Lipoxygenase independent hexanal formation in isolated soy proteins induced by reducing agents.
Lipoxygenase independent hexanal formation in isolated soy proteins induced by reducing agents.
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DOI：
10.1111/j.1750-3841.2008.00810.x
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发表时间：
2008-08
影响因子：
3.9
通讯作者：
Q. Lei;W. L. Boatright
中科院分区：
文献类型：
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作者：
Q. Lei;W. L. Boatright
与相应的对照相比，6.5 mM二硫苏糖醇（DTT）提高了顶部空间己醛水平，超过了用80 ℃处理制备的商业分离大豆蛋白（ISP）和实验室ISP的水性浆液。进一步的分析表明，脂氧合酶（LOX）的活性没有检测到这些ISP，表明LOX是不参与观察到的己醛增加。诱导的顶空己醛在ISP的含水浆料的水平成比例的DTT的量在0至65 mM的范围内添加。随后的系统研究与模型系统显示，铁是所需的还原剂诱导的己醛形成从亚油酸。异抗坏血酸，另一种还原剂，也可以诱导己醛形成在ISP和模型系统。作为比较，检测了脱脂大豆粉中的LOX活性和己醛合成。结果表明，脱脂大豆粉保持了较高的LOX活性，高浓度DTT（130 mM以上）显著抑制了该样品中己醛的合成。从目前的调查数据表明，存在LOX独立的己醛形成诱导的还原剂在ISP和铁作为催化剂的潜在需求。
Compared to corresponding controls, 6.5 mM dithiothreitol (DTT) elevated headspace hexanal level over aqueous slurries of both commercial isolated soy proteins (ISP) and laboratory ISP prepared with 80 degrees C treatment. Further analysis revealed that lipoxygenase (LOX) activity was not detected from these ISP, indicating that LOX is not involved in the observed hexanal increase. Levels of the induced headspace hexanal over the ISP aqueous slurries were proportional to the amount of DTT added in the range of 0 to 65 mM. Subsequent systematic investigations with model systems revealed that iron was required for the reducing agent-induced hexanal formation from linoleic acid. Erythorbate, another reducing agent, can also induce hexanal formation in both ISP and model systems. As a comparison, the LOX activity and hexanal synthesis in defatted soy flour were examined. The corresponding results showed that defatted soy flour maintained high LOX activities and that hexanal synthesis in such sample was significantly inhibited by high concentration DTT (above 130 mM). Data from the current investigation demonstrate the existence of LOX independent hexanal formation induced by reducing agents in ISP and the potential requirement of iron as a catalyst.