# Bread Biopreservation through the Addition of Lactic Acid Bacteria in Sourdough
## 3 Results and Discussion
### Biopreservation of Breads  
The shelf life results in the loaves showed a similar trend against the three fungi inoculated. In all of them, sourdough bread with propionate prevented the fungus's visible growth during all the study days. In addition, loaves of sourdough bread had a longer shelf life than control breads, especially the treatment SB\({}_{2}\) (Table 5). Figure 4: Result of the band pattern of the protein compounds in gel (SDS-PAGE) by electrophoresis. (**a**): doughs at T0; (**b**): fermented doughs; (**c**): baked breads. St: standard; BC: bread control; SBC: sourdough bread control; SBC\({}_{\text{P}}\): sourdough bread control with propionate; SB\({}_{\text{B}}\): sourdough bread with _L. plantarum_ 5L1 inoculum (0.5%); SB\({}_{2}\): sourdough bread with _L. plantarum_ 5L1 inoculum (5%). The loaves of bread inoculated by _A. flavus_ had the shortest shelf life because, in the control bread, the visible growth of the fungus began on day 2, and on the third day, all the spots had grown. In SBC and in SB1, the fungal growth began to be visible on the third day, so the shelf life was prolonged compared to the control. In addition, the total growth of the spots occurred on the seventh day. In SB2, the visible growth of the fungus began on the fifth day; however, it did not grow in all the spots on the seventh day. In this case, the study of the shelf life in an observational way ended on the seventh day because of the higher infective characteristic of this fungus. In the case of loaves inoculated by _P. verrucosum_, the growth of the control began on the fourth day and was complete in all spots on the seventh. On the other hand, the growth of SB1 began on the fifth day and completed 100% of the spots on the seventh day. In contrast, in SBC, visible growth began on the seventh day, and when the study was stopped on the tenth day, it had only grown in 56% of the inoculated spots. The bread with the better results against the growth of this fungus, apart from the propionate treatment (SBCp), was also SB2. This sourdough delayed the fungal growth for eight days, and at the end of the experiment, only 19% of the spots showed contamination. The shelf life was also studied for ten days in the loaves of bread inoculated by _P. commune_. In this case, the fungus in the control group began to grow on the fourth day, similar to the conventional sourdough bread (SBC) and the addition of 1 g of LAB (SB1). Despite this, there was a notable difference in the speed of growth. In the control group, the growth of the spots was complete on the fourth day, while in the SBC and SB1, it took five days. The S2 treatment evidenced fungal growth after the sixth day; the percentage of grown spots increased by 31% on the tenth day. In studies such as [PERSON] et al. [PERSON] et al. (2016), the antifungal capacity of different LABs against the growth of _A. parasitic_ in sliced breads was evaluated. In this case, no lyophilized LAB was added to the meal preparation, but a cell-free supernatant (CFS) of BAL-fermented media was added. Furthermore, they were added directly into the bread dough and not onto the sourdough. Thus, an increase in the shelf life was observed in breads treated with _L. plantarum_ and _L. johnsoni_. In similar studies such as [PERSON] et al. [PERSON] et al. (2016), different sourdoughs inoculated by _L. plantarum_ and _L. bulgarcus_ were fermented to be subsequently lyophilized and used as a powdered ingredient in the preparation of breads. These were inoculated by _P. expansum_, and it was possible to observe an increase in the shelf life of both types of bread with respect to the control. Sourdough with _L.