Influence of Reverse Osmosis on Milk Lipolysis

Abstract
Reverse osmosis concentration of subpasteurized whole milk may cause excessive shearing of milk fat globules and increase lipolytic cleavage of fatty acids from milk triglycerides. Free fatty acid content of subpasteurized milk was increased during reverse osmosis. The type of device used for pressure regulation in the reverse osmosis unit was a key factor that was related to increase of free fatty acids. Use of a high pressure throttle valve or a diaphragm valve caused substantial increases of free fatty acids. Pressure regulation by various lengths of milk retentate exit pipes of small diameter were evaluated as a replacement for a valve. Pressure regulation could be accomplished by appropriate reduction of the diameter of retentate exit pipe. This method of pressure regulation allowed concentration of subpasteurized whole milk by reverse osmosis without causing an increase of concentration of free fatty acids.