The influence of concentration and addition of 0.5 and 1.0% acid casein on the heat stability (determined as heat coagulation time (HCT) at 130°C) as well as the salt balance of buffalo milk was studied. This was compared to bovine milk. It was observed that buffalo milk was more stable than bovine milk when heated in its fluid state with HCT values of 32.3 min as compared to 31.3 min for cows'milk. However, concentration caused a greater destabilization of buffalo milk (HCT = 2.9 min) as compared to bovine milk (HCT = 6.6 min). The greater decrease in the HCT of buffalo milk may be attributed to a greater disruption of the salt equilibrium and a larger decrease in pH caused during concentration. Casein addition had a stabilizing effect on the concentrated buffalo milk but not on the fluid milk due to its effect on the salt balance. While calcium, magnesium and phosphate shifted from the dissolved to the colloidal phase the shift in the citrate ion was reverse.

No abstract

The influence of three different concentrations (0.05%, 0.10% and 0.15%) of two stabilizers, disodium phosphate and trisodium citrate on the salt balance (concentration and molar ratios of salt constituents in the dissolved phase) and pH of buffalo milk and its 2 : 1 concentrate was determined. The disodium phosphate caused a significant shift in all the salt constituents (calcium, magnesium, phosphate and citrate) from the dissolved to the colloidal phase while the trisodium citrate produced a significant shift from the colloidal to the dissolved phase. Further, the phosphate caused a uniform decrease in the molar ratios of Ca/P and (Ca+Mg)/(P+Cit.) in the dessolved phase, while the citrate produced only a small and non-significant effect. Both salts caused a significant increase in pH which was progressive with increase in the concentration of added salts. Therefore, the primary effect of stabilizers in stabilizing or destabilizing the milk is a consequence of their influence on the pH and not on the mineral equilibrium of milk.

The influence of homogenization (two stage) on heat stabilit-y (determined as heat coagulation time at 130") as well as the salt balance of buffalo milk and its 1:2 concentrate was determined. Homogenization had no significant influence on the heat stability and salt balance (molar ratio of Ca + Mg to P + Cit. i n the dissolved phase) of fluid milk. Howevel; during concentration both the heat coagulation time and salt balance of homogenized milk were affected significantly. Homogenization caused a significant decrease in the dissolved phosphate but had no significant effect on calcium and magnesium and this resulted in a significant increase in the molar ratio of Ca + MglP + Cit. This disruption in the salt equilibrium caused the destabilization of homogenized concentrated milk.