Tea is a significant aquaculture species in China (Y. F. Li, et al., 2017). Tea white scab disease were found to occur at varying levels in tea. Consumer acceptability of tea greatly depends upon its sensory quality evaluation. Tea quality depends upon spatiotemporal variability of geographical origin, manufacturing process, which in turn highly influence the chemical composition, and which are very critical in determining its quality. On the other hand, sensory quality evaluation factors like color, appearance, flavor and taste also determines its commercial value (Bhattacharyya, et al., 2012; Bhondekar, et al., 2010). Qin et al (2017) compared the difference on sensory quality evaluation by human panel test and spectroscopy system, and revealed the variation on tea from different areas and variety. As shown in Table 1, tea white scab seases can strongly effect on the tea in sensory quality evaluation. The characteristic of high quality tea (CK) were green, smooth appearance; clean, high aroma; sweet, mellow taste, and fat, tender infused leaves. but the diseased one were quite another thing. Sensory quality evaluation, as first tea standard of National Food Safety Standards of China, is important for appraisaling tea quality. The effect of Tea white scab disease could be paied attention to.
Aqueous extract, caffeine, tea polyphenols, and flavonoids were the significant component in tea (P. Li, Wang, Ma, & Zhang, 2005). The tea polyphenols content in tea are about 28.4%, and be proved the more and more important functions, such as antimutagenic activity, antioxidant activity, depressor effect on renal hypertension, inhibitory effect on lipid peroxidation, and inhibitory effect on arteriosclerosis (L. Chen & Zhou, 2005; Z. Chen, 1989; Yamamoto, Juneja, Chu, & Kim, 1997). Caffeine makes a significant contribution to the briskness and creaming properties of tea brew, Its average content was about 4.2%. When on the low-caffeine tea, it will lose special tea aroma and taste (L. Chen & Zhou, 2005; Willson & Clifford, 1992). Flavonoids are the main regulators of plant growth and defense, and also contribute to the color, taste and aroma of tea (Jay-Allemand, Tattini, & Gould, 2015; Q, M, & J, 2017). Our result show caffeine, tea polyphenols and water extract were dramatic decline. It is agree with the previous report about the tea influence by Tea white scab disease (Zhou, Deng, & Deng, 2007). We believe that Tea white scab disease in tea can damage basic biochemical component on tea.
Tea polyphenols are mainly composed of five catechins and their derivatives. Epigallocatechin gallate (EGCG) is the largest portion, next epigallocatechin (EGC), epicatechin gallate (ECG), epicatechin (EC), gallocatechin (GC), respectively(L. Chen & Zhou, 2005). As a marker for superior quality in tea, catechins index is very important(Magoma, Wachira, Obanda, Imbuga, & Agong, 2000). Fan et al (2016) show difference thermal processing can cause variation in tea catechins. Our study also uncover the tea catechins content change along with tea white scab disease .Tea contain high levels of amino acids, the profile of which beneficial health effects have also been proposed (Bryan, 2008). Good quality teas require high concentrations of amino acids principally contributing to mellowness and freshness, and an optimum ratio of amino acids for a balance of astringent to mellow tastes (Wang, Cheng, Yuchen, & Liu, 1988). It consistent with our results that many amino acids varied along with the increase of morbidity (from CK to Ⅳ).
In conclusion, the present study showed the new pathogen (Elsinoe leucospila) of Tea white scab disease in tea from south China and comprehensive analysis the tea quality along with the increase of morbidity (from CK to Ⅳ). In our study, sensory quality evaluation, basic biochemical component, catechin and monomer content and amino acid composition of tea are obvious change after infected by tea white scab disease. Thus, the result will give advice to farm operators to understand and control Tea white scab disease in tea.