HEATED FAT-BASED OIL SUBSTITUTES, OLEIC AND LINOLEIC ACID-ESTERIFIED PROPOXYLATED GLYCEROL

Four oils [triolein, trilinolein, oleic acid-esterified propoxylated g lycerol (EPC-08 oleate), and linoleic acid-esterified propoxylated gly cerol (EPC-08 linoleate)], each without added antioxidants, were heate d for 12 h/d at approximately 190 degrees C in a small deep-fat fryer until the polymer concentration exceeded 20%, as determined by high-pe rformance size-exclusion chromatography. Increases in the free fatty a cid content, total acid value, food oil sensor value, and p-anisidine value during heating indicated that significant thermal oxidation had occurred in each oil. Capillary supercritical fluid chromatography (SF C) was used to determine the substrate concentration of each oil after each heating interval. The average, apparent first-order reaction rat e constant (as determined by SFC) for trilinolein was 0.0348 +/- 0.003 4 h(-1), while the rate for EPG-08 linoleate was 0.0253 +/- 0.0032 h(- 1). The average apparent reaction rate constant for triolein was 0.256 +/- 0.0011 h(-1), while the rate for EPG-08 oleate was 0.0252 +/- 0.0 608 h(-1). Triolein contained >20% polymer after 60 h of heating, EPC- 08 oleate contained >20% polymer after 36 h of heating, and both trili nolein and EPG-08 linoleate contained >20% polymer after 24 h of heati ng.