Enzymatic Interesterification of High Oleic Sunflower Oil and Tripalmitin or Tristearin

The objective of this study was to produce low saturated, zero-trans, interesterified fats with 20 or 30 % saturated fatty acids (SFA) such as C16:0 or C18:0. Tripalmitin (TP) or tristearin (TS) was blended with high oleic sunflower oil (HOSO) at different ratios (0.1:1, 0.3:1, and 0.5:1 [w/w]). Total C16:0 and C18:0 compositions of the resulting TP/HOSO and TS/HOSO blends, respectively, were plotted against blending ratios. Linear interpolation was used to estimate blending ratios that would yield physical blends (PB) with 20 or 30 % SFA. Interesterified blends (IB) were then synthesized from the customized PB using Lipozyme TL IM as the biocatalyst. Total and sn-2 fatty acid compositions, triacylglycerol (TAG) molecular species, thermal behavior, and oxidative stability of PB and IB were compared. The total fatty acid compositions of PB and IB were similar but fatty acid positional distributions and TAG molecular species composition differed. IB contained 5-10 % more SFA at the sn-2 position than corresponding PB. Furthermore, interesterification generated mono- and disaturated TAG species which resulted in broader melting profiles for IB. However, IB had lower oxidative stability than PB. The reformulation of food products with zero-trans interesterified fats may be advantageous to the reduction of cardiovascular disease burden in the population.