Study on the Changes of Physical and Chemical Components during the Frying Process of Green Tea by Computer Vision

WU Xun; LIU Fei; CHEN Zhiwei; WANG Yuwan; CHEN Lin; TU Zheng; ZHOU Xiaofen; YANG Yunfei; YE Yang; TONG Huarong

doi:10.13305/j.cnki.jts.2020.02.006

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Journal of Tea Science ›› 2020, Vol. 40 ›› Issue (2) : 194-204. DOI: 10.13305/j.cnki.jts.2020.02.006

Study on the Changes of Physical and Chemical Components during the Frying Process of Green Tea by Computer Vision

WU Xun^1,2, LIU Fei³, CHEN Zhiwei^2,4, WANG Yuwan², CHEN Lin², TU Zheng², ZHOU Xiaofen⁵, YANG Yunfei², YE Yang^2*, TONG Huarong^1*

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Abstract

In order to find out the physical and chemical changes during the frying process of green tea, the computer vision technology was applied to real-time monitor the changes of color and shape, and chemical changes were simultaneously measured. The results show that with the increase of frying time, (1) the radius of curvature of unfinished tea gradually decreased, which showed the highest decreasing rate from 10-30 min. R, G, B and average gray value decreased first and then rose. The consistency value was opposite to their trends, with the extreme value in 20 min. H value increased significantly, S value decreased significantly. (2) Epigallocatechin gallate (EGCG), epigallocatechin (EGC), chlorophyll a, chlorophyll b and carotenoids decreased significantly, while gallocatechin gallate (GCG) increased significantly. Experimental results show that the radius of curvature was highly correlated with water content and leaf temperature. H was significantly correlated with chlorophyll a, chlorophyll b. S was significantly correlated with chlorophyll a, carotenoids and epicatechin gallate (ECG). The linear fit of EGCG and H values showed the highest value at 0.922 1. In the future, water content, leaf temperature and H value could be monitored online to predict changes of the radius of curvature and chemical composition during frying.

Key words

computer vision / correlation / green tea / the frying process / the radius of curvature

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WU Xun, LIU Fei, CHEN Zhiwei, WANG Yuwan, CHEN Lin, TU Zheng, ZHOU Xiaofen, YANG Yunfei, YE Yang, TONG Huarong. Study on the Changes of Physical and Chemical Components during the Frying Process of Green Tea by Computer Vision[J]. Journal of Tea Science. 2020, 40(2): 194-204 https://doi.org/10.13305/j.cnki.jts.2020.02.006

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