Change of Main Chemical Components of Bead Tea during Spreading
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Fresh leaves of bead tea were processed bydifferent spreading method and their leaf appearance, color and main chemical compositions were investigated by sensory evaluation, Hunte-Lab color space method, high performance liquid chromatography and chemical analysis. SPSS (Statistical Product and Service Solutions) statistical software was used for significant difference analysis and correlation analysis. The results showed that during spreading processing of the tea leaf, their moisture content decreased significantly and color was gradually deepened. The leaf became soft and showed delicate fragrance. The most suitable moisture contents and -b / a value for bead tea processing were 74% and 3.66, respectively. Moisture content, (-)-epicatechin gallate (ECG), (-)-epigallocatechin gallate (EGCG), (-)-gallocatechin gallate (GCG), total amount of catechins and ester type catechins showed a decreasing trend. Tea polyphenols, phenol ammonia ratio, (-)-epicatechin (EC), total amount of catechins presented a downward trend at first then went up with prolonging the processing time. (-)-Epigallocatechin (EGC) decreased first then increased, but decreased again at last period of the spreading processing, while the catechin (C) content increased first, decreased then and increased again lastly. Change of moisture content had a positive correlation with EC, but a negative correlation with soluble sugar content, neither of which was significant. Significant positive correlations of moisture content with phenol ammonia ratio, EGC, EGCG, GCG, ECG, total amount of catechins and ester type catechins, however were found. In particular, the correlation coefficient with EGCG could reach 0.99. In addition, moisture content showed extremely significant negative correlation with contents of amino acids and C.
