Optimization of ultrasound-assisted extraction of phenols from Crocus sativus by-products using sunflower oil as a sustainable solvent alternative

In the last decade, there's been a rising emphasis on eco-friendly solvents in industry and academia due to environmental concerns. Vegetable oils are now recognized as a practical, non-toxic option for extracting phytochemicals from herbs. This study presents a novel, green, and user-friendly method for extracting phenolic content from Crocus sativus L. waste using ultrasound. It replaces conventional organic solvents with sustainable sunflower oil, making the process eco-friendly and cost-effective. The effects of temperature (18–52 °C), ultrasonic time (5–55 min), and solid-solvent ratio (5–31 g/100 mL) were assessed by applying response surface methodology (RSM) and Central composite design. The combined impact of solid-solvent ratio, temperature, and ultrasonic time led to heightened phenolic content and antioxidant activity in the enriched oil. However, when these variables were at their maximum levels, there was a decline in these attributes. The specific conditions found to be ideal were a solid-to-liquid ratio of 26 g/100 mL, a temperature of 45 °C, and a duration of 45 min. The optimum extraction condition yielded the expected highest phenolic content (317.15 mg/ Kg), and antioxidant activity (89.34%). The enriched oil with flower saffron enabled the utilization of renewable natural ingredients, ensuring the production of a healthy extract or product. Also, enriched oils find diverse applications in areas such as food, aquaculture, and cosmetics. •Sunflower oil serves as a “green” alternative to petroleum solvents for extraction;•Box-Behnken design with desirability function was applied for the optimization;•Effect of parameters on extraction efficiency was studied;•High antioxidant activity and phenol in 26 g/100 mL, 45 °C, and 45 min;•An oil enriched with antioxidants potency is produced.