Comparative Analysis of Quality Components inHakka Roasted Green Tea Made by Semi-continuousProduction Line and Classic Single-machine

【Objective】The study was to clarify the biochemical ingredients and sensory quality characteristics of Hakka roasted green teas made by semi-continuous production line and traditional single-machine, and provide a theoretical foundation for the standardized and precised processing of Hakka roasted green tea.【Method】Taking Matu tea (local variety) as experiment material, experiment samples were conducted repeatedly for three times from6 key procedures during the whole processes of two different processing. All samples were comparatively analyzed on 3 aspects, including the water content, physical-chemical ingredients and sensory qualities.【Result】A slow decreasing tendency of water contents of tea leaves was revealed in the two process. Water loss mainly occurred in the‘first roasting’procedure in two processing, within the percentage of 64.4%-76.0%. The contents of tea polyphenols and caffeine increased significantly in both processing, with 21.25% of tea polyphenols and 4.63% of caffeine from semicontinuous production line, 22.86% of tea polyphenols and 4.96% of caffeine from traditional single-machine. The trends of free amino acids, soluble sugars and catechins were dissimilar due to different processing techniques. Gallate catechin (GC), catechin (C), gallate catechin gallate (GCG), epicatechin gallate (ECG) and catechin gallate (CG) increased significantly periodically in production line processing. No conspicuous difference appeared between epigallate catechin (EGC), epigallate catechin gallate (EGCG) and epicatechin (EC). In traditional single-machine processing, GC, C, GCG and CG increased significantly, while EGC, ECG and EC decreased significantly, and no conspicuous difference was found in EGCG. The result of sensory assessment showed the quality of Hakka roasted green teas from the production line was equivalent or superior to that from the traditional single-machine.【Conclusion】The better appearance and quality of Hakka roasted green teas were prone to be shaped by semi-continuous production line, but the mellowness and delayed sweetness were more refined in traditional single-machine.