Determination of the effect of sourdough prepared with the use of various lactic acid bacteria on mold growth in bread

This study deals with the optimization of various conditions and preparation of liquid sourdoughs with high antifungal activity using three different bacterial strains (Lactiplantibacillus pentosus SC-9, Lactocaseibacillus rhamnosus E-106 and Lactobacillus paraplantarum N-15) having antifungal activity for liquid sourdough production. Sourdoughs were prepared separately with wheat, rye, einkorn and oat flours and optimization studies were carried out with control groups at 30°C and 37°C. Total viable count, lactic acid bacteria count, total yeast and mold counts, pH, titratable acidity, metabolite determinations by HPLC, GS-MS and LS-MS/MS methods and antifungal activity tests were carried out on Penicillium expansum, Fusarium oxysporum and Aspergillus niger molds. The results showed that liquid sourdough prepared with. E-106 had good antifungal activity against Fusarium oxysporum mold with a zone diameter of 32,58 mm at 30°C for 48 hours. Again, in sourdoughs containing E-106, lactic acid was detected by HPLC, richer volatile metabolites than normal bread by GS-MS and the presence of phenyllactic acid in sourdoughs K3 and K4 according to the LS-MS/MS results. In addition, in silico modeling studies were carried out using the Molecular docking method and it was found that lactic acid bacteria; The binding energies of important metabolites such as phenyllactic acid, lactic acid, acetic acid, malic acid, reuterin, hydrogen peroxide and natamycin, which was selected as the control group, to fungal hyphae growth proteins were calculated and it was found that phenyllactic acid had higher antifungal activity than other metabolites with -6.3 kcal/mol. Within the scope of this thesis, functional liquid sourdough with antifungal activity was produced for the first time and strain and condition optimizations were carried out in terms of antifungal metabolite production.