NOVEL APPLICATION OF FREEZE-DRIED AMARANTH SOURDOUGH IN GLUTEN-FREE BREAD PRODUCTION

The purpose of this study was to describe the freeze-drying of amaranth sourdough. Also, changes in the physical properties of bread caused by the addition of fresh or freeze-dried amaranth sourdough were determined. Control gluten-free bread was prepared from corn, rice and amaranth flour in two variants (45:45:10% and 40:40:20%). Amaranth flour was substituted with fresh or freeze-dried sourdough. Two freeze-drying temperatures (20 and 40C) were used for sourdough freeze-drying. Consequently, the Page model was found to be the most appropriate to describe the drying of sourdough. Significant and beneficial changes in the physical properties of bread under the effect of both fresh and freeze-dried sourdough were noted. Sensory evaluation of bread showed that bread with 20% amaranth sourdough is characterized by an unfavorable taste and smell; however, gluten-free bread with 10% amaranth sourdough was accepted by consumers. Practical ApplicationThe obtained results have important meaning, as the use of freeze-dried amaranth sourdough may improve the process of the production of natural gluten-free bread by significantly shortening the production time required for this bread on the day of baking. The freeze-dried amaranth sourdough in an amount of 10% may be a good substitute for fresh sourdough. To produce this sourdough, a freeze-drying temperature of 40C is suggested. An increase of heating plate temperature from 20 to 40C caused a decrease of drying time of 26%. The bread is distinguished by a favorable qualitative assessment. Also, the reduced value of pH has a beneficial influence on extending bread durability.