Antioxidant Properties of Roasted Whole-Grain, Oilseed and Nut Snacks and Effect of Roasting Process on These Properties.

In this research, the antioxidant properties of unroasted and roasted snacks such as hazelnut, pistachio, peanut, sunflower seed, pumpkin seed, chickpea, corn and wheat were determined using Trolox® (6-hydroxy-2,5,7,8- tetramethylchromane-2-carboxylic acid) equivalent antioxidant capacity (TEAC), ferric-reducing antioxidant power (FRAP) and Folin-Ciocalteu total phenolic methods, besides their acrylamide contents. Variations were detected in the total antioxidant capacity (TAC) and total phenolic (TP) contents of roasted snacks, which were obtained from at least four different processing plants. Although antioxidant capacity tests produced different values for snacks, a significant and positive correlation (r2=0.91, P<0.01) was found between TEAC and FRAP results. Similarly, significant and positive correlations were obtained between TP contents and TEAC (r2=0.91, P<0.01) and FRAP (r2=0.94, P<0.01) values. Among snack foods, roasted sunflower seed had the highest mean TAC and TP content (TEAC 46.6 µmol TE/g, FRAP 63.9 µmol TE/g and TP 1021.5 mg GAE/100 g), followed by roasted pistachio (TEAC 28.9 µmol TE/g, FRAP 22.3 µmol TE/g and TP 530.5 mg GAE/100 g) and roasted corn (TEAC 5.6 µmol TE/g, FRAP 10.6 µmol TE/g and TP 178.0 mg GAE/100 g). The TAC of remaining snacks (TEAC 2.4-3.3 µmol TE/g, FRAP 2.9-5.7 µmol TE/g) and their TP contents (37.2-265.1 mg GAE/100 g) were lower and somewhat comparable. The TAC and TP contents of hazelnuts and peanuts decreased significantly (P<0.05) upon roasting, while those of sunflower seed, pumpkin seed, corn and wheat were influenced to a lesser extent. Acrylamide contents of roasted snacks were low (<290.9 µg/kg). [ABSTRACT FROM AUTHOR]