Impact of Lactic Acid Bacteria on the Quality of Yeast-Fermented Multigrain Bread

Objective: To explore the impact of lactic acid bacteria on the quality of yeast-fermented multigrain bread. Methods: It was detected the changes of pH value, fermentation volume and rheological properties of multigrain dough fermented with lactic acid bacterias in different proportions (0, 0.03%, 0.06%, 0.09%, 0.12%). Changes of the hardness, stickiness and chewiness of multigrain bread, as well as specific volume, sensory quality and flavors were analyzed. Results: The pH value of the fermented multigrain dough fermented with lactic acid bacteria was reduced. The dough volume fermented with 0.03%~0.12% lactic acid bacteria, increasing from 50.00% to 88.12%, which was higher than yeast fermentation (increasing 48.51%). The storage modulus (G') and loss modulus (G") of dough decreased with lactic acid bacteria powder. The values of G' and G" decreased by 33.33% and 30.00% respectively, with 0.06% lactic acid bacteria powder. The textural properties including hardness, stickiness and chewiness of the multigrain bread fermented with 0.06% lactic acid bacteria were reduced, while elasticity improved significantly(P<0.05). The specific volume of the multigrain bread increasing 24.88% fermented with 0.06% lactic acid bacteria, was higher than yeast fermentation. The sensory quality of the multigrain bread was improved significantly(P<0.05) with 0.06% lactic acid bacteria, including shape, texture, structure, flavor and mouthfeel, and the sensory score was over 80. It was detected 65 different substances from the multigrain bread fermented with yeast and 0.06% lactic acid bacteria, more than the yeast-fermented wheat bread of 43 substances, and much stronger flavor than yeast-fermented multigrain bread. Conclusion: There was a positive effect on the quality of yeast-fermented multigrain bread with lactic acid bacteria.