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Obtaining high-quality value-added bread with extended shelf-life by utilizing food industry by-products that would have minimal negative effect on gluten structure while avoiding the usage of synthetic preservatives, was the challenge of this study. For this purpose the influence of the combination of carob pod flour (C, 0–15%), sugar beet fibers (F, 0–10%) and sugar beet molasses (M, 0–6%) on dough rheology and bread quality was investigated. Selected materials were of good microbiological quality, while carob flour and sugar beet fibers were rich in dietary fibers (43.6% and 67.0%, respectively). The presence of high share of dietary fibers (combination of C and F) increased dough resistance to extension up to 2.5 times, while dough extensibility was reduced by 50%. The addition of molasses had less pronounced single effect on dough properties however its impact in combination with fiber-rich materials outweighed the individual effect (an increase of dough resistance at about 55%). Molasses alone and in combination with other ingredients had positive effect on bread quality. Sample M(6)F(5) attained crumb quality score (6.0 of maximum 7.0) higher than in control sample (5.6). High share of C and F reduced loaf volume and crumb quality of bread up to 56% and 50%, respectively and increased hardness 7.5 times. However, carob flour (7.5%) increased polyphenols content and antioxidant capacity 3 and 4 times, respectively. Moreover, carob flour and molasses and their combination showed inhibitory effect on mold mycelia growth and spores formation. Regarding all of the above, C(7.5)M(3)F(5) was chosen as optimal sample.

© 2020, Springer Science+Business Media, LLC, part of Springer Nature. The rheological behavior of dough supplemented with sugar beet fibers (SBF) and carob (pod) flour (CF), as fiber-rich by-products of the agricultural industry, was investigated using the standard Brabender extensograph and the Kieffer micro method. The addition of CF (0–20%) and SBF (0–6%) to the wheat dough formulation increased resistance to extension to about 75% and 55% respectively, while the combined effect of CF and SBF addition increased the dough resistance by up to 100%. The extensibility of the dough decreased in almost identical ranges (up to 40%), while the combined effect of CF and SBF addition had a stronger influence on the decrease in dough extensibility (75%). The evaluation of the correlation between the extensographic and the Kieffer micro method showed a high compatibility with regard to the results of the dough extensibility (r = 0.89, p < 0.05), but did not confirm the agreement of the results obtained in the resistance measurements (r = 0.13, p < 0.05). Considering that the absolute correlation between the two rheological methods used was not confirmed in this study, it is clear that the precise and complete definition of rheological properties requires the use of other methods, not only empirical but also fundamental.

The effect of functional additives (carob flour and sugar beet fiber) on empirical rheological dough performance and bread quality was examined. Also the microbiological quality of bread was investigated during 16 days of storage. The study included 5 samples: control (CON), with preservative calcium propionate (CONP), with carob flour (CON-CAR), with sugar beet fiber (CON-SBF) and with a combination of carob flour and sugar beet fibers (CON-SBF-CAR). Samples with functional additives had a higher water holding capacity (2-10%) and extended dough development time due to the presence of dietary fiber. Dough resistance of these samples was significantly increased, especially in CON-CAR, in which the time of final fermentation is remarkably prolonged (20% in comparison to CON). The addition of the functional ingredients (due to hydration properties of dietary fiber) improved texture and sensory characteristics of bread. In sample CON-SBF crumb firmness was significantly reduced (by 70%) while elasticity was increased by 25% compared to CON. Positive effect of addition of sugar beet fiber was proved by improving the elasticity of the crumb and finer crumb structure (sample CON-SBF) in comparison with the addition of carob flour (sample CON-CAR). In bread sample with carob flour there was no microbiological contamination for 16 days of examination, which confirms the fact that carob flour can be used as a natural preservative.