factsheet

Milk Quality: Impact of Mild or Intense Mechanical Treatments

Project entitled:

Do Mechanical Treatments Have an Impact on the Technological Quality of Milk?

Yves Pouliot, Michel Britten

Highlights

This project aims to study the impact of mechanical treatments on the technological quality of milk intended for cheese production. The effects of light treatments (pumpage, skimming) and intense treatments (churning, high pressure homogenization) are also studied.

Objectives

The general objective of the project is to demonstrate the effect of mechanical treatments on the physico-chemical properties of milk and its cheesemaking ability.

The specific objectives are to measure the effect of 1) pumpage; 2) skimming; 3) churning; 4) high pressure homogenization of skimmed milk; and 5) partial homogenization of whole milk.

Results and potential benefits

Cheesemakers are aware of the importance of optimizing the technological qualities of milk intended for cheese production. In a highly competitive environment, improving yields and controlling cheese composition is essential. Standardizing milk and mastering heat treatments have been the subject of many studies. In comparison, the impact of mechanical treatments on milk’s cheesemaking ability has not received much attention.
Our work will make it possible to quantify the effect of mechanical treatments on the dispersion state of fats, the physico-chemical properties of casein micelles and the balance between the colloidal and soluble phases. Despite the changes observed and the preciseness of analysis methods, no significant impacts on the coagulation ability of milk or cheese yields have been recorded. The only exception concerns the churning of cream, which produces buttermilk whose fractions’ technological qualities are inferior to those of milk.
The next portion of the project aims to evaluate the partial homogenization of cheesemaking milk as a control tool for cheese composition and characteristics. The presence of a fraction of homogenized fat in milk will modify the structural organization of the curd, its syneresis and the cheese’s properties (composition, texture, melting properties).