Enrichment of Phenolic Compounds from Olive Mill Wastewater and In Vitro Evaluation of Their Antimicrobial Activities
Al-Natsheh, Mahmoud Sami
The production of olive oil generates massive quantities of by-product called olive mill wastewater (OMWW). The uncontrolled disposal of OMWW poses serious environmental problems. The OMWW effluent is rich in several polyphenolic compounds. Liquid-liquid extraction of OMWWusing ethyl acetate solvent was used to enrich phenolic compounds under investigation. Total phenolic and flavonoid content and antioxidant activity of the extract were determined. HPLC coupled to photodiode array (PDA) detector was used to analyze the main three phenolic compounds of OMWW, namely, hydroxytyrosol, tyrosol, and oleuropein. The antimicrobial activity of the extract was also investigated. Additionally, the OMWW extract was used as natural preservative and antioxidants for olive oil. Results showed that OMWWis very rich in phenolic compounds and has strong antioxidant activity. HPLC analysis showed that the extract contains mainly hydroxytyrosol and tyrosol but no oleuropein.TheOMWWextract showed also positive activities as antibacterial (gram positive and gram negative) and antifungal as well as activities against yeast. The addition of OMWWextract to olive oil samples has an effect on the stability of olive oil as reflected by its acid value, peroxide value, 𝐾232 and 𝐾270, and total phenolic content.