Showing 3 results for Black Tea
R. Hojat Ansari, M. Hasanpour Asil, A. Hatamzadeh, B. Rabiei, S.h. Roofigari Haghighat,
Volume 12, Issue 43 (4-2008)
Abstract
Variations in theaflavin and thearubigin content during fermentation and the effects of these variations on brightness and total color in black tea were evaluated at the Tea Research Center in Lahijan in the year 2004. Percentages of theaflavin (TF), thearubigin (TR), total color and brightness were determined in two clones 100 and in the natural Chinese hybrid during flushing in the months of June, August and October and different fermentation time (30, 60, 90, 120 and 150 minutes). It is evident from the results obtained that apart from genetic differences in the clones under study, changes in climatic conditions during different periods of flushing and fermentation time can to a great extent influence the amount of TF, TR, total color and brightness in black tea. Results obtained also indicated significant interacting effects of clones, different flushing and fermentation times on the quality-determining characteristics of black tea. No significant correlations were found between TR and brightness however, significant correlations were found between other characteristics studied at the 1% probability level. On the basis of regression analysis with fermentation time (independent variable) and each of the characteristics studied (dependent variable), linear relationships were detected between fermentation time and brightness and TF content. Multi-variable regression analysis between brightness (dependent variable) and TF and TR (independent variables) showed that more than 56% of variations in brightness in black tea was related to TF and TR. Also multi-variable regression analysis between total color (dependent variable) and TF and TR (independent variable) indicated that more than 43% of variations in total color in black tea can be attributed to TF and TR percentages
F Parsa, R Azadi Gonbad, A Moghadam Dorodkhani,
Volume 12, Issue 46 (1-2009)
Abstract
Every year lots of waste will produce in factories from black tea. These waste will remain unusable or through away but only little amount will be used in industry. In this survey, important components of tea dust and three kinds common tea wastes was studied from 1382 to 1383. Four compounds (caffeine, protein, fiber and fluor) were extracted and measured separately from four samples of wastes (dust, fluff, footstalk and stalk) as experimental component. In three periods of plucking (spring, summery and autumn) from two kinds of arrangement (from curve and flat bushes). The experiment were conducted in four experimental components with replications and were analyzed with Duncan method. The results indicated that effects all of wastes, plucking periods and two kinds of arrangement (except effect of that on amount of caffeine) were significant on caffeine, protein, fiber and fluor whereas maximum amounts of caffeine, fluor and protein in dust but maximum amounts of fiber was in stalk and Effect of plucking period indicated maximum amount of fluor and caffeine in summer plucking and maximum amount of fiber and protein in autumn plucking and effect of plots indicated maximum amount of fiber in flat plot and maximum amount of fluor and protein in curve plot.
Sh Rofigari Haghighat, S Sabori Helestani, K Cheraghi, S.a.t Shokrgozar,
Volume 13, Issue 47 (4-2009)
Abstract
Changes in black tea quality were studied for three subsequent years and in different times of plucking (spring, summer and autumn) in the form of two leaves and a bud. Percentage of waste, total sensory scores, total soluble solid, caffeine, theaflavin, thearobigin, total color and brightness were evaluated in black tea. The data were analyzed in split plot design based on randomized complete blocks. In hybrid tea, quality parameters in second time of plucking (summer) were high. In clone 100, total soluble solid and caffeine were in summer 1.85, 0.18 and 6.14, 0.79 more than spring and autumn tea, respectively. Total sensory scores, thearobigin and total color were more in spring and summer than autumn. The waste in autumn was more than spring and summer. Hybrid tea and clone 100 were significantly different in quality characters but not in waste amount (P<0.05).
