| Tie Guanyin, Jin Guanyin, Baiyaqilan were used as explants to carry out studies on the chromatic value during green-making process under different green-making intensities. The correlation was analysed between biochemical components and chromatic value of tea leaf, tea powder and liquor. Meanwhile, the studies on chromatic value about Tie Guanyin and Jin Guanyin under different green-making temperature treatments were carried out. The main results were described as follows:The results showed that the tea powder with mesh size of 100 was the best choice to determine tea powder chromatic value of Oolong tea, which was smashed 60s with 50g of tea. The measurement result was relatively stable. The best extraction conditions were an extraction time 5min and solid-solvent ratio 1:125g·mL-l with 100 mesh size for determination of liquor chromatic value of Oolong tea. The best extraction conditions were an extraction time 9min and solid-solvent ratio 1:50g·mL-1 for determination of liquor chromatic value of semifinished tea.The results showed that the best extraction process parameters of chlorophylls and carotenoids were an extraction temperature of 50℃,ultrasonic power 648W,extraction time 60min,solid-solvent ratio 1:12g·mL-1 under the condition of ultrasonic frequency of 40 kHz and the miscible liquids with the ratio of 3:6:1 (acetone:ethanol:water).In this study, the direct assay method on leaf chromatic value of Oolong tea was used firstly. The test results showed that the changes of leaf chromatic value of Tie Guanyin, Jin Guanyin and Baiyaqilan were consistent on the whole during the process of Oolong tea. The changes of leaf brightness L* of three varieties were increased firstly and then decreased during green-making process. Overall, the leaf brightness after rotation was higher than before rotation in the prophase of green-making, on the contrary, the leaf brightness after rotation was lower than before rotation in the anaphase of green-making. The leaf brightness was increased quickly after de-enzyming. The results showed that the changes of chromatic value a* during process existed some differences when green-making intensity and tea variety were different. The change of leaf a of Jin Guanyin was increased firstly and then decreased, and the change of leaf a* of Tie Guanyin and Baiyaqilan were decreased gradually during green-making process. The chromatic value a was higher after rotation in the prophase of green-making, on the contrary, the chromatic value a was lower after rotation in the anaphase of green-making. The variation tendency of b* was similar to L*. The leaf chromatic value b* was increased quickly after de-enzyming. The results showed that the changes of chromatic value b* during process existed some differences when tea variety was different. The results indicated that there was a negatively significant correlation between chromatic value with water content. As well as chlorophyll and carotenoid, the oxidation products of tea polyphenols could affect the leaf chromatic value. There existed some differences between different green-making intensities and tea varieties.The studies on chromatic value during green-making process under different green-making tempertures about Tie Guanyin and Jin Guanyin were carried out. The tea powder chromatic value L*, a*, b* of Tie Guanyin were higher than Jin Guanyin. The changes of tea powder brightness L* of Tie Guanyin and Jin Guanyin were increased firstly and then decreased during process, and it was recovered slightly in the anaphase of process of Jin Guanyin. In the whole process, the range of variation of tea powder brightness L was as the order-22℃>27℃>17℃. The tea powder chromatic value a* of Tie Guanyin and Jin Guanyin were trended towards increase, and green degree reduced gradually. The range of variation of tea powder chromatic value a* was as the order-22℃>27℃>17℃. The tendency and range of variation of tea powder chromatic value b* were differences between different green-making intensities and tea varieties. The liquor brightness L of Tie Guanyin was trended towards increase, on the contrary, the liquor chromatic value a*, b* of Tie Guanyin was trended towards decrease during process. When the green-making temperature was 22℃, brightness L* and green degree were increased in the anaphase of process. In the whole process, the ranges of variation of liquor brightness L* and b* of Tie Guanyin were as the order-17a℃>22℃>27℃; the range of variation of liquor a was as the order-22℃>17℃>27℃. The change of liquor chromatic value of Jin Guanyin was similar to Tie Guanyin as a whole, and there was a contrary tendency in the anaphase of process. The range of variation of liquor brightness L of Jin Guanyin was as the order-27℃>22℃>17℃; the range of variation of liquor a* was as the order-22℃>17℃>27℃; the range of variation of liquor b was as the order-17℃ >27℃>22℃. The ranges of variation of liquor chromatic value L*, a*, b* of Tie Guanyin were higher than Jin Guanyin.The main factors of effecting on tea powder chromatic value were oil-soluble pigments and water-soluble pigments, which included chlorophyll, carotenoid, water soluble matter, total amino acids, tea polyphenols and its oxidation products. The main factors of effecting on liquor chromatic value were carotenoid, water soluble matter, flavone, tea polyphenols and its oxidation products TF and TR. There existed some differences between different green-making temperatures and tea varieties.The studies on chromatic value during green-making process under different green-making intensities about Tie Guanyin, Jin Guanyin and Baiyaqilan were carried out. The test results showed that the changes of tea powder brightness L* of Tie Guanyin, JinGuanyin and Baiyaqilan presented the changing curve of "(?)" shape under the severe treatment during the entire process. The powder brightness L* of semifinished tea was lower than other processes. The range of variation of brightness L* of Jin Guanyin was more obvious under the severe green-making treatment. The tea powder brightness L* under the mild green-making treatment had different trends about different tea varieties. The influence of green-making intensity on the range of variation of brightness L during green-making process was as the order-Tie Guanyin>Jin Guanyin>Baiyaqilan. The chromatic value a* was trended towards increase gradually and the influence of green-making intensity on the range of variation of tea powder a* during green-making process was as the order-Tie Guanyin>Baiyaqilan>Jin Guanyin. The chromatic value b* was trended towards decrease gradually and the influence of green-making intensity on the range of variation of tea powder b* during green-making process was as the order-Tie Guanyin>Jin Guanyin>Baiyaqilan. The test results showed that the changes of liquor brightness L* of Tie Guanyin, Jin Guanyin and Baiyaqilan presented the changing curve of "V" shape under the mild and severe treatments during the entire process. The liquor brightness L* of the end of green-making was lower than de-enzyming leaf and semifinished tea. The influence of green-making intensity on the range of variation of liquor brightness L* during green-making process was as the order-Tie Guanyin>Jin Guanyin>Baiyaqilan. In the study, the changes of liquor chromatic value a* of Tie Guanyin, Jin Guanyin and Baiyaqilan presented the changing curve of "A" shape during the entire process, and the range of variation under severe treatment was more than the range of variation under mild treatment. The influence of green-making intensity on the range of variation of liquor chromatic value a* during green-making process was as the order-Tie Guanyin>Jin Guanyin>Baiyaqilan. The changes of liquor chromatic value b* of Tie Guanyin, JinGuanyin, Baiyaqilan presented the changing curve of "(?)" shape during the entire process, and the range of variation under severe treatment was more than the range of variation under mild treatment. The liquor chromatic value a* of the end of green-making was higher than de-enzyming leaf and semifinished tea. The influence of green-making intensity on the range of variation of liquor chromatic value b* during green-making process was as the order-Tie Guanyin>Baiyaqilan>Jin Guanyin. The main factors of effecting on tea powder chromatic value were oil-soluble pigments and water-soluble pigments, which included chlorophyll, carotenoid, tea polyphenols and its oxidation products TF, TR, TB. The main factors of effecting on liquor chromatic value were water soluble matter, flavone, tea polyphenols and its oxidation products TF and TR. The changes of chlorophyll and carotenoid had an effect on the liquor colour, too. There existed some differences between different green-making intensities and tea varieties. |
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