Harnessing Natural Antioxidants From Herbs to Enhance the Oxidative Stability and Shelf Life of Cottonseed Oil

Abstract

This study explores the potential of herb extracts from thyme, sage, marjoram, and fennel to enhance the oxidative stability of cottonseed oil, providing a natural alternative to synthetic antioxidants. The antioxidant potential of these extracts was evaluated through phenolic content and free radical scavenging activity using the DPPH and ABTS methods. Antioxidant activity, expressed as TEAC, ranged from 1.25 ± 0.05 to 3.07 ± 0.15 for DPPH and 1.38 ± 0.08 to 3.93 ± 0.11 for ABTS, showcasing the extracts’ strong antioxidant properties. Stability assessments via Rancimat and heating tests revealed a remarkable improvement in the induction period (IP) and a significant reduction in oxidative markers. Thyme methanol extract demonstrated the highest efficacy, extending the IP from 3.0 (control) to 9.0 h and reducing peroxide value (PV) from 10.8 to 2.89 meq O₂/kg, p-anisidine value (P-AnV) from 9.7 to 5.78, and Totox value from 31.3 to 11.56 after 5 h of heating at 100°C. These results confirm that herb extracts, particularly from thyme and sage, can substantially enhance oil stability, offering a safer and more sustainable alternative to synthetic antioxidants. This study underscores the potential of natural additives in improving food quality and meeting the growing demand for clean-label products.