中文摘要：

以水杨酸为效应物，研究其酶学效应和微生物效应．实验结果表明：水杨酸对马铃薯多酚氧化酶有明显的抑制作用，半抑制率（IC50）为2．05mmol／L，抑制作用表现为非竞争性的可逆过程，其抑制常数为2．00mmol／L．水杨酸对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌3种细菌和白色假丝酵母、黑曲霉两种真菌均有明显的抑制作用，其最小抑菌浓度（MIC）分别为0．75、0．5、0．5、0．25和0．75mg／mL，最小杀菌浓度（MBC）分别为0．75、1．0、0．5、0．25和0．75mg／mL．本研究为水杨酸在果蔬保鲜中的应用提供实验理论依据．

英文摘要：

Used salicylic acid as the inhibitor, we studied its inhibitory effect on the activity of potato polyphenol oxidase （PPO） and some bacteria and fungi. Salicylic acid could obviously inhibit the PPO activity and the inhibitor concentration leading to 50% activity lost （IC50） was determined to be 2.05 mmol/L. The inhibition mechanism of salicylic acid belonged to a reversible noncompetitive reaction, and the constant of inhibition （K1） was 2.00 mmol/L. The inhibition of salicylic acid on some bacteria such as E. coli, S. aureus and B. subtilis and some fungi such as C. albicans and A. niger has been studied. The values of MIC were determined to be 0.75, 0.5, 0.5, 0.25 and 0.75 mg/mL, respectively, and the values of MBC were 0.75, 1.0, 0.5, 0.25 and 0.75 mg/mL, respectively. This study gave theoretical support for salicylic acid used as food preservative agent.