Abstract
Summary: Cheddar cheeses were made from milks concentrated approximately 2·3-and 3·4-fold by ultrafiltration, then heated at 90 °C for 15 s. They were compared with cheeses made from pasteurized unconcentrated milks and unheated 5·3-fold concentrates. The recoveries of fat and protein were comparable in the cheeses from heated 2·3-fold concentrates and unheated 5·3-fold concentrates and both were higher than the controls. However, fat losses were high in curds from 3·4-fold heated concentrates. The use of paired fast and slow starter strains and coagulation at 26 °C optimized the curd composition. Proteolysis and flavour development were only slightly reduced in all the cheeses from concentrated milks, perhaps aided by higher starter levels in the curd than in the controls. The structures of the curds from the heated concentrated milks were coarser than those of the controls and the curd particles fused poorly. This may explain the grainy, dry, crumbly texture in the cheeses from the heated concentrates. The texture was not improved by adding a bacterial proteinase to the curd.