Development of probiotic-loaded calcium alginate-maltodextrin microparticles based on electrohydrodynamic technique

Abstract

Maintaining the viability of probiotic bacteria in food products for intestinal delivery remains a challenge. Consequently, the objective of this study was to encapsulate Lactobacillus rhamnosus (NCDC 18) in calcium alginate–maltodextrin hydrogel systems by combining electrospraying and freeze-drying techniques. The microparticles were produced using varying concentrations of sodium alginate (SA) (2, 3, and 4%) in conjunction with maltodextrin (MD) (0, 2, and 4%). A definitive screening design (DSD) was used to design experiments and explain the effect of independent variables (concentrations of SA, calcium chloride, and MD and electrospraying voltage) on the response variables: loss of viability, encapsulation efficiency, drying yield, Carr's index, and Hausner ratio. The obtained microparticles were characterized by employing Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). The addition of MD significantly increased encapsulation efficiency up to 75.19% and decreased viability loss up to 2.539 log CFU/mL in microparticles. The morphological analysis revealed the particle surface structure and variation in porosity in response to varying variables. The FTIR spectra confirmed that the addition of SA, MD, and probiotics caused synergistic changes in the functional bonding. The XRD analysis could further elucidate the interactions of SA with MD in the microcapsules. Our study could confirm that MD acted as a cryoprotectant and decreased the concavities and pores on the surface of the microparticles, thereby enhancing their probiotic-related properties.