Inhibition and Promotion of Heat-Induced Gelation of Whey Proteins in the Presence of Calcium by Addition of Sodium Caseinate

Abstract

Heat-induced aggregation and gelation of aqueous solutions of whey protein isolate (WPI) in the presence of sodium caseinate (SC) and CaCl was studied at pH 6.6. The effect of adding SC (0-100 g/L) on the structure of the aggregates and the gels was investigated by light scattering and confocal laser scanning microscopy at different CaCl concentration ([CaCl] = 0-30 mM). The gelation process was studied by oscillatory shear rheology. At the whey protein concentrations studied here (34 and 60 g/L), no gels were formed in the absence of CaCl and SC. However, WPI solutions gelled above a critical CaCl concentration that increased with increasing SC concentration. In the absence of CaCl, WPI gels were formed only above a critical SC concentration. The critical SC concentration needed to induce WPI gelation decreased weakly when CaCl was added. In an intermediate range of CaCl concentrations, gels were formed both at low and high SC concentrations, but not at intermediate SC concentrations. Finally, at high CaCl concentrations gels were formed at all SC concentrations. The gelation rate and the gel structure of the gels formed at low and high casein concentrations were very different. The effect of SC on the thermal gelation of WPI was interpreted by competition for Ca, a chaperon effect, and microphase separation.

Controlling denaturation and aggregation of whey proteins during thermal processing by modifying temperature and calcium concentration

“…[Colour figure can be viewed at wileyonlinelibrary.com] UH, with the presence of Ca giving sample WPI-H85Ca an opaque appearance, and a negative b* value of À12.2 as measured on the Hunter chromaticity L*a*b* scale. Similar results were reported by Marangoni et al (2000), who stated that the addition of calcium to a whey protein system led to the formation of large aggregates and caused an opaque appearance of cold-set gels, and Nguyen et al (2016), who noted a visual transition in the appearance of heated WPI samples (3.40 g protein/100 mL) from transparent liquids at a low Ca 2+ level (0.0-1.0 mM/L) to highly turbid solutions or gels at high Ca 2+ concentrations (1.5-6.0 mM/ L).…”

“…(), who stated that the addition of calcium to a whey protein system led to the formation of large aggregates and caused an opaque appearance of cold‐set gels, and Nguyen et al . (), who noted a visual transition in the appearance of heated WPI samples (3.40 g protein/100 mL) from transparent liquids at a low Ca 2+ level (0.0–1.0 mM/L) to highly turbid solutions or gels at high Ca 2+ concentrations (1.5–6.0 mM/L).…”

Novel multicomponent organic–inorganic WPI/gelatin/CaP hydrogel composites for bone tissue engineering

“…The reduction of Ca concentration in SBF and also the presence of small amount of Ca in WPI/Gel hydrogel after incubation may confirm the calcium‐binding capacity of gelatin and WPI. It was shown that whey proteins after heat‐induced aggregation bind Ca 2+ ions more easily (Nguyen et al, ). Although XRD, FTIR, and SEM/EDX analyses did not show mineralization of WPI/Gel upon incubation in SBF, calcium‐binding capacity may additionally promote this process in composite hydrogels, where high degree of supersaturation can be induced by high solubility of residual α‐TCP phase.…”

Mechanism of Hydration and Hydration Induced Structural Changes of Calcium Alginate Aerogel

“…0.4 g/g water content. Parallel to this, the primary hydration sphere of the Ca-alginate macromolecules builds up from several molecular layers of water. , Water molecules in the primary hydration sphere are in strong association with the Ca-alginate macromolecules forming the aerogel backbone, which results in fast transversal relaxation (second relaxation domain; low T 2 ) and the slow interdomain exchange of water . Because of the extremely hydrophilic character of calcium alginate, its primary hydration sphere is extensive, and most of the water is localized in the primary hydration sphere in the aerogel.…”