Aging Time-dependent Changes in the Concentrations of Key Components of Liubao Tea Produced Using Different Processes
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Aging is an important process that enhances the flavor of Liubao tea by affecting the concentrations of key components, such as water extracts, alkaloids, polyphenols, and polysaccharides. To clarify the effect of aging on the concentrations of these components, samples of Liubao tea prepared using traditional and modern processes and aged for one, three, five, ten, or fifteen years were tested via chemical analysis and high-performance liquid chromatography (HPLC). The results indicated that from one to fifteen years of aging, the tea samples prepared using either of the processes did not show any significant change (P>0.05) with respect to the dry matter content. However, there was a continuous decrease in the flavonoid content (from 16.70 mg/g and 7.93 mg/g in tea samples prepared using the traditional process to 15.67 mg/g and 3.40 mg/g in tea samples prepared using the modern process after one year of aging and fifteen years of aging, respectively). A similar continuous decrease was also observed in the polyphenol content (from 19.93 mg/g and 6.13 mg/g in tea samples prepared using the traditional process to 15.57 mg/g and 4.33 mg/g in tea samples prepared using the modern process after one year of aging and 15 years of aging, respectively). The free amino acid content in the Liubao tea prepared using either of the processes was significantly lower after five years of aging than after one year of aging (P≤0.01) and significantly lower after fifteen years of aging than after ten years of aging (P≤0.01). After five years of aging, the water extract content peaked at 566.37 mg/g and 500.10 mg/g in tea samples prepared using the traditional process and modern process, respectively, which was significantly higher than the corresponding values after fifteen years of aging (P≤0.01). After five years of aging, the polysaccharide content increased to 43.07 mg/g and 34.80 mg/g in tea samples prepared using the traditional process and modern process, respectively, which was significantly higher than the corresponding values (17.73 mg/g and 13.47 mg/g) in tea samples prepared using the traditional process and modern process, respectively, after fifteen years of aging (P≤0.01). The two types of tea samples exhibited similar trends with respect to the concentrations of the key components. However, the transformation of the different components occurred more rapidly in tea samples prepared using the modern process than in tea samples prepared using the traditional process in the early years of aging. After 15 years of aging, the two types of tea samples had essentially the same key compound contents. The metabolism and transformation of key compounds during aging are responsible for the unique qualities of the Liubao tea, i.e., red color, rich fragrance, smooth taste, and mellow flavor. This study provides scientific data for the quality control and evaluation of Liubao tea by analyzing the aging time-dependent changes in the concentrations of the key compounds in Liubao tea.
