Direct enrichment through conventional and ultrasound-assisted maceration of sunflower (Helianthus annuus L.) oil with saffron (Crocus sativus L.) stigmas as a natural antioxidant

Abstract

The flavoring of vegetable edible oils (VEO) with extracts from aromatic plants improves their acceptance, oxidative stability, and nutritional value. This study investigates the direct enrichment of sunflower oil (SO) with saffron stigmas (SS) using both conventional maceration (CM) and ultrasound-assisted maceration (UAM) at different concentrations (0.2, 0.4, and 0.6%). Antioxidant properties, oxidative stability, and quality indices were evaluated. SS exhibited high levels of phenolics (52.4 ± 0.6 mg of GAE/g DM), flavonoids (100 ± 2 mg of QE/g DM), and antioxidant activity (16.77 ± 0.27 mg of TE/g DM for ABTS and 55.0 ± 0.6 mg of TE/g DM for FRAP). The enriched oils demonstrated significantly higher antioxidant and stability levels compared to non-enriched oils. No significant differences were found in oxidative stability indices or Rancimat test results between CM (5.5 ± 0.3 h with 0.6% of SS) and UAM (5.4 ± 0.2 h with 0.6% of SS). The control oil exhibited the lowest induction time at 4.5 ± 0.2 h. However, UAM resulted in lower pigments content, with chlorophyll and carotenoid levels measuring of 0.15 ± 0.03 and 0.26 ± 0.04 mg/kg respectively, for 0.6% of SS. Antioxidant activity and oxidative stability were found to be dose-dependent. UAM effectively enhanced oil stability without affecting the fatty acid composition. By reducing processing time and eliminating the need for chemicals, this innovative method demonstrates that SS can be used directly as a natural antioxidant, particularly at a concentration of 0.6%, to improve the sunflower oil stability.