Stability of low linolenic acid canola oil to frying temperatures

The effect of heating on the oxidation of low (1.6%) linolenic acid canola oil (C18∶3) at frying temperature (185 ±5°C) under nitrogen and air was examined and then compared to a laboratory deodorized (9.0%, C18∶3) and a commercially deodorized (8.5%, C18∶3) canola oil sample. A significantly lower development of oxidation was evident for the low C18:3 canola oil, based on the measurement of peroxide value (PV), thiobarbituric acid (TBA), free fatty acids (FFA), dienals and carbonyls. The greater stability of the low C18:3 canola oil was also reflected by a corresponding improvement in heated room odor intensity scores. Heating under nitrogen (rather than air) not only improved the odors but limited the oxidation in all oils. While the low C18:3 canola oil heated under nitrogen was acceptable in 94% of odor judgments the same oil heated in air was acceptable in only 44%. This suggests that even low levels of C18:3 may contribute to the development of the heated room odor phenomenon.