Effect of high-intensity ultrasound on cowpea flours optimized by response surface methodology and the impact on their techno-functional properties

Abstract

High-intensity ultrasound (HIU) is a sustainable technology that modifies the techno-functional properties of foods, preserving their nutritional quality and aligning with current food trends. HIU was applied to a cowpea flour aqueous suspension (10 % w/v) to optimize the amplitude and time conditions through a response surface methodology, aiming to maximize the techno-functional properties of flours. Compositional, structural, morphological and thermal studies of two optimums C-US/87–15 (87 % amplitude/15 min HIU), C-US/39–52 (39 % amplitude/52 min HIU) and the untreated flour (NC) were carried out. HIU decreased the bulk density and increased the water and oil retention capacity, solubility and swelling power of the flour. HIU did not change the macronutrient content or in starch granule morphology; however, it significantly increased the amylose content due to the cleavage of α(1 → 6) bonds in the amylopectin branches, and increased the total dietary fiber (16.11 ± 0.04 g/100g_flour to 18.3 ± 0.4 g/100g_flour and 17.0 ± 0.4 g/100g_flour), with the conversion of insoluble to soluble fiber. HIU unified the particle size (trimodal to bimodal distribution), increased the starch crystalline structures (FT-IR ratio 1022/995) and the peak viscosity from 1.7755 ± 0.0007 Pa.s to 1.90 ± 0.07 Pa.s and 1.91 ± 0.05 Pa.s. Gelatinization enthalpy reflected a greater molecular order, confirming the increase in crystalline structures as a result of HIU. This research demonstrates that HIU modifies the techno-functional properties of cowpea flour, expanding the possibilities for the production of plant-based foods using legume flours with better technological qualities with a gluten-free approach.