Antioxidant activity of amaranth protein hydrolysate against thermal oxidation of vegetable oils.

TIRONI, V Y AÑÓN, M. C.

JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY (JAOCS)

SPRINGER

Lugar: Nueva York; Año: 2014 vol. 91 p. 1583 - 1594

0003-021X

The antioxidant capacity of amaranth protein hydrolysate (AH) during the thermal induced oxidation of two different vegetable oils, sunflower oil (SO) and canola oil (CO), was assessed by differential scanning calorimetry (DSC) by means of isothermal and non-isothermal assays. Interactions between AH and tocopherols were also analyzed. In both oils, AH (10 % w/w) produced an increase of the induction period (IP) in isothermal assays, presenting a synergistic effect with tocopherols. In the case of non-isothermal assays, thermograms of oils with AH showed a significant diminution in the second exothermic peak, suggesting an inhibition of the decomposition of primary to secondary oxidation products. In addition, AH produced an increase in the oxidation rate constant (k) value at low temperatures being more evident in the case of canola oil. However, this effect decreased as a function of the temperature increase, which suggests that AH would have a pro-oxidant effect at low temperatures but an heat stabilizing effect at high temperatures (above 210 °C for SO and 190 °C for CO).