Location: Functional Foods Research Unit
Title: Impact of endogenous canola phenolics on the oxidative stability of oil-in-water emulsions Authors
|Sorensen, Ann-Dorit M -|
|Friel, James -|
|Jacobsen, Charlotte -|
|Huidrom, Dayanidhi -|
|Reddy, Narsi -|
|Thiyam-Hollander, Usha -|
Submitted to: European Journal of Lipid Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 4, 2013
Publication Date: March 11, 2013
Citation: Sorensen, A., Friel, J., Winkler-Moser, J.K., Jacobsen, C., Huidrom, D., Reddy, N., Thiyam-Hollander, U. 2013. Impact of endogenous canola phenolics on the oxidative stability of oil-in-water emulsions. European Journal of Lipid Science and Technology. 115:501-512. Interpretive Summary: This research demonstrated that natural components from canola seeds prevented lipid oxidation in oil-in-water emulsions. Lipid oxidation is one of the greatest challenges to the shelf-life and quality of food products because it is difficult to control and it causes deterioration of the flavors, odors, and nutritional quality of foods. Lipid oxidation in foods is often controlled by the addition of synthetic antioxidants, but consumers are concerned about the health effects and potential toxicity of some these chemicals, while food producers are interested in replacing synthetic antioxidants with natural antioxidants to satisfy consumer concerns and to reduce the number of synthetic ingredients added to foods. Several phenolic compounds with antioxidant activity have been identified from canola seeds that are left over after removal of canola oil. In this research, these components were purified from canola seeds, and tested for their antioxidant activity in oil-in-water emulsions. While none of the canola seed components performed as well as the synthetic antioxidant butylated hydroxytoluene, they all prevented lipid oxidation of the emulsions compared to control emulstions with no antioxidants. In conclusion, these canola components may be useful as natural antioxidants to replace synthetic antioxidants in food emulsions, such as beverages and salad dressings. These antioxidants are widely and cheaply available from canola seedmeal.
Technical Abstract: The aim of this study was to evaluate the antioxidative effect of phenolics naturally present in canola seeds and meal. Individual phenolics were extracted from ground, defatted canola seeds and meal. Fractionated extracts rich in sinapic acid, sinapine or canolol as well as a non-fractionated extract were used. These extracts (100 and 350 µM) were evaluated as antioxidants in stripped canola oil-in-water (o/w) emulsion. For comparison, the antioxidative effect of phenolic standards for sinapic acid and sinapine (as sinapine thiocyanate) and BHT as a positive control were also evaluated. The concentration of lipid hydroperoxides and selected volatiles measured at different time points was used to evaluate the antioxidative effect. Moreover, the properties of extracts and corresponding phenolic standards were evaluated in 3 different in vitro antioxidant assays. All extracts and standard antioxidants had radical scavenging activity and reducing power. The antioxidant standards and extracts inhibited lipid oxidation in the emulsions compared to no antioxidant added. Extracts had higher antioxidative effect than the corresponding pure standards, but were less efficient than BHT. At 100 µM the effectiveness of the extracts was as follows: sinapine^a^ > whole extract^b^ > sinapic acid^b^ > canolol^b^ > Con2^c^ (no antioxidant). At 350 µM the ranking was as follows: canolol^a^ > sinapine^a^ > whole extract^a^ > sinapic acid^b^ > Con2^c^. The differences in effectiveness may be ascribed to mainly the different chain attached to the phenolic ring, which results in different polarity and thus different location in the emulsions.