Optimization of Wall Material Composition for Encapsulating Bioactive Compounds From Giloy (Tinospora cordifolia) Stems

Abstract

Giloy plant offers notable health advantages due to its abundant bioactive components. The encapsulation technique demonstrated significant potential in maintaining/enhancing such compounds’ stability and nutraceutical properties. Thus, this study is aimed at obtaining an optimized composition of wall materials for microencapsulation of giloy stem extract (core material) using spray drying. The Box–Behnken design was applied to optimize the wall material composition based on significant responses using Design Expert V11 software. The concentration of wall materials ranged from 0% to 10% for maltodextrin (MD), 0%–10% for whey protein (WP), and 0%–10% for pea protein (PP). The air input and exit temperature in the spray dryer were maintained at an average constant value of 110 °C and 50 °C at a 2.5 mL/min flow rate. The optimal composition of wall material was 4.42% MD, 6.95% WP, and 9.99% PP. At this condition, 86.67 ± 2.32% encapsulation efficiency, 79.02 ± 3.25 g/100 mL process yield, 9.07 ± 0.87% (w/w) moisture content, 120.25 ± 4.97 mg GAE/g total phenolic compound, 124.32 ± 4.33 mg QE/g total flavonoid compound, and 34.47 ± 1.25 mg GAEAC/g antioxidant activity were observed as responses. Further, the optimal spray-dried microcapsules (SDMs) had a smoother outer surface than the other wall material combinations/compositions and showed amorphous characteristics as confirmed by SEM and X-ray diffraction (XRD) analysis, respectively. The Fourier-transform infrared spectroscopy (FTIR) results revealed adequate chemical bonding within core and wall materials at optimal encapsulation conditions. The encapsulated giloy bioactive can be used as a functional ingredient in food.