Synthesis of confectionery fat from illipé butter stearin and palm mid-fraction blend via enzymatic interesterification

Cocoa butter equivalent (CBE) was synthesised from blends of illipé butter stearin (IBS) and palm mid-fraction (PMF) via enzymatic interesterification (EIE). IBS was blended with PMF in three wt ratios (70:30, 60:40 and 50:50) and the EIE reactions were performed at 50°C for 30 min using an sn-1,3-specific lipase from Rhizopus oryzae as a catalyst. The triacylglycerol (TAG) compositions, slip melting points (SMP), crystallisation and melting thermograms, solid fat content (SFC) curves, and crystal microstructure of the blends before and after EIE were studied and compared with cocoa butter (CB). After EIE, the contents of POP and StOSt decreased, whereas the POSt content increased in all blends. Blend EIE 60:40 exhibited the POP and StOSt contents that situated within the ranges of POP and StOSt contents of CB. It also showed SMP, melting peak and melting completion temperatures, melting enthalpy and crystal microstructure most similar to CB. Most importantly, its SFC curve completely matched that of CB. Consequently, EIE 60:40 was chosen for further investigation and it was found to be fully compatible with CB and crystallised into the same polymorphic form (β) as CB. Therefore, EIE 60:40 has a high potential for use as a commercial CBE.