Effect of Low-Temperature Fermentation by Yeast and Lactic Acid Bacteria on the Quality of Wheat Bread

Low-temperature fermentation is gaining recognition for its ability to enhance the flavour and texture of bread, in line with consumer preferences for natural, high-quality products. The aim of this study was to evaluate the effects of low-temperature (15 °C) fermentation using fresh and lyophilised monoculture of yeast and yeast-LAB cocultures on wheat bread quality. A modified two-phase baking technique was used. Three types of breads were compared: those made from lyophilised sourdough/sponge, from fresh sourdough/sponge fermented with a lyophilised starter, and from fresh sourdough/sponge. Sucrose (1%, 5%, 10%), calcium carbonate (0.5%, 1%, 2%), and peptone (1%, 5%, 10%) were tested as cryoprotectants. Bread quality was assessed based on physicochemical analyses (specific volume, colour, texture profile), electronic nose (volatile compounds), electronic tongue (taste), and sensory evaluation. A combination of 5% sucrose and 0.5% calcium carbonate was found to be the most effective starter for preserving yeast and lactic acid bacteria (LAB) viability in the lyophilised starters (98% for LAB, 86% for yeast). Breads made from fresh sourdough/sponge exhibited higher loaf volumes compared to samples prepared from lyophilised starters. Rehydrated lyophilised starters led to breads with increased hardness, gumminess, and chewiness. Bread prepared from fresh sourdough fermented by a lyophilised mixed culture (S. cerevisiae D3 and L. brevis B46) demonstrated the highest ester content and received the highest scores in the sensory analysis for taste, aroma, and overall acceptability. The results of this study confirm that low-temperature fermentation with selected cold-adapted and appropriately cryopreserved microbial strains can produce high-quality wheat bread with enhanced sensory profiles. This method may therefore be considered for potential applications in the baking industry.