Effect of ultrasound on olive oil extraction and optimization of ultrasound-assisted extraction of extra virgin olive oil by response surface methodology (RSM)

A Y Aydar,O Köseoğlu,N Bağdatlıoğlu

doi:10.3989/gya.1057162

A Y Aydar, O Köseoğlu + Show 1 more

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https://doi.org/10.3989/gya.1057162

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Abstract

In this study, the effects of different extraction parameters including ultrasound time, temperature and malaxation time on olive oil quality were investigated. The extraction variables ultrasound initial temperature (20–50 °C), ultrasound time (2–10 min) and malaxation time (30–50 min) were studied to obtain ideal conditions of ultrasonic treatment on the olive paste for obtaining of a greater yield in the extraction of oil, while maintaining a maximum level of commercial quality. To evaluate the level of commercial quality, absorbance in the UV region, peroxide (PV) and free acidity values (AV), the total chlorophyll, carotenoid, phenol contents, total antioxidant activity and sensory analysis of EVOOs extracted from Edremit cultivar were determined. The optimum conditions were found to be 50 °C, 2 min and 43.23 min for ultrasound initial temperature, sonication time and malaxation time, respectively. This optimal condition gave an extraction yield of 8.25 % and the acidity value of 0.24 mg oleic acid/100 g olive oil. The experimental values obtained under optimal conditions were in agreement with the theoretical values.

Highlights

Virgin olive oil (VOO) is extracted from the olive fruits (Olea europaea L.) by using physical or mechanical processes and can be used without further treatments (Gómez-Rico et al, 2009; Montedoro and Servili, 1992)
Applying long malaxation times and high temperatures in olive oil extraction can cause a deterioration in oil quality and reduce the oxidative stability of olive oil (Di Giovacchino et al, 2002; Taticchi et al, 2013) due to the activity of the enzymes, naturally present in the olive paste, which may affect the percentage of free fatty acid content, peroxide value and phenol content of the oil (De Fernandez et al, 2014; Franco et al, 2014; Stefanoudaki et al, 2011; Taticchi et al, 2013)
Extraction yield is accepted as one of the main parameters determining the efficiency of olive oil extraction

Summary

Introduction

Virgin olive oil (VOO) is extracted from the olive fruits (Olea europaea L.) by using physical or mechanical processes and can be used without further treatments (Gómez-Rico et al, 2009; Montedoro and Servili, 1992). Malaxation is a low (20–30 rpm) and continuous kneading of olive pastes (Clodoveo, 2012), and influences the oil quality and the optimal extraction yield (Puértolas and Martínez de Marañón, 2015). Finding innovative techniques to eliminate residues of oil in the pomace, improving the yield and the working capacity of the industrial plants has become significant for many researchers (Abenoza et al, 2013; Clodoveo and Hachicha Hbaieb, 2013; Jiménez et al, 2007; Puértolas and Martínez de Marañón, 2015)

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