In recent days, my attention was drawn to a particular cultivars of tea: the albino tea cultivars.
There are two main types of albino cultivars, light-sensitive and another thermosensitive.
The light sensitive albino cultivar manifested most clearly its characteristics when it is more exposed to light, in fact the leaves of these plants are clearer precisely in summer when the light exposure is stronger.
The other type (thermosensitive) manifests a greater albinism when the temperature is lower.
The tea leaves belonging to a thermosensitive albino cultivar develop in three stages.
The pre-albinistic stage, albinistic stage and the regreening stage.
The pre-albinistic stage includes the budding and phase just next to it which is in spring with a temperature lower than 20 ° C, at this stage the leaves are light green. With the passage of time the leaves turn more and more white reaching the albino stage. With the approach of summer, however, temperatures rise and the leaves turn green again (regreeing stage), usually that happens when the temperature exceeds 22 ° C.
Different teas on the market come from the albino varieties, among which some are Anji Bai Cha and Bai Ji Guan.
As you can guess the leaves of these plants are lighter because of the smaller amount of chlorophyll.
As a result of this lower content of chlorophyll the plants belonging to this cultivars to try to maintain a good photosynthetic capacity produce a large amount of zeaxanthin (much more compared to other cultivars) a carotenoid that is capable of absorbing solar radiation in excess, They would otherwise damage the plant. This carotenoid has a yellow colour and being vary abundant this molecule will have an impact on the color of the leaf that has a color to yellow.
What instead determines a particular taste in these teas is the large amount of free amino acids (especially theanine) present. As mentioned in a previous post the theanine gives a strong umami taste to the brew that fact is clearly perceptible even in this type of tea. In addition, the theanine in liaison with caffeine also has positive effects on mental focus.
The particular abundance of this kind of molecules is closely linked to the lack of chlorophyll. In fact the amino acids in the plant by binding between them serve as bricks to build various proteins, but in this cultivar protein production is reduced due to the decrease of chloroplasts and photosynthetic pigments, so the amino acids present in the leaf do not use them all from the plant, a good amount remains free (ie, the amino acids are not bound to each other) and therefore capable of giving the pleasing effects above.
Another feature of this tea cultivar is to have in general a lower amount of polyphenols which makes the tea very little astringent, in fact, as we remember the astringency is mainly caused by this type of compounds.
Personally I think almost certainly the lack of polyphenols also have an influence on the final color of the infusion of these teas making it clearer than others, but not having bibliographic evidence I can not be quite sure (because the color of the infusion depends a lot from how the tea is processed).
Determination of quality constituents in the young leaves of albino tea cultivars.
Feng L, Gao MJ, Hou RY, Hu XY, Zhang L, Wan XC, Wei S. Food Chemistry, Volume 155, 15 July 2014, Pages 98-104
Effect of sunlight shielding on leaf structure and amino
acids concentration of light sensitive albino tea plant
Wang K. R. , Li N. N. , Du Y. Y. and Liang Y. R. 1. African Journal of Biotechnology.
Proteomic analysis of young 450 leaves at three developmental stages in an albino tea cultivar. Li, Q., Huang, J., Liu, S., Li, J., Yang, X., Liu, Y., Liu, Z., 2011b. Proteome Sci. 9, 44.
Comparison of the Quality Characteristics of4 Albinos Tea.
Ronglin Li, Zhengzheng Li, Yiyang Yang, Hao Yuan, Yunlong Kong.
Food and Nutrition Sciences, 2013, 4, 1102-1107.