为探究大果山楂果肉的酶促褐变，研究了沸水加热时间对山楂块褐变度、多酚氧化酶和过氧化物酶活性、总酚、黄酮、花青苷含量的影响。此外，研究了加热灭酶后山楂的褐变度、抗坏血酸和还原糖含量随存放时间的变化情况。结果表明，对于5 g的山楂块而言，沸水加热2 min，多酚氧化酶、过氧化物酶基本失活。随着热处理时间的增加，山楂褐变度越低，山楂多酚氧化酶、过氧化物酶活性显著下降，总酚、黄酮含量较未加热山楂多，花青苷含量有少量的减少，说明山楂果肉的褐变与酶促褐变密切相关；加热灭酶后的山楂块在存放过程中，山楂褐变度、抗坏血酸和还原糖含量几乎无变化，说明山楂果肉几乎不进行非酶褐变反应。

To explore the enzymatic browning inMalus domeri (Bois) Chev., effects of boiling time on the browning degree, activity of polyphenol oxidase and peroxidase, total phenols, flavone and anthocyanin were studied. Besides, the browning degree, ascorbic acid and reducing sugars content inMalus domeri(Bois) Chev.of enzymes destruction were measured. For about5 gof hawthorn pieces, the polyphenol oxidase and peroxidase were hardly inactivated in 2 min. With the increase of heating time, the browning degree, polyphenol oxidase and peroxidase activity were decreased significantly, accompanied by more total phenols and flavone, and slightly less anthocyanin. These results indicated thatMalus domeri (Bois) Chev.flesh browning was closely related to enzyme browning. For the hawthorn pieces of enzyme deactivation, the browning degree, ascorbic acid and reducing sugars content had no significant changes during the storage, which suggested that non-enzymatic browning was not happened in the flesh ofMalus domeri (Bois) Chev..