Development of a technology for functional wheat bread enriched with licorice root extract

<jats:p>Background: The increasing prevalence of obesity, diabetes mellitus, and other diet-related chronic diseases has intensified the demand for functional bakery products formulated with natural bioactive ingredients. Licorice (Glycyrrhiza glabra L.) root is a valuable source of glycyrrhizin, flavonoids, phenolic compounds, and other phytochemicals possessing antioxidant, anti-inflammatory, and natural sweetening properties, making it a promising ingredient for the development of functional foods.   Objective: This study aimed to develop and optimize a functional wheat bread formulation containing licorice root extract (LRE) by selecting an appropriate nominal sucrose-equivalent addition level and evaluating its effects on gluten properties and bread quality. The study further compared straight-dough and sponge preparation methods to identify the most technologically suitable formulation.   Materials and Methods: Bread samples were prepared from premium wheat flour by incorporating licorice root extract (LRE) at nominal sucrose-equivalent levels of 2%, 4%, and 6% based on the experimental formulation scheme and published information on the sweetening properties of glycyrrhizin. Because the glycyrrhizin/glycyrrhizic acid content of the prepared extract was not analytically quantified, these levels represent formulation-based nominal designations rather than analytically verified sweetness equivalents. The influence of LRE on wet gluten content, gluten extensibility, gluten deformation index, moisture content, titratable acidity, porosity, specific volume, and shape stability was evaluated using standardized analytical methods. Three independent experimental trials were performed for each formulation, and each analytical determination was carried out in quadruplicate. Data were expressed as mean ± standard deviation (SD), and differences among formulations were evaluated using one-way analysis of variance (ANOVA).   Results: The incorporation of licorice root extract slightly reduced the wet gluten content while improving gluten strength and resistance to deformation. Increasing extract concentrations resulted in a gradual increase in bread acidity and a moderate reduction in porosity and specific volume compared with the control. Among the tested formulations, the nominal 4% sucrose-equivalent LRE level provided the most favorable balance between dough performance and bread quality. Bread produced by the straight-dough method exhibited superior technological characteristics compared with bread prepared using the sponge method. The integrated optimization of LRE concentration and dough preparation method identified the nominal 4% sucrose-equivalent LRE level combined with the straight-dough method as the most suitable technological approach among the tested variants. Conclusion: Licorice root extract can be incorporated into wheat bread as a natural sweetener and functional ingredient without markedly compromising its technological quality. Among the tested formulations, the nominal 4% sucrose-equivalent LRE level provided the most favorable balance of physicochemical and technological characteristics, particularly when combined with the straight-dough method. The practical significance of this study lies in defining a technologically applicable LRE level and dough preparation method that can serve as a basis for the development of reduced-sugar functional wheat bread. Further studies are required to evaluate the nutritional composition, bioactive compounds, sensory acceptance, and potential health-related effects of the developed product. Novelty of the Study: The scientific contribution of this study lies in establishing an integrated technological approach for the preliminary development of a reduced-sugar bakery product incorporating licorice root extract (LRE) as a natural sweetener and potential source of bioactive compounds. Unlike studies that evaluate plant-derived ingredients primarily as nutritional or bioactive enrichments, the present work combines the formulation of nominal sucrose-equivalent LRE levels with a systematic assessment of its effects on the technological and physicochemical characteristics of wheat-based bakery products. Among the tested formulations, bread containing the nominal 4% sucrose-equivalent LRE level and produced using the straight-dough method demonstrated the most favorable overall combination of the evaluated quality characteristics. Thus, the study establishes a formulation- and process-related technological basis for further functional food development rather than claiming full functional-food validation. In accordance with the staged approach to functional food development, further research is required to quantify the relevant bioactive constituents of LRE, establish their effective doses, elucidate potential mechanisms of action, and verify the product's biological efficacy, safety, and health effects through appropriate preclinical and clinical studies. Keywords: Functional bread; Glycyrrhiza glabra; licorice root extract; wheat flour; gluten; bakery technology; functional foods.</jats:p>