In the Bachelor thesis we compared the oxidative stability of rusk with addition of sunflower oil and rapeseed oil and effectiveness of antioxidants that were added and dry onion skin. The oxidative stability was determined with the rancimat method. Results show that rusks have different oxidative stability. Rusk with rapeseed oil has shorter induction time and consequently lower oxidative stability as compared to rusk with sunflower oil. Rapeseed oil contains more polyunsaturated fatty acids that render faster oxidation. Additionally, rusk samples supplied with antioxidants had longer induction time and increases oxidative stability. Lower antioxidant contents lead to shorter induction time which can be interpreted as decrease in oxidative stability. Dry onion skin, which was used as a natural antioxidant, turs out as a very good source of antioxidant that improves resistance to oxidation of oils and rusk. These results could be useful for food industry, where a growing trend of using natural ingredients to satisfy consumer desire for healthy food products is observed.
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