Physicochemical changes of barley flour subjected to different modification treatments

This study examined the morphological, structural, and physicochemical characteristics of modified barley flours prepared from non-waxy cultivars Sogang and Huknuri and waxy cultivars Nulichal and Boseokchal using heat-moisture treatment (HM), enzyme treatment (EZ), and combined treatment (HM-EZ). Particle size and distribution decreased after modification, and SEM images revealed that starch granules became rough and irregular, exhibiting swelling, fissures, micropores, and layered structures depending on the treatment type. Color analysis showed decreased L* and increased a* values, mainly due to non-enzymatic browning during heat treatment. X-ray diffraction indicated that all samples maintained an A-type crystalline pattern, while partial transformation to a V-type structure occurred in heat-moisture and combined treatments. FT-IR spectra showed intensified β-glucosidic bond peaks in enzyme- and combined-treated flours, suggesting enhanced molecular bonding, whereas waxy cultivars exhibited weakened hydrogen bonding. Amylose content decreased in non-waxy cultivars but increased in waxy cultivars, and damaged starch content was highest in heat-moisture and combined treatments. These results demonstrate that modification treatments altered starch granule structure and molecular order, thereby influencing the physicochemical stability of barley flour. The findings provide fundamental data for the development of functional and clean-label barley-based food ingredients.