Composition and shear crystallization of milkfat fractions extracted with supercritical carbon dioxide

ABSTRACT

Milkfat was fractionated at 40°C using supercritical carbon dioxide (CO₂) at pressures of 10, 15, and 20 MPa. Fractions were collected for 6 h at each pressure and evaluated for extraction yield, fatty acid composition, thermal transition temperatures, and shear crystallization behavior. The mass extraction yields at 10, 15, and 20 MPa were 34%, 26%, and 33%, respectively, with the remaining raffinate representing ~7% of the starting milkfat. As a function of time within each successive pressure, there was a decrease in the proportion of short-chain (C₄–C₈), medium-chain (C₁₀–C₁₄), and total saturated fatty acids as well as an increase in long-chain (C₁₈–C_18:2) and total unsaturated fatty acids extracted. Shear showed little effect on the growth behavior of any fractions, but showed large effects on nucleation onset. This study showed that the composition and crystallization behavior of fractionated milkfat can be greatly tailored based on supercritical CO₂ pressure and extraction time.

KEYWORDS:

• Milkfat
• Fractionation
• Supercritical CO₂
• Fatty acid composition
• Thermal properties
• Shear crystallization

Acknowledgment

The Scientific and Technical Council of Turkey (TÜBİTAK) is gratefully acknowledged for funding support.

Conflict of interest

The authors have declared no conflict of interest.