不同定植期及採收次數對紫色葉菜甘藷酚類化合物及抗氧化能力之影響 - 農業知識入口網

本研究以農業部農業試驗所嘉義農業試驗分所育成紫葉品系的葉菜甘藷CYY84–67 作為試驗材料，並以2017–2018 年種植在農業部農業試驗所農場之試材進行機能性成分分析。本研究目的旨在探討不同定植期與採收次數對紫色葉菜甘藷酚類化合物與抗氧化能力之影響。研究結果顯示，紫色葉菜甘藷於2017–2018年不同採收期之葉片總酚含量為87.3–269.0 mg gallic acid equivalent g-1 fresh weight (FW)，莖部總酚含量為16.6–41.5 mg gallic acid equivalent g-1 FW，葉片總花青素含量為2.8–21.2 mg g-1 FW，莖部總花青素含量為0.2–2.1 mg g-1 FW，葉片總黃酮含量約在21.9–77.5 mg quercetin equivalent g-1 FW，莖部含量則在5.8–11.7 mg quercetin equivalent g-1 FW。在抗氧化能力部分，葉片2,2-diphenyl-1-picrylhydrazyl (DPPH) 自由基清除能力為34.6–83.7%，莖部為3.5–11.4%，而葉片的半致效應濃度 (concentration for 50% of maximal effect; EC50) 為22.05 μg mL-1，莖部的EC50 濃度則為184.08 μg mL-1。在普魯士藍還原力部分，紫色葉菜甘藷之葉片為10.4–75.9 mg ascorbic acid equivalent g-1 FW，莖部之還原力則為1.2–6.4 mg ascorbic acid equivalent g-1 FW。綜合試驗結果顯示，在3 月7 日以第3 次採收之機能性成分與抗氧化能力較佳，在6 月28 日與12 月7 日定植期以第1 次採收較佳，在9 月5 日定植期則以第2 次採收較佳。再者，紫色葉菜甘藷之葉片酚類化合物與抗氧化能力具有極顯著正相關。
In this study, the experimental material of purple leafy sweet potato strain CYY84–67 was bred by Chiayi Agricultural Experiment Branch of Taiwan Agricultural Research Institute (TARI), and the field experiment and functional ingredients analyses were conducted at TARI in 2017 and 2018. The objectives of this study were to investigate the effects of planting periods and number of harvesting times on phenolic compounds and antioxidant capacity of purple leafy sweet potato. The results showed that functional ingredients were present in the leaves and stems of purple leafy sweet potato CYY84–67 at different harvest periods during 2017–2018. The total phenolic content in leaves ranged from 87.3–269.0 mg gallic acid equivalent g-1 fresh weight (FW), while the content in stems ranged from 16.6–41.5 mg gallic acid equivalent g-1 FW. Leaves had a total anthocyanin content of 2.8–21.2 mg g-1 FW, while stems had a content of 0.2–2.1 mg g-1 FW. The total flavonoid content in leaves was between 21.9 and 77.5 mg quercetin equivalent g-1 FW, while the content in stems was between 5.8 and 11.7 mg quercetin equivalent g-1 FW. Regarding antioxidant capacity, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging effect of the leaves was 34.6–83.7%, while that of the stems was 3.5–11.4%. The concentration for 50% of maximal effect (EC50) of the leaves was 22.05 μg mL-1, and the EC50 concentration of the stems was 184.08 μg mL-1. The reducing power from the leaves of purple leafy sweet potato CYY84–67 was 10.4–75.9 mg ascorbic acid equivalent g-1 FW, while the stems had 1.2–6.4 mg ascorbic acid equivalent g-1 FW. The results showed that the functional ingredients and antioxidant capacity were better in the third harvest on March 7. For the planting periods on June 28 and December 7, the first harvest was the best, while for the planting period on September 5, the second harvest was the superior. Furthermore, there was a significant positive correlation between the antioxidant capacity and the phenolic compounds in the leaves of purple leafy sweet potato.