FUNCTIONALITY OF CASEIN PRECIPITATED BY CARBON-DIOXIDE

The functionality of casein that was precipitated by batch by a novel process using CO2 was investigated for solubility in water and NaCl, f oam stability, overrun, emulsion activity index, and emulsion stabilit y. These properties were compared with those of acidified casein and N a caseinate prepared in the laboratory, commercial acid casein, and co mmercial Na caseinate and Ca caseinates. The pH of the CO2 casein was 6.61 in water and 6.51 in 0.1 M NaCl; only 65.5% of the casein dissolv ed in water, which was significantly less than the 97.5% that dissolve d in NaCl. The precipitated casein had better foam stability (29 min i nstead of 1 to 20 min) than did the other caseins, although the percen tage overrun was lower (397% compared with 511 to 868%; 15-min whippin g time). Emulsion stability (222 min) and emulsion activity index (56 m(2)/g) of the precipitated casein were not significantly different fr om those of caseins prepared in the laboratory but were significantly different from those of commercial caseins. All properties except foam stability were not significantly affected by variations between batch es or days. The precipitated casein had functional properties that wer e significantly different from caseins and caseinates that were produc ed commercially or in the laboratory.