Effect of pH, calcium concentration and temperature on the evolution of the refractometric signal produced during rennet coagulation of milk

Abstract

SummaryAn industrial refractometer connected to a microcomputer was used to study the rennet coagulation of milk. The amplitude of the refractometer's signal changes during coagulation was about 104 times more important than the resolution of the computerized refractometer. The signal v. time derivatives were calculated and the inflection point time (ti) was correlated with pH, Ca concentration and temperature. The inflection point time was inversely proportional to the rennet and Ca concentrations and the logarithm of the proportionality factor (k) was linearly correlated with pH. The relation between ti and temperature was curvilinear. It is concluded that the refractometer tested could be used for research on the coagulation process.