Stabilisation of calcium phosphate using denatured whey proteins

Denatured whey proteins (3% w/w) were shown to stabilise 30 mM calcium and phosphate. Subsequent stability to heat was dependent on the initial pH of the calcium phosphate/whey protein mixture. At 6.4 < pH < 6.7, stand-up gel s were formed on heating to 90 degrees C for 30 min. At pH >6.7 no gelation was evident. The degree of unfolding/aggregation of whey protein prior to addition of calcium and phosphate had a significant effect on the strength of the gel observed after subsequent heating. The duration of heating at 70 degrees C showed major effects on gel strength following calcium and phosp hate addition, at pH 6.5, and subsequent re-heating. The strength of the ge ls following pre-heating at 80 degrees C was also affected by duration of h eating but less so than at 70 degrees C. Pre-heating at 90 degrees C result ed in gels which decreased in strength with increased duration of heating. The strength of the gels formed from whey protein which had been pre-heated at 90 degrees C, especially for the longer times, were weaker than gels fo rmed from the 80 degrees C pre-heat treatment. The secondary heating step w as shown to induce a major release of protons due to secondary calcium phos phate formation, and the accompanying decrease in pH aided in gel formation .