Investigating the microstructure of chickpea and navy bean flour blends produced by roller milling: Insights from Fourier transform mid-infrared spectroscopy, scanning electron microscopy and synchrotron X-ray techniques

Abstract

Flour blending ratios influence the micro- and molecular properties of flour, which, in turn, determine the essential structure-function relationships crucial for shaping ingredient functionality and creating customized end-products. Conventional laboratory-scale X-ray instruments, constrained by limited brightness and measurement time, present obstacles in investigating porosity, starch lamellar structure, and crystallinity in pulse flours. To address these challenges, this study uses synchrotron X-rays, laser diffraction, mid-infrared spectroscopy, and scanning electron microscopy to non-invasively examine micro and molecular changes in roller-milled chickpea and navy bean flour, accounting for flour blending ratios. The results illustrate a multimodal particle size distribution curve, with each flour blend displaying a distinctive morphology. Chickpea blends showed greater overall porosity than navy bean blends, while navy bean flour blends displayed slightly higher absorbance ratios. The macromolecular changes in flour properties as a result of blending unravel novel information that will be of immense use to food manufacturers.