Nutritional quality, potential health promoting properties and sensory perception of an improved gluten-free bread formulation containing inulin, rice protein and bioactive compounds extracted from coffee byproducts

The present study aimed to improve the formulation of a gluten-free commercial bread-making premix by adding inulin, rice protein and extracts of coffee by-products (silverskin and husk) to obtain healthier products enriched in protein and dietary fiber with the potential to reduce the risk of chronic diseases. The new formulation combines well-known and novel food ingredients. To validate the novel ingredients, we determined the physicochemical characterization, caffeine and chlorogenic acid contents, and food safety of coffee silverskin (CSE) and husk (CHE) extracts. Sensory and nutritional quality, bioactive compounds (chlorogenic acid, total phenolic compounds, melanoidins and browning), in vitro bioaccessibility, and health-promoting properties (overall antioxidant capacity and alpha-glucosidase activity) of the breads were evaluated as well.Results support the feasibility of CSE and CHE as natural sustainable sources of antioxidants, alpha-glucosidase inhibitors and colorants. The observed health-promoting properties suggest that coffee by-product extracts could potentially be used as functional food ingredients or supplements to reduce the risk of chronic diseases associated with oxidative stress and to control postprandial glucose levels. Based on consumers' preferences, we obtained new bread formulations with a high nutritional and sensorial quality, suitable for celiacs and with the potential to reduce the risk of gastrointestinal disease related to oxidative stress. Data on in vitro digestion indicated a significant (p<0.05) decrease in the bioaccessibility of sugars and a significant increase (p<0.05) in antioxidants.