Valorization of olive oil solid waste using high pressure–high temperature reactor

The production of olive oil leads to considerable amounts of solid wastes rich in bioactive compounds with antioxidant properties, which have been partly used as inefficient polluting heating fuels for many years. This work was aimed to study the effect of extraction time and temperature on phenolics recovery from olive pomace. For this propose, different tests were performed, varying time from 15 to 120 min and temperature from 100 to 180 °C, using a high pressure–high temperature agitated reactor under a modified atmosphere. Total polyphenols, o-diphenols and total flavonoids were quantified. Maximum total polyphenols yield (45.2 mgCAE/gDP) was achieved at 180 °C and 90 min. HPLC analysis showed that oleuropein (2433 mg/100 gDP) and tyrosol (485 mg/100 gDP) were predominant phenolics in the extracts. Methanolic extracts, after additional purification processes, can be used in food, cosmetic and pharmaceutical industries. Solid residues, after phenolics extraction, are considered to have little environmental impact.

► The effect of high pressure-high temperature on olive pomace phenolics was studied. ► Extraction time and temperature affect phenolics yield. ► The main single phenolic compounds detected by HPLC were oleuropein and tyrosol. ► High-added value compounds were extracted from olive oil industrial waste.