Firmness and melting properties of Requeijao cheese

Requeijao cheese, a typical spreadable processed cheese, was prepared from a cheese base obtained by ultrafiltration of pre-acidified milk at pH 5.2 or 5.7, with and without added whey protein concentrate (WPC) and emulsifying salt Joha S9 or S10. At both pH levels there was complete retention of the fat and almost complete retention of the protein. At pH 5.2 there was a lower retention of Ca and P. The addition of WPC increased the firmness of the cheeses. The type of emulsifying salt used also had a significant effect on firmness. The interaction between ultrafiltration pH and the addition of WPC decreased the melting capacity of the cheeses, the greatest reduction being observed when the milk was pre-acidified to pH 5.2.