Green extraction of antioxidants from black carrot pomace and their multifunctional applications

Antioxidants are recognized as bioactive compounds that prevent or mitigate major health issues by eliminating reactive species. These compounds can be either synthesized chemically or obtained through the consumption of natural foods. In this study, a microwave-assisted extraction (MAE) process was developed using black carrot pomace as an industrial by-product of black carrots to extract antioxidants, emphasizing its contribution to waste valorization by exploring the applications of the resulting extracts. The MAE process was optimized using response surface methodology, and the highest antioxidant capacity (0.358 mmol TR per g-DS) was obtained at 83 °C, 11 min, a solvent-to-solid ratio of 25 mL/0.2 g-DS, and 80% (v/v) ethanol. Compared with the automated Soxhlet extraction system, MAE provided higher antioxidant activity together with a better AGREE score (0.76 vs. 0.60). The extract was successfully incorporated into pudding formulations, and samples prepared with 1% fat milk showed more favorable antioxidant and phenolic properties after digestion than those prepared with 3.3% fat milk. The same extract was also used for the green synthesis of silver nanoparticles and the preparation of biodegradable films, demonstrating the potential of black carrot pomace as a value-added raw material for food and packaging applications.