CONICET | Buscador de Institutos y Recursos Humanos

Argentina is an important peanut producer and exporter in the world. Peanuts and peanut products are susceptible to lipid oxidation and to develop undesirable flavor. In consequence, the shelf-life of these products is relatively low due to peanuts have a 50% of lipids in their chemical composition. The use of natural additives in foods is increasing and many of them have antioxidant activity like essential oils obtained from aromatic plants. Essential oils could be added to peanut products for improving the stability and prolonging their shelf-life. The objective of this work was to evaluate the antioxidant properties of essential oils added on dry-roasted and salted peanuts. Blanched peanuts were roasted at 160 ºC for 25 min. After roasting, peanuts were sprayed with 2% refined sunflower oil and salted with 2% NaCl. The essential oil was incorporated in the sunflower oil reaching a final concentration of 0.02g/100g of product. The treatments were the following: dry-roasted and salted peanut without essential oil (RP), with 0.02% butyl hydroxytoluene (RP-BHT) and with rosemary (RP-R), oregano (RP-O) and laurel (RP-L) essential oils. Dry-roasted and salted peanut samples were stored at 23ºC during 84 days. The samples were removed at 28, 56 and 84 days from storage. Peroxide values (PV), conjugated dienes (CD), and p-anisidine values (AV) were analyzed. ANOVA and LSD test were used for statistical analysis. PV, AV and CD increased much more in RP during storage with respect to the other treatments. Lower PVs were detected in RP-BHT (3.2 meqO2/kg) and RP-L (3.2 meqO2/kg) followed by RP-O (4.3 meqO2/kg) and RP-R (5.2 meqO2/kg). Similar results were observed in the other parameters (PV and CD). Laurel, oregano and BHT showed similar antioxidant activity on dry-roasted and salted peanuts. These essential oils showed protection against lipid increasing the shelf-life oxidation in dry-roasted and salted peanuts.