제주지역에서 차나무(Camellia sinensis L.) 품종 및 수확기에 따른 신초의 품질 및 무기성분 특성

Abstract

This study was conducted to evaluate factors affecting tea quality with analyzing shoot quality and inorganic elements in some cultivars at different harvesting seasons and shoot growth stages. Shoot growth stage, shoot part, and stem part were classified with five growth stages from one and a bud to five and a bud, seven shoot parts consisting of a bud, 1st leaf, 2nd leaf, 3rd leaf, 4th leaf, 5th leaf, and stem, and three stem parts of upper, middle, and lower, respectively for all three cultivars of Saemidori (early maturing), Yabukita (middle maturing), and Hushun (late maturing) grown at Jeju, Korea. Total free amino acids and theanine were similar in tendency of content levels at different growth stages of three cultivars with different harvesting seasons and these contents were the highest at the 1st crop and decreased gradually with growth stages. Total cathechins contents were the lowest at the 1st crop and declined with growth stages. Caffeine contents were similar at the 1st and 3rd crop and showed the tendency to decrease gradually with growth stages. Tannin contents were little different among harvesting seasons and decreased with growth stages. Vitamin C contents were the highest at the 1st crop and increased with growth stages, whereas similar at all growth stages of the 2nd and 3rd crops. There were no differences in crude fiber contents with different harvesting seasons, whereas they increased gradually with growth stages. Cultivars showed significant differences in contents of these components with different harvesting seasons and shoot growth stages. While evaluating inorganic elements of new shoots at different growth stages of three cultivars with different harvesting seasons, total nitrogen (T-N) contents decreased with growth stages and were not different among cultivars. Also, they were the highest at the 1st crop and similar at the 2nd and 3rd crops. K and Mg contents did not show significant differences among cultivars, harvesting seasons, and shoot growth stages. Ca contents showed the tendency to increase with the growth stages, whereas did not show differences among cultivars and harvesting seasons. Differences in Fe contents were not great among cultivars and growth stages and Fe contents were a little bit low at the 3rd crop. Cu and Zn showed similar levels among cultivars and harvesting seasons, whereas slightly declining tendency in contents with different growth stages. Mn contents were the highest at the 3rd crop, followed with the 1st and 2nd crops in order and had an increasing tendency with growth stages. Na contents were the highest at the 1st crop and similar at the 2nd and 3rd crops with a little bit small differences among growth stages and cultivars. In evaluating yearly variation for three years in shoot quality of Yabukita, tendencies of contents with different growth stages and harvesting seasons were so similar. Total free amino acids and theanine contents at the 1st, 2nd, and 3rd crops were the highest in the year of 2011, whereas at the 4th crop in 2010. Total catechines contents at the 1st crop were the highest in 2011, whereas at the 2nd to 4th crops in 2010. Caffeine contents at the 1stm 2nd, and 4th crops were the highest in 2011, whereas at the 3rd crop in 2010. Tannin, vitamin C, and crude fiber were components having very small yearly variation in contents with different growth stages and harvesting seasons. Quality characteristics of different shoot parts were evaluated at different harvesting seasons of three cultivars. Total free amino acids, theanine, and caffeine showed very similar tendencies of contents to decrease from a bud to lower shoot parts and the content at stem was higher that of the 4th or 5th leaf. However, the decreasing levels differed depending on cultivars and harvesting seasons. Total catechins and tannin contents had similar tendencies to decline slightly from a bud to lower part, whereas those contents of stem were considerably lower than those of the 5th leaf unlike that of total free amino acids. Vitamin C did not have distinctive tendency of content at different parts, whereas the content at stem was the lowest. Crude fiber contents increased from a bud to lower part and then stem and the 5th leaf showed similar level, irrespective of cultivars and harvesting seasons. The contents of all quality components at different stem parts were at so similar levels to those of shoot parts nearby each stem part. From analyzing inorganic components of different shoot parts at different harvesting seasons of three cultivars, T-N of macro elements was at the highest level, followed with K, Mg, Ca, and Na in order and Mn of micro elements was the highest level, followed with Fe, Zn, and Cu in order. There were significant and distinct differences in T-N and Mn contents just at the first harvesting season in different cultivars, while little in the other elements at the other harvesting seasons. T-N and Zn contents definitely decreased, while Ca content increased at lower parts. The others were hardly changed at different shoot parts. The content of Fe, Mn and Na was definitely differed at different harvesting seasons.