脂肪氧化酶、红米种皮在抗米糠酸败中的作用

Effect of Lipoxygenase Activity and Red Seed Coat on Rice Bran Rancidity

米糠酸败的主要原因是由于脂肪酶作用的结果,但对米糠酸败过程中脂肪氧化酶同功酶和红米种皮的作用却研究甚少。利用人工加速老化方法处理水稻脂肪氧化酶同功酶LOX-1、LOX-2和LOX-3活性均低的白米、LOX-1,2活性低、LOX-3活性高的白米及LOX-3活性低、LOX-1,2活性高的红米材料的米糠,旨在研究脂肪氧化酶同功酶、红米种皮对稻谷米糠酸败的影响,结果表明:在人工加速老化试验条件下,随老化时间的延长,LOX-1、LOX-2和LOX-3活性均低的白米材料,米糠酸败氧化的程度为最高,游离脂肪酸的累积速度最快;而LOX-1,2活性低、LOX-3活性高的白米材料,米糠酸败氧化的程度和游离脂肪酸的累积速度则低于LOX-1、LOX-2和LOX-3活性均低的白米材料;LOX-3活性低而LOX-1,2活性高的红米材料,米糠酸败氧化的程度为最低,游离脂肪酸的累积速度也最慢。由此可见,LOX-3活性低、LOX-1,2活性高与红米种皮的协同作用能显著抗米糠酸败。

Many papers report that the main cause for rice bran rancidity is lipase, and there is no report about the relationship among lipoxygenase （LOX） activity, red seed coat and rice bran rancidity. In this work, the relationship among lipoxygenase activity, seed coat of red rice and rice bran rancidity were studied with an accelerated - aging experiment. Results indicate that subjected to the accelerated - aging experiment the free fat acid （FFA） of the rice bran material with low activity values of LOX - 1, LOX - 2 and LOX - 3 increases with relatively high speed; the FFA of the rice bran material with low activity values of LOX - 1, LOX - 2 and high activity of LOX - 3 increases with relatively low speed; and the FFA of the red rice bran material with high activity values of LOX - 1, LOX - 2 and low activity of LOX - 3 increases with the lowest speed. So, the degree of rice bran rancidity would be reduced greatly by utilizing the rice characteristics in LOX activity and seed coat color.