Gluten‐Free Bread Prepared with Fresh and Freeze‐Dried Rice Sourdough‐Texture and Sensory Evaluation

Abstract

AbstractNew possibilities for using freeze‐dried rice sourdoughs in the processing of gluten‐free bread (GFB) are demonstrated in this study. Fresh and freeze‐dried (at temperatures of 20 and 40C) rice sourdoughs were added in the amounts of 10, 20, 30 and 40% of the total flour content. Significant and beneficial changes in the texture (elasticity and cohesiveness) of bread under the influence of different quantities of fresh and freeze‐dried sourdough addition were observed. In most cases, there were no significant differences between the firmness and cohesiveness of bread made with fresh or freeze‐dried sourdough. A lower degree of crumb staling was obtained for bread produced with a 10% addition of fresh sourdough and sourdough freeze‐dried at 40C. The best overall sensory assessment was achieved by bread with 10 and 20% rice sourdough. At these levels of sourdough addition, there were no significant changes in the assessment of bread made with either fresh or lyophilized sourdough. Sensory evaluation of texture was positively correlated with other physical properties: pore area, firmness, elasticity and cohesiveness of crumb (r = 0.869; 0.836; 0.596; 0.848, respectively) and negatively correlated with bread pH values (r= −0.801).Practical ApplicationThe results have important significance, as the use of freeze‐dried rice sourdough may improve the process of the production of natural GFB. Freeze‐dried rice sourdoughs used directly in processing eliminate the requirement for a long period of fermentation of the sourdough. Freeze‐dried rice sourdough, in an amount of 10 or 20%, may be a good substitute for fresh sourdough. An increase in heating plate temperature from 20 to 40C caused a decrease in drying time of about 25%; therefore, to produce this sourdough, a freeze‐drying temperature of 40C is suggested. The bread is distinguished by a favorable qualitative assessment. Also, the reduced pH value has a beneficial influence on extending bread durability and freeze‐dried rice sourdough can be used as a natural preservative.