| Abstract
| - A direct qualitative and quantitative determination of the glycosides of tea aroma compounds atthe four stages of the oolong tea manufacturing process (plucking, solar withering, indoor withering,and oolong tea product) was carried out by a capillary gas chromatographic−mass spectrometricanalysis after trifluoroacetyl derivatization of the glycosidic fractions. Sixteen glucosides andprimeverosides were identified and quantified in cv. Chin-shin-oolong and cv. Chinhsuan-oolong. Acomparison of the glycosides in dried fresh leaves between the two cultivars showed significantdifferences. During the manufacturing process, the amounts of most of these glycosides increasedfrom the solar-withering stage, reaching the highest level at the final stage of oolong tea production.It was noted that no glycoside decreased in its content during the manufacturing process, this beingquite different from the manufacture of black tea. In addition, the contents of these alcoholic aromacompounds in the free aroma concentrate from each cultivar remained almost unchanged or slightlydecreased, and they constituted only about 12 and 17% in amount of the whole oolong tea aromacompounds. However, jasmine lactone and indole were markedly higher in the final oolong teaproducts. Keywords: Oolong tea; aroma formation; glycoside quantification; primeveroside; glucoside
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