Impact of heterogeneously crosslinked calcium alginate networks on the encapsulation of β-carotene-loaded beads.

This study investigated the impact of heterogeneity of crosslinking on a range of physical and mechanical properties of calcium alginate networks formed via external gelation with 0.25-2% sodium alginate and 2.5 and 5% CaCl2. Crosslinking in films with 1-2% alginate was highly heterogeneous, as indicated by their lower calcium content (35-7 mg Ca·g alginate-1) and apparent solubility (5-6%). Overall, films with 1-2% alginate showed higher resistance (tensile strength = 51-147 MPa) but lower elasticity (Elastic Modulus = 2136-10,079 MPa) than other samples more homogeneous in nature (0.5% alginate, Elastic Modulus = 1918 MPa). Beads with 0.5% alginate prevented the degradation of β-carotene 1.5 times more efficiently than 1% beads (5% CaCl2) at any of the storage temperatures studied. Therefore, it was postulated that calcium alginate networks crosslinked to a greater extent and in a more homogeneous manner showed better mechanical performance and barrier properties for encapsulation applications.