Alginate-lignin and alginate-silica microcapsules containing grapefruit essential oil and their controlled release modelling

Abstract

The encapsulation methodology protects essential oils from external factors (air, light, moisture, and high temperatures), limits its degradation, and allows its slow release. This study aimed at optimizing the encapsulation by ionic gelation of grapefruit essential oil in sodium alginate matrix obtaining a yield of more than 50 % and having an efficiency of more than 90 %. Two new matrices were studied, combining sodium alginate with lignin and silica. These components were obtained from biomass rice husks and showed an efficiency of 99,91 %, a yield of 67,183 % when having 1 % of lignin concentration and an efficiency rate of 97,67 %, and a yield of 52,306 % with 0,8 % of silica. Furthermore, vacuum drying was used and it significantly reduced the size and moisture of the microcapsules. The profiles of controlled release considered in each case were adjusted to Peppas and Korsmeyer’s model for polymeric systems.