Application of Cheese-Derived Exopolysaccharide-Producing Lactobacilli in Type II Sourdough to Delay Bread Staling

This study aimed to evaluate the technological, functional and nutritional effects of exopolysaccharide-producing lactic acid bacteria (LAB) strains, isolated from artisanal Tulum cheese as type II sourdough starters. The objective of this study was to improve bread quality, delay staling, and enhance bioactive properties, such as antioxidant capacity and estimated glycaemic index (eGI). Six LAB strains (Loigolactobacillus coryniformis, Lactiplantibacillus plantarum, Levilactobacillus brevis, Lacticaseibacillus paracasei, Lactobacillus helveticus, and Lacticaseibacillus rhamnosus) were individually used for sourdough fermentation. Bread samples were analyzed for pH, titratable acidity (TA), LAB counts, specific volume, colour, total phenolic content (TPC), antioxidant activity (DPPH and ABTS), starch digestibility, eGI, staling kinetics (Avrami model) and amylopectin retrogradation (DSC). Strain-dependent improvements in bread functionality were observed. L. brevis and L. coryniformis strains increased sourdough acidity to a greater extent, and resulting in lower pH values. Accordingly, bread produced with sourdough fermented by these strains exhibited higher specific volume than the control. Although higher ABTS radical scavenging activity and TPC were detected in sourdough bread compared to the control bread, no significant differences were observed among the breads in terms of total antioxidant activity measured by DPPH. L. rhamnosus significantly improved antioxidant activity and reduced the eGI. L. coryniformis, L. plantarum and L. brevis were the most effective at retarding staling, reducing the increase in hardness and limiting amylopectin retrogradation. This study is the first to demonstrate the functional potential of LAB strains from artisanal Tulum cheese as sourdough starters. These findings reveal the potential for developing clean-label bakery products with an extended shelf life and improved health-related functionality.