Enzymatic acyl exchange to vary saturation in di‐ and triglycerides

The reaction rac ‐glyceryl‐1‐palmitate‐2,3‐dioleate (POO) and palmitic acid (P) (excess) → glyceryl‐2‐oleate‐1, 3‐dipalmitate (POP) + O catalyzed by porcine pancreatic lipase is a model for the general reaction AAA′’ + A′’ → A′'AA′’ +A.(P,O,A = palmitoyl, oleyl, acyl groups or palmitic, oleic, or fatty acids; AAA′’ , etc., are triglycerides). The re‐esterification is accom‐panied by formation of palmitate‐enriched digly‐ceride — rac ‐glyceryl‐1‐palmitate‐2‐oleate (PO‐ OH @@) exceeds rac ‐glyceryl‐1,2‐dioleate ( OO ‐OH) — and glyceryl‐2‐monoleate (HO‐ O ‐OH). Buffer pH optimum for maximum POO conversion and palmitate enrich‐ment in 15 min is between 6.0 and 6.5 at 38 C. Hexane is used to dissolve P in the oil phase. In‐creasing the amount of dissolved P by increasing the amount of hexane added increases palmitate enrich‐ment and decreases reaction rate. At 36 C and 6.0 buffer pH (26 volume % POO and 15 volume % P in oil phase), yields after 3 hr were POP , 22%; PO‐ OH, 27%; HO‐ O ‐OH, 11%; POO , 27%; glyceryl‐1,2,3‐tri‐oleate (OOO) , 3%; and OO ‐OH, 10%.