Antioxidant/Preservative Effect on Omega Acids (Grape Seed Oil)Grape seed oil consists of ca. 90% omega unsaturated fatty acids which are subject to photo-oxidation (light induced oxidation) when exposed to light and air. This is the process of oils going rancid - free radicals generated by light and air exposure react with the fatty acids.
Antioxidant activity can be tested by comparing the relative rates of
oxidation of oils in the presence of the antioxidant of interest.
The signs of rancidity are most notably an unpleasant odor, which at the onset smells faintly of paint or paint thinner, and which becomes progressively stronger and more unpleasant, and a noticeable thickening and sticky feeling of the oil. To prevent the oxidation of oils, antioxidants are added as preservatives (two of the most commonly used in the food industry are BHA and BHT). These compounds react with free radicals, preserving the oil from oxidation.
Description of the Study and Results
Untreated grape seed oil (Wajos, GmbH) was exposed to light and air (10 ml set in window with Easterly exposure in Gronigen, NL, in April), as well as grape seed oil treated with 0.3% Oxofulleram (Combray formulation) at the same conditions, except beginning in June.
Oxofulleram signficanty inhibits the photo-oxidation of grape seed oil.
- After 1 month, the untreated grape seed oil had a faint odor of paint, indicating the onset of rancidity. No change was observable in the treated grape seed oil sample.
- At 2 months, still no change in odor or appearance of treated grape seed oil.
- At 3 months, untreated grape seed oil has started to thicken and has a stronger odor.
- At 10 months, slight odor and thickening of treated grape seed oil, indicating onset of rancidity.
|
|
|
