Sulfur improves cookie-making quality by modulating protein composition and structure in wheat grown under shading

The components and structures of proteins critically determine the food-use properties of wheat. However, the mechanism by which sulfur affects the protein structures and cookie-making quality of wheat grown under shading remains elusive. Here, we evaluated the combined effects of inorganic sulfur supplementation (0, 50, and 100 kg S ha −1 ) and shading (pre- and post-anthesis shading) on the protein structures and cookie-making quality of strong-gluten (Chuanmai 39; CM39) and weak-gluten (Cangmai 34; CM34) cultivars. Shade stress decreased the ω-/(α, β, γ)-gliadin and high-molecular-weight subunit (HMW-GS)/low-molecular-weight subunit (LMW-GS) glutenin ratios, with more significant effects were observed in CM34 than in CM39. In shaded environments, sulfur increased the glutenin/gliadin and HMW-GS/LMW-GS ratios. Secondary and tertiary structural analysis revealed that sulfur increased the β-turn, disulfide bonds, ionic bonds, and hydrophobic interactions in the proteins of wheat under shading. The consequent modifications increased the gluten performance index, essential amino acid index and biological value of the proteins, and decreased cookie hardness. Our results revealed that sulfur improves cookie texture and protein nutritional value by regulating amino-acid profiles and protein composition and structure. These findings provide a promising approach for achieving superior cookie texture in the context of global dimming. • Sulfur alleviates the adverse effect of shading on gliadin and glutenin fractions. • Sulfur increases the β-turn but decreases the β-sheet structure in wheat proteins under shading. • Sulfur improves dough performance via disulfide and non-covalent bond-mediated protein cross-linking. • Dough performance is closely related to the composition and structural features of wheat proteins. • Contributions of protein composition and structural features to cookie taste were evaluated.