| Summary: | The influence of polyphosphates upon the emulsification of
enzymatic hydrolyzates of casein and lactalbumin and upon salt-soluble
meat proteins was determined by a model system in which
oil-in-water emulsions were formed.
Sodium acid pyrophosphate, sodium tripolyphosphate and
sodium hexametaphosphate were mixed together in a weight ratio
of 4:2:4, respectively, to form a polyphosphate blend. This blend
was added at a level of 0.5% (w/v) to casein or lactalbumin dissolved
in 3% NaCl, pH 6.0. The polyphosphate blend was also added at the
above level to meat proteins solubilized in 3% NaCl, pH 5.7.
Emulsified volume (EV), total g of oil emulsified per 25 ml of protein
solution, was determined for the above proteins with or without
polyphosphates at varying protein concentrations. Data were also graphically expressed as emulsifying capacity (EC) and oil phase volume (OPV).
For all proteins studied with or without polyphosphates, EV
and OPV values increased with increasing protein concentration
whereas EC values decreased.
Addition of the polyphosphate blend to casein solutions containing
protein levels in excess of 2 mg/ml resulted in significantly
(P<0.01) higher EV levels than those of the controls. Conversely,
the EV values of the polyphosphate-treated lactalbumin solutions
were significantly (P< 0.01) lower than those of the controls at all
protein levels tested. The diverse data obtained with these two
proteins appear to be related to variations in molecular size and
shape and to differences in the manner in which the proteinphosphate
interactions occurred to cause the polyphosphates to
enhance the emulsification of casein while depressing that of lactalbumin.
Addition of the polyphosphate blend had little or no effect upon
the emulsification of meat protein extracts obtained from fresh,
frozen or refrozen samples. Thus, it was concluded that the polyphosphate
blend did not modify nor exert any detectable influence
upon the emulsification of solubilized meat proteins as tested in a
model system. === Graduation date: 1975
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