Prunus mahaleb, L. fermented fruits: a potential source of antioxidant activity and probiotic microrganisms

PRUNUS MAHALEB, L. FERMENTED FRUITS: A POTENTIAL SOURCE OF ANTIOXIDANT ACTIVITY AND PROBIOTIC MICRORGANISMS Gerardi Carmela1, Tristezza Mariana1, Giordano Luca1, Maiorano Gabriele1, Blando Federica1, de Candia Silvia2, Grieco Francesco1 1 Institute of Sciences of Food Production, CNR, Territorial Unit of Lecce, Italy 2 Institute of Sciences of Food Production, CNR, Territorial Unit of Bari, Italy Fermentation is a process traditionally adopted to preserve food which results in novel fermented products, provided with specific organoleptic properties. Prunus mahaleb L. is an autochthonous tree of the Mediterranean area. Its highly pigmented small-stone fruits are characterized for astringent and sour taste and therefore not used for fresh consumption. Recently, Prunus mahaleb L. fruits were found endowed with high bioactive compound content, especially anthocyanins, and strong antioxidant capacity [1]. With the aim to reduce their sourness, P. mahaleb fruits were dipped in water and fermented for 20 days at 25°C with four starter cultures of Lactobacillus plantarum strains alone or in mixture with a single strain of Saccharomyces cerevisiae. During this period, viable cell count of L. plantarum strains was never found lower than 107CFU/ml that is the lower concentration request to probiotic microorganisms to promote beneficial effects on human health. S. cerevisiae in all trials reached a maximum population three days after inoculation and then, cells counts slightly decreased in a range from 107 to 103 CFU/mL depending on the co-inoculated bacteria strain. Among L. plantarum strains, only the FG68 survived after an in vitro digestion protocol specifically set up for the selection of potentially probioitic lactic acid bacteria [2]. As concerns the antioxidant activity, the fermentation medium always showed higher values when L. plantarum strains were co-coltured with S. cerevisiae. Conversely, no differences were found in fermented fruits even though their antioxidant capacity values were higher than the large part of fruits included in the human diet. References 1.Gerardi C, Tommasi N, Albano C, Blando F, Rescio L, Pinthus E, Mita G (2015) Prunus mahaleb L., fruit extracts: a novel source from natural food pigments. European Food Research & Technology 241: 683-695. 2.Baruzzi F, Poltronieri P, Quero GM, Morea M. (2011) An in vitro protocol for direct isolation of potential probiotic lactobacilli from raw bovine milk and traditional fermented milks. Applied Microbiology and Biotechnology 90: 331-342.