The effect of the NaCl addition on the emulsifying properties of casein and tryptic casein hydrolysates was studied in two pH values (4,0 e 5,0). A 0.02 M concentration of salt was added to the buffer solutions used for preparing the samples. The protein solubility, the emulsifying capacity (EC), the emulsifying activity index (EAI) and the emulsion stability (ES) were determined. The mean radius (R) of fat droplets was also calculated. The results showed that the addition of NaCl increased the solubility and the EC of casein and casein hydrolysates, in both pH values. However, this salt addition reduced the EAI of casein and increased that of the hydrolysates.The opposite was observed relating to the R of fat droplets. Regarding the ES, that of casein presented little increase in pH 5.0, and the same result was obtained for only some hydrolysates in pH 5.0 or 4.0.
casein; solibility; emulsifying properties; triptic hydrolysis; NaCl
