Simple Test for Milk Lipolysis and Changes in Rancidity in Refrigerated Pasteurized Milk

Abstract

The Rhodamine 6G method for determining fatty acids of Chakrabarty et al. (J. Amer. Oil Chem. Soc., 46:473. 1969) was modified for quick detection of lipolysis in milk. Two milliliters of milk are extracted with 5 ml of benzenc, A ml of 30% potasium oxalate and one drop of phosphoric acid. Two milliliters of the filtered extract are mixed with 1 ml of Rhodamine 6G in benzene and the color is compared with a standard prepared by mixing lauric acid with Rhodamine 6G. This method is simpler than the previous Rhodamine B method. (J. Dairy Sci., 53:537. 1970) as evaporation of solvents is unneccessary. The acid degree values in commercial pasteurized milks increased by .3 to .6 during refrigerated storage for seven days. A relationship was observed between the acid degree values and the bacterial counts after 7-day storage. © 1972, American Dairy Science Association. All rights reserved.