Abstract: This study investigated the effects and potential mechanisms of Lcc5, a fungal laccase derived fromCoprinopsis cinerea, on the quality and physicochemical properties of rye bread. Rye dough was treated with varying concentrations of Lcc5, and comprehensive analyses were performed to assess the structural and textural attributes of both dough and bread. Analytical methods included rheological measurements, texture profile analysis (TPA), free sulfhydryl group determination, and scanning electron microscopy (SEM) imaging. From the texture and rheological results, the addition of Lcc5 increased the elastic (G′) and viscous modulus (G″) of rye dough and affected the gluten strength of the dough, rye bread quality was improved. The hardness, chewiness and stickiness of rye bread were significantly reduced when Lcc5 was added up to 6 U. Microstructural observations using SEM indicated that Lcc5 promoted protein cross-linking within the gluten network. This cross-linking led to a smoother and tighter dough surface, with a significant decrease in the exposure of starch granules. These findings suggested that Lcc5 effectively improved the textural and structural qualities of rye bread by enhancing the degree of gluten network cross-linking and, consequently, gluten strength. Lcc5 served as a potent improver for rye bread and dough, offering a method to optimize the sensory and structural properties of rye-based products. This study provided a theoretical basis for the optimization of rye bread and dough processing.

Key words: fungal laccase, rye bread, enzymatic cross-linking, dough rheology, gluten network structure