Encapsulation of extract from capsicum frutescens in alginate-chitosan particles

Abstract

Alginate-chitosan microparticles were prepared using complex coacervation technique. These microparticles were formed with different ratio of alginate and chitosan. From the SEM images, microparticles using a chitosan:alginate (CS:ALG) mass ratio of 1:1 showed the best morphology which was spherical and smooth-surface with the average size of 560 ± 38.9 µm. Moreover, particles cross-linked with sodium tripolyphosphate (TPP) had the smaller sizes than those without TPP. The swelling degree of alginate-chitosan microparticles in simulated gastric fluid (SGF, pH 1.2) (about 50%) was lower than that (about 400%) in simulated intestinal fluid (SIF, pH 7.4). Chili oleoresin-loaded alginate-chitosan microparticles were prepared with the CS:ALG mass ratio of 1:1 and using TPP as a cross-linked agent. The highest encapsulation efficiency (73.90%) and loading capacity (10.44%) were obtained from the chitosan/alginate/chili oleoresin mass ratio of 1/1/0.5. The release profile of entrapped chili oleoresin in SGF and SIF was constructed by determining the amount of release capsaicin. At the initial three hours in SGF, capsaicin was slowly release from the microparticles with the release level of 32%. When microparticles were transferred from SGF into SIF medium, capsaicin releasing level increased to be 78% within 4 hours and complete release was not attained in 8 hours. Therefore, the encapsulation can be protected the carotenoids content in chili oleoresin from light, masking pungent taste and reduce irritation to the stomach. Chili extract-loaded alginate-chitosan microparticles can be used as supplementary food.