Biochemical And Quality Characters Of ‘Lifeng' Cultivar Using Different Tea Processing Methods

‘Jiukeng' is one of national tea cultivars in China,and ‘Lifeng' is a new,early-growing,and high-quality tea cultivar selected from the natural hybrid offspring of ‘Jiukeng'.In the present work,the characteristics of biochemical components in fresh leaves of ‘Lifeng'(LF)were analyzed,and a systematic comparison was conducted with those in ‘Longjing 43'(LJ43)fresh leaves.The spring fresh LF leaves were made into Maofeng tea and Longjing tea.The effects of picking date and drying temperatures on the quality components and volatile aroma substances these samples were discussed.The quality components of green tea(LFGT),white tea(LFWT),green tea(LFOT)and black tea(LFBT)made from LF autumn fresh leaves were also analyzed.These results provided experimental basis for a futher utilization of LF autumn resources.The main findings are as following:1.The results of biochemical components and volatile substances showed that the total polyphenols,catechins,amino acids,soluble sugars,and flavones in LF fresh leaves were significantly higher than those in LJ43 fresh leaves,the protein content was equivalent to that of LJ43,and the caffeine content was significantly low.Among 20 tested amino acids,umami amino acids of LF accounted for a larger proportion.Both LF and LJ43 were rich in cis-,trans-linalool oxide(furan),linalool,phenethyl alcohol,geranylacetone,(E)-?-farnesene and other high-quality tea aroma characteristics.Compared with LJ43,the contents of(Z)-3-hexen-1-ol,acetate,sweet rose-like flowers in LF were higher.The LF cultivar is rich in biochemical components and volatile aroma substances,that is the material basis for high quality tea making.2.Comparisons of the biochemical compositions of two typical green types(Longjing and Maofeng)made from LF spring fresh leaves were conducted.The results showed that samples of earlier picking leaves had more sweet amino acids and less bitter amino acids and astringent flavonol glycosides,tasted luscious.All samples are rich in linalool oxide,benzyl alcohol and phenyl ethanol which have fried bean flavors and floral fragrance.The Maofeng tea samples had a greener color when dried at 70 °C,and the Longjing tea samples had a typical brown beige color at 150 °C drying.These two drying temperatues were the optimal drying temperatures for Maofeng and Longjing tea making.3.The biochemical components and volatile substances of four kinds teas from LF autumn fresh leaves were analyzed.The results showed that the catechins of the four kinds teas showed a law of LFGT> LFOT> LFBT> LFWT,and LFGT retained a large amount of catechins which has strong astringency.During LFBT fermentation and LFWT long-term withering,part catechins were converted to theaflavin.The total amounts of amino acids decreased with fermentation processing.During the fermentation,the amino acids of LFBT may combine with the aroma precursors to form new aroma substances.LFGT presented a floral fragrance;LFWT was rich in fragrance,characterized with rich and restrained aroma;LFOT had a rich floral and fruity scent;LFBT had floral and woody fragrance.