Effect of Olein Fractions of Milk Fat on Oxidative Stability of Ice Cream

The effect of low melting fractions of milk fat on oxidative stability of ice cream was investigated. Cream was fractionated at three different temperatures (25, 15, and 10 degrees C), designated as LF-25, LF-15, and LF-10. All the low melting fractions were individually incorporated into ice cream and compared with a control, unmodified milk fat. The other ingredients were the same as in the control. Ice creams were stored at -18 degrees C for six months and sampled every 30 days. Fractionation induced major changes in the fatty acid composition of all fractions. Concentration of short-chain and long chain unsaturated fatty acids increased in the low melting fractions. Peroxide value and anisidine value of LF-10 increased from 0.23 to 3.95 (meq/kg O-2) and 3.87 to 8.04. Conjugated dienes of control and LF-10 after six months were 1.39 and 4.72 at the same storage period. The flavor score of LF-10 was more than the control and remained indifferent from the control until two months of storage. After six months, the flavor score of LF-10 dropped by 3.6 points as compared to the control, 1.2 points. Low melting fractions of milk fat can be added in the formulation of ice cream to improve its nutritional value with acceptable sensory attributes. However, storage of ice cream formulated from low melting fractions is not recommended for over 60 days at -18 degrees C.