白肉枇杷多酚氧化酶酶学特性研究

Study on Characteristics of Polyphenol Oxidase in White Pulp Loquat

以“白梨”枇杷(EriobotryajaponicaLindl．cv．Baili)果实为试材,采用硫酸铵分级盐析及透析法提取PPO研究其理化特性,包括温度、pH、抑制物对PPO活性的影响及其底物特性;测定果实＼贮藏期间pH值变化。结果表明:PPO的最适温度为30—40℃,在30℃有较好的热稳定性;最适pH值为5．0和7．0,pH值为6．0和9．0时酶的稳定性较好;维生素C和L-半胱氨酸抑制物对PPO有较强的抑制作用,以维生素C抑制作用最强。

PPO in loquat （Eriobotrya japonica Lindl. cv. Baili） was extracted anti purltleti Wltla [NH4）2SO4 fraction. The influences of different pH, temperature, zymolyte and inhibition on the activity of PPO were studied. The changes of store loquat fruits pH were determined. The results showed that the optimal pH were 5.0 and 7.0, the optimal temperature was 30-40℃. PPO was still stable at 30℃, The activity of PPO at pH 6 and pH 9 were more stable than others. Vitamin C and L-cysteine were strong inhibitors for PPO, and Vitamin C was the strongest one.