Curie-point pyrolysis-gas chromatography-mass spectroscopic analysis of theabrownins from fermented Zijuan tea

Zijuan tea theabrownins (ZTTBs) was extracted from a type of fermented Zijuari tea and separated into fractions according to molecular weight. The extract was found to contain predominantly two fractions: <3.5 kDa and >100 kDa. These two fractions were analyzed for chemical composition, structural characteristics by Curie-point pyrolysis-gas chromatography-mass spectroscopy (CP-Py-GC/MS). The affects of pyrolysis temperature on pyrolytic products were also investigated. The fraction >100 kDa produced 50 GC/MS peaks during pyrolysis at 280 degrees C. 70 peaks at 386 degrees C. and 134 peaks at 485 degrees C. Fourteen of the products formed at 280 degrees C, 12 of those formed at 386 degrees C. and 21 of those formed at 485 degrees C were identified with match qualities of greater than 80%. The fraction <3.5 kDa gave 51 peaks during pyrolysis at 280 degrees C. 99 peaks at 386 degrees C, and 257 peaks at 485 degrees C. Six products formed at 280 degrees C, four products formed at 386 degrees C. and 61 products formed at 485 degrees C were identified with match qualities of greater than 80%. Pyrolysis temperatures of 485 degrees C and 386 degrees C were found suitable for the two fractions respectively. CP-Py-GC/MS revealed that, the fraction >100 kDa mainly consisted of phenolic pigments, esters, proteins, and polysaccharides, while the fraction <3.5 kDa contained no polysaccharide. CP-Py-GC/MS is an effective tool for the composition difference and structural characteristics of ZTTBs as well as other complex macromolecular plant pigments. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.