Effect of γ-oryzanol on oxygen consumption and fatty acids changes of canola oil

gamma-oryzanol has been well studied for its hypolipidemic, antidiabetic, antiallergic, and anti-inflammatory abilities. However, its ability against lipid oxidation has not been thoroughly explored. The present study examined the effects of gamma-oryzanol against canola oil oxidation under Chinese cooking temperatures compared with that of butylated hydroxytoluene (BHT). Changes of oxygen consumption and fatty acids of canola oil with addition of 2-8 mg/g gamma-oryzanol were conducted under 60, 90, 120, and 180 degrees C, respectively. Results showed although gamma-oryzanol was not as effective as BHT against lipid oxidation of heated canola oil, it showed an inhibitory effect on the headspace oxygen consumption dose-dependently. Besides, gamma-oryzanol significantly prevented the decrease of total polyunsaturated fatty acids in canola oil heated at 60-120 degrees C, while such effect was not observed in canola oil heated at 180 degrees C. beta-sitosteryl ferulate, one of the major components constituting gamma-oryzanol, degraded faster than cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, and campesteryl ferulate at all treatment conditions. In conclusion, gamma-oryzanol might have a potential application against lipid oxidation in foods as a functional antioxidant.

Automated summary

Gamma-oryzanol has been found to have potential as a functional antioxidant in foods, although its ability to combat lipid oxidation is not as effective as butylated hydroxytoluene (BHT). This study demonstrated that gamma-oryzanol can inhibit oxygen consumption and prevent the decrease of polyunsaturated fatty acids in heated canola oil, especially at lower cooking temperatures.