Oxidative stability of fish oil enriched drinking yoghurt

The oxidative stability of fish oil enriched drinking yoghurt as well as the antioxidative effect of citric acid ester, vitamin K and disodium ethylenediaminetetra acetic acid (EDTA) were investigated by measuring peroxide value and volatile secondary oxidation products and by sensory analysis. No oxidation was observed in yoghurt stored at 2 degrees C for up to 19 days, with or without addition of citric acid ester. Fish oil enriched yoghurt was also very stable even when compared to yoghurt with added rapeseed oil or a mixture of rapeseed oil and fish oil stored for up to 29 days. The addition of 50 mu m iron to yoghurt did not promote oxidation. The results obtained may indicate an antioxidative effect of EDTA and pro-oxidative effect of vitamin K. All yoghurts had similar viscosity and droplet size. In summary, fish oil enriched drinking yoghurt is very stable towards oxidation. (C) 2007 Elsevier Ltd. All rights reserved.