Investigating the Characteristics of the Nepeta binaludensis Encapsulated Extract and Its Release Kinetics in Laboratory Conditions

Abstract

This study aimed to investigate the encapsulation of the Nepeta binaludensis extract and its release kinetics under laboratory conditions. The Nepeta extract (extracted using a pulse electric field process, 6000 v and pulse number 60) was encapsulated with maltodextrin (with dextrose equivalent of 7 (MD7) and 20 (MD20)) and Arabic gum (AG) with a mass ratio of 1:5 (extract/wall material, w/w). Response Surface Methodology (RSM) has been used to optimize the microencapsulation efficiency and the physicochemical properties of encapsulated powders, considering the type of wall content. To investigate the release kinetics under laboratory conditions, the microcapsules stored for 35 days at a relative humidity of 55 and 75% at 4 and 25 °C and every 7 days were measured the amount of microencapsulated phenolic compounds. The results showed that the combination of MD7 (16.67), AG (16.67), and MD20 (66.67) had higher efficiency in the production of microcapsules, total phenolic compounds, antioxidant power and glass transition temperature compared to other cases. These microcapsules were thin, uniform, non-porous, and indented in shape. The monitoring of release kinetics during storage showed that the loss of phenolic compounds was significantly affected by the type of wall composition, such that the wall with formula MD7 (16.67), AG (16.67), and MD20 (66.67), had a higher inhibitory effect on reducing total phenolic compounds compared to other walls.