摘要
对不同品种梨多酚氧化酶（ＰＰＯ）粗提液，以邻苯二酚为底物，测定了不同ｐＨ值、温度及抑制剂对其活性的影响。结果表明：雪花梨、安梨、白梨、鸭梨ＰＰＯ的最适ｐＨ值分别为６．４，６．２，６．０，６．６；最适温度分别为２４，２２，２０，３０℃；在最适ｐＨ值和温度条件下果肉中所含ＰＰＯ的活性分别为３．２１２×１０３，４．７５２×１０３，３．３４４×１０３，３．８７２×１０３ｕ·ｇ－１ＦＷ。雪花梨和安梨ＰＰＯ对偏二亚硫酸钠反应最敏感，白梨ＰＰＯ对ＧＳＨ（谷胱甘肽）反应最敏感，鸭梨ＰＰＯ对Ｖｃ（维生素Ｃ）反应最敏感。
PPOindifferentspeciesofpearwascrudelyextracted.ThePPOactivityofpearwithcatecholsubstratewasdeterminedindifferentpH,temperatureandinhibitors.TheresultsshowedthattheoptimumpHofPPOwasfoundtobe6.4forXuehua,6.2forAn,6.0forBaiand6.6forYapearrespectively,andtheoptimumtemperatureofPPOwas24forXuehua,22forAn,20forBaiand30forYapearrespectively.ThePPOactivityinpulpattheoptimumpHandtemperaturewas3.212103unit/gforXuehua,4.752103unit/gforAn,3.344103unit/gforBaiand3.872103unit/gforYapearrespectively.SodiummetabisulfitewasfoundtobethemosteffectiveinhibitorforthePPOinXuehuaandAnpear,GSHforBaipearandascorbicacidforYapear.
关键词
梨
多酚氧化酶
抑制剂
pear
polyphenoloxidase
inhibitor
