Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/17/2006
Publication Date: 6/24/2006
Citation: Gajula, H., Liu, S., Alavi, S., Herald, T., Bean, S. 2006. Effect of drying methods on functional properties of pre-cooked wheat flour obtained by extrusion. Proceedings of 2006 IFT meeting. Presentation number 096-06.
Technical Abstract: Cereal products with high fibre can reduce calorie uptake and provide health benefits linked to chronic disease. However, high fiber content tends to diminish the final product quality and consumer acceptability of cereal products like baked goods and pasta. Overall objective of this project is to produce high-fibre pre-cooked flour using extrusion in order to increase functional properties. Our specific objective of this study was to compare rheological and functional properties of extrusion processed wheat pre-cooked whole wheat flour obtained by oven drying and freeze drying. Pre-Cooked flours were produced using lab-scale twin-screw co-rotating extruder configuring for low shear, low temperature. Swelling and pasting properties of the pre-cooked flours was characterized using rapid visco-analyser standard methodology. Rheological properties were characterized using mixograph standard methodology. The quality of cookies and tortillas were also characterized by AACC Approved Methods. The results showed that pre-cooked flour using freezer dryer had a similar swelling and pasting properties with oven dried flour. Water absorption increased in the pre-cooked flours as compared to the commercial available flours. The drying methods had no significant effect on the quality of the cookies using pre-cooked flour and commercial available wheat flours. The diameters of cookies using these flours were 9.3 cm, 9.8 cm and 10 cm, respectively with similar spread factor (118.70, 107.09, and 129.35). The weight, diameter, height, and specific volume of tortilla using oven dried, freeze dried pre-cooked flour and controlled wheat flour were 22.34 g, 11.33 cm, 0.20 cm, 0.947 cm3/g, 22.65 g, 11.39 cm, 0.215 cm, and 0.964 cm3/g, and 22.69 g, 12.21 cm, 0.18 cm, and 0.952 cm3/g, respectively. The results suggest that extrusion technology can produce pre-cooked wheat flour with same functionality for baked products, and pre-cooked flour obtained by oven-drying have similar rheological and functional properties as freeze dried flour.