Melting characteristic and solid fat content of milk fat and palm stearin blends before and after enzymatic interesterification

Melting characteristics and solid fat content of anhydrous milkfat (AMF), s oft palm oil stearin (SPOs), hard palm oil stearin (HPOs) and their blends were studied by differential scanning calorimetry (DSC) and nuclear magneti c resonance (NMR) spectroscopy, respectively. Solid fat contents (SFC) dete rmined by NMR were used to construct isosolid diagrams; these indicated the presence of an eutectic effect along the binary blends of AMF:SPOs which o nly could be observed at 5 and 10C. The effect was reduced after interester ification by sn-1,3-specific lipase. The modification also reduced the numb er of the distinct DSC melting peaks, demonstrating a better miscibility am ong the blended fats. A substantial decrease in DSC melting enthalpy of int eresterified blends was found to be parallel to a decrease in SFC that was observed at 25-40C. Fatty acid composition showed that improved functionali ty of AMF may be due to an enrichment in long-chain saturated fatty acids c ontributed both by SPOs and HPOs.