| Summary: | 碩士 === 國立高雄海洋科技大學 === 水產食品科學研究所 === 101 === The objective of present work is to extract and isolate the antioxidative substances from banana leaves, and to study their antioxidative activity. The banana leaves were dried and milled into powder. The proximate composition of banana leaf powder was listed as follows: moisture content, 29.6%; carbohydrate, 49.6%; ash, 19.5%; crude fat, 0.3%; crude protein, 0.9%. Efficiency of solvent to extract antioxidative substance from banana leaf powder was in the following: boiling water> cooling water > 50% ethanol. Those extracted by 95% ethanol, methanol, ethyl acetate, hexane, acetone showed less efficiency. The optimal extracting conditions were boiling water for 30 min. Crude extract of banana leaves was further fractionated by using XAD column separation, the 4th fraction (named XAD-4) was obtained with IC50 287.76(μg/mL) and purification fold 1.36. The antioxidative substances from XAD-4 were possessed of ability to prevent peroxidation of linoleic acid, DPPH and hydroxyl radical scavenging activity, reducing power, Fe (II) chelating activity. Total phenol content of crude extract from banana leaf was 1.34 ± 0.06 mg/g; flavonoid content, 2.14 ± 0.06 mg/g. Total phenol content of XAD-4 from XAD column separation was 2.44± 0.06mg/g; flavonoid content, 3.48 ± 0.06 mg/g.
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