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 ∼180°C until a selected end point of ≥20% 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 head‐space‐GC‐MS. 1‐Heptene (239.9 ppm) and hexanal (1486.1 ppm) were present at the greates 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.