不同葉位及不同乾燥處理對甘藷葉片葉黃素含量之影響

Abstract

本研究目的為瞭解甘藷不同生育過程植體內葉黃素累積之變化，以及不同乾燥處理對甘藷葉片葉黃素累積之影響。選用台農57號（TNG57）及紫葉品系CYY98-63作為試驗材料，收取（1）種植後第1、2、3、4及5個月新鮮甘藷葉；（2）種植後第5及第6個月後葉片、葉柄及莖部；（3）種植後第5及6個月後植株先端15cm及25cm植株之葉片，葉柄及莖部，以及小於5節、5至16節及大於16節地上部樣品。這些樣品分別經過冷凍乾燥及熱烘乾燥處理後，再利用HPLC分析比較葉黃素含量。經分析結果得知，甘藷葉片之葉黃素含量遠高於甘藷葉柄及莖部；隨著甘藷種植時間增加，甘藷葉片葉黃素含量上升；種植4至5個月以上其甘藷葉之葉黃素含量較顯著增加；取樣部位為節位少於5節者，萃取出葉黃素含量較低，而取樣部位為節位5節至16節以上者，萃取出葉黃素含量較高；而比較不同乾燥處理條件下，冷凍乾燥較熱烘乾燥甘藷地上部，可萃取出較多葉黃素含量。 This study investigates the changes of lutein content in sweet potato in various growth stages and evaluates the effect of drying treatments on lutein accumulation in different tissues. Experimental materials were collected from green-leaf cultivar Tainong No. 57 (TNG57) and purple-leaf line CYY98-63. Temporal changes of lutein in sweet potato were examined by collecting samples from (1) Fresh sweet potato leaves from 1 to 5 months after planting; (2) Leaves, petioles, and stems on 5- and 6-month-old plants; (3) Leaves, petioles, and stems of 15 cm and 25 cm shoots below the youngest leaf of 5- and 6-month-old plants, and shoots contained the first five nodes, 5th to 16th nodes and shoots more than 16 nodes. These samples were subjected to freeze-drying and hot-air-drying treatment. HPLC was used to analyze lutein content. The results showed that the lutein content of leaves was much higher than that of petioles and stems. With the increasing of sweet potato planting time, the lutein content of sweet potato leaves increased significantly. The lutein content was much lower in the first five nodes, while the 5th to 16^(th) nodes had high lutein content. Compared with different drying methods, freeze-drying method had more lutein than hot-air-drying method.