Assembly of artificial casein micelles with sodium hexametaphosphate

• Published in: International dairy journal 2025-03, Vol.162, Article 106158
• Main Authors: Antuma, Laurens J., Yau, Amber S.Y., Boom, Remko M., Keppler, Julia K.
• Format: Article
• Language: English
• Subjects: Calcium sequestering salt; Phosphorylation; Polyphosphate; Re-assembled casein micelles; Rennet coagulation
• ISSN: 0958-6946
• DOI: 10.1016/j.idairyj.2024.106158

This study explored the potential of hexametaphosphate (HMP) to assemble caseins into artificial casein micelles (ACM) as an alternative to calcium phosphate nanoclusters. HMP cross-linked caseins through their phosphoserine residues in the presence of calcium ions. At high calcium-to-HMP ratios, insoluble calcium-HMP complexes formed, cross-linking the calcium-sensitive caseins and resulting in stable ACM that were smaller, more hydrated, and formed weaker curds upon chymosin coagulation than conventional ACM with calcium phosphate nanoclusters. As the HMP concentration increased, micelle formation reached an optimum at a molar calcium-to-HMP ratio of 10:1. However, at lower ratios, HMP chelated calcium ions, leading to the formation of soluble calcium-HMP complexes that impeded micelle formation. These findings highlight the dual functionality of HMP as both a micelle-forming agent at high calcium-to-HMP ratios and a calcium-chelating agent at lower ratios, providing new insights into alternative mechanisms for casein micelle assembly. •Hexametaphosphate (HMP) cross-links caseins in presence of calcium ions.•HMP can facilitate the assembly of caseins into artificial casein micelles.•Insoluble casein-calcium-HMP complexes form at high calcium-to-HMP ratios.•At low ratios, micelle formation is impeded due to chelation of calcium by HMP.•Micelle formation is optimal at a molar calcium-to-HMP ratio of 10:1.