Relationship between sensory and chemical properties of Assam green teas under different pan-firing and rolling time conditions

Assam green tea possesses health benefits and aromatic compounds in the tea leaves. Effects of pan-firing time (0, 5, and 10 min) and rolling time (0, 2, and 4 min) on chemical and antioxidant properties and sensory descriptive analysis of Assam green tea were investigated. Increasing pan-firing time increased total phenolic content (TPC), total catechin content, and antioxidant activity (2,2-diphenyl-1-picprylhydrazyl (DPPH), (2,2′-azinobis)-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and ferric ion reducing antioxidant power (FRAP)) values, whereas increasing rolling time tended to decrease such chemical properties. There were four categories of volatile functional groups analysed by gas chromatography-mass spectrometry (GC-MS) during green tea preparation, including aldehyde, alcohol, furan, and ether. A sensory lexicon consisting of ten attributes developed by trained descriptive panellists showed a significant relationship with chemical properties. The green tea under pan-firing process expressed bitter taste, total catechin, TPC, and antioxidant activity. These active chemical compounds and critical sensory attributes of drinking green tea could potentially be beneficial for healthy beverage production.