Comparison of re-micellised casein prepared from acid casein with micellar casein prepared by membrane filtration

Re-micellised casein was prepared by adding various calcium and phosphate salts to acid casein followed by heating and dispersing in distilled water or simulated milk ultrafiltrate (SMUF). The rheological properties, solubility, particle size, ethanol stability and heat stability of the re-micellised acid casein were examined in water or SMUF and compared with micellar casein prepared by membrane filtration. Acid and rennet gelation behaviour of both micellar casein types was different in water than in SMUF. Re-micellised casein had poorer acid gelation properties than phosphocasein but formed stronger rennet gels. Re-micellised casein exhibited increased heat stability at pH <= 6.6 under both low and higher ionic strength conditions compared with phosphocasein. Ethanol stability was greater in SMUF than in water. Differences between re-micellised casein and phosphocasein were attributed to the inherent increased ionic strength of re-micellised casein dispersions. It was shown that insoluble acid casein could be successfully re-micellised while retaining good functionality.