Comparison of properties of raw pulse flours with those of jet-cooked, drum-dried flours

Authors: Felker, Frederick; Kenar, James - Jim; Byars, Jeffrey; Singh, Mukti; Liu, Sean

Submitted to: LWT - Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2018
Publication Date: 6/11/2018
Citation: Felker, F.C., Kenar, J.A., Byars, J.A., Singh, M., Liu, S.X. 2018. Comparison of properties of raw pulse flours with those of jet-cooked, drum-dried flours. LWT - Food Science and Technology. 96:648-656.

Interpretive Summary: Although it is widely known that beans and chickpeas are good sources of important nutrients such as protein, fiber, starch, and other substances like vitamins, minerals, and antioxidants, their use as a basis for food ingredients has not been growing as fast as the demand for more nutrient-dense foods. Whole bean flours have some negative properties that limit the degree to which they can be used to replace wheat flour in certain food classes such as gluten-free foods. In order to enable increased bean flour utilization, this study was undertaken to determine the effects of steam jet cooking and drum drying as processing steps toward the goal of making bean flour more versatile and acceptable. Differences in particle size and structure, solubility, water absorption, color, thickening ability when cooked, and protein digestibility were observed, suggesting beneficial effects with regard to ease of use and nutrient delivery efficiency. These results will be useful to food product developers seeking more diverse opportunities for increased pulse flour utilization in various food systems.

Technical Abstract: Whole bean flours of navy, pinto, and black beans and chickpeas were processed by excess steam jet cooking, drum drying, and milling to a state outwardly similar to the raw flours. Analysis of the structure and size of the particles, color, solubility and pasting characteristics, and protein digestibility revealed differences that could provide advantages 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. Differences between the diverse bean 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.