Abstract: [Objective]Milk,as a natural source of animal protein with rich nutritional value,is rich in calcium,protein and other nutrients,but also contains rich biological active substances,including immunoglobulin,lactoferrin,α-lactobumin,β-lactoglobulin and lactoperoxidase.[Method]The effects of six different heat treatments with different temperature and time combinations on the active substances in milk were studied.[Result]The content of active substance decreased with the increase of heat treatment intensity.The lactoperoxidase with the worst heat resistance was completely inactivated at 80 ℃/15 s.The highest heat resistance is α-lacubumin,which has a retention rate of 25% even at the highest heat treatment at 137 ℃/4 s.Under the heat treatment intensity of 85 ℃/15 s,the retention rate of α-lactoalbumin is not less than 90%,but the retention rate of lactoferrin and immunoglobulin G is less than 5%,and the lactoperoxidase is almost completely inactivated.The temperature sensitivity of the five active substances was as follows：lactoperoxidase>lactoferrin>immunoglobulin G>β-lactoglobulin>α-lactobumin.[Conclusion]The test results of several active substances in the combined heat treatment emulsion at different temperature and time showed that different heat treatment processes had obvious influence on the retention of active substances.The research results of this paper provide theoretical basis and data support for enterprises to choose the appropriate heat treatment process to produce series of products with different active ingredients.

Key words: heat treatment, active substance, retention rate