Enrichment of Phenolic Compounds from Olive Mill Wastewater andIn VitroEvaluation of Their Antimicrobial Activities

Saleh Abu-Lafi,Reem Yaghmoor,Fuad Al-Rimawi,Mahmoud Sami Al-Natsheh

doi:10.1155/2017/3706915

Saleh Abu-Lafi, Reem Yaghmoor + Show 2 more

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https://doi.org/10.1155/2017/3706915

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Abstract

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 OMWW using 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 OMWW is very rich in phenolic compounds and has strong antioxidant activity. HPLC analysis showed that the extract contains mainly hydroxytyrosol and tyrosol but no oleuropein. The OMWW extract showed also positive activities as antibacterial (gram positive and gram negative) and antifungal as well as activities against yeast. The addition of OMWW extract 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.

Highlights

Olive oil production accumulates large amounts of olive mill wastewater (OMWW) remnants
Results showed that OMWW ethyl acetate extract has only hydroxytyrosol and tyrosol (Figure 2) at a concentration of 371 ± 2.3 mg/L and 272.8 ± 2.1 mg/L, respectively
Ethyl acetate is found to be an excellent solvent for phenolic compound extraction and enrichment from OMWW

Summary

Introduction

Olive oil production accumulates large amounts of olive mill wastewater (OMWW) remnants. The OMWW is known to be one of the most polluting effluents produced by the agrofood industries because of its high polluting phytotoxins [1]. It exhibits high toxicity towards plants, bacteria, and aquatic organisms, due to its composition of organic substances (1415%) and phenolic compounds (up to 10 g/l) [1]. This perception is changing since OMWW has the potential to become a low-cost starting material rich in bioactive compounds, phenolics which can be extracted, enriched, and applied as natural antioxidants in food, cosmetics, and pharmaceutical industries [2, 3]. OMWW contains a lot of phenolic compounds of which three phenolic compounds, tyrosol, hydroxytyrosol, and oleuropein (Figure 1), are the main components

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