validated using techniques such as molecular docking and molecular dynamics simulations. The model demonstrated an outstanding performance with a precision of 98.7%, an accuracy of 96.5%, a recall rate of 91.9%, an F1-score of 95.2%, and a specificity of 99.2%, showcasing excellent efficiency, interpretability, and practical application value alongside robust generalization capabilities. Post-training, the model successfully identified several peptides with significant antimicrobial potential, with a subset chosen for further investigation. The findings revealed that the screened peptide Gly-Thr-Ala-Trp-Arg-Trp-His-Tyr-Arg-Ala-Arg-Ser could effectively attach to the bacterial transcription regulator protein MrkH, exhibiting inhibitory effects on Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus. This study aims to provide a theoretical basis for the application of new antimicrobials in the food industry by integrating deep learning with molecular simulation technologies.
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Effect of thermal sterilization on the physicochemical stability of flaxseed milk
yuxiao, yang fan, dengqianchun
Abstract:
Flaxseed, as a functional food raw material, was rich in α-linolenic acid, high-quality proteins, soluble polysaccharides, lignans and other active lipid concomitants, thereby possessing high nutritional value and potential for development and utilization. This paper aimed to explore the effect of different thermal sterilization conditions (65 ℃-30 min, 85 ℃-15 min and 95 ℃-15 s) on the physicochemical stability of flaxseed milk, focusing on the changes in interfacial properties of oil bodies. The results showed that the thermal sterilisation treatment resulted in a gradual increase in the mean particle size of flaxseed milk by 95.58% (p<0.05) and a gradual decrease in the absolute value of the zeta potential by 12.26% (p<0.05), which was accompanied by the weakening viscoelastic properties and an increase in the physical stability of the milk. thermal sterilisation, the ratio of protein at the oil bodies interface in flaxseed milk increased by 64.42% (p<0.05) and the ratio of total sugar mass increased by 97.95% (p<0.05). The cryo-scanning electron microscopy imaging further confirmed the adsorption of exogenous storage proteins and soluble polysaccharides at the interface of oil bodies. In addition, the thermal sterilisation treatment increased the total phenolic content of the oil bodies interface in flaxseed milk by 1.42 times (P<0.05), the flavonoid content by 4.94 times (P<0.05), as well as the free radical scavenging capacity of 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) by 4.64 times (P<0.05), and FRAP ferric reducing antioxidant power by 54.05% (P<0.05). In conclusion, suitable thermal sterilization treatment (85 ℃-15 min) could enhance the physical and chemical stability of flaxseed milk based on the interfacial remodeling of oil bodies, which is hoped to provide a certain theoretical basis for further broadening the intake form and application scenarios of flaxseed.
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Liangli (Lucy) Yu, LU Weiying, LIU Jie, DU Lijuan
2016,34(6):1-6, DOI: 10.3969/j.issn.2095-6002.2016.06.001
Abstract:
Non-targeted detection technique has been extensively applied in the food safety and quality in recent years. In general, a non-targeted detection combines analytical approaches,fingerprinting techniques and chemometrics to detect toxicants or foreign components in foods without knowing their chemical structures. The key purpose of non-targeted detection technique is to detect whether the sample is abnormal, without prior knowledge of what caused the abnormality. This manuscript introduces and reviews the current progress and the prospect non-targeted food detection techniques, including chromatographic, mass spectrometric, spectroscopic, cell-based non-targeted detection techniques. Foods and ingredients including milk, Chinese wolfberries, Chinese angelica,oregano, honey, etc., were introduced. The non-targeted detection technique can help the healthy development of food industry and play an important role in protecting public welfare and human wellbeing.
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WEI Yi-min, WEI Shuai, GUO Bo-li, TIAN Yang
2013,31(2):1-6, DOI: 10.3969/j.issn.2095-6002.2013.02.001
Abstract:
Cadmium -Cd- , a kind of heavy metal pollutant, can enter the food chain though soil, dust, and crops. As a staple crop in China, rice can easily enrich Cd from soil, which can represent a health risk to consumers. Cd concentration in soil shows obvious heterogeneity in China. Cd concentration in rice is over the limit in some regions of China, due to the geological environment or soil pollution. At present, remedying polluted soil, screening low-accumulation material, and processing polluted rice have been developed to deal with Cd contamination. This paper summarized the present situation of cadmium contamination in rice and soil, analyzed the main factor of Cd enrichment in rice, reviewed the control technology of Cd contamination, and provided suggestions on Cd contamination research.
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LI Jianrong, LI Tingting, DING Ting
2016,34(1):1-8, DOI: 10.3969/j.issn.2095-6002.2016.01.001
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Aquatic product freshness evaluation standards were reviewed in this paper, including the traditional freshness evaluation methods and some kinds of new methods in recent years. Meanwhile, shelf-life predicting models of aquatic products were also introduced, including primary shelf-life model, secondary shelf-life model and tertiary shelf-life model. Moreover, the main problems and the research tendency of freshness comprehensive evaluation and establishment of shelf-life model of aquatic products were discussed, aiming to provide the convenience for the future research of aquatic products.
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CHEN Feng, LI Hedong, WANG Yaqi, FU Haiyan, ZHENG Fuping
2017,35(3):1-15, DOI: 10.3969/j.issn.2095-6002.2017.03.001
Abstract:
Chemometrics is a novel and unique interdisciplinary technique that integrates mathematics, statistics, chemistry and computer science. Pattern recognition and multivariate calibration method, as the core aspects of the technique, have exhibited overwhelming advantages in massive data mining and processing, as well as resolution and analysis of analytic signals. In addition, it is able to solve complex problems which are difficult to be solved by conventional analytic methods, resulting in the method to be widely used in many research fields, including food analysis. This paper reviews the fundamental principles of chemometrics in regards of its advantages and disadvantages,applications, and recent progresses. Furthermore, the review has pointed out problems which need to be solved in current researches, and highlighted the prospective aspects of the technique.
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2016,34(2):1-11, DOI: 10.3969/j.issn.2095-6002.2016.02.001
Abstract:
The existence of granular crystals seriously impairs the quality of plastic fats, and consequently, it is important to investigate the formation mechanisms and inhibitions of granular crystals in order to optimize the processing parameters and improve the product properties. The migration and aggregation of high-melting triglycerides as well as β polymorphism evolution are the possible mechanisms for the formation of granular crystals when temperature fluctuates. The fats composition and processing parameters have influences on the granular crystals formation such as shearing rates, temperature, cooling rates. To prevent their generation, modifying lipids by blending and interesterification and the application of emulsifiers were adopted to reduce the content of the high-melting triglycerides and stabilize the β′ polymorphism. Emulsifiers are mainly associated with the triglycerides present in the fat through acyl-acyl interactions, thus the chemical structures' similarity between the acyl groups would likely promote the cocrystallization, while the dissimilarities in fats structure might delay the nucleation and possibly inhibit crystal growth. Emulsifiers have different effects on the crystallization of plastic fats which strongly depend on their concentration and the molecular structure. In addition, when the degree of undercooling is high enough, addictive effects of emulsifiers will be weakened.
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JIA Yingmin, LIU Yangliu, CHEN Zhou
2017,35(6):1-9, DOI: 10.3969/j.issn.2095-6002.2017.06.001
Abstract:
For problems of food safety caused by microbial contamination and environmental safety due to drug-resistant strains, the development of emerging natural food additives with broad-spectrum and high-efficiency has been vital study trends in a modern food safety. Antimicrobial peptides(AMPs) are paid much attention for its advantage of broad-spectrum, good stability, unique antimicrobial mechanism of action and lower residue. With the further research, AMPs are expected to play a vital role in the application of food safety. Considering it, AMPs-related researches abroad were concluded in recent years. A review of the exploring and classification situation of AMPs,the development of bio-resistance and mechanism for bacteria, fungi, parasites, virus and tumor cells was provided. Meanwhile, the potential application fields of AMPs in food safety and scientific problems urgent to solve were analyzed. The resolution strategy also is provided for researchers as a reference in the field.
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WANG Shuo, ZHAO Yijie, LU Yang
2015,33(4):1-5, DOI: 10.3969/j.issn.2095-6002.2015.04.001
Abstract:
In this paper,the principles and the application of the molecular imprinted polymer-based sensors, such as lectrochemical sensors,piezoelectric sensors, and optical sensors, were discussed. Meanwhile, the developing trend of the molecular imprinted polymer-based sensor was addressed.
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2013,31(4):1-5, DOI: 10.3969/j.issn.2095-6002.2013.04.001
Abstract:
The dairy industry is related to the people's livelihood and a lot of attentions have been paid to its current situation and future development tendency. This paper introduced the current situation of Chinese dairy industry and analyzed the main problems occurred during the developing process. Moreover, the development tendencies of the basic research, and quality control were also discussed.
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2014,32(5):1-5, DOI: 10.3969/j.issn.2095-6002.2014.05.001
Abstract:
The current situation, main existing problems and trends of post-harvest processing of leafy vegetables were clarified in this study, and the key technologies to be solved during leafy vegetables processing were also discussed. The solution methods of fresh-cut process, freeze-drying process, disinfection process, packaging technology and equipment automation were emphatically analyzed. All these would give a clear instruction for the processing of leafy vegetables.
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CHEN Jian, ZHOU Shenghu, WU Junjun, ZHOU Jingwen, DU Guocheng
2015,33(1):1-5, DOI: 10.3969/j.issn.2095-6002.2015.01.001
Abstract:
Flavonoids are plant secondary metabolites, which are valuable natural products widely used in human health and nutrition due to its biochemical properties such as antiviral, antiobesity, and anticancer. The efficient production of pure flavonoid compounds through plant extraction or chemical production continues to be a major challenge for drug development. Hence, the microbial production of flavonoids has emerged as an interesting and commercially attractive approach. The emergence of systems metabolic engineering offers new perspectives on strain and process optimization. In this review, the strategies of systems metabolic engineering used to overcome these challenges are summarized, which will offer insights into overcoming the limitations and challenges of large-scale microbial production of these important pharmaceutical compounds.
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2012,30(3):1-12, DOI: 10.3969/j.issn.2095-6002.2012.03.001
Abstract:
China is the world's largest fruits processing country. The fruits processing industries have become an industry with comparatively superiority and international competitive capability. The importance to develop the processing industry of fruit was elaborated in this article as well as the overseas trend and current situation. The major restriction of the development were analysed, and the countermeasures for the development of this industry in China were also pointed out.
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ZHU Yun-ping, YUAN Zuo-yun, LV Yue-gang
2011,29(1):15-17, DOI: 10.3969/j.issn.2095-6002.2011.01.004
Abstract:
The water and oil content in the instant noodle are two important factors for the quality of the noodle. In this paper, the effect of fried time and fried temperature on the quality of the instant noodle was investigated. The results showed that the longer fried time and higher fried temperature would lead the lower water and higher oil content in the noodle. In addition, the effect of fried time was correlative with that of fried temperature on the quality of the noodle.
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RAO Pingfan, LIU Shutao, ZHOU Jianwu, GUO Jingke, KE Lijing
2015,33(3):1-4, DOI: 10.3969/j.issn.2095-6002.2015.03.001
Abstract:
Started from food processing, modern food science and food industry have provided the world enormous amount of food and always played a vital role in the development and evolution of human society. To date, food science has systematically studied the food storage, nutrition and sensory characteristics, while the interaction between food and body remains as a puzzle except a few pieces revealed by nutrition science and toxicology. Modern food industry has totally changed the way food is produced and consumed, and more importantly the way food interacts with human body. The ignorance of such changes in food science has made the debates in safety and health risks of industry food even more confusing. Three research topics are proposed for food-body interaction:elucidate the existing status of food compositions; interpret the body response to food; methods to utilise the complementary characteristics of different food compositions. From these new perspectives, some unique approaches and original discoveries of food science ought to be achieved, to provide answers to the major criticism upon food industry and transform food science to an intact science of food, an independent discipline of science.
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2011,29(1):54-58, DOI: 10.3969/j.issn.2095-6002.2011.01.012
Abstract:
The effects of culture conditions on the growth of Chlorella. sp were studied. The nutrient factors showed obvious effect on Chlorella.sp. The culture conditions based on BG-11 were optimized by orthogonal experiments: Na2CO 3 0.02g/L, the initial pH 6, the ratio of nitrogen to phosphorus 30, inoculum 5%, temperature 25℃, illumination 8800lx. Under the optimal culture conditions, the growth rate of Chlorella.sp was enhanced significantly.
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ZHAO Jie-wen, HUANG Xiao-wei, ZOU Xiao-bo, HUANG Lin, SHI Ji-yong.
2013,31(1):9-13, DOI: 10.3969/j.issn.2095-6002.2013.01.002
Abstract:
Olfaction visualization technology is a gas imaging technology and a new branch of artificial olfactory technology, which can solve common problems of traditional gas sensor. In order to detect the dominant spoilage bacteria (Clostridium, Brochothix thermosphacta and Pseudomonas) and evaluate freshness of pork, porphyrins and pH indicators were used as gas-sensing materials. The three spoilage bacteria were inoculated into three groups of pork samples and stored under three temperatures (16,4℃and 20℃). The images before and after the colorimetric sensor array interacted with pork's volatile flavors were collected, then image processing techniques was used to get digital signals which reflected the freshness of pork. The results showed that the olfaction visualization technology can be applied in rapid detection of dominant spoilage bacteria and evaluation freshness of pork.
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WANG Shao-yun, ZHAO Jun, WU Jin-hong, CHEN Lin
2011,29(4):50-57, DOI: 10.3969/j.issn.2095-6002.2011.04.013
Abstract:
Antifreeze proteins (AFPs) are the thermal hysteresis proteins that have the ability to modify the growth and inhibit the recrystallization of the ice. Antifreeze proteins aroused great interests of many researchers due to its special structure and functions. In this article, the recent advance in antifreeze protein was reviewed, and the types, properties, measurements, gene structures of antifreeze protein, and its applications in food industry were introduced. The application trials indicated that antifreeze protein could significantly improve the qualities of frozen foods, which suggested the potential food additives of antifreeze protein in future frozen food industry.
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2012,30(1):1-5, DOI: 10.3969/j.issn.2095-6002.2012.01.001
Abstract:
The research on aquatic products safety and the quality control technology was summarized and analyzed to reveal the present situation of aquatic products safety and quality control in China. Most of the research was focus on quality detection and control technology, others were about tracing system, early warning mechanism and risk assessment. At present, the enormous progress was made in technologies of quality detection and control. However, comparing with the advanced technology at abroad, the technology and management system in China still need to be improved. In the future, the aquatic food quality security technology should be promoted furtherly.
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2012,30(4):8-11, DOI: 10.3969/j.issn.2095-6002.2012.04.002
Abstract:
Mycotoxins, including aflatoxins (AFT), ochratoxin (OT), fumonisin (F), zearalenone (ZEN), deoxynivalenol (DON) and patulin (PAT) frequently contaminating agricultural products and feed were summarized. And then the influences of mycotoxin contaminants on human health and animal production were expatiated.
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Application of Low Field Nuclear Magnetic Resonance on the Rapid Determination of Frying Oil Quality
SHEN Yun-gang, XIAO Zhu-qing, CHEN Shun-sheng, ZHANG Ying-li, JIANG Wei, LAI Ke-qiang
2013,31(5):37-42, DOI: 10.3969/j.issn.2095-6002.2013.05.007
Abstract:
There has been growing concern about the frying oil quality due to its remarkable deterioration during the frying process. To investigate the performance of LF-NMR in the rapid determination of frying oil from various frying conditions, deep frying oil samples (n=107) including 96 soy bean oil samples and 11 shortening samples were collected from street vendors in 10 districts of Shanghai. Total polar compounds (TPC) and viscosity of the oil samples were determined. TPC values of 6 oil samples (56% of all the oil samples) were above the national standard for frying oil, indicating the quality problem of frying oil from the street vendors. The linear analysis showed a good linear relationship (R2=0892) between TPC and viscosity, while R2 was 0927 after the removal of shortening samples. After the analysis of the ratio of T21 areas (S21) in transverse relaxation (T2) spectra, the good correlations between S21 and TPC and viscosity were obtained and R2 was 0860 and 0840. After removing the shortening samples, R2 slightly increased to 0865 and 0854. The results demonstrate that LF-NMR has the potential to rapidly evaluate the quality of deep frying oil.
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LUO Zhi-wen, LIN Jian-long, YU Xiu-hong
2010,28(2):66-70, DOI: 10.3969/j.issn.2095-6002.2010.02.015
Abstract:
Aim at the problems about camera calibration for train wheel flange of dynamic testing system,the paper discusses the radial constraint-based camera calibration,chooses the camera calibration which contains distortion factors and developed the method of it by LabVIEW. This method makes use of the LabVIEW graphical development environment, embed core programs written in Matlab, has powerful data processing and nice interactive interface.
