摘要
为探究李子发酵为李子酵素前后挥发性成分及游离氨基酸的变化规律,采用顶空固相微萃取-气相色谱-质谱法(HS-SMPE-GC-MS)和氨基酸分析仪分析了其中的挥发性成分和游离氨基酸。将新鲜的李子样品去核、匀浆、熟化后,加入白砂糖和发酵剂发酵3个月制备李子酵素。发酵前后的样品用顶空固相微萃取仪提取挥发性成分,然后通过HP-5MS色谱柱在程序升温条件下分离,用带有电子轰击(EI)离子源的质谱仪测定;通过质谱碎片信息、保留指数、保留时间等进行定性分析。选择LCAK07/Li型标准分析阳离子型交换树脂为固定相,用pH分别为2.90,4.20,8.00的柠檬酸-柠檬酸锂缓冲溶液和0.5mol·L^(-1)的氢氧化锂再生液的混合溶液为流动相进行梯度洗脱,分别在440nm(脯氨酸)和570nm(其他30种氨基酸)检测波长处测定发酵前后样品中的游离氨基酸,定量方法为单点外标法。结果显示:李子酵素中的挥发性成分增加了20种,这是其香气浓郁,风味和口感得到显著改善的主要原因;李子酵素中的游离氨基酸总量降低,必需氨基酸的种类和总含量增加,且新增了牛磺酸、胱氨酸、蛋氨酸、3-甲基组氨酸、1-甲基组氨酸等共5种氨基酸。
In order to explore the changes of volatile components and free amino acids before and after Prunus salicina Lindl fermented into enzyme of Prunus salicina Lindl,the volatile components were analyzed by HS-SPMEGC-MS and free amino acids were determined by amino acid analyzer.The fresh Prunus salicina Lindl samples were pitted,homogenized,and ripened,and then fermented with sugar and starter for 3 months to prepare enzyme of Prunus salicina Lindl.The volatile components were extracted by headspace solid phase microextraction,separated on HP-5 MS chromatographic column under temperature programmed conditions,determined by MS with EI ion source,and results of qualitative analysis were obtained by mass spectrometry fragment information,retention index,and retention time.LCAK07/Li type standard analysis cation exchange resin was selected as stationary phase.The mixture of three parts of citric acid-lithium citrate buffer solution(pH of 2.90,4.20 and 8.00)and one part of 0.5 mol·L^(-1)lithium hydroxide regeneration solution was used as mobile phase for gradient elution.Free amino acids were determined at 440 nm for proline and 570 nm for the other 30 amino acids,and results of quantitative analysis were obtained by single point external standard method.The results showed that 20 volatile components were added in enzyme of Prunus salicina Lindl,which was the main reason for its strong aroma and the significant improvement of flavor and taste;the total content of free amino acids in enzyme of Prunus salicina Lindl decreased,but types and total content of essential amino acids were increased,and 5 amino acids including taurine,cystine,methionine,3-methylhistidine,and 1-methylhistidine were newly added.
作者
周美
王瑜
李春燕
张明
李青
魏福晓
王道平
ZHOU Mei;WANG Yu;LI Chunyan;ZHANG Ming;LI Qing;WEI Fuxiao;WANG Daoping(State Key Laboratory of Medicinal Plant Efficacy and Utilization,Guizhou Medical University,Gutyang 550014,China;The Key Laboratory of Chemistry for Natural Product of Guizhou Province,Chinese Academy of Sciences,Guiyang 550014,China)
出处
《理化检验（化学分册）》
CAS
CSCD
北大核心
2021年第3期210-217,共8页
Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
基金
贵州省科技支撑项目(黔科合支撑[2017]2851)
贵州省科技计划项目(黔科合支撑[2019]2753号)
贵州省科技计划项目(黔科合支撑[2017]2825)
贵州省科技计划项目(黔科合支撑[2018]2352)。
