17B-7 |
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H. M. NELSON, Dept. of Food Science & Technology, Univ. of Georgia, Food Science Bldg., Athens, GA 30602 and G. S. Choudhury, Dept. of Food Science & Nutrition, California State Univ., Fresno, 5300 North Campus Dr., MS FF-17, Fresno, CA 93740-8019. Research in our laboratory and elsewhere has shown that the addition of proteins to starchy ingredients reduces extrudate expansion and increases hardness. This study was undertaken to examine the possibility of reducing/eliminating such detrimental effects by using hydrolyzed whey proteins. To evaluate the effect of added hydrolyzed whey proteins on macroscopic attributes of corn meal extrudates. Hydrolyzed whey proteins with four degrees of hydrolysis (0%, 4.5%, 10%, 14.9%) and yellow corn meal were supplied by Davisco Foods International, Inc. (LeSueur, MN) and Cereal Mills, Inc. (Paris, IL), respectively. Four blends for each degree of hydrolysis were prepared by mixing corn meal flour (100%, 95%, 90%, 85%) with hydrolyzed whey protein powder (0%, 5%, 10%, 15%), and were extruded using a single screw extruder (Tiger 20 Bake Type Extruder, American Extrusion International, South Beloit, IL), equipped with a screw (7.62 cm in diameter and 24.48 cm long) and a four-opening (3.57 mm diameter) circular die. Feed flow rate, screw speed, moisture content, and die temperature were maintained constant at 60 kg/h, 180 RPM, 13.5%, and 175°C, respectively. Macroscopic characteristics evaluated were densities (true and apparent), expansion ratio (radial, axial, overall), porosity and breaking strength. Addition of hydrolyzed whey proteins to corn meal did not produce detrimental effects on textural attributes of extrudates and product expansion. The extrudates obtained from blends of hydrolyzed whey proteins and corn meal had characteristics similar to those obtained from corn meal alone. These extrudates were more porous and had higher expansion, lower density and lower breaking strength than those produced from corn meal and unhydrolyzed whey proteins. The data clearly indicated that the detrimental effects of proteins on attributes of expanded products can be overcome or eliminated by using hydrolyzed proteins. This may lead to increased use of proteins in expanded snack food products.
Session 17B, Dairy Foods: General
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