Optimisation of process conditions on the physical and functional properties of extruded defatted oat-corn mix.

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2001 AACC Annual Meeting

Charlotte, North Carolina
October 14-18, 2001
Charlotte Convention Center

292
Optimisation of process conditions on the physical and functional properties of extruded defatted oat-corn mix. H. KARACAN (1), A. Seylam (1), H. Olmez (1), and H. Koksel (2). (1) Tubitak Marmara Research Center Food Science and Technology Research Institute Gebze, Kocaeli, Turkey; (2) Dept. of Food Engineering, Hacettepe University, Ankara, Turkey.

Although oats are sixth largest cereal crop in the world behind wheat, corn, rice, barley and sorghum and are important grain for livestock and poultry feed, only 7% of the total oat production is used for human consumption. This picture may change, because of recent reports on health-promoting effects of oats. However, unlike most cereal flours, 100% oat flour is difficult to be used in expanded snacks and cereal due to a high level of fat and soluble gum in oats. This problem might be overcome through defatting of oat and using blend of oat and corn flours. The objective of this study was the production of a puffed, expanded, snack-type food from corn flour-defatted oat flour blends. The ratio (80% defatted oat flour and 20% corn flour) of defatted oat flour to corn that gives a puffed product at a minimum concentration of corn was determined as a result of the preliminary extrusion trials. A Brabender counter-rotating twin-screw extruder under various processing conditions. Three level, three variable Centeral Composite Design was used. The effects of extrusion conditions (feed moisture content, barrel temperature, screw speed) on the functional (water absorption index and degree of gelatinization) and physical (expansion ratio and cutting strength) properties of the extrudates were investigated by means of response surface methodology (RSM). The second order model indicated an optimum product could be obtained by maximization of starch gelatinization and expansion ratio and minimization of cutting strength which corresponded to a feed moisture content of 15%, barrel temperature of 162°C and screw speed of 95 rpm.