Ultrasound-assisted enrichment of argan oil (Argania spinosa L.) with thyme (Thymus vulgaris L), oregano (Origanum vulgare L.) and saffron (Crocus sativus L.) powders: Impact on bioactive compounds and oxidative stability

Abstract

This study deals with the ultrasonic enrichment of argan oil using oregano, thyme and saffron powders in order to improve its bioactive compounds and nutritional properties. Once enriched, a series of characterizations were carried out, namely: Total phenolic content, antioxidant activities (FRAP and DPPH•) and the scanning electron microscopy for the plant powders used before and after treatment. Samples were also subjected to accelerated ageing for 120 days at 60 °C and quality indices were monitored every 30 days (Free fatty acids, peroxide value, p-anisidine value and total oxidation). The induction period by Rancimat and fatty acids were also assessed. The results show a significant improvement in antioxidant activity and polyphenol content. This Innovative, fast, and straightforward approach not only improves the functional profile of argan oil, but also offers a long shelf-life, since the quality index values presented by the enriched oils are significantly less intense than those of the non-enriched oil. After 120 days of accelerated ageing, the peroxide value of unenriched argan oil presented an amount of 36.50 ± 1.50, while minimum values of 17.44 ± 1.00 and 15.22 ± 0.04 mEq O2/kg were recorded by enriched argan oils with saffron at 0.2 and 0.5 % respectively.

Keywords

• Aromatisation
• Lipid stability
• Natural antioxidants
• Rancimat test
• SEM