Deamidated zein improves the rheological properties of gluten-free dough: insights from liquid lamella and interfacial mechanisms.

Buckwheat, which is rich in flavonoids, serves as a high-quality protein source despite lacking gluten, leading to poor dough structure and fermentation performance. Therefore, we investigated the effects of moderately deamidated zein on the rheological properties of buckwheat gluten-free dough and the interfacial properties of dough liquor (DL). The results showed that zein treated with 30 U/g protein glutaminase (PG) significantly increased the fermentation height from 5.89 mm to 7.39 mm (p < 0.05), while enhancing the dough's resistance to deformation and the uniformity of its protein network. Moreover, moderate deamidation improved the structural and functional properties of zein, facilitating its rapid adsorption at the gas-water interface and leading to the formation of a viscoelastic interfacial network surrounding gas cells. Consequently, the interfacial tension of DL decreased, whereas the interfacial dilatational modulus increased. A correlation analysis revealed that foaming property and interfacial dilatational modulus of DL are key factors regulating the rheological properties of gluten-free dough. Therefore, moderately deamidated zein improves the quality of gluten-free dough through the enhancement of rheological and interfacial properties.