title: Quantitative Analysis of Major Phytochemicals in Orthodox tea (Camellia sinensis), Oxidized under Compressed Air Environment.
abstract: This study describes major changes in phytochemical composition of orthodox tea (Camellia sinensis var. Assamica) oxidized under compressed air (CA). The experiments for oxidation were conducted under air pressure (101, 202, and 303 kPa) for 150 min. Relative change in the concentrations of caffeine, catechins, theaflavins (TF), and thearubigins (TR) were analyzed. Effect of CA pressure was found to be nonsignificant in regulating caffeine concentration during oxidation. But degradation in different catechins as well as formation of different TF was significantly affected by CA pressure. At high CA pressure, TF showed highest peak value. TR was found to have slower rate of formation during initial phase of oxidation than TF. Even though the rate of TR formation was significantly influenced by CA, a portion of catechins remained unoxidized at end of oxidation. Except caffeine, the percent change in rate of formation or degradation were more prominent at 202 kPa.
authors.affiliation: Agricultural and Food Engineering Dept, Indian Inst. of Technology Kharagpur, Kharagpur, 721 302, India.
authors.forename: Brajesh Kumar
authors.initials: BK
authors.lastname: Panda
authors.affiliation: Agricultural and Food Engineering Dept, Indian Inst. of Technology Kharagpur, Kharagpur, 721 302, India.
authors.forename: Ashis Kumar
authors.initials: AK
authors.lastname: Datta
mesh_terms: D000388:Air; D000975:Antioxidants / Q000032:analysis*; D044946:Biflavonoids / Q000032:analysis; D002110:Caffeine / Q000032:analysis; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000031:analogs & derivatives / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D058868:Compressed Air; D005511:Food Handling / Q000379:methods*; D006801:Humans; D010084:Oxidation-Reduction; D010100:Oxygen; D064209:Phytochemicals / Q000032:analysis; D010936:Plant Extracts / Q000737:chemistry; D059808:Polyphenols / Q000032:analysis; D011312:Pressure; D013045:Species Specificity; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D044946:Biflavonoids; D064209:Phytochemicals; D010936:Plant Extracts; D059808:Polyphenols; D013662:Tea; C086701:thearubigin; C056068:theaflavin; D002110:Caffeine; D002392:Catechin; D010100:Oxygen
keywords: flavonoids; high-performance liquid chromatography (HPLC); oxidation; phenolic compounds; tea