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Chitsuda Chaisakdanugull & Chockchai Theerakulkait 《International Journal of Food Science & Technology》2009,44(4):840-846
Polyphenol oxidase (PPO) from pulp of banana [Musa (AAA Group) 'Gros Michel'] was extracted and precipitated with 80% saturated ammonium sulphate followed by conventional column chromatography on Sephacryl S-200 HR and fast protein liquid chromatography on Mono Q column. The lyophilised PPO obtained from Sephacryl S-200 HR column was used for characterisation and inhibition studies. The partially purified PPO obtained from the Mono Q column exhibited at least three isoenzymes. The banana PPO had optimum pH for activity at 7 and it was stable around the same pH. Only 48% of initial enzyme activity was lost after heating at 70 °C for 30 min. The enzyme was completely inhibited by 2 m m sodium metabisulphite, 2 m m l -cysteine, 4 m m ascorbic acid, and 100 m m 4-hexylresorcinol. The K m and V max of banana PPO for dopamine were 2.08 m m and 0.124 m m min−1 respectively. 相似文献
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The application of response surface methodology in studying the effect of heat and high hydrostatic pressure on anthocyanins,polyphenol oxidase,and peroxidase of mulberry (Morus nigra) juice 下载免费PDF全文
Felix N Engmann Yongkun Ma Haining Zhang Lizhi Yu Nana Deng 《Journal of the science of food and agriculture》2014,94(11):2345-2356
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目的 以黄鲫蛋白肽(Half-fin anchovy hydrolysate peptides,HAHp)为基料复配抗坏血酸和茶多酚制备南美白对虾多酚氧化酶(Polyphenol oxidase,PPO)复合生物抑制剂(Composite biological inhibitor,CBI)。方法 以南美白对虾PPO抑制率为检测指标,分别研究HAHp、抗坏血酸、茶多酚、柠檬酸和EDTA-2Na单独抑制PPO活性,选取HAHp、抗坏血酸和茶多酚进行三因素三水平正交优化实验优化CBI配方组成,通过酶促动力学研究CBI对南美白对虾PPO的抑制模式。结果 HAHp、抗坏血酸、茶多酚、柠檬酸和EDTA-2Na对南美白对虾PPO都有一定的抑制作用,且有一定的剂量依赖性,但单一抑制剂对PPO的抑制作用有限。HAHp与天然抗氧化剂抗坏血酸和茶多酚复配,经(L9 33)正交试验优化CBI的最佳配方含有0.7%HAHp、0.02%抗坏血酸和0.20%茶多酚。经测定CBI对南美白对虾PPO抑制率达到94.71±0.46%,酶促动力学结果表明CBI是一种混合型抑制剂,通过降低南美白对虾PPO对底物亲和力实现抑制PPO活力。结论 以HAHp为基料复配抗坏血酸和茶多酚制备的CBI能够有效地抑制南美白对虾PPO活性,有望开发成一种防虾黑变的天然抑制剂,为南美白对虾天然保鲜剂的研究奠定了理论基础。 相似文献