Milk beverage base with lactose removed with ultrafiltration: Effect of fat and protein concentration on sensory and...

Our objectives were to determine the effect of fat (skim to whole milk) and protein (3.4%-10.5%) concentration on the sensory and physical properties of milk beverage base that had lactose and other low molecular components removed by ultrafiltration (UF). In experiment 1, a matrix of 16 treatments was produced to achieve 4 levels of lactose removal (0%, 30%, 70%, and 97%) at each of 4 fat levels (skim, 1%, 2%, and whole milk). In experiment 2, a matrix of 12 treatments was produced to achieve 4 levels of lactose removal (0%, 30%, 70%, and 97%) at each of 3 protein concentrations (3.4%, 6.5%, and 10.5% protein). Physical and sensory properties of these products were determined. Removal of >95% of milk lactose by UF required a diafiltration volume of approximately 3 times the milk volume. Lactose and low molecular weight solute removal increased whiteness across the range from skim to whole milk while decreasing viscosity and making milk flavor blander. In addition, lactose (and other low molecular weight solute) removal by UF decreased titratable acidity by more than 50% and increased milk pH at 20°C to >7.0. Future work on milk and milk-based beverages with lactose removed by UF needs to focus on interaction of the remaining milk solids with added flavorings, changing casein to whey protein ratio before removal of lactose by UF, and the effect of lactose and low molecular weight solute removal on heat stability, particularly for neutral-pH, shelf-stable milk-based beverages.