Optimization and quality attributes of novel toast breads developed based on the antistaling watermelon rind powder

Abstract

In the current research, production of watermelon rind (WMR) powder was studied as a promising additive to improve the quality characteristics of toast breads. The main formulation (WMR (4.6–11.4%)), and bread-baking process (temperature (166–233 °C) and time (17–33 min)) parameters using response surface methodology (RSM) were optimized to retard the acceleration of staling rate in toast breads. The second-order polynomial regression equations (R2 > 0.939) were adequately fitted for all response variables. The highest moisture (22%), volume (1431 cm3), and organoleptic acceptability (8.10) values and the lowest firmness (10.50 N) and total color difference (9.80) values were achieved under the following conditions: WMR concentration of 9.06%, baking temperature of 206.66 °C and baking time of 20 min. The analysis of dough farinographic and extensographic characteristics showed a significant more water absorption (72.5%), development (6.7 min) and stability (7.8 min) time, and extensibility (143 mm) values for the optimal sample compared to the control. Scanning electron microscopy demonstrated that the thicker cell wall induced by WMR in the optimal bread (183.54 μm) than the control (78.39 μm) was able to maintain air bobbles during the storage time. A negligible staling rate was also found for the optimal breads with the lowest moisture, textural, color and sensory changes.