Influence of polyphosphates on the emulsifying capacity of milk and meat proteins

• Main Author: Cummins, Armando
• Other Authors: Anglemier, A.
• Language: en_US
• Published: 2011
• Subjects: Proteins > Analysis
• Online Access: http://hdl.handle.net/1957/26151

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