Coagulation Traits of Sheep and Goat Milk

SIMPLE SUMMARY: The suitability of milk for cheese production is usually predicted at dairy plants using mathematical formulas, which are based on milk protein and fat content. In addition, several methods, which use a small volume of milk to simulate the cheesemaking processes and stages, are currently available at the laboratory level. Those methods have been developed and improved for cow milk. In the present review, the author reports the available literature and current methods to analyze coagulation traits from sheep and goat milk. ABSTRACT: Milk production from sheep and goat species is continuously growing worldwide, and its main use is for cheesemaking. Given that the final quality of cheese is linked to the traits of raw milk cheese yield at dairy plants, it is often calculated by using predictive formulas based on fat and protein content. Predictive formulas have been studied for bovine milk and are very effective but not appropriate for sheep and goat milk. Several methods, which simulate the actual coagulation processes, are available at the laboratories. This article reviews the available literature about rennet coagulation and cheese yield traits from sheep and goat milk and the methods used at the laboratory level. In general, if compared to cow milk, sheep and goat milk are characterized by shorter rennet coagulation times and a very limited amount of non-coagulating samples. Curd firmness of sheep milk is almost independent from the rennet coagulation time, and some coagulation traits can be predicted by infrared spectra. In addition, coagulation traits are characterized by appropriate values of heritability to be considered in selective breeding plans. With regard to goat milk, rennet coagulation time and cheese yield are strongly influenced by the breed effect.