Optimization of antioxidants extraction from peanut skin to prevent oxidative processes during soybean oil storage

- Optimal conditions for antioxidant compounds extraction was assessed.
- Antioxidant activity showed non-linear relationship with PSE concentration.
- PSE is an effective antioxidant in soybean oil stabilization.
- Optimal conditions for antioxidant recovery were achieved at 75% ethanol and >60 °C.

The aim of this study was to determine the antioxidant efficacy of peanut skin extracts (PSE) to prevent the oxidative processes of soybean oil during storage and to compare the results with those obtained after using a positive control with butylated hydroxytoluene (BHT) under accelerated oxidation conditions (16 d at 60 °C). Progress in lipid oxidation of soybean oil was followed by chemical indices (peroxide value, p-anisidine value, and conjugated dienes) at the end of the storage. A second goal was to achieve the optimal conditions for the extraction of antioxidant molecules from peanut skin using response surface methodology. At level of 750 mg/kg of PSE, primary and secondary oxidation inhibition was equivalent to the obtained with BHT, hence our results revealed PSE as an effective antioxidant for the stabilization of soybean oil. The best conditions for the recovery of antioxidant compounds were dependent on the variables measured but, in general, concentration of ethanol (73.9%) and temperature of 66.5 °C maximized the responses and the recovery of activities was not significantly influenced by extracting time.