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Title: Lipoxygenase from Banana Leaf: Purification and Characterization of an Enzyme That Catalyzes Linoleic Acid Oxygenation at the 9-Position
Authors: Jen-Min Kuo
Ann Hwang
Dong-Bor Yeh
Min-Hsiung Pan
Mei-Ling Tsai
Bonnie Sun Pan
Contributors: 國立臺灣海洋大學:食品科學系
Keywords: banana leaf
flavor formation
Date: 2006
Issue Date: 2018-05-23T08:17:52Z
Publisher: Journal of Agricultural and Food Chemistry
Abstract: Abstract: The objective of the present study was to purify and characterize the lipoxygenase (LOX) from banana leaf (Giant Cavendishii, AAA), an unutilized bioresource. LOX was extracted, isolated, and purified 327-fold using 25−50% saturation of ammonium sulfate fractionation, hydroxyapatite column separation, and gel filtration on Superdex 200. The molecular mass of the purified LOX was 85 kDa, Km was 0.15 mM, and Vmax was 2.4 μM/min·mg using linoleic acid as substrate. Triton X-100 was required in the extraction medium; otherwise, no LOX activity was detected. LOX activity increased with the concentration of Triton X-100 with an optimum at 0.1%. The optimal pH of the purified LOX from banana leaf was 6.2, and optimal temperature was 40 °C. The LOX showed the highest reactivity toward 18:2 followed by 18:3 and 20:4. A very low reaction rate was observed toward 20:5 and 22:6. On the basis of retention time in normal phase HPLC, the products of 18:2 or 18:3 catalyzed by purified LOX were hydroperoxyoctadecadienoic acid or hydroperoxyoctadecatrienoic acid. It seems that 9-LOX is the predominant enzyme in banana leaf. Banada leaf dried at 110 °C for 2 h developed algal aroma. Banana leaf extract stored at 10 °C for 12 h formed an oolong tea-like flavor. Banana leaf extract reacted with 18:2 or soybean oil pretreated with bacterial lipase produced green and melon-like aroma, whereas the same reaction with 18:3 produced a sweet, fruity, cucumber-like flavor note.
Relation: 54(8) pp.3151–3156
URI: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/46570
Appears in Collections:[食品科學系] 期刊論文

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