The high-performance liquid chromatography(HPLC) method for the determination of trans-resveratrol in 34 germplasms and processing methods of peanut seeds has been modified. Peanut germplasms contained trans-resveratrol contents of 0.14~4.96μg/g, but findings for the testa color were not significant. However, two germplasms, 'KIGAN' and 'CS1', contained more trans-resveratrol contents than the other germplasms. The contents of their were 2.26μg/g and 4.96μg/g. The tested processing methods caused no significant changes in trans-resveratrol contents. The contents of fresh, boiled, and roasted peanuts were 0.36, 0.32, and 0.40μg/g, respectively in cv. Palkwang, and 0.22, 0.22, and 0.26μg/g, respectively, in cv. Jakwang. Differences were not significant among fresh, boiled, and roasted peanuts. The grains of 'Palkwang' and 'Jakwang' contained trans-resveratrol contents of 0.34μg/g and 0.24μg/g, and testa contained 1.12μg/g and 1.00μg/g, respectively. However, when comparing absolute quantity, the trans-resveratrol contents appears to be approximately 3~4 times higher in the testa than in the grain of the peanut, although the total contents were not different because the ratio of testa was low in peanut seeds.

The purpose of this study is to establish an extraction and analysis method for α-tocopherol, and to then distinguish among varieties. The α-tocopherol contents of 22 varieties of peanut seeds were analyzed by HPLC. Peanut seeds of cv. Palkwang were processed in two ways, by boiling and roasting. The α-tocopherol contents of the two types of peanuts were compared with fresh seeds without any processing. α-Tocopherol was detected at a retention time of 2.95 minutes. Five standards of α-tocopherol covering a range of 20~100μg/ml were made up in 2% isopropyl alcohol/n-hexane and analyzed in duplicate. The α-tocopherol contents differed according to extraction temperature. The contents were 85μg/g or less at 10℃ and 20℃ and 94μg/g at 30℃, but they were decreased at 40℃ or higher. The α-tocopherol contents in 22 peanut varieties were 61.36~96.80μg/g according to variety. Fresh peanuts contained 106.7μg/g of α-tocopherol, while boiled peanuts contained 108.8μg/g of α-tocopherol, and roasted peanuts contained 109.2μg/g of α-tocopherol.

This study was conducted to determine the optimal planting distance in cultivation of yacon (Polymnia sonchifolia Poeppig ＆ Endlicher). Plug seedlings were planted with 6 different plant densities of 80 ~times 60, 80 ~times 50, 70 ~times 50, 70 ~times 45, 70 ~times 40 and 60 ~times 45 cm. The plant height and the petiole length were increased with increasing the planting distance. The tallest plant height of yacon was 165.4cm with the plant density of 80 ~times 60 cm. However, branch number per plant, leaf number on main stem and stem diameter were not significantly difference among planting densities. Tuberous root was harvested 31.42 tons/ha in 70 ~times 50 cm spacing. The ratio of heavier tuberous roots than 200 g to total tuberous roots decreased significantly according to increase of planting density. Fresh weights of shoot and root, contain the crown bud, were decreased, as planting distance was shorter. Tuberous root number was fewer but its weight was heavier in wide planting than in dense planting. We think that optimal planting density is about 30,000 plants/ha, if it were to be 70 cm row spacing, intrarow spacing should calculate about 47cm.