SỰ BIẾN ĐỔI MỘT SỐ TÍNH CHẤT VẬT LÍ CỦA LÁ CHÈ TRONG QUÁ TRÌNH LÀM HÉO
THE CHANGE OF SOME PHYSICAL PROPERTIES
OF TEA LEAVES DURING THE WITHERING PROCESS
Determining the change of some physical properties of tea leaves during the withering process helps technologists and managers establish technological mechanism of properly wilting and crumpling tea leaves for the process of black tea production. Midland tea with one bud and three leaves, which is equivalent to material type B according to Vietnamese standards TCVN 2843-79, it was harvested in district Thanh Ba, province Phu Tho. Then it was withered in the conditions as follows tea layer thickness is 25 cm, wilting air temperature is 34,50C, wilting time is 378 minutes. This process is to determine the transformation of tea block’s area and volume, and to identify tea leaves’ tension, elongation and tearing resistance. The results show that the more young tea leaves are, the more tea leaves’ area decrease, namely: Leaf 1’s area decreases by 67.5% compared with starting material, leaf 2’s area decreases by 45.1% and leaf 3 decreases by 28, 6%. Elongation of leaf 1, 2, 3 stem increases compared with the starting materials is 51.3%, 40.1%, 14.2% - 13.2%. Tearing resistance of leaf 1, 2, 3 also increased compared with starting materials, which is 38.35%, 12.01%, 7.09%, 7.80%. The solid volume of tea block decreases by 29.3% compared with the origin and the porous volume decreases by 50%.
How to Cite
Vietnam Journal of Sciences and Technology (VJST) is an open access and peer-reviewed journal. All academic publications could be made free to read and downloaded for everyone. In addition, articles are published under term of the Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA) Licence which permits use, distribution and reproduction in any medium, provided the original work is properly cited & ShareAlike terms followed.
Copyright on any research article published in VJST is retained by the respective author(s), without restrictions. Authors grant VAST Journals System a license to publish the article and identify itself as the original publisher. Upon author(s) by giving permission to VJST either via VJST journal portal or other channel to publish their research work in VJST agrees to all the terms and conditions of https://creativecommons.org/licenses/by-sa/4.0/ License and terms & condition set by VJST.
Authors have the responsibility of to secure all necessary copyright permissions for the use of 3rd-party materials in their manuscript.