Enhancing Bread Quality and Shelf Life via Glucose Oxidase Immobilized on Zinc Oxide Nanoparticles—A Sustainable Approach towards Food Safety

The foremost wastage of bakery products which mainly disturbs the food supply chain, especially in remote areas, is fungal growth. Good quality bread, especially with good height and volume, is the demand of every customer. Here, we aimed to develop a unique antimicrobial approach for the enhancement of the quality aspects and longevity of bread, using the synthesis of hydrogen peroxide in bread, the glucose oxidase (GOx) bioactivity, and oxidation of thiol protein bonds, which greatly enhance dough rheology, volume, and height by providing structural stability to the bread. An Aspergillus niger -purified enzyme was immobilized on zinc oxide nanoparticles (ZnONPs) and afterwards immersed in a buffered solution to create a mixture of GOx/ZnONPs. Analyses conducted after localization revealed that the immobilized enzyme was more active than the mobilized enzyme. GOx/ZnONPs were employed in the mixing process of bread production. The treated and control groups were evaluated for dough rheology and quality metrics including bread height and volume and storage at ambient temperature and conditions to determine shelf life by demonstrating fungal growth. In addition, antimicrobial activity was evaluated by measuring the microbiological load in terms of colony-forming units. Contrary to the control, the use of GOx/ZnONPs significantly improved bread quality, particularly bread height by 34.4%, crumb color, and volume by 30%. The shelf life of bread treated with GOx/ZnONPs was greatly extended, and the microbiological load, including yeast and mold, and total bacterial count were much lower in the GOx/ZnONPs treatment group than in the control group.