15C-15 |
Physical properties of ice cream substituted with milk protein concentrates |
C. L. MUELLER1, V. B. Alvarez, and W. J. Harper. (1) Department of Food Science and Technology, The Ohio State University, 2015 Fyffe Court, Columbus, OH 43210-1007 Consumer acceptance of ice cream depends largely on its textural quality and flavor. Milk protein concentrate (MPC) is a relatively new ingredient with potential to influence the structural, textural, and quality characteristics of ice cream. Our objectives were to examine the effects of MPC substitution on the physical properties of ice cream and to determine appropriate protein concentration and substitution levels. Three different MPC concentrations (56, 70, and 81%) were studied as substitutes for 25, 50, or 75% of the protein supplied by non-fat dry milk (NFDM). All mix formulations were standardized at 12% fat, 11% NFMS, 15% sweetener, and 0.3% stabilizer/emulsifier blend. Increased MPC concentration and usage level increased total protein. Mix viscosity was studied using a rotational viscometer; melting rate was measured by plotting the volume of melted liquid as a function of time; particle size was analyzed using laser light diffraction. Mixes with MPC had higher apparent mix viscosity (318 cps) than control (149 cps). Average fat globule diameter increased as protein concentration and substitution level increased. Average diameter sizes after freezing ranged from 2.01 µm (control) to 13.96 µm (highest protein/substitution combination). Analysis of the drip loss collected during melting showed that MPC-substituted ice creams lost less fat (5.4%) in the melted portion than the control (8.7%), resulting in a slower melting rate (0.24 mL/min compared to 0.45 mL/min for control). These results suggest possible structural differences in both the unfrozen emulsion and frozen foam. Further investigation of the structural differences responsible for the observed changes in physical properties of MPC-substituted ice creams may lead to better control of melting and texture characteristics, thus improving the quality of ice cream products.
Session 15C, Dairy Foods
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