Optimization of Ultrasound-Assisted Extraction of Bioactive Compounds from Pelvetia canaliculata to Sunflower Oil

Gabriela Sousa,Isabel Miranda,Rajko Vidrih,Marija Trifunovska,Marta Neves,Madalena Antunes,Margarida Moldão,Suzana Ferreira-Dias,Luis Aparicio,Vítor Alves,Carla Tecelão,Paula Allen Lopes

doi:10.3390/foods10081732

Abstract

In this study, Pelvetia canaliculata L. macroalga, collected from the Atlantic Portuguese coast, was used as a source of bioactive compounds, mostly antioxidants, to incorporate them in sunflower oil with the aim of increasing its biological value and oxidative stability. The lyophilized alga was added to the oil, and ultrasound-assisted extraction (UAE) was performed. Algae concentration and UAE time varied following a central composite rotatable design (CCRD) to optimize extraction conditions. The following parameters were analyzed in the oils: oxidation products, acidity, color, chlorophyll pigments, carotenoids, flavonoids, total phenolic content, antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays, and sensory analysis. Extraction conditions did not affect the acidity and the amount of oxidation products in the oil. Chlorophylls and carotenoid contents increased with algae concentration, while flavonoid extraction did not depend on algae content or UAE time. Total phenolics in the oil were highly related only to FRAP antioxidant activity. Storage experiments of supplemented oil (12.5% algae; 20 min UAE) were carried out under accelerated oxidation conditions at 60 °C/12 days. Antioxidant activity (FRAP) of supplemented oil was 6-fold higher than the value of non-supplemented oil. Final samples retained 40% of their initial antioxidant activity. The presence of algae extracts contributed to the increased oxidative stability of sunflower oil.

Highlights

Sunflower (Helianthus annuus L.) oil is obtained by physical or chemical (n-hexane) extraction of the sunflower seeds
The samples of supplemented sunflower oil have higher antioxidant activity than the non-supplemented oil (Table 7). These results indicate that the compounds with antioxidant activity that migrated from the algae to the oil are mainly non-polar
Our results showed that the antioxidant activity of the supplemented oils, associated with the presence of phenolic compounds, is not derived from radical elimination by results indicate that Pelvetia improved radical scavenging activity and, inhydrogen donation

Summary

Introduction

Sunflower (Helianthus annuus L.) oil is obtained by physical or chemical (n-hexane) extraction of the sunflower seeds. This oil has wide culinary uses, i.e., for cooking, bakery, and frying. It is used in the food industry for frying, production of emulsions, sauces, spreads, fillings, and in many different food formulations, namely margarine and mayonnaise. The improvement of both the quality and stability of sunflower oil are central points for the food industry. The limited oxidative stability of edible oils is one of the main constraints for the food industry, leading to a loss of nutritional value, a decrease in shelf-life, and the development of undesirable flavors. Sunflower oil is rich in polyunsaturated (PUFA) linoleic acid, C18:2 (48.3–74.0%) and monounsaturated (MUFA) oleic acid, C18:1

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