Response surface methodology for the optimization of biophenols recovery from “alperujo” using supercritical fluid extraction. Comparison between Arbequina and Coratina cultivars

Alpeorujo is a semi-solid residue from the olive oil industry that accounts for around 80–85% of the total processed olives; it contains phenolic compounds that could be used as natural preservatives in the food industry. The objective of this study was to optimize supercritical fluid extraction (SFE) of antioxidant compounds from alperujo using a Box-Behnken Design and response surface methodology. Antioxidant (ABTS and ORAC assays) and antimicrobial (MIC) potential of SFE extracts from Arbequina and Coratina were compared for extracts obtained in the optimal conditions to maximize the antioxidant activity (200 bar, 60 °C and 10% ethanol as modifier). Extracts from Coratina presented a significantly higher (p < 0.05) TPC (1487–2073 mg GAE/kg) and tocopherol content (345–454 ppm), although, in general, a correlation between these values and antioxidant activity of extracts was not observed. Moreover, Arbequina and Coratina SFE extracts showed moderate bacterial inhibitory potential against most of the bacteria studied.