Modification of whole flours of navy bean, pinto bean, black bean and chickpea by steam jet cooking and drum drying
F. FELKER (1), J. Kenar (1), J. Byars (2), M. Singh (2), S. Liu (2) (1) USDA/ARS/NCAUR, Peoria, IL, U.S.A.; (2) USDA/ARS/NCAUR, , U.S.A..
The health-promoting value of pulses is widely recognized, and utilization of them in food products could be expanded with new processing technologies. This study was undertaken to explore steam jet cooking as an approach to increase the level of pulse flour incorporation into food products by improving its properties. Whole bean flours of navy bean, pinto bean, black bean and chickpea were processed by excess steam jet cooking, drum drying, and milling to a state resembling the raw flours. Analysis of the structure and size of the particles, color, solubility and pasting characteristics, dietary fiber, and protein digestibility revealed differences that could provide advantages of this processing technique for certain food applications. Solubility in hot water and protein digestibility were increased by the processing, while average particle size, water absorption index, viscosity after pasting, and lightness of color were decreased. Color changes suggested slight Maillard browning and solubilization and redistribution of seed coat pigments. Starch granules were completely solubilized and the starch, along with fiber and denatured protein components, formed a uniform composite matrix with lower solubility at 25 °C than raw flours. Fiber analysis revealed that jet cooking converted a portion of insoluble fiber to soluble fiber. Differences between the diverse pulse types were observed, but they were minor and reflected composition differences between the bean types. These results suggest that further investigations to distinguish jet cooking from drum drying effects, as well as to characterize the functional performance and nutritional profile of the processed flours in various food systems, are warranted.
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