B.B. Borse and L. Jagan Mohan Rao
Novel bio-chemical profiling of Indian black teas covering all the regions and seasons (s1:April-June, s2:July-Sept., s3:Oct.-Dec., s4:Jan.- Mar.) from select gardens cutting across all climatic conditions so as to represent the variables was carried out. The profiling was carried out with reference to physico-bio-chemical quality indices based on parameters as well as volatiles and non-volatiles which are important from quality viewpoint. Different fingerprint markers in terms of volatiles and non-volatiles for tea quality were identified. Seasonal variation of TF/TR ratio over tea producing region/grade and with respect to quality was deliniated. Also the seasonal variation of sum of Yamanishi-Botheju and Mahanta ratio over tea producing region/grade and concomitant tea quality profile has been deliniated. The sum of TF/TR ratios of tea and the sum of the VFC ratios (Yamanishi-Botheju ratio and Mahanta ratio) added together is proposed for the first time as a new and novel quality index, hence forth referred to as Borse-Rao quality index, considered to be an overall quality indicator of tea as both the non-volatiles and volatiles are given due consideration. By using this quality index, seasonal variations of the tea quality over the producing regions/grades in all the four seasons (s1,s2,s3,s4) were carried out. Accordingly based on the Borse-Rao quality index, tea can be categorized as good (upto 1), better (>1-4) and best (>4) quality tea respectively.