Polycarboxylic acids(PACs)are important metabolic products in almost all living bodies,yet current analytical methods for detection of PACs in tea beverages are still unsatisfactory due to the complex matrix and physi...Polycarboxylic acids(PACs)are important metabolic products in almost all living bodies,yet current analytical methods for detection of PACs in tea beverages are still unsatisfactory due to the complex matrix and physicochemical properties of PACs.In this work,a rapid method was developed for the simultaneous determination of 7 PACs,including tartaric acid,α-ketoglutaric acid,malic acid,malonic acid,cis-aconitic acid,succinic acid,and fumaric acid,in beverages,based on selective removal of the matrix in combination with liquid chromatography–mass spectrometry(LC-MS)analysis.By stirring with activated carbon and the Na2CO3 solution,the matrix in beverages was selectively removed,and PACs were almost retained in the supernatant of diluted Na2CO3 solution.Under optimized parameters,the limit of quantitation for the PACs was in the range of 1–50 ng/mL,and the content of the PACs in 8 beverages was determined with the recovery range of 72.2%–122.5%.The contents of malic acid,malonic acid,and succinic acid in tea beverages were found to be greater than those in non-tea beverages.Moreover,the concentration of these PACs in beverages was found to be multiplied many times in their deterioration period,especially for fumaric acid andα-ketoglutaric acid.These results indicated that PACs can be selected as a criterion to differentiate qualified tea beverages from spoiled beverages.展开更多
The objective of this study was to isolate and identify a yeast strain from the kombucha beverage and evaluate its potential as a novel starter in beverage fermentation in vitro.Starmerella davenportii Do18 was charac...The objective of this study was to isolate and identify a yeast strain from the kombucha beverage and evaluate its potential as a novel starter in beverage fermentation in vitro.Starmerella davenportii Do18 was characterized for its cholesterol reduction;growth at different conditions such as temperatures(25,30,37 and 42◦C),low pH(1.2,1.5,2.03.0,and 7.0),bile salts(0%,0.25%,0.5%,1%and 2%)high-sucrose stress(2%,10%,20%,40%and 60%);and in-vitro survival in gastric and intestinal environments.Results showed that the yeast strain has a cholesterol-lowering capacity of 45%±2%,grew at temperature of 37◦C and is resistant to pH 1.5,2%bile and 40%sucrose solution,could survive in simulated gastric and intestinal environments.The physicochemical characteristics of the fermented beverages were also evaluated,which indicated that the yeast has pH reduction capacity and can produce organic acids and volatile compound such as 2-phenylethanol.Furthermore,the fermented beverage also has high total phenolics and flavonoids content and showed great antioxidant and antimicrobial activities.Therefore,the findings of this research provide strong evidence that S.davenportii Do18 has good fermentation properties,can be a potential starter in food and beverage fermentation.展开更多
基金the Analysis and Detection Foundation of Science and Technology Department in Zhejiang Province,China(No.LGC21B050009)the Hangzhou Normal University Innovation Practice and Service Local Plan‘Diligent,Careful Research and Innovation'Scientific Research Project,China(No.YJS2022055).
文摘Polycarboxylic acids(PACs)are important metabolic products in almost all living bodies,yet current analytical methods for detection of PACs in tea beverages are still unsatisfactory due to the complex matrix and physicochemical properties of PACs.In this work,a rapid method was developed for the simultaneous determination of 7 PACs,including tartaric acid,α-ketoglutaric acid,malic acid,malonic acid,cis-aconitic acid,succinic acid,and fumaric acid,in beverages,based on selective removal of the matrix in combination with liquid chromatography–mass spectrometry(LC-MS)analysis.By stirring with activated carbon and the Na2CO3 solution,the matrix in beverages was selectively removed,and PACs were almost retained in the supernatant of diluted Na2CO3 solution.Under optimized parameters,the limit of quantitation for the PACs was in the range of 1–50 ng/mL,and the content of the PACs in 8 beverages was determined with the recovery range of 72.2%–122.5%.The contents of malic acid,malonic acid,and succinic acid in tea beverages were found to be greater than those in non-tea beverages.Moreover,the concentration of these PACs in beverages was found to be multiplied many times in their deterioration period,especially for fumaric acid andα-ketoglutaric acid.These results indicated that PACs can be selected as a criterion to differentiate qualified tea beverages from spoiled beverages.
基金This work was supported by the Jiangsu Agricultural Industry Technology System[No.JATS-2018-296]and the National Natural Science Foundation of China[Grant No.31501460].
文摘The objective of this study was to isolate and identify a yeast strain from the kombucha beverage and evaluate its potential as a novel starter in beverage fermentation in vitro.Starmerella davenportii Do18 was characterized for its cholesterol reduction;growth at different conditions such as temperatures(25,30,37 and 42◦C),low pH(1.2,1.5,2.03.0,and 7.0),bile salts(0%,0.25%,0.5%,1%and 2%)high-sucrose stress(2%,10%,20%,40%and 60%);and in-vitro survival in gastric and intestinal environments.Results showed that the yeast strain has a cholesterol-lowering capacity of 45%±2%,grew at temperature of 37◦C and is resistant to pH 1.5,2%bile and 40%sucrose solution,could survive in simulated gastric and intestinal environments.The physicochemical characteristics of the fermented beverages were also evaluated,which indicated that the yeast has pH reduction capacity and can produce organic acids and volatile compound such as 2-phenylethanol.Furthermore,the fermented beverage also has high total phenolics and flavonoids content and showed great antioxidant and antimicrobial activities.Therefore,the findings of this research provide strong evidence that S.davenportii Do18 has good fermentation properties,can be a potential starter in food and beverage fermentation.
