EVALUATION OF THE BEHAVIOUR OF BAKER’S YEAST IN FROZEN DOUGH UNDER VARYING FREEZING-THAWING AND STORAGE PARAMETERS

Abstract

This study systematically evaluates the influence of freezing–thawing regimes and storage duration on the fermentative performance of baker’s yeast and the quality attributes of bakery products obtained from frozen dough. Dough samples were subjected to rapid freezing to thermal centre temperatures of −5 °C, −10 °C, and −15 °C, followed by storage at −18 °C for up to 56 days and subsequent application of controlled thawing protocols. Yeast activity was quantified based on CO₂ production after 60 and 120 minutes of fermentation, while product quality was assessed through specific volume, textural parameters, and sensory evaluation using a 9-point hedonic scale. The results demonstrate that decreasing the final freezing temperature significantly enhances yeast viability and preserves functional performance during storage. Samples frozen to −15 °C consistently exhibited superior fermentative capacity, improved structural characteristics, and higher sensory acceptability. A progressive decline in yeast activity and product quality was observed with increasing storage time, reaching reductions of approximately 30% after 56 days. Statistical analysis revealed strong positive correlations (r = 0.927–0.990) between fermentative activity and overall acceptability, confirming the central role of yeast metabolic performance in determining final product quality. These findings provide robust evidence that the optimization of freezing and thawing parameters represents a critical factor in maintaining the technological functionality of yeast and ensuring the quality stability of frozen dough-based bakery products.