Fatty acid profile and elemental content of avocado (Persea americana Mill.) oil –effect of extraction methods

Abstract

Interest in vegetable oil extracted from idioblast cells of avocado fruit is growing. In this study, five extraction methods to produce avocado oil have been compared: traditional solvent extraction using a Soxhlet or ultrasound, Soxhlet extraction combined with microwave or ultra-turrax treatment and supercritical fluid extraction (SFE). Traditional Soxhlet extraction produced the most reproducible results, 64.76 ± 0.24 g oil/100 g dry weight (DW) and 63.67 ± 0.20 g oil/100 g DW for Hass and Fuerte varieties, respectively. Microwave extraction gave the highest yield of oil (69.94%) from the Hass variety. Oils from microwave extraction had the highest fatty acid content; oils from SFE had wider range of fatty acids. Oils from Fuerte variety had a higher monounsaturated: saturated FA ratio (3.45–3.70). SFE and microwave extraction produced the best quality oil, better than traditional Soxhlet extraction, with the least amount of oxidizing metals present.

Keywords:

• Avocado
• Persea Americana
• fatty acid profile
• oil extraction
• elemental content of oils
• metals
• mono-unsatuarated fatty acids

Acknowledgments

The University of KwaZulu-Natal and the National Research Foundation (NRF) are thanked for financial support. Authors thank the technical team in the School of Chemistry at UKZN (Westville) for their assistance. Ms. Reddy acknowledges and appreciates the help she received from Mr. Lynton Freese (Operations Manager) and Mr. Cecil Hackney (Production Manager) of Everdon Estate as well as Mr. Shaeen Chetty for the help in sample collection.