Solubility of protein fibers obtained from casein solutions and liquid two‐phase water‐casein‐sodium alginate systems

Abstract

The solubility of protein and protein-polysaccharide matrix fibers obtained from casein solutions and two-phase water-casein-sodium alginate (W-C-A) systems in water and in 1 M NaCl solutions at different pH at 20 and 100 degrees C has been studied. The matrix fibers obtained from the two-phase W-C-A system are shown to be considerably less soluble than those from the casein solutions. This difference is seen particularly clearly when pH amounts to 5-7. However, it disappears with the spinning two-phase system at temperature above 80 degrees C. An assumption has been made about the matrix fibers being either mixed gels of the thermo-reversible, soluble calcium caseinate and thermo-irreversible insoluble calcium alginate, or complex protein-polysaccharide gels formed with the participation of the calcium ions. This latter assumption is in conformity with the negligible solubility of the protein fibers obtained as a result of the lyotropic gelation of the skimmed milk proteins.

Formation of Fibrous Materials from Dense Calcium Caseinate Dispersions

“…Typically, the resulting fibers (∼100 μm) are coagulated in baths containing acid and salt solutions, and then washed. Hydrocolloids, such as carrageenan , and alginate, , or vegetable proteins, such as soy or field bean protein, were used in combination with casein in a two-phase blend to decrease the solubility in water of the casein-based fibers produced. In the case of spun pea and fababean protein, fibers with a granular core and strand-like cortex were formed .…”