The effect of different drying methods on phytochemicals, antioxidant activity and functional groups of dayak onion (Eleutherine bulbosa) extract

Abstract

Abstract Dayak onion, prized for its phenolic compounds, flavonoids, and antioxidants, finds applications in medicine and as a functional food. However, improper drying techniques can lead to the degradation of these valuable compounds. This research investigates the phytochemical content, antioxidant activity, and functional groups of Dayak onion extracts processed through freeze-drying and oven-drying methods. Fresh Dayak onions underwent both drying procedures and were subsequently evaluated for phenolics, flavonoids, flavanols, and antioxidant activity. The findings revealed that freeze-dried extracts contained higher concentrations of these phytochemicals compared to their oven-dried counterparts. Fourier Transform Infrared (FTIR) spectroscopy analysis showed no notable differences in the primary functional groups (OH and CH) between the two drying techniques. The study concludes that higher drying temperatures diminish phytochemical content and antioxidant activity, although both freeze-drying and oven-drying maintain functional groups. These results have implications for sustainable agricultural practices, indicating that optimal drying methods can enhance the health benefits of this agricultural product, supporting its use as a natural antioxidant and antibacterial agent in food and medicine while promoting environmentally sustainable farming practices.