Total and "free" lipids in commercial infant formulas: fatty acid composition and their stability to oxidation.

The aim of this paper was to study the fatty acid composition of total and "free" lipids in powdered infant milks and to evaluate the fatty acid oxidation after package opening. In its first step the application of Principal Component Analysis and Design of Experiments has allowed to take a comprehensive picture of powdered infant formulas on sale in Italy on the basis of their labelled composition and to select a limited number of representative samples. Both total and "non encapsulated" or "free" lipids were considered and analysed and no significant differences were found between their fatty acids contents. The possible modification of the fatty acid composition in the "free" lipids caused by oxidation was also studied, simulating the domestic habits after opening. No significant changes were observed up to 30 days even when formulas had an high content of unsaturated fatty acids and valuable Long Chain Polyunsaturated fatty acids.