Dissolving and water absorption ability of spray-dried willow gentian extract

Abstract

Roots of the willow gentian (Gentiana asclepiadea L., Gentianaceae) are used in folk medicine to treat gastrointestinal diseases.Spray drying is the most commonly used technique for microencapsulation of plant extracts in the pharmaceutical, cosmetic and food industries. The choosing of suitable carriers is one of the critical points in the development of microencapsulated powder with the desired physicochemical properties.The extract of the willow gentian roots was spray-dried using different carriers (maltodextrin (MD) and whey protein (WP)at concentrations of 20, 40, and 60%; pectin (P), starch (S), and gelatin (G) at concentrations of 2.5, 5, and 7.5%).The aim of this study was to examine the ability of the obtained powdersto dissolveand absorb water.For this purpose, the values of water solubility (WSI) and water absorption index (WAI) were determined.WSI is a measure of the powder degradation and dissolving in water, while WAI represents an indicator of water absorption ability. It is desirable that instant tea powders show high WSI and low WAI values.WSI values ranged from 71.15% (7.5% P) to 91.94% (7.5% G) indicating good powder disintegration properties. Concentration-dependent decrease in WSI values was observed for WP, P and S, while the opposite trend was observed in the case of MD.The carrier-free powdershowed relatively low WAI value (13.32%). Powders with 20% MD and 5% S showed slightly lower WAI values (12.77 and 12.72%, respectively). On the other hand, powders with 5 and 7.5% P showed remarkably high WAI values of 91.59 and 91.49%, respectively. A concentration-dependent increase in WAI was observed in powders encapsulated withMD and WP.All encapsulated powders showed acceptable disintegration properties (high WSI), while in terms of water absorption (low WAI) powders with 20% MD and 5% S were the most suitable.