A simple and sensitive analytical procedure for the determination of multi-component compounds in water samples was developed and optimized using the headspace solid-phase microextraction(HSSPME) coupled with gas chro...A simple and sensitive analytical procedure for the determination of multi-component compounds in water samples was developed and optimized using the headspace solid-phase microextraction(HSSPME) coupled with gas chromatography-mass spectrometry(GC-MS). Ten off-flavor compounds, including geosmin(GSM), 2-methylisoborneol(2-MIB), 2-isopropyl-3-methoxypyrazine(IPMP), 2-isobutyl-3-methoxypyrazine(IBMP), β-ionone, trans-2,cis-6-nonadienal(NDE), 2,3,4-trichloroanisole(2,3,4-TCA), 2,3,6-trichroloanisole(2,3,6-TCA), 2,4,6-trichloroanisole(2,4,6-TCA), and 2,4,6-tribromoanisole(2,4,6-TBA) were used as the target analytes. The optimization of extraction parameters including fibers types, extraction time, extraction temperature, stirring rate, sample volume, and ionic strength was carried out through the univariate approach. Ten off-flavor compounds were quantified within 50 min under the optimal conditions. Calibration curves with good linearity(r^2=0.990-0.998) were obtained in the range 1.0/2.0-100 ng/L, while the limits of detection for all compounds were lower than or close to the odor threshold concentration. Furthermore, the proposed method was applied to analyzing and determining the off-flavor compounds in real water samples from water-treatment plants.展开更多
Fluorescent in situ hybridization(FISH) is an important technique in plant genome research,because it provides integrated information about DNA,chromosomes and genomes.Genomic in situ hybridization(GISH) is a modifica...Fluorescent in situ hybridization(FISH) is an important technique in plant genome research,because it provides integrated information about DNA,chromosomes and genomes.Genomic in situ hybridization(GISH) is a modification of FISH that can be used to rapidly compare genome content,relatedness,organization and/or behavior.GISH results often provide insight into genome evolution and species relationships.The cotton genus Gossypium consists of about 50 species,including 5展开更多
研究不同添加量(2%、4%、6%)大豆分离蛋白(soy protein isolate,SPI)、蛋清蛋白(egg white protein,EWP)、乳清分离蛋白(whey protein isolate,WPI)对白鲢鱼糜肌原纤维蛋白(myofibrillar protein,MP)结构及其结合特征腥味物质(己醛、壬...研究不同添加量(2%、4%、6%)大豆分离蛋白(soy protein isolate,SPI)、蛋清蛋白(egg white protein,EWP)、乳清分离蛋白(whey protein isolate,WPI)对白鲢鱼糜肌原纤维蛋白(myofibrillar protein,MP)结构及其结合特征腥味物质(己醛、壬醛、1-辛烯-3-醇)能力的影响。结果表明,适量外源蛋白可促进MP展开,MP的表面疏水性、浊度、粒径、Zeta电位也随之增加,此时暴露出的疏水基团可增强MP结合己醛、壬醛的能力,暴露出的羟基则可增强MP对1-辛烯-3-醇的结合。外源蛋白添加量进一步增加,添加EWP、WPI的MP结合1-辛烯-3-醇的能力由于蛋白表面增加的亲水基团进一步增强。此外,添加WPI能更好地增强MP结合3种腥味物质的能力。展开更多
银鲫(Carassius auratus gibelio)喜好栖息在泥塘底部,土腥味重。研究腥味物质的成分是进行脱腥处理的重要前提和理论依据,为了探究鱼体不同部位腥味物质差异,找到一种有效测定包括土腥味物质在内全部腥味物质的检测方法,采用固相萃取...银鲫(Carassius auratus gibelio)喜好栖息在泥塘底部,土腥味重。研究腥味物质的成分是进行脱腥处理的重要前提和理论依据,为了探究鱼体不同部位腥味物质差异,找到一种有效测定包括土腥味物质在内全部腥味物质的检测方法,采用固相萃取整体捕集-气相色谱/质谱联用(solid phase extraction and gas chromatography/mass spectrometry,MMSE-GC-MS)分析比较银鲫背部、腹部、尾部及鱼皮中腥味物质的异同,对鱼体不同部位腥味物质分布规律进行深入分析;采用微波蒸馏-固相微萃取-气相色谱/飞行时间质谱联用(microwave distillation-solid-phase microextraction-gas chromatography/time-of-flight mass spectrometry,MAD-SPME-GC-TOFMS)同时检测出银鲫的2种典型土腥味物质:2-甲基异莰醇和土臭素;同时采用固相微萃取-全二维气相色谱/飞行时间质谱联用(solid-phase microextraction coupled with full two-dimensional gas chromatography/time-of-flight mass spectrometry,SPME-GC×GC-TOFMS)对银鲫鱼肉的挥发性风味物质进行检测,并对3种方法进行探究和比较。结果显示,微波蒸馏前处理能有效提高腥味物质的富集效果,未来可结合一维气相色谱实现全部腥味物质的同时检测。展开更多
The flavor is a decisive sensory characteristic that determines the popularity of French fries(FFs).During high-oleic rapeseed oil(RO)frying,the flavor development of FFs showed three noticeable stages including break...The flavor is a decisive sensory characteristic that determines the popularity of French fries(FFs).During high-oleic rapeseed oil(RO)frying,the flavor development of FFs showed three noticeable stages including break-in(3.5%-7.5%of total polar compounds(TPC)),optimum(7.5%-22.18%of TPC),and degrading stages(above 22.18%of TPC).Further,in order to distinguish the key aroma compounds in each stage,the FFs prepared in RO at TPC of 3.5%(FF4),14.5%(FF15),and 26.96%(FF27)and their relevant oils(RO4,RO15,RO27)were selected for sensory-directed analysis.The results revealed that the FF4 had low contents of(E,E)-2,4-decadienal(deep-fried odor)which also caused lower sensory score in FF4 sample.The higher contents of(E,E)-2,4-decadienal in FF15 induced its higher deep-fried odor.The FF27 had higher hexanoic acid(sweaty odor),heptanoic acid,nonanoic acid,benzene acetaldehyde(stale odor),and trans-4,5-epoxy-(E)-2-decenal(metallic odor)compared with FF4 and FF15,thus leading to the undesirable flavor of FF27.Moreover,the decrease of 2,5-dimethylpyrazine and 2-ethyl-6-methyl-pyrazine in FF27 induced the lower roasty flavor,which may also lead to the decline of the sensory score.Similarly,the higher contents of(E)-2-undecenal,hexanoic acid,heptanoic acid,and nonanoic acid in RO27 lead to increase its rancid score and thus lower the sensory score.展开更多
基金Project(21277175) supported by the National Natural Science Foundation of ChinaProject(JCYJ20120618164317119) supported by Shenzhen Special Fund for Development of Strategic Emerging,China
文摘A simple and sensitive analytical procedure for the determination of multi-component compounds in water samples was developed and optimized using the headspace solid-phase microextraction(HSSPME) coupled with gas chromatography-mass spectrometry(GC-MS). Ten off-flavor compounds, including geosmin(GSM), 2-methylisoborneol(2-MIB), 2-isopropyl-3-methoxypyrazine(IPMP), 2-isobutyl-3-methoxypyrazine(IBMP), β-ionone, trans-2,cis-6-nonadienal(NDE), 2,3,4-trichloroanisole(2,3,4-TCA), 2,3,6-trichroloanisole(2,3,6-TCA), 2,4,6-trichloroanisole(2,4,6-TCA), and 2,4,6-tribromoanisole(2,4,6-TBA) were used as the target analytes. The optimization of extraction parameters including fibers types, extraction time, extraction temperature, stirring rate, sample volume, and ionic strength was carried out through the univariate approach. Ten off-flavor compounds were quantified within 50 min under the optimal conditions. Calibration curves with good linearity(r^2=0.990-0.998) were obtained in the range 1.0/2.0-100 ng/L, while the limits of detection for all compounds were lower than or close to the odor threshold concentration. Furthermore, the proposed method was applied to analyzing and determining the off-flavor compounds in real water samples from water-treatment plants.
文摘Fluorescent in situ hybridization(FISH) is an important technique in plant genome research,because it provides integrated information about DNA,chromosomes and genomes.Genomic in situ hybridization(GISH) is a modification of FISH that can be used to rapidly compare genome content,relatedness,organization and/or behavior.GISH results often provide insight into genome evolution and species relationships.The cotton genus Gossypium consists of about 50 species,including 5
文摘研究不同添加量(2%、4%、6%)大豆分离蛋白(soy protein isolate,SPI)、蛋清蛋白(egg white protein,EWP)、乳清分离蛋白(whey protein isolate,WPI)对白鲢鱼糜肌原纤维蛋白(myofibrillar protein,MP)结构及其结合特征腥味物质(己醛、壬醛、1-辛烯-3-醇)能力的影响。结果表明,适量外源蛋白可促进MP展开,MP的表面疏水性、浊度、粒径、Zeta电位也随之增加,此时暴露出的疏水基团可增强MP结合己醛、壬醛的能力,暴露出的羟基则可增强MP对1-辛烯-3-醇的结合。外源蛋白添加量进一步增加,添加EWP、WPI的MP结合1-辛烯-3-醇的能力由于蛋白表面增加的亲水基团进一步增强。此外,添加WPI能更好地增强MP结合3种腥味物质的能力。
文摘银鲫(Carassius auratus gibelio)喜好栖息在泥塘底部,土腥味重。研究腥味物质的成分是进行脱腥处理的重要前提和理论依据,为了探究鱼体不同部位腥味物质差异,找到一种有效测定包括土腥味物质在内全部腥味物质的检测方法,采用固相萃取整体捕集-气相色谱/质谱联用(solid phase extraction and gas chromatography/mass spectrometry,MMSE-GC-MS)分析比较银鲫背部、腹部、尾部及鱼皮中腥味物质的异同,对鱼体不同部位腥味物质分布规律进行深入分析;采用微波蒸馏-固相微萃取-气相色谱/飞行时间质谱联用(microwave distillation-solid-phase microextraction-gas chromatography/time-of-flight mass spectrometry,MAD-SPME-GC-TOFMS)同时检测出银鲫的2种典型土腥味物质:2-甲基异莰醇和土臭素;同时采用固相微萃取-全二维气相色谱/飞行时间质谱联用(solid-phase microextraction coupled with full two-dimensional gas chromatography/time-of-flight mass spectrometry,SPME-GC×GC-TOFMS)对银鲫鱼肉的挥发性风味物质进行检测,并对3种方法进行探究和比较。结果显示,微波蒸馏前处理能有效提高腥味物质的富集效果,未来可结合一维气相色谱实现全部腥味物质的同时检测。
基金financially supported by the National First-Class Discipline Program of Food Science and Technology (JUFSTR20180202)Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX20_1852)+1 种基金National Natural Science Foundation of China (31901728)Jiangsu Planned Projects for Postdoctoral Research Funds (2020Z297)
文摘The flavor is a decisive sensory characteristic that determines the popularity of French fries(FFs).During high-oleic rapeseed oil(RO)frying,the flavor development of FFs showed three noticeable stages including break-in(3.5%-7.5%of total polar compounds(TPC)),optimum(7.5%-22.18%of TPC),and degrading stages(above 22.18%of TPC).Further,in order to distinguish the key aroma compounds in each stage,the FFs prepared in RO at TPC of 3.5%(FF4),14.5%(FF15),and 26.96%(FF27)and their relevant oils(RO4,RO15,RO27)were selected for sensory-directed analysis.The results revealed that the FF4 had low contents of(E,E)-2,4-decadienal(deep-fried odor)which also caused lower sensory score in FF4 sample.The higher contents of(E,E)-2,4-decadienal in FF15 induced its higher deep-fried odor.The FF27 had higher hexanoic acid(sweaty odor),heptanoic acid,nonanoic acid,benzene acetaldehyde(stale odor),and trans-4,5-epoxy-(E)-2-decenal(metallic odor)compared with FF4 and FF15,thus leading to the undesirable flavor of FF27.Moreover,the decrease of 2,5-dimethylpyrazine and 2-ethyl-6-methyl-pyrazine in FF27 induced the lower roasty flavor,which may also lead to the decline of the sensory score.Similarly,the higher contents of(E)-2-undecenal,hexanoic acid,heptanoic acid,and nonanoic acid in RO27 lead to increase its rancid score and thus lower the sensory score.