Flie�verhalten von Schmelzk�sen unter der Wirkung verschiedener Phosphate

Abstract

Processed cheese was manufactured with different types of phosphates (P1 monophosphate to P4 tetrapolyphosphate) and by various techniques. The limiting viscosity numbers of sodium casein and the casein of processed cheese were determined and the axial ratio calculated. The axial ratio of processed cheese protein was a/b=20,0 and that of sodium casein 10,0 resp. We deduce that the apparent increase of the axial ratio is caused by the depolymerization of casein caused by emulsifying salts. The flow curves of processed cheese were analysed. There is good agreement with the power law of Ostwald tau=k.Dn. Therefore processed cheeses are characterized as pseudoplasts. The influence of melting salts on the flow properties can be described by a differing emulsifying effect (P1 less than or equal P4). Temperature, concentration and salt effects are discussed for the viewpoint of correlation between aggregation-desaggregation processes and dehydration and hydration of casein.

Effect of Emulsifying Salts on Casein Peptization and Apparent Viscosity of Processed Cheese

“…Processed cheese in liquid state behaves as a pseudoplastic liquid and follows the power law (Kirchmeier et al, 1978;Dimitreli and Thomareis, 2004). Figure 4 shows the flow curves of sample 4 made with different emulsifying salts.…”

“…Schulz and Hetzel (1960) and Meyer (1973) have reported the Brabender Plastograph's consistency of processed cheeses made with different types of emulsifying salts. Kirchmeier et al (1978) studied the effect of phosphates (monophosphate to tetrapolyphosphate) on processed cheese apparent viscosity by the use of a coaxial-cylinder viscometer. Furthermore, the effects of trisodium citrate and phosphates on water-soluble nitrogen and relative casein content of processed cheeses were evaluated by Thomas et al (1980).…”

Processed Cheese Products

“…60 Differences in depolymerization of casein and changes in the flow properties of processed cheese are related to differences in calcium complexation between mono-and tetrapolyphosphates. 61 Melting rate, ultrafiltratable calcium concentration and textural properties (stress/relaxation, hardness, gumminess and elasticity) of processed cheese are affected more by varying the condensed phosphate than the polyphosphate concentrations. 62 Sharpf 63 suggested that the emulsifying effect of chain phosphates is associated with their interaction with paracasein in such a way that phosphate anions form bridges between protein molecules.…”