Analysis of heated chemically and genetically modified lipids.

摘要

The changes occurring in three oil samples; EPG-08 Soyate (soy oil esterified propoxylated glycerol), EPG-00 Soyate (transesterified soybean oil) and a 50/50 blend of the two samples were compared after heating at ∼190°C for 12 h/day. The objectives were to compare the physico-chemical changes that occur in both oil samples when subjected to deep fat frying temperatures. The EPG-08 Soyate sample required 36 h of heating to attain a polymer content >20%, while the EPG-00 Soyate and EPG blend required 48 h. Physico-chemical analysis indicated that free fatty acid value (FFA), p-anisidine value (p-AV), acid value (AV), color intensity, Foodoil sensor (FOS) reading and UV absorbance all increased as the heating time increased for all three samples. Statistical analysis suggested that the EPG-00 Soyate or transesterified soybean oil is more stable than EPG-08 Soyate (p 0.05).; In addition, genetically modified low-linolenic acid soybean oil (LL-SBO) was compared to partially hydrogenated soybean oil (PH-SBO). The purpose was to develop a pan-frying protocol and to monitor the stability of the oil samples during pan-frying process by physico-chemical analyses with and without food. Instrumental methods included high performance size exclusion chromatography (HPSEC) and static headspace GC-MS. Samples were heated on a Teflon pan at ∼180°C until a selected endpoint of 20% polymer content was reached. HPSEC analysis of the PH-SBO indicated >20% polymer after 20 min of heating in comparison to LL-SBO which required 10 min of heating to reach >20% polymer content. The FFA, p-AV, FOS, color intensity value and concentration of volatile decomposition products of LL-SBO were all significantly greater, after 10 min of heating, than those of PH-SBO after 20 min of heating indicating that PH-SBO is more stable than LL-SBO. The results from hash brown frying experiments indicated that PH-SBO is more stable with regard to both volatile and non-volatile formation, as compared to LL-SBO (p 0.05).; This sample of PH-SBO is slightly more stable; however, the LL-SBO should provide an acceptable substitute for PH-SBO for pan-frying applications.