Enhancement of wheat bread quality using xylanase cellulase from gamma radiated Trichoderma afroharzianum mutant

This study explores the production and application of a xylanase-cellulase enzyme complex derived from a gamma radiation-induced mutant strain of Trichoderma afroharzianum NAS107-M82 to enhance wheat bread quality. The mutant strain exhibited significantly elevated extracellular enzyme activities, with xylanase and cellulase levels approximately 3.3 and 1.7 times higher than those of the wild type, respectively, indicating superior lignocellulosic substrate hydrolysis. The enzyme complex, optimized at 45 °C and pH 5.0 for xylanase and 50 °C and pH 4.8 for cellulase, contained key isoforms including Xyl I, Cel12A, and Xyl IV, which acted synergistically to degrade arabinoxylan and cellulose components in wheat flour. Rheological assessments via farinograph and extensograph demonstrated that supplementing dough with 300 to 600 U/kg of the enzyme complex reduced water absorption, and decreased dough development and stability times, while improving dough extensibility and mixing tolerance. These changes produced a softer, more manageable dough with enhanced fermentation performance. Bread made with enzyme treatment showed significantly improved specific volume, crumb porosity, and sensory properties such as crust color, texture, aroma, and taste compared to control and commercially improver-enriched breads. Notably, breads containing 300 U/kg enzyme exhibited enhanced softness and delayed staling over seven days, attributed to increased moisture retention and modified crumb structure. These results suggest that the gamma radiation-induced mutant strain is a promising source of industrially valuable xylanase-cellulase enzymes for bakery applications. Overall, targeted enzymatic treatment of wheat flour represents a viable strategy to improve bread quality, shelf life, and consumer acceptability.