Fractionation of buffalo butter oil by supercritical carbon dioxide

Buffalo butter oil was fractionated by supercritical carbon dioxide into four fractions (F1–F4). Fractionation was performed at 50 and 70 °C over a pressure range of 10.9–40.1 MPa. Short chain fatty acids (C4–C8), medium chain fatty acids (C10–C14) and saturated fatty acids were decreased from F1 to F4, while long chain fatty acids (C16–C18:3) and unsaturated fatty acids were increased. Triacylglycerol molecular species exhibited a similar trend as fatty acids. Cholesterol was concentrated in F1, and with increasing the fluid density, it decreased by more than 50% in F4. Substantial changes occurred in the chemical composition of the fractions led to distinctive differences in their thermal profile and solid fat content. Fractions obtained in the initial stages of the fractionation exhibited lower melting behavior that obtained in the late stages.