Lipid occurrence, distribution and degradation to flavour volatiles duringtea processing

The contents of neutral lipid, glycolipid and phospholipid and their fatty acid composition in three cultivars (clones) and processed leaves at differ ent stages of black tea manufacture were measured. Glycolipids account for nearly 50% of the total lipids and are rich in linolenic acid. Phospholipid s were present in the least amount (15%) and had a high proportion of oleic , linoleic and palmitic acids. Neutral lipids were found in moderate amount s (35%) and had a high content of lauric, myristic, palmitic, stearic, olei c and linoleic acids. Well-marked clonal variations in fatty acid compositi on of the lipid fractions were registered. With the maturation of the tea s hoot, the lipid content increased. Considerable losses of lipids/fatty acid s were observed in the withering process and again in the firing process. T he other stages of processing (rolling and fermentation) registered only a minor change in lipid/fatty acid contents. Wide variation in lipid and flav our content was observed with season and a relation was evolved between the m. The reason for the superior flavour of orthodox teas over CTC teas is ex plained on the basis of their lipid degradation. The changes in lipid conte nt/fatty acids were related to the volatiles produced. (C) 1999 Elsevier Sc ience Ltd. All rights reserved.