Radiofrequency/cold plasma drying of black wheat flour: enhanced extractability of bound phenolics, 3D printing adaptability, and enhanced antioxidant activity after steaming

This study compared the effects of RF and CP drying on the bioactivity and 3D printing performance of black wheat flour. The aim was to expand the processing depth of black wheat flour in cereal products. After RF and CP treatments, starch granule surfaces exhibited varying degrees of damage, with surface damage becoming more pronounced as treatment time increased, making the black wheat flour surface more porous and has more ability to absorbers water. RF and CP treatments initially enhanced rheological properties; however, prolonged treatment led to starch granule damage, subsequently weakening the gluten network and reducing rheological performance. The rapid alternating electromagnetic field of RF and the ionized particles generated by CP can disrupt the cell walls of black wheat flour, releasing phenolic compounds originally bound by covalent bonds and significantly increasing the total phenolic and total flavonoid content of the samples. Additionally, CP-15 exhibited the best 3D printing performance, featuring complete and smooth patterns that retained good porosity after steaming. The antioxidant activity of 3D-printed steamed bread made from the treated flour was also significantly enhanced. These results have expanded the long-term commercial application of RF and CP in cereal processing.