ENZYMATIC-SYNTHESIS OF POSITION-SPECIFIC LOW-CALORIE STRUCTURED LIPIDS

An immobilized sn-1,3-specific lipase from Rhizomucor miehei (IM 60) w as used to catalyze the interesterification of tristearin (C-18:0) and tricaprin (C-10:0) to produce low-calorie structured lipids (SL). Acc eptable product yields were obtained from a 1:1 mole ratio of both tri acylglycerols with 10% (w/w of reactants) of IM 60 in 3 mL hexane. The SL molecular species, based on total carbon number, were 44.2% C-41 a nd 40.5% C-49, with 3.8 and 11.5% unreacted tristearin C-57 and tricap rin C-27, respectively, remaining in the product mixture. The best yie ld of C-41 species (44.3%) was obtained with zero added water. Tricapr ylin (C-8:0) was also successfully interesterified with tristearin in good yields at 1:1 mole ratio. Products were analyzed by reverse-phase high-performance liquid chromatography with an evaporative light-scat tering detector. Reaction parameters, such as substrate mole ratio, en zyme load, time course, added water, reaction media, and enzyme reuse, were also investigated. Hydrolysis by pancreatic lipase revealed the specific fatty acids present at the sn-1,3 positions of SL.