30E-1 |
Effect of okara on properties of rice-whey beverage |
P. N. DIAS1, T. A. Howell, Jr., and E. de Feliz. (1) Dept. of Food Science, University of Arkansas, 2650N Young Avenue, Fayetteville, AR 72704 Okara, also known as soy pulp, is an abundant by-product of the soy and tofu industries. The high quality protein and lipid fractions present in okara and its emulsifying properties make it a potential ingredient in rice beverages. Rice beverages require addition of proteins to enhance their nutritional profile. However, the use of whey protein and okara in such applications is under-investigated. Because whey proteins enhance foaming, antifoaming agents are required. The addition of okara provides oil and lecithin that could inhibit foam formation of whey proteins and provide a desirable texture and appearance in the final product. Our objective was to investigate the flow properties of rice-whey dispersions with okara and compare them with commercially available cow’s milk. The flow properties of rice-whey beverages, containing 0 to 16% okara, were measured by a rotational viscometer. A programmed shear rate, which increased from 0 to 400 1/s in 3 min, was held constant at 400 1/s for 3 min and decreased to 0 1/s over 3 min was employed in measuring rheological properties. Commercial milk samples and rice-whey dispersions containing okara showed Newtonian behavior. Hysteresis loops were present in flow curves at lower concentrations of okara. With the addition of 0 to 16% okara, the viscosity of rice-whey dispersions increased from 0.05 to 0.06 Pas and 0.06 to 0.07 Pas at 22 °C and 4 °C respectively. Rice-whey dispersions that contained 12 and 16% okara had nearly the same viscosity as commercial whole milk (~0.062 Pas) at 22 °C. The foam formation of whey proteins was suppressed at high concentrations of okara. Okara at high concentrations reduced foam formation and did not produce high viscosities in a rice-whey beverage. Thus, okara enhanced the nutritional and functional properties of rice-whey dispersions without impairing the flow behavior.
Session 30E, Food Engineering: Rheology and texture
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