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ABSTRACT
The effects of using cold ultrafiltered (UF) retentates (both whole and skim milk) on the coagulation, yield, composition, and ripening of Parmesan cheese were investigated. Milks for cheese making were made by blending cold UF retentates with partially skimmed milk to obtain blends with 14.2% solids and a casein:fat ratio of 1.1. Cutting times, as selected by the cheesemaker, were ~15 and ~20 min for experimental and control milks, respectively. Storage modulus values at cutting were similar, but yield stress values were significantly higher in UF retentate standardized milks. Cheese yields were significantly higher in UF retentate standardized milks (~12%) compared with control milk (cream removed) (~7 to 8%). Significantly higher protein recoveries were obtained in cheeses manufactured using cold UF retentates. There were no differences in the pH and moisture contents of the cheeses prior to brining, and there was no residual lactose or galactose left in the cheeses. Using UF retentates resulted in a significant reduction in whey volume as well as a higher proportion of protein in the solids of the whey. Proteolysis, free fatty acids, and sensory properties of the cheeses were similar. The use of milk concentrated by cold UF is a promising way of improving the yield of Parmesan cheese without compromising cheese quality. The question remaining to be answered by the cheesemaker is whether it is economical to do so.
(Key words: Parmesan cheese, ultrafiltration, cheese yield, rennet coagulation)
Abbreviation key: G' = storage modulus, LCF-UF = low concentration factor UF, SUF = skim milk, WUF = whole milk UF.
INTRODUCTION
Most of the recent growth in the US milk production has been in the West or Southwest. Milk production in Wisconsin has remained stable over the past few years, while demand by cheese manufacturers for milk continues to increase. As a result, cheese plants in the Upper Midwest (Minnesota, Wisconsin) are often short of sufficient milk for cheese making and use NDM for standardization and to help increase cheese yield. In 1996, the FDA approved the use of cold (<7°C) UF of milk for use in standardized Cheddar and Mozzarella cheese making (Code of Federal Regulations, 2003). Concerns about on-farm UF of milk were addressed by maintaining a low operating temperature and using a...