Antioxidative ability of native and thermized sour whey in oxidation-catalysed model systems†

Antioxidative properties of sour (cottage) were evaluated with (thermized) and without (native) heat treatment (80°C for 30 min). A model system comprising a Tween 20 stabilized peanut oil in phosphate buffer (pH 7.0) emulsion containing lipid oxidation catalysts, FeCl 3 , H 2 O 2 and ascorbate was used. Native sour whey powder (SWP) was significantly better than thermized whey in terms of limiting the formation of thiobarbituric acid-reactive substances and peroxide value. Antioxidative ability was best at pH 3.0 and decreased with increasing pH. SWP (20%, w/v) was significantly better than all commonly used antioxidants tested after 96 h of incubation at 40 °C.