Effects of low-pressure homogenisation pre-treatment of cheesemilk on the ripening of Cheddar cheese

Abstract

Homogenisation of milk breaks the protective fat globule membrane, allowing access of indigenous lipoprotein lipase and hydrolysis of free fatty acids (FFA) from triglycerides. The use of homogenisation in cheesemaking is limited due to the deleterious impact on cheese quality. The objective was to investigate the effects of a pre-processing routine (homogenisation of raw milk, incubation and pasteurisation) on the resultant cheese. Pilot- and laboratory-scale Cheddar cheeses were produced where raw bovine milk was homogenised at various pressures (0, 5 and 10 MPa in the pilot-scale and 0, 5, 10, 15, 20 and 25 MPa in the laboratory-scale trial), incubated at 37 °C for 1 h and batch-pasteurised at 63 °C for 30 min. A control milk was not homogenised. Acid degree value increased with increasing homogenisation pressure. Moisture and salt contents were higher in cheeses made with milk homogenised at 5 and 10 MPa, as was pH. The cheese made from milk homogenised at 10 MPa contained the highest level of FFA initially and throughout ripening. Breakdown of α_s1-casein was more extensive in cheese made from non-homogenised milks and breakdown of β-casein was more extensive in homogenised milk cheeses. The use of low-pressure homogenisation in a controlled pre-processing routine may be suitable for cheesemaking; however, further investigation into the effects of the pre-treatment and effects on cheese microstructure and sensory properties is warranted.