Effect of jet-cooking on rheological properties of navy bean flour suspensions

Abstract

Navy beans are a gluten-free pulse containing great heathy sources for human beings. In this work, we compared the rheological properties of untreated navy bean flour suspensions (UNBFS) and jet-cooked navy bean flour suspensions (JCNBFS). Jet-cooking is a direct-contact heating process employing high-temperature and high-pressure steam for producing food and beverage products. We found that the linear rheological properties of 8% (wt.%) UNBFS exhibited viscoelastic fluid behavior; while 10% (wt.%) UNBFS displayed viscoelastic fluid/solid cross-over behavior; but 12% (wt.%) UNBFS displayed weak viscoelastic solid behavior. Unlike UNBFS, all three (8%, 10%, and 12%) (wt.%) jet-cooked navy bean flour suspensions (JCNBFS) displayed linear rheological properties having viscoelastic solid gel-like behaviors. The rheological properties of JCNBFS were strongly dependent on the concentration of the suspensions. The non-linear viscoelastic properties of the three suspensions of UNBFS exhibited similar viscosity shear thinning behavior. The degree of shear thinning was slightly reduced both at very low and high shear rates. The non-linear rheological properties of the three suspensions of JCNBFS also displayed shear thinning behaviors. The viscosity curves of the JCNBFS were much steeper than those of the UNBFS. This demonstrates that JCNBFS possessed greater shear thinning capacity than UNBFS. Both linear and non-linear rheological property studies for UNBFS and JCNBFS revealed that jet-cooking processing alters the molecular structures of navy bean flours’ starch and proteins, which would influence the navy bean flour suspensions’ properties. The results of this work will be useful to develop new food products from navy beans.