Protective agents to preserve lactic acid bacteria cell viability in type III sourdough dried by spray- and freeze-drying, and the influence on bread production

Sourdough is a traditional baking method. Type II sourdough is made by inoculating lactic acid bacteria (LAB) into a flour-water mixture, which can be dehydrated (type III) for better storage. This study evaluated the impact of gum Arabic and maltodextrin on LAB viability and fermentative capacity in type III sourdough, as well as their effects on bread quality. Freeze-drying preserved LAB viability better than spray-drying, with reductions of 1.1 and 2.3 log CFU.g- 1, respectively, in unprotected samples. Gum Arabic was the most effective protector in both methods, maintaining 7.9 log CFU.g(-)(1) viability after 30 days when combined with freeze-drying. Scanning Electron Microscopy analysis showed that gum Arabic coated the particles, preventing direct exposure during drying and reducing oxygen contact. Fermentation tests showed TTA values of 16.2 and 14.8 mL NaOH 0.1 N after 20 h for freeze-dried and spray-dried samples, respectively. Sensory evaluation confirmed positive acceptance of type III sourdough in bread. This study emphasizes the importance of drying methods that maintain LAB viability while meeting industry standards.