Treatment of refrigerated raw milk with Co2 : Effect on proteolysis, Lipolysis and organoleptic characteristics

The objective of this study was to determine the effect of CO2 treatment on proteolysis, lipolysis and quality characteristics of refrigerated raw milk. Four treatments of raw milk were selected (controlled milk (milk without any special treatment) and milks treated with CO2 until pH = 6.4, 6.2, 6). All experiments were triplicate. Samples were stored at 4°C for 10 days and were analyzed on 1, 5, 8, 10 day for chemical evaluations. Statistical evaluation of the effects of treatments was performed using of split plot experiment with randomized complete block design (RCBD). Statistical analysis, indicated that no significant proteolysis and lipolysis were observed during 10 days of storage using addition of CO2 to pH = 6, 6.2 and an increase in CO2 concentration did further reduce proteolysis and lipolysis. The sensory panel did not detect significant difference between CO2 treated milks and fresh milk. The research revealed that the best treatment was using of CO2 to pH = 6, although in the most cases there was no significant difference between pH 6.2 and 6.