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. •Extent of crosslinking decreased with higher alginate content.•Entanglement prior crosslinking severely impacts thickness, solubility and swelling.•According to PCA, calcium content was indirectly associated to mechanical properties.•Barrier properties are highly impacted by extent and heterogeneity of crosslinking.•β-Carotene showed better chemical stability when encapsulated in 0.5% alginate beads.