The Study On The Changes Of Volatile Components During The Instant Tea Powder Processing Of Oolong Tea

Tea is one of the traditional major economical crops in China, instant tea powder is an important product of deep processing products. As a result, study instant tea powder in tea deep processing have great significance.This paper based on the typical region and characteristic tea of Fujian, illuminate the effects of processing procedure on the volatile changing of instant tea powder. Optimized the method of extraction, and the volatile components were analyzed by gas chromatography coupled with a mass spectrometer(GC-MS), further more, pasteurization, resin adsorption and naringinase treatment effect on the volatiles and aromatic profile of instant Oolong tea powder were explored using statistical method.The results showed that the optimum extraction conditions of instant Oolong tea powder using by solid-phase micro-extraction were: extracted by the 50/30 μm DVB-CAR-PDMS fiber for 40 min at 70°C.The GC-MS results showed that the main volatile components in Oolong tea were indole, hexanal, benzyl nitrile, benzene acetaldehyde, pentyl alcohol. Their concentrations were 22362.0, 8900.7, 3436.7, 1772.7, and 1731.3 μg/kg, respectively. The main volatile components in vacuum freeze-drying Oolong tea powder were Indole, Hexanal, their concentrations were 2168.9 and 1060.9 μg/kg, respectively. The main volatiles in spray drying Oolong tea powder were linalool, beta.-trans-ocimene, cis-linalool oxide, trans-linalool oxide, their concentrations were 16422.8, 3407.8, 2163.1 and 2549.7 μg/kg, respectively.Odour activity values(OAVs) results showed that the characteristic aroma in Oolong tea were decanal and hexanal, in vacuum freeze-drying Oolong tea powder were decanal, 1-octen-3-ol and linalool, in spray drying Oolong tea powder was linalool. The total odour activity values(OAVs) of vacuum freeze-drying Oolong tea powder and spray drying Oolong tea powder was lower than Oolong tea, besides, the odour activity values(OAVs) of vacuum freeze-drying oolong tea powder was higher than the spray drying Oolong tea powder.The research suggested the tea powder processing technology, including extraction, filtration, concentration and drying has significant influence on the volatile components of tea. The volatiles and characteristic flavor compositions of Oolong tea, vacuum freeze-drying Oolong tea powder and spray drying Oolong tea powder had a quite different distribution. The study provided an experimental reference of tea in deep processing.