Optimization and nanoencapsulation of dandelion leaf extract for herbal tea: a comparative study of spray and freeze drying

Abstract

This study focuses on optimizing the brewing conditions and nanoencapsulation of dandelion tea extract (DTE) to enhance its stability and bioavailability. The most suitable brewing conditions were determined by using Response Surface Methodology (RSM) with a Box-Behnken design resulting in an extraction time of 110 min, temperature of 85.28 °C and water-to-tea ratio of 150 mL/5 g. The extracted polyphenols were nanoencapsulated using maltodextrin via spray and freeze-drying. The spray-dried powder exhibited higher encapsulation efficiency (88.5%) and controlled release (89.92%) compared to freeze-dried powder (83.51% and 75.76%, respectively), whereas freeze-dried powder showed higher antioxidant activity (85.87%) compared to spray-dried powder (81.35%) indicating better preservation of bioactive compounds. FTIR confirmed successful encapsulation via peak shifts, while SEM showed dented spray-dried nanoparticles and flaky, irregular freeze-dried nanoparticles. The findings suggest that nanoencapsulation of DTE via spray drying enhances stability and bioavailability compared to freeze drying, making it an ideal ingredient for herbal tea, and functional beverages.