Chemical profiling of domestic grape peel and its potential in bread quality improvement

Background: The development of functional foods begins with selecting raw materials rich in bioactive compounds. Incorporating grape peel by-products into wheat manufacturing offers a sustainable strategy to enhance the product's nutritional value. Objectives: This research aimed to review the health properties of grape peel-enriched bread and its functional food potential through vitamin and mineral evaluation. Furthermore, the study optimized grape skin drying conditions to preserve its chemical composition. Methods: Grape pomace powder was produced by drying grape skins at 23°C for seven days, with regular mixing. Dried skins were then ground and sieved (420µm). Bread was produced using a one-phase method, with grape skins added at 10%, 15%, and 20% of the flour mass. Results: Sensory and physicochemical analyses indicated that incorporating 15% grape peel produced the optimal bread quality. Despite its thermal instability, preserving vitamin C in baked products significantly contributes to functional food science. Novelty of the Study: This study introduces an innovative approach to enhancing bread production's nutritional value and sustainability by incorporating grape peel by-products. Furthermore, optimal drying conditions (23°C for 7 days) that preserve bioactive compounds in Areni Clone 2 grape skins have not been established before this study. Grape peel by-products have also demonstrated their potential as a functional food ingredient, rich in dietary fibers, vitamins, and minerals. Notably, maintaining vitamin C in baked goods highlights a unique contribution to functional food science that grape peel by-products could offer. Conclusion: This study demonstrates that waste products from the wine industry are valuable functional food ingredients. Areni Clone 2 grape skins were rich in dietary fibers, vitamins (B1, B2, PP, C), and minerals (calcium, sodium). Overall, 15% grape peel incorporation was optimal for bread quality. Keywords: Grape peel, functional foods, bioactive compounds, by-product, bread