title: Simultaneous determination of free amino acids in Pu-erh tea and their changes during fermentation.
abstract: Pu-erh ripened tea is produced through a unique microbial fermentation process from the sun-dried leaves of large-leaf tea species (Camellia sinensis (Linn.) var. assamica (Masters) Kitamura) in Yunnan province of China. In this study, the changes of amino acid profiles during fermentation of Pu-erh tea were investigated, based on the improved HPLC-UV method with PITC pre-column derivatization for the simultaneous determination of twenty free amino acids. Results showed that aspartic acid, glutamic acid, arginine, alanine, theanine and tyrosine were the major amino acids in tea samples. Fermentation significantly influenced on the amino acid profiles. The total free amino acid contents significantly decreased during fermentation (p<0.05). Meanwhile, low amount of acrylamide were detected. Its concentration increased after 7-days' fermentation and then decreased gradually. The results provided the useful information for the manipulation of fermentation process according to the changes of amino acids and acrylamide contents in Pu-erh ripened tea.
authors.affiliation: College of Food Science & Nutritional Engineering, National Engineering Research Centre for Fruits and Vegetables Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China.
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742-7640, USA.
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Luo
authors.affiliation: College of Food Science & Nutritional Engineering, National Engineering Research Centre for Fruits and Vegetables Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China.
authors.forename: Pengpu
authors.initials: P
authors.lastname: Wang
authors.affiliation: College of Food Science & Nutritional Engineering, National Engineering Research Centre for Fruits and Vegetables Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China.
authors.forename: Mengyao
authors.initials: M
authors.lastname: Zhao
authors.affiliation: College of Food Science & Nutritional Engineering, National Engineering Research Centre for Fruits and Vegetables Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.affiliation: College of Food Science & Nutritional Engineering, National Engineering Research Centre for Fruits and Vegetables Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Hu
authors.affiliation: College of Food Science & Nutritional Engineering, National Engineering Research Centre for Fruits and Vegetables Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China. Electronic address: chenfangch@sina.com.
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D028241:Camellia sinensis / Q000737:chemistry; D002681:China; D002851:Chromatography, High Pressure Liquid; D005285:Fermentation; D005971:Glutamates / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry; D013662:Tea / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D005971:Glutamates; D013662:Tea; C026166:theanine
keywords: Acrylamide; Amino acids; Determination; Fermentation; PITC pre-column derivatization; Pu-erh tea