engleski

Dough Proofing Optimization by Application of Modified Gompertz Equation

INTRODUCTION The preparation of dough is important process that strongly influences the quality of baked breads. During proofing, gas bubbles incorporated into dough during mixing ; expand due to CO2 production by yeast. The proofing temperature influences the content of produced CO2 in certain time. The yeast type and its fermentation activity directly influences dough expansion rate. Among the other important ingredients, the yeast type effects the bread flavour and structure. For production of conventionally baked bread, baker’ s yeast (Saccharomyces cerevisiae) is the commonly used while the application of bottom fermenting yeast gives fruity and estery note. In production of frozen dough that is relatively stable and enables production of freshly baked bread at desired time, it is necessary to use freeze tolerant baker’ s yeast. The optimal fermentation conditions for reaching the maximum dough volume expansion ratio using three yeast types at six different proofing temperatures by application of modified Gompertz equation are determined. MATERIALS AND METHODS Dough was prepared from white wheat flour using three types of Saccharomyces cerevisiae strain: baker’ s yeast, bottom fermenting yeast and freeze- tolerant baker’ s yeast in amount of 0.92%, 2%, 3.5%, 5% and 6.08%. Proofing temperatures were 22.5°C, 25°C, 27.5°C, 30°C, 32.5°C and 35°C according to the experimental plan. Dough volume expansion rate was measured by linear displacement transducer and amount of CO2 produced and released was measured by rheofermentometer. By applications of the modified Gompertz model the optimal fermentation condition were determined. RESULTS AND DISCUSSION The significant influence of proofing temperature on specific volume growth rate was proven. The maximum relative expansion ratio was not influenced significantly by increased yeast content and proving temperature although the maximum volume in those conditions was reached in shorter time. The optimal yeast content for reaching the maximal dough volume was 2% of fresh baker’ s yeast, bottom fermenting yeast 6.08% and 3.5% of freeze tolerant yeast.

Dough fermentation ; Yeast ; Modified Gompertz equation ; Volume expansion ratio ; Linear Displacement Transducer.

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