Preparation optimization and characterization of chitosan-tripolyphosphate microcapsules for the encapsulation of...

Herbs have a long history of use as galactagogues and several commercial formulations have been prepared using herbs. Several active substances such as polyphenols, flavonoids, isoflavones and terpenes are present in the herbal formulations that produce unpleasant taste and decreases consumption of the products. Furthermore, some of these active compounds are unstable when exposed to environmental conditions. In this respect, different approaches can be utilized in order to mask the taste and increase the stability of core substances such as microencapsulation. In the present study, microcapsules containing galactagogue herbs extract were developed through ionotropic gelation and Box-Behnken design was used to investigate the effects of independent variables (chitosan (CS): 1-2%, extract: 1-5% and sodium tripolyphosphate (TPP): 1-3%) on encapsulation efficiency (EE%). Following evaluation of the model, the optimum condition of encapsulation process was selected as 1.19% chitosan, 2.69% extract and 2.08% TPP with EE% of 83.054%. Microcapsules had an acceptable spherical morphology and the results of Fourier transform-infrared spectroscopy (FTIR) revealed the presence of the extract within the microcapsules. The mean diameters of CS-TPP microcapsules containing extract was 27 μm with polydispersity index of 0.53, indicative of polydisperse nature of the microcapsules. The in vitro release in simulated gastric fluid (SGF; pH 1.2) and simulated intestinal fluid (SIF; pH 7.4) were 55.19% and 85.04%, respectively during 24 h. The freeze-dried extract-loaded microcapsules were stable during 150 days of storage and have potential to be used in food matrices with neutral pH.