Estimation of catechins concentration of green tea using hyperspectral remote sensing
Agricontrol, Volume # 3 | Part# 1
Sohara, Yusuke; Ryu, Chanseok; Suguri, Masahiko; Park, Si-Bum; Kishino, Shigenobu
Digital Object Identifier (DOI)
catechins concentration,hyperspectral image,the reflectance of new shoots,PLS regression,regression coefficient
Models for the estimation of the concentration of catechins concentration in new green tea shoots were established using ground-based hyperspectral remote sensing. The coefficient of determination (R2) was determined to be more than 0.913, the root mean squared error of prediction (RMSEP) was determined to be less than 0.617 % and the relative error of prediction (REP) was determined to be less than 6.17%, except in the EGC model (R2=0.512, RMSEP=0.272%, and REP=15.7%). The regression coefficients of the green, red edge and near infrared regions were all changed, indicating that those regions were important for the estimation of catechin concentration. A similar trend was noted for the regression coefficients of ECg and EGCg. Therefore, the X -loadings of the first latent variables of ECg and EGCg (ester-type catechins) and EC and EGC (free-type catechins) were compared and the similarities between each type of catechin were determind. Therefore, each type of PLS regression model was designed based on date of the ester- and free-type catechins. The accuracy of the free-type model was as follows: R2=0.774, RMSEP=0.273% and REP=7.85%. The accuracy of ester-type model was as follows: R2=0.869, RMSEP=0.991% and REP=6.99%. The regression coefficients of the free-type catechins differed from those of the ester-type catechins. Large changes to the regression coefficients of the green to red, and red edge regions were also demonstrated.
 Chen, Q., Zhao, J., Huang, X., Zhang, H., and Liu, M. (2006). Simultaneous determination of total polyphenols and caffeine contents of green tea by near-infrared reflectance spectroscopy. Micro chemical Journal, 83, 42-47.  Feng, W., Yao, X., Zhu, Y., Tian Y.C., and Cao, W.X. (2008). Monitoring leaf nitrogen status with hyperspectral reflectance in wheat. European Journal of Agronomy, 28, 394-404.  Gall, G. L., Colquhoun, I. J., and Defernez, M. (2004). Metabolite Profiling Using H NMR Spectroscopy for Quality Assessment of Green Tea, Camellia sinensis. J. Agric. Food Chem, 52, 692-700.  Goto, T., Uozumi and Suzuki, T. (1986). Near infrared spectoroscopic analysis of total nitrogen content in tea "Sen-cha". Bull. Shizuoka Tea Exp (in Japanese with English summary), 12, 61-81.  Horie, H., Fukatsu, S., Mukai, T., Goto, T., Kawanaka and Shimohara, T. (1988). Quality evaluation on green tea. Sensors and Actuators B(Kanetani)13-14, 451-454.  Ikegaya, K., Takayanagi, H., Anan, T., Iwamoto, T., Uozumi, J., Nishinari, K., Cho, R. (1988). Determination of the content of total nitrogen, caffeine, total free amino acids, theanine and tannin of sencha and maccha by near infrared reflectance spectroscopy. Bulletin of the National Research Institute of Vegetables, Ornamental Plants and Tea. Series B, 47-90.  Ruan, J., Gerendás, J., Haerdter, R., Sattelmacher, B. (2007). Effect of alternative anions (Cl-vs. SO2-
4) on concentrations of free amino acids in young tea plants. Journal of plant nutrition and soil science, 170, 49-58.  Ryu, C.S., Suguri, M., Asai, A., Kurimoto, T., and Umeda, (2007). M., Estimation of quality of green-tea by hypersprctral image, 2nd Advanced Nondestructive Evaluation, 988-993.  Smiechowska, M., Dmowski, P. (2008). Crude fibre as a parameter in the quality evaluation of tea. Food Chemistry, 94, 366-368.  Saba, T., Aono, H., Tanaka, S. (1993). Methods for the Estimation of Optimum Plucking Time in Reration to. Tea Quality Based on the Characteristics of New Shoots of Tea Plants. Bulletin of the National Research Institute of Vegetables, Ornamental Plants and Tea. Series B, 6, 11-20.  Yang, C.S., Maliakal, P., and Meng, X. (2002). Inhibition of carcinogenesis by tea. Annual Review of Pharmacology and Toxicology, 42, 25-54.  Yang, C.S., Wang, Z. Y. (1993). Tea and Cancer. Journal of National Cancer Institute, 85, 1038-1049.