Elongational flow studies of processed cheese spreads made from traditional greek cheese varieties

Five series of cheese spreads were prepared and pasteurized at either 92 or 98 degrees C. The basic ingredient of the samples was a blend of traditional greek cheeses i.e. Myzithra, a whey cheese and Feta cheese in proportion 0.9/0.1. The first series of samples contained only this mixture whereas the other series consisted of samples to which apart from the mixture of the cheeses, either UHT milk or water or olive oil were added in various proportions. The flow properties of the samples were studied by performing lubricated squeeze flow experiments. The results indicated that the elongational viscosity values exhibited, under steady conditions, by the samples were considerably lower to that of the sample contained only the blend of the two cheeses which was not heat treated. It was found that the various ingredients added to the samples affected their flow behavior in various degrees with the olive oil to cause the most noticeable changes. Creep experiments performed using the same samples supported, in general, the findings from the elongational flow measurements.