Effect of the Leavening Agent on the Compositional and Sensorial Characteristics of Bread Fortified with Flaxseed Cake

Featured Application Different fortified bread formulations were developed combining the use of flaxseed cake as an extra ingredient and different leavening agents (sourdough versus baker's yeast). By the analysis of physicochemical, nutritional, and sensorial data, the best recipe in terms of percentage of flaxseed cake as a function of the leavening agent utilized was defined. This research approach allowed achieving the desired quality level of the flaxseed cake fortified bread regardless of the leavening agent utilized. Therefore, the innovative approach proposed could represent a tool for the bakery industry to select the breadmaking process that better fits with their production needs. Health and well-being improvement is currently driving innovation in bread, using a wide variety of value-added compounds as extra ingredients, including food industry by-products in a circular economy concept. In this context, this research aimed at evaluating the effect of the fortification of bread with different percentages of flaxseed cake, comparing two leavening agents: sourdough and baker's yeast. Sensorial, physicochemical, and nutritional properties, including pH, the main fermentative metabolites, fatty acids, total phenols, antioxidant capacity, and volatile organic compounds were determined for fortified bread. The results showed a significant improvement of nutraceutical profile of the bread fortified with flaxseed cake in a dose-dependent manner. Regardless of the leavening agent, the fortification determined a decrease of n-6:n-3 ratio, reaching the recommended value (<3) already at the 7.5% level. Furthermore, under the same fortification level, sourdough breads showed a higher level of total phenols and antiradical activity than baker's yeast breads. Sensory profiles were instead deeply influenced by both the fortification percentage and the leavening agents. In conclusion, considering both nutritional and sensory results, the best formulation as a function of leavening agent utilized was defined as 5% and 7.5% when sourdough and baker's yeast were used, respectively.