# Manufacture of a Potential Antifungal Ingredient Using Lactic Acid Bacteria from Dry-Cured Sausages
## 3 Results and Discussion
### Chemical Characterization of the Postbiotic Antifungal Ingredient  
#### 3.3.1 Organic and Phenolic Acid Production  
The metabolites generated after fermentation of the antifungal strains selected were investigated in the BFS of the MRSb and MB10. As plotted in Figure 2, two organic acids, lactic acid and acetic acid, were identified in both formulations. For lactic acid, the mean values of this metabolite ranged from 2.49 to 3.00 g/L, whereas for acetic acid, the concentration detected was lower, with mean values ranging from 0.24 to 0.38 g/L. The highest amount of lactic acid was detected in the fermented MRSb (2.973 g/L) and MB10 (3.00 g/L) fermented by the _P. pentosacous_ C15 strain. There were no statistical differences in lactic acid production between these two formulations (\(p\leq 0.05\)). Regarding acetic acid, the higher concentration (\(p\leq 0.05\)) was also quantified in the fermented MB10 with _P. pentosacous_ C15 (0.38 g/L), followed by the MRSb of _P. pentosacous_ C15 (0.32 g/L) and the fermented MRSb with _L. plantarum_ C60 (0.31 g/L). Concerning the phenolic acids, a total of 12 different metabolites, described in the literature as antifungals, were identified and quantified through the UHPLC Q-TOF MS technique. Among them, it is noteworthy that the concentration of benzoic acid, DL-3-phenyllactic acid, syringe acid, and vanillic acid stood out regardless of the fermented broth and bacteria tested (Table 5). In general, it could be noted that MRSb produced higher concentrations of phenolic acids compared to its analog MB10. However, in most cases the difference was not significant (\(p\leq 0.05\)). In view of these results, we suggest further  
Figure 2: The concentration of organic acids produced by LAB in meat broth (MB10) and MRS broth (MRSb) after incubation for 48 h at 37 \({}^{\circ}\)C. The meat broth was prepared with 10% freeze-dried loin pork and fermented by _P. pentosacous_ C12, _P. pentosacous_ C15, and _L. plantarum_ C60. Different letters represent statistical differences in the same group of molecules between treatments (\(p\leq 0.05\)). studies to evaluate the synergistic effect of these four compounds in order to evaluate their antifungal activity and to increase the understanding about the mechanism of antimicrobial action of LAB. The selected microorganisms grew on the MB10 and produced a broad variety of metabolites previously described in the literature as antimicrobial compounds. The phenolic acid most produced by _P. pentosaceus_ C12 in MB10 was syringe acid, showing values of 19.47 ug/L: these values are significantly higher than bacteria C60. [PERSON] et al. (2018) demonstrated that syringe acid at 300 mg/L inhibited _A. flavus and A. parasitic_ growth and aflatoxin production. In addition, [PERSON] et al. (2018) demonstrated that lower doses of syringe acid (100 mg/L) avoided the growth of _A. niger_. Therefore, it seems that a higher concentration of phenolic acids is required to achieve an antifungal effect when they are applied in isolation. These findings reinforce the hypothesis that the LAB antifungal effect is obtained via a synergistic effect. Regarding _P. pentosaceus_ C15 and _L. plantarum_ C60, vanillic acid was the most produced phenolic acid, reaching values of 25.18 and 24.00 ug/L in MB10 and 30.83 and 27.60 ug/L in MRSb, respectively. An oxidized derivative of vanillin, vanillic acid, is a monohydrobenzoic acid composed of a 4-hydroxybenzoic acid with a methoxy group at position 3 ([PERSON], 2018). It has been noted for its antioxidant properties, but its antifungal activity is poorly reported, and more research is required. In contrast, its precursor, vanillin, has been the subject of extensive research, and its antifungal activity varies depending on the microorganism tested ([PERSON], 2018; [PERSON], 2018). These findings also suggest that the antifungal ingredient obtained from MB10 could be incorporated into meat food products to provide a significant source of phenolic and organic acids.