Effects of thermal processing on physicochemical and storage properties of Tartary buckwheat bran

To maintain the stable properties of whole Tartary buckwheat and improve its utilization rate, it is crucial to deactivate the lipolytic enzymes. This study assessed the storage and physicochemical properties of Tartary buckwheat bran (TB) after thermal processing, which included roasting, extrusion, and roasting-assisted extrusion for enzyme inactivation. The results showed that the lipase, lipoxygenase (LOX), peroxidase (POD), and catalase (CAT) of TB were effectively inactivated by these thermal processing techniques, particularly by roasting-assisted extrusion. After three months of storage, thermally processed TB maintained low values of fatty acid (FAV), peroxide (POV), and carbonyl (CV). With the water activity of TB decreased by processing, the ability of lipolytic enzymes to access and interact with lipid substrates would also be limited. After undergoing thermal processing, TB exhibited smaller and more dispersed particles. Additionally, the water absorption index (WAI) and water solubility index (WSI) of TB significantly increased, while the pasting viscosities decreased. These changes could alter the action sites of lipolytic enzymes, hinder the sensitivity of lipids towards these enzymes, weaken the enzymatic reaction, ultimately enhancing the storage stability of TB.