Abstract: In order to improve the processing quality of wheat, newly harvested wheat was treated with glow discharge cold plasma. The changes in the physicochemical properties of wheat flour and the rheological properties of wheat flour dough after the treatment were studied, and the molecular mass distribution and secondary structure of wheat flour proteins were furthermore analyzed. The results showed that the gluten index of wheat was significantly increased after cold plasma treatment with oxygen or argon as the gas source. Dough development time and stability time were improved, and the mixographic parameters midline integral at 8 min (MTxI) and midline width at 8 min (MTxW) were significantly increased (P < 0.05), while weakening slope (WS) was significantly decreased (P < 0.05). The content of macromolecular polymeric storage protein fraction F1 was increased, and the ratio between macromolecular polymeric storage protein fraction F1 and small-molecule polymeric storage protein fraction F2 was significantly increased (P < 0.05). The protein secondary structure was transformed from β-sheet and β-turn to more ordered intermolecular β-sheet. In conclusion, glow discharge cold plasma treatment changed the molecular mass distribution and secondary structure of wheat storage proteins, significantly enhanced the elasticity and mixing tolerance of dough, and improved the tensile resistance of dough, thereby enhancing the processing quality of wheat to some extent.

Key words: glow discharge cold plasma; wheat; processing quality; flour physicochemical properties; dough rheological properties; protein structure