Abstract: From now on, there is no original method to determinate the peroxide value of dry milk in our country. But the percent of fat in the infant formula is almost 27%, and most of which is unsaturated fatty acid, so the peroxide value is a very important norm to determine whether a kind of dry milk is good. The number of peroxide in the dry milk is very little, so it’s hard to use the means like oli. This paper studies to choose a good method to take fat from dry milk, and how to determinate the peroxide value of dry milk. There are three methods of iodometry colorimetry. The method of ferric ion and a method based on the mean of determinate the peroxide value of milk fat of Australia. The experiment results show that the ultrasonic method had a 81.89% extraction rate. And the precision of Australia method is best the relative deviation is (0.18), then is the method of ferric ion ,the last is three methods of iodometry colorimnate. So use the ultrasonic method to take fat and the method of AS2300-8-6-2004 to determinate the peroxide value.
Keywords：infant formula, fat, peroxide value，measuring method
