Effect of minerals on casein micelle stability of cows' milk

Tsioulpas, A., Lewis, M.J. and Grandison, A.S. (2007) Effect of minerals on casein micelle stability of cows' milk. Journal of Dairy Research, 74 (2). pp. 167-173. ISSN 0022-0299 doi: 10.1017/s0022029906002330

Abstract/Summary

The effects of minerals on casein micelle stability of individual cows' milk, throughout a complete lactation, were investigated. Calcium and calcium ions, magnesium, phosphorus, sodium, potassium and citrate contents were analysed, together with the following physical properties of milk; pH, ethanol stability, rennet clotting time and coagulum firmness. There was an inverse non-linear relationship between free calcium ion concentration and ethanol stability (ES; r=0.84). Rennet coagulation time showed a weaker relationship with free calcium ion concentration (r=0.44) but a stronger relationship with pH (r=0.66). In addition, samples containing higher amounts of free calcium ions produced a firmer gel. Citrate in natural samples acts as a stabilizing factor, as it slightly improves milk stability. Potassium, on the other hand, exhibited a negative correlation, but only with rennet clotting time (r=-0.52). Throughout lactation the average values were; free Ca 21 concentration 1.88 mm,, pH 6.63, ES 83.2% and clotting time 13.6 min. The equilibrium relationship between pH and free Ca2+ concentration was investigated by adjusting milk pH from 5.9 to 7.1, using acid and alkali. There was a good inverse linear relationship between pH and log (free Ca 21) for individual milk samples, with a gradient of -0.62 and a standard deviation of 0.042.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/12935
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Food and Nutritional Sciences
Uncontrolled Keywords	ionic calcium, casein micelle stability, ethanol stability, mineral, composition, ETHANOL STABILITY, BOVINE-MILK, CHEMICAL COMPOSITION, IONIC CALCIUM, SALTS, COAGULATION, COMPLEX, RENNET
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