Enzymatic interesterification of anhydrous butterfat with flaxseed oil and palm stearin to produce low-trans spreadable fat

Lipase-catalysed interesterification was performed to produce low-trans spreadable fat (LTSF) with anhydrous butterfat (ABF), flaxseed oil (FSO), and palm stearin (PS) using biocatalysts (Lipozyme RM IM and Novozym SP435). The reaction was carried out for 24 h at 60 °C in a shaking water bath (180 rpm). Seven substrate blends for the production of LTSF were prepared: 12:6:2, 10:6:4, 9:6:6, 8:6:6, 6:6:8, 6:6:9, and 4:6:10 (ABF/PS/FSO, by weight). After 24-h interesterification, decreased saturated fatty acid (SFA) contents in LTSFs were observed with ranges from 67% to 41%. LTSFs exhibited low atherogenic index (AI) with ranges from 2.8 to 0.8, compared with 3.3–4.7 AI of butter fat. Equivalent carbon number (ECN) 42–46 in the newly produced triacylglycerol (TAG) increased according to rearrangement of FAs on TAG backbone. The α-linolenic acid contents (mol%) of each LTSF were 5.6% (12:6:2), 10.7% (10:6:4), 15.1% (9:6:6), 15.8% (8:6:6), 20.8% (6:6:8), 22.4% (6:6:9) and 26% (4:6:10). The trans fatty acids in the LTSFs was not more than 2%. Melting point ranges of LTSF were from 37 (9:6:6) to 32 °C (4:6:10).