| TF(Theaflavin), TR(thearubigin) and TB(theabrownin) were studied as research object in this article. Statistical correlation relationship between 16 kind bio-chemical components including 3 types of tea pigment and black tea color, infusion condition of tea pigment in Kongfu black tea, color rendering property of tea pigment, color rendering stability of tea pigment and interaction effect of color rendering of 3 types of tea pigment were the main research content. The results were as follows:1. Path analysis showed that,(a) four kinds of bio-chemical components affected the L value directly or indirectly. The absolute value of direct path coefficients were |PEGC|>|PEGCG|>|PTF|>|PC|, of which EGC and C had positive effect while TF and EGCG had negative on L value.(b) Content of TB positively affected the a value.(c)Six kinds of bio-chemical components affected the b value directly or indirectly. The absolute value of direct path coefficients were |P EGC|>|P EGCG|>|P TB|>|P C|>|P Sugar|>|P TF|, of which TB,EGC and C had positive effect while TF and EGCG and sugar had negative on b value. The obscure result between path analysis and correlation analysis reported in documents published might be deemed to the nonrepresentative sample, regional disparity or the complex of liquor system of black tea cause by the interaction effect of other components.2. Color rendering property of tea pigment showed that,(a) the maximum absorption wavelength of TF, TR and TB were 274nm、271nm and 270 nm. Wavelength of replicates ranged from 1nm to 4nm which could be deem to the impurity of tea pigment isolation for the catechins had absorption at 280 nm or low concentration of tea pigment liquor while measuring the color value.(b)Comparing of color value was TF>TR>TB which can be referred that capability of color rendering was also TF>TR>TB.(c) Threshold concentration of 3 types of tea pigment while rendering yellow color was the same which was far less than that while rendering red color. It could explain that liquor color was still yellow while red disappeared after black tea was infused for a short time or infused many times later. Threshold concentration of 3 types of tea pigment rendering red color was different. Threshold concentration of TF was the lowest, which was respectively 2/5 and 1/3 of that of TR and TB. It could be referred that color rendering capability of TF was higher than TR and TB under low concentration.3. Color rendering stability of tea pigment showed that,(a) impact of color rendering under indoor natural light was not significantly different with that under dark condition.(b) L value declined rapidly, and half-life period shortened under high temperature while low temperature was benefit for stability of L value. Response of L value of 3 types to temperature was not the same.(c) Changes of chromatic aberration of 3 types of tea pigment with time was not conspicuous under low p H value but was conspicuous under high p H value. a value, b value increased while L value decreased with time under water bath. Liquor color of tea pigment got more red and yellow but less bright and the change of chromatic aberration of 3 types of tea pigment was not the same under same p H condition.(d) Impact of days on L value of 3 types of tea pigment was basically the same while a value and b value was not the same. And change of chromatic aberration between 1d and 2d was the biggest.4. Interaction effect of color rendering of 3 types of tea pigment showed that,(a) Though the b value between original black tea liquor and liquor of combination of 3 types of tea pigment was significantly different, L and a value was not significantly different. It could be refereed that the 3 types of tea pigment was the main explanation of black tea color.(b) TF played an important role in rendering red color and the extent of interaction between 2 types of tea pigment was not affected equally.(c) a value changed more than L and b value when adding 1 type of tea pigment to combination of 2 types of tea pigment. And influence of a was the largest when adding TF to combination of TR and TB liquor which could reflected that TF might be the key factor affecting red of black tea color.5. Infusion condition of tea pigment in Kongfu black tea showed that,(a)Lab changed significantly with dissolution interval and dissolution time. After samples were dissolved for 2 times, a values of tea infusion were all(+) while were all(-) when being dissolved for 4 times.(b)TB had the highest leaching rate followed by TR and TF, while quiet small difference of leaching rate could be discriminated between TR and TF.(c)As the dissolution time increased, difference of L values between the two adjacent dissolution time gradually decreased, tending to be the same value. This phenomenon also applied to a and b values, as well as the content of TF, TR and TB.(d) When the dissolution interval was 30 s, the relationship between ALR(the accumulative leaching rate) of the 3 kinds of tea pigment and dissolution time respectively matched the kinetic equation of zero level while mostly the kinetic equation of one level at dissolution interval of 1 min, 3 min and 5 min. |
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