PHYSICOCHEMICAL AND RHEOLOGICAL CHARACTERIZATION OF LIPASE-INTERESTERIFIED TRANS-FREE BLENDS OF FULLY HYDROGENATED PALM OLEIN AND SOYBEAN OIL

摘要

Interesterification is widely used for modification of the physicochemical properties of fats. In this work, fully hydro-genated palm olein (FHPO) and soybean oil blends (formulated by mixing 15-85 % FHPO in increments of 10 %), were interesterified using the commercial lipase Lipozyme TLIM. Fatty acid composition, free fatty acid (FFA) content, slip melting point (SMP), solid fat content (SFC), plastic range, iso-solid diagram and rheological properties of the initial or interesterified blends werestudied. Generally, all the blends could be regarded trans-free as they contained low amounts of (<1.3 %) of trans-fatty acids. The interesterified blends displayed reduced SMP, SFC and elastic (G') and loss (G") modules, as compared to the initial blends. Interesterified fats contained higher amounts of FFAs than the initial blends. Non-interesterified blends had very flat SFC curves. Interesterification shifted the plastic range of fats to the lower temperatures. Iso-solid diagram before and after thereaction showed monotectic behavior with no eutectic interactions. The 25:75 and 35:65 interesterified FHPO: soybean oil blends displayed characteristics suited for production of soft tub margarine and stick margarine, respectively. Interesterified blends containing 45-55 % FHPO could be used for production of puff pastry margarine, roll-in margarine and cake shortening.