Effect of Vacuum-Condensed or Ultrafiltered Milk on Pasteurized Process Cheese

Abstract

Milk was concentrated by ultrafiltration (UF) or vacuum condensing (CM) and milks with 2 levels of protein: 4.5% (UF1 and CM1) and 6.0% (UF2 and CM2) for concentrates and a control with 3.2% protein were used for manufacturing 6 replicates of Cheddar cheese. For manufacturing pasteurized process cheese, a 1:1 blend of shredded 18- and 30-wk Cheddar cheese, butter oil, and disodium phosphate (3%) was heated and pasteurized at 74°C for 2min with direct steam injection. The moisture content of the resulting process cheeses was 39.4 (control), 39.3 (UF1), 39.4 (UF2), 39.4 (CM1), and 40.2% (CM2). Fat and protein contents were influenced by level and method of concentration of cheese milk. Fat content was the highest in control (35.0%) and the lowest in UF2 (31.6%), whereas protein content was the lowest in control (19.6%) and the highest in UF2 (22.46%). Ash content increased with increase in level of concentration of cheese milk with no effect of method of concentration. Meltability of process cheeses decreased with increase in level of concentration and was higher in control than in the cheeses made with concentrated milk. Hardness was highest in UF cheeses (8.45 and 9.90kg for UF1 and UF2) followed by CM cheeses (6.27 and 9.13kg, for CM1 and CM2) and controls (3.94kg). Apparent viscosity of molten cheese at 80°C was higher in the 6.0% protein treatments (1043 and 1208 cp, UF2 and CM2) than in 4.5% protein treatments (855 and 867 cp, UF1 and CM1) and in control (557 cp). Free oil in process cheeses was influenced by both level and method of concentration with control (14.3%) being the lowest and CM2 (18.9%) the highest. Overall flavor, body and texture, and acceptability were higher for process cheeses made with the concentrates compared with control. This study demonstrated that the application of concentrated milks (UF or CM) for Cheddar cheese making has an impact on pasteurized process cheese characteristics.