Precipitation of Milk Proteins by Sodium Carboxymethylcellulose
Open Access
- 1 August 1969
- journal article
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 52 (8), 1181-1185
- https://doi.org/10.3168/jds.s0022-0302(69)86721-4
Abstract
A study was made to determine optimum conditions for precipitation of milk proteins by sodium carboxymethylcellulose and to elucidate the chemical nature of the resulting gum-protein complex. Carboxymethycellulose precipitated a maximum of 90 to 96% of the casein from a simplified casein system and about 71% of the total protein (principally casein) from natural skimmilk. Maximum protein precipitation occurred at pH 7.5 in simplified casein systems and results indicate a similar relationship in natural skimmilk. The reaction was calcium-dependent, and protein-calcium-carboxymethylcellulose bridging appears to be involved at pH levels above the isoelectric point of casein. At the isoelectric point (pH 4.6), carboxymethylcellulose stabilizes casein, preventing precipitation. The typical cellulose-protein complex contained 51.7% protein, 7.3% ash, 0.44% calcium, and 10 to 17% carboxymethylcellulose.Keywords
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