320 Characteristics of extruded products for instant cereal drinks.

S. Wei, G. H. RYU, and P. K. W. Ng. Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824.

Instant drinks for meal replacement or nutritional supplementation have become increasingly popular with consumers. Processing of instant cereal drink powders by extrusion cooking provides many advantages over the conventional drum drying method. This study examined the effects of extrusion conditions on the characteristics of extrudates and extrudate powders for instant cereal drinks. Wheat flour, corn meal, soy meal, and blends of these materials were extruded by using a co-rotating twin-screw extruder under various processing conditions (screw speed, water injection rate, and temperature). Extrudates were analyzed for texture properties, water absorption index (WAI), water solubility index (WSI), and Rapid-Visco Analyser (RVA) pasting properties. Results with wheat flour showed that WAI, RVA cold viscosity, and RVA hot peak viscosity were inversely related to specific mechanical energy (SME) input, while WSI and degree of starch gelatinization were directly related to SME input. Desired product quality for instant drinks could be achieved by identifying a set of appropriate extrusion conditions.