Development of soy protein isolate/sodium carboxymethyl cellulose synbiotic microgels by double crosslinking with transglutaminase and aluminum chloride for delivery system of Lactobacillus acidophilus

Abstract

This study was carried out to develop soy protein isolate (SPI)/sodium carboxymethyl cellulose (NaCMC) synbiotic microgels by applying a double-crosslinking technique using transglutaminase and different concentrations of AlCl3 (0 %, 6 %, 7 %, 8 %) and also by adding Lactobacillus acidophilus (L. acidophilus) and pectic oligosaccharide. Synbiotic microgels crosslinked using 8 % AlCl3 (SPI/NaCMC-Al3+8 microgels) showed the highest encapsulation efficiency (92 %). The double-crosslinked microgels exhibited a smooth surface as proved by SEM. FT-IR, XRD, and DSC analyses showed the possible interaction within matrices and demonstrated the higher thermal stability of synbiotic microgels prepared using a higher concentration of AlCl3. All in all, after exposure to simulated digestion fluid, heat treatment (72 °C, 15 s), and refrigerated storage, more cells in double-crosslinked microgels survived compared to single-crosslinked microgels. In particular, probiotic viability was highest in SPI/NaCMC-Al3+8 microgels. These results indicate that the SPI/NaCMC-Al3+8 microgels developed in this study can effectively protect L. acidophilus against the external environment.