Ultrasound assisted maceration with Pistachia lentiscus (lentisk) leaves to enhance the antioxidant activity and the oxidative stability of extra virgin olive oil

Abstract

The development of new functional olive oils may help in prevention of chronic diseases and improving the quality of life for many consumers. This is focused on the enrichment of enrich virgin olive oil (VOO) with Pistachia lentiscus leaves powder using optimized ultrasound assisted maceration (UAM) to enhance antioxidant activity and its oxidative stability. For plant extract, total phenolic compounds (TPC) content, antioxidant activities assay and inhibition of copper-induced LDL oxidation have been determined. The TPC content, antioxidant capacity and oxidative stability (Rancimat test, PV, K₂₃₂ and K₂₇₀) of VOO enriched by US (US-VOO) have been evaluated and compared to those obtained by the conventional method (CM-VOO) and VOO control. Chemical tests showed that lentisk extracts exhibited a stronger scavenging effect more than chemical standards. Lentisk extracts may protect strongly LDL from oxidation and delaying the lag time for about 3.3 h compared to the control. The enriched US-VOO with optimum conditions (100% amplitude, 15% ratio and 10 min of time exposition) showed contents of 1.6, 3 and 4 times more than the control (VOO) for TPC, chlorophyll and carotenoids. The enriched oils by US and CV methods showed a DPPH inhibition percentage and reducing power 2.4 and 1.6 times more than those of VOO. During heat treatment, peroxide value, K₂₃₂ and K₂₇₀ values remained significantly lower in enriched oils than VOO control. These results demonstrate the great potential of USM and the use of natural preservation ingredient such as P. lentiscus leaves to improve VOO nutritional quality oxidation stability, and extend the shelf-life of olive oil.