A comparison of the methods for determination of the rennet coagulation properties of milk

Abstract

The objective of the present study was to compare two methods for measuring the rennet coagulation properties of milk: the Formagraph, and the Optigraph. The parameters used to describe rennet coagulation of 81 milk samples were rennet coagulation time (RCT, Formagraph, and R, Optigraph) and curd firmness 30 min after the addition of rennet (E30, Formagraph, and A30, Optigraph). New Optigraph system recipes were found: R slope = 1.784 and R offset = − 2.303. Using the above Optigraph system recipes, no statistically significant differences were found in rennet coagulation time measurements in either of the studied methods. Regarding curd firmness, the best approximation to describe the relationship between the methods was polynomial: E30= − 0.0357*A30 2+2.8795*A30 −5.2991 (R 2 =0.925). Such strong correlations indicate that the two techniques for detecting milk coagulation properties are comparable and that the data obtained by these methods allow for data interpretation in studies using either method.