Optimisation of spray-drying parameters for encapsulation of Helicteres isora L. extract

Helicteres isora L. (family Sterculiaceae) is a valuable herbal remedy and has been reported to exhibit remarkable hepatoprotective, antioxidant, hypolipidaemic, antibacterial and anticancer activities, underscoring its potential as a functional ingredient. However, despite its widespread use in traditional medicine, there is still limited scientific evidence to validate its bioactive compounds. In addition, the instant powder form of H. isora extract offers a convenient and stable formulation while retaining its hepatoprotective potential. Developing this preparation is essential to ensure standardised dosage, improved shelf life and wider applicability in therapeutic and nutraceutical products. In this study, the hydroethanolic extract of the plant was encapsulated using the spray drying method. The spray-drying experiments were conducted using the One-Factor-at-a-Time (OFAT) method with 4 varying extract concentrations (ranging from 5–20 °B), 4 different maltodextrin concentrations (5–20 % w/v), 4 different inlet temperatures (160–190 °C) and 4 different feed flow rates (555–1200 mL/h). The process yield (PY), encapsulation efficiency (EE) and physicochemical characteristics [total phenolic content (TPC), moisture content, hygroscopicity, water solubility index (WSI) and Carrs’ index(CI)] of the exulting granules were examined. The results have shown that the encapsulation of H. isora extract by the spray-drying method with an extract concentration of 10 °B, maltodextrin concentration of 10 % w/v, feed flow rate of 750 mL/h and inlet air temperature of 170 °C produces the best quality product, while also achieving the highest encapsulation efficiency. These optimised spray-drying conditions, which produce powders with desirable physicochemical characteristics and efficient retention of bioactive constituents, establish the technological foundation for the subsequent formulation and production of instant H. isora tea.