Quality Analysis of Traditional and Wild Yunnan Congou Black Tea

Abstract

To reveal the difference of quality between traditional and wild Yunnan Congou black tea, five traditional and wild Yunnan Congou black tea were collected, respectively. Sensory qualities and biochemical components were compared. Sensory evaluation results showed that the shape, infusion color and infused leaves of the samples collected in this paper conform to the characteristics of Yunnan Congou black tea, that was, color of the dry tea leaves were dark with oily gloss, the infusion were red or orange red and bright, and the infused leaves were tender and uniformity. However, traditional Yunnan Congou black tea had a strong taste, while the wild Yunnan Congou black tea had a mellow and fresh taste. The contents of water extract, total catechins and caffeine in traditional Yunnan Congou black tea were 41.07%, 18.53 and 14.60 mg/g, respectively, which were significantly higher than those of wild Yunnan Congou black tea with 38.42%, 10.58 and 9.54 mg/g, respectively. While the average content of free amino acid in traditional Yunnan Congou black tea (3.92%) was lower than that of wild Yunnan Congou black tea (5.01%). The average contents of tea polyphenols were 16.61% and 16.56%, respectively, with no significant difference. The average contents of theaflavin, thearubigins and theabrownin in traditional Yunnan Congou black tea were 0.64%, 6.75%, 10.93%, and 0.61%, 2.70%, 11.80% in wild Yunnan Congou black tea respectively, among them, the content of thearubigins were significantly different. The average contents of quercetin, rutin, kaempferol and myricetin were 0.09, 0.67, 0.01 and 0.07 mg/g in traditional Yunnan Congou black tea, while 0.14, 0.27, 0.16 and 0.15 mg/g in wild Yunnan Congou black tea, respectively, which showed significant differences. Principal component analysis (PCA) and clustering analysis (CA) based on contents of 19 biochemical components showed that traditional and wild Yunnan Congou black tea divided into two clusters, indicating that contents of biochemical component between these two type black tea were significantly different. In general, the contents of water extract, catechins, caffeine and flavonols in traditional Yunnan Congou black tea were higher, which resulting the strong taste. However, the content of free amino acids in wild Yunnan Congou black tea were higher, resulting in fresh and mellow taste.

Keywords

• black tea
• yunnan congou black tea
• sensory quality
• biochemical components