Pan-heating of low-linolenic acid and partially hydrogenated soybean oils

Genetically modified low-linolenic acid soybean oil (LL-SBO) was compared to partially hydrogenated soybean oil (PH-SBO). Samples were heated on a Teflon pan at similar to180degreesC until a selected end point of greater than or equal to20% polymer content was reached. High-performance size-exclusion chromatography analysis indicated the PH-SBO contained >20% polymer after 20 min of heating, whereas the LL-SBO sample contained >20% polymer after 10 min. Supercritical fluid chromatography analysis indicated degradation rates of 0.161 +/- 0.011 min(-1) for LL-SBO and 0.086 +/- 0.004 min(-1) for PH-SBO. The volatile compounds were identified and quantitated with static headspace-GC-MS. 1-Heptene (239.9 ppm) and hexanal (1486.1 ppm) were present at the greatest concentration among the volatile compounds in LL-SBO. The volatile compounds present in the greatest concentrations in heated PH-SBO were hexanal (376.9 ppm) and pentane (82.1 ppm). After 10 min of heating, the LL-SBO oil FFA value (2.66%), p-anisidine value (386.5 abs/g oil), Food Oil Sensor reading (18.75), and color intensity (Y = 4.0, R = 1.0) were significantly greater than those of PH-SBO after 14 min of heating (4.28%, 298.5 abs/g oil, 16.08, Y = 1.0, R = 0.1, respectively). There was a significant difference in the degradation rates between LL-SBO and PH-SBO (P < 0.05). The PH-SBO was more stable than the LL-SBO.