The optimal harvest season of Japanese green tea in Japan is judged by individual farmers based on their experiences. To confirm that optimal season, it requires a lot of efforts such as sampling of tea flushes by plucking, chemical component measuring by near-infrared spectroscopic analysis. Thus, an efficient method to determine the optimal season which can cover a wide area at once is considered highly helpful for farmers. This research measured normalized difference vegetation index (NDVI) of tea flushes by a multi-spectrum sensor mounted on an unmanned aerial vehicle. At the same time, chemical component of tea flushes was measured to compare with the result of NDVI. The result showed that the value of NDVI for the optimal harvest season of tea-leaf is 0.6 to 0.7. The result of chemical component measuring showed the increase of total free amino acids and reduction of total free sugars while tea-leaf ripens. Therefore, there was a positive relation between the value of NDVI, and total free amino acids and total free sugars. It indicates a high possibility to predict the optimal harvest season of tea flushes by NDVI.
Composition of Free Sugars, Organic Acids, Free Amino Acids and Oligopeptides of Kochujang Seasoning Made in Korea.