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Aim of this work was to evaluate the impact of bread enrichment with different concentrations of lentil flour (LF) (0 g/100g, 10 g/100g and 20 g/100g) on some physico-chemical, structural, and nutritional features of bread. The addition of LF in formulation affected its properties, leading to a darker appearance and to a more compact structure (e.g., higher density and lower gas bubble area fraction). Besides, it led to a significant rise in the protein, free glucose, and rapidly digestible starch content as well as in the expected glycemic index. Concerning the investigation of nutritional properties, starch and protein digestibility has been evaluated by the combination of different digestion models. Each type of bread was subjected to an in vivo oral phase followed by a semi-dynamic in vitro gastrointestinal digestion. During the oral and the gastric phases of digestion, bread with the greatest LF content (20 g/100g) exhibited an extensive starch digestibility and a partial protein digestibility compared to the other samples, due to its higher protein content. In contrast, during the intestinal phase, control (0 g/100g) showed a stronger starch digestibility compared with the LF samples, while no differences could be observed in terms of protein digestibility investigated by SDS-PAGE., This work has received financial support from project PID2019-107663RB-I00 from the Spanish Ministry of Science and Innovation (MICINN).

The effects of three leavening times (60, 105 and 150 min) on structure and some physico-chemical and nutritional properties of bread added with 20 % of green lentil flour were investigated. Leavening time largely affected bread physico-chemical properties, leading to a significant reduction in moisture content, an increase in weight loss and a darker appearance of bread crumb as leavening time increased. Besides, crumb of bread leavened for the longest time (B150) showed a compact structure and the highest resistance to the compression, while the Young’s modulus increased linearly with the rising of leavening time. By contrast, breads leavened for shorter times (B60 and B105) had a more porous structure with more circular bubbles compared to B150, exhibiting lower deformation resistance. Different bread macrostructure had a significant impact on the in vitro protein and starch digestibility. The α amino nitrogen release and the estimated Glycemic Index (eGI) at the end of digestion reached the lowest values in bread leavened for the longest time (B150). In particular, eGI showed a linear correlation both with the Young’s modulus (R2 = −0.926) and macrostructural properties (R2 = 0.902), suggesting that modelling bread structure by acting on leavening time can be a novel approach to develop healthier products.