We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. G...We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. Gas chromatography-mass spectrometry was applied to measure off-flavor compounds dimethyl sulfide（DMS）, dimethyl trisulfide（DMTS）,2-methylisoborneol, geosmin（GEO） and β-cyclocitral. During the lag phase of co-cultured M. aeruginosa（first 15 days）, P. pseudoalcaligenes significantly increased the production of DMS, DMTS and β-cyclocitral at all three temperatures. In the exponential phase of co-cultured M. aeruginosa（after 15 days）, M. aeruginosa became the main factor on off-flavors in the co-culture system, and β-cyclocitral turned to the highest off-flavor compound. These results also indicated that DMS, DMTS and β-cyclocitral were the main off-flavor compounds in our M. aeruginosa/P. pseudoalcaligenes co-culture system. Univariate analysis was applied to investigate the effects of M. aeruginosa and P. pseudoalcaligenes on the production of off-flavors. The results demonstrated that both M. aeruginosa and P. pseudoalcaligenes could increase the production of DMS and DMTS, while β-cyclocitral was mainly determined by M. aeruginosa. Our results also provide some insights into understanding the relationship between cyanobacteria and heterotrophic bacteria.展开更多
We are facing the challenge of climate change and food insecurity for a growing population.The current mode of animal protein production via animal agriculture is resource-intensive and unsustainable.Therefore,there i...We are facing the challenge of climate change and food insecurity for a growing population.The current mode of animal protein production via animal agriculture is resource-intensive and unsustainable.Therefore,there is a need to find alternative sources of food protein that are environmentally sustainable.Plant-based proteins,specifically pulse-based proteins,provide a promising solution to the problem.This review aims to provide an overview and perspective on extraction,functionality,digestibility,sensory,and new food applications of pulse proteins.Two main methods,namely wet fractionation and dry fractionation are used to extract pulse-based proteins.As compared to dry fractionation,wet fractionation yields high purity protein,but the process alters the structure and function of the proteins.Various biochemical and physical techniques can be used to assist wet extraction process to increase protein yield and/or reduce extraction time.The main techno-functional properties of plant-based proteins determining their practical applicability are solubility,water/oil holding capacity(WHC/OHC),gelation,emulsification,foaming,and rheological properties.Nutritionally,pulse proteins are deficient in one or more essential amino acids.Strategies to overcome the deficiency are discussed.Volatile and non-volatile compounds inherent to pulses or developed during processing are mostly responsible for the off flavors in the extracted protein.Approaches to improve the pulse protein flavor and remove or modify off-flavors are discussed.Pulse-based protein ingredients have applications in bakery products,pasta,meat analogues,dairy alternatives,and beverages.Beyond these applications,there is a need to explore novel applications of pulse proteins in infant and children’s formula,beverages,breakfast cereals,flavor development,and extruded snack products,develop new applications such as personalized and precision nutrition and bioactive peptides,and employ innovative technologies such as 3D printing,extrusion,and artificial intellig展开更多
建立一种顶空-气相色谱-质谱法结合保留指数分析食品包装用纸中挥发性气味成分的分析方法。采用顶空直接进样方式,经气相色谱-质谱上机检测,在美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)质谱库检...建立一种顶空-气相色谱-质谱法结合保留指数分析食品包装用纸中挥发性气味成分的分析方法。采用顶空直接进样方式,经气相色谱-质谱上机检测,在美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)质谱库检索的基础上,结合保留指数及气味物质谱库对挥发性气味物质进行定性分析,最后用面积归一法计算各物质的相对含量。结果表明,19种食品包装用纸中共鉴别出113种挥发性化合物,通过检索气味物质谱库,最终确定出36种挥发性气味物质,主要为醛类、羧酸类、酮类、烯烃类、呋喃类、醇类、酚类及含硫化合物共8大类。其中,主要气味物质包括糠醛、苯甲醛、2-戊基呋喃、乙酸、2-乙基-1-己醇、苯乙烯等。此方法可以快速、准确地鉴别出食品包装用纸中挥发性气味物质,提高了定性分析的工作效率;食品包装纸中挥发性气味物质可能会影响食品气味,需引起高度关注。展开更多
基金supported by the National Basic Research Program (973) of China (No. 2008CB418101)the State Key Laboratory of Freshwater Ecology and Biotechnology (No. 2008FBZ01)
文摘We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. Gas chromatography-mass spectrometry was applied to measure off-flavor compounds dimethyl sulfide（DMS）, dimethyl trisulfide（DMTS）,2-methylisoborneol, geosmin（GEO） and β-cyclocitral. During the lag phase of co-cultured M. aeruginosa（first 15 days）, P. pseudoalcaligenes significantly increased the production of DMS, DMTS and β-cyclocitral at all three temperatures. In the exponential phase of co-cultured M. aeruginosa（after 15 days）, M. aeruginosa became the main factor on off-flavors in the co-culture system, and β-cyclocitral turned to the highest off-flavor compound. These results also indicated that DMS, DMTS and β-cyclocitral were the main off-flavor compounds in our M. aeruginosa/P. pseudoalcaligenes co-culture system. Univariate analysis was applied to investigate the effects of M. aeruginosa and P. pseudoalcaligenes on the production of off-flavors. The results demonstrated that both M. aeruginosa and P. pseudoalcaligenes could increase the production of DMS and DMTS, while β-cyclocitral was mainly determined by M. aeruginosa. Our results also provide some insights into understanding the relationship between cyanobacteria and heterotrophic bacteria.
基金the USDA Pulse Crop Health Initiative projects(0439205 and 0439200)the USDA National Institute of Food and Agriculture Hatch project(7003330).
文摘We are facing the challenge of climate change and food insecurity for a growing population.The current mode of animal protein production via animal agriculture is resource-intensive and unsustainable.Therefore,there is a need to find alternative sources of food protein that are environmentally sustainable.Plant-based proteins,specifically pulse-based proteins,provide a promising solution to the problem.This review aims to provide an overview and perspective on extraction,functionality,digestibility,sensory,and new food applications of pulse proteins.Two main methods,namely wet fractionation and dry fractionation are used to extract pulse-based proteins.As compared to dry fractionation,wet fractionation yields high purity protein,but the process alters the structure and function of the proteins.Various biochemical and physical techniques can be used to assist wet extraction process to increase protein yield and/or reduce extraction time.The main techno-functional properties of plant-based proteins determining their practical applicability are solubility,water/oil holding capacity(WHC/OHC),gelation,emulsification,foaming,and rheological properties.Nutritionally,pulse proteins are deficient in one or more essential amino acids.Strategies to overcome the deficiency are discussed.Volatile and non-volatile compounds inherent to pulses or developed during processing are mostly responsible for the off flavors in the extracted protein.Approaches to improve the pulse protein flavor and remove or modify off-flavors are discussed.Pulse-based protein ingredients have applications in bakery products,pasta,meat analogues,dairy alternatives,and beverages.Beyond these applications,there is a need to explore novel applications of pulse proteins in infant and children’s formula,beverages,breakfast cereals,flavor development,and extruded snack products,develop new applications such as personalized and precision nutrition and bioactive peptides,and employ innovative technologies such as 3D printing,extrusion,and artificial intellig
文摘建立一种顶空-气相色谱-质谱法结合保留指数分析食品包装用纸中挥发性气味成分的分析方法。采用顶空直接进样方式,经气相色谱-质谱上机检测,在美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)质谱库检索的基础上,结合保留指数及气味物质谱库对挥发性气味物质进行定性分析,最后用面积归一法计算各物质的相对含量。结果表明,19种食品包装用纸中共鉴别出113种挥发性化合物,通过检索气味物质谱库,最终确定出36种挥发性气味物质,主要为醛类、羧酸类、酮类、烯烃类、呋喃类、醇类、酚类及含硫化合物共8大类。其中,主要气味物质包括糠醛、苯甲醛、2-戊基呋喃、乙酸、2-乙基-1-己醇、苯乙烯等。此方法可以快速、准确地鉴别出食品包装用纸中挥发性气味物质,提高了定性分析的工作效率;食品包装纸中挥发性气味物质可能会影响食品气味,需引起高度关注。
