Cheesemaking aptitude of two Spanish dairy ewe breeds: Changes during lactation and relationship between physico-chemical and technological properties

Individual milk samples from two Spanish ewe breeds (Guirra and Manchega) were collected and evaluated during the lactation. Changes in the physico-chemical and technological characteristics during the lactation period were studied, and correlations between variables were estimated. Bulk milks from both ewe breeds were sampled three times during lactation, and physico-chemical and technological properties studied by using mini cheese productions. Fat, protein, casein, lactose, total solids, gel firmness and rate of curd aggregation were the physico-chemical and coagulation variables significantly influenced throughout lactation. With the advance of the lactation, milk took more time to coagulate, produced a less strong gel and showed a lower rate of curd aggregation. Milk total solids and estimated cheese yield increased, while curd draining capacity decreased during lactation. Correlation study showed that rennet clotting time had a positive correlation with pH and protein components. However, gel firmness and rate of curd aggregation were negatively correlated with fat and protein, while these two last parameters correlated positively with cheese yield. Curd draining and somatic cell counts did not show a significant correlation with any factor. The physico-chemical evaluation of bulk milks and their technological parameters studied by means of mini cheese productions did not show differences between the breeds evaluated.