This study examines the influence of lactic acid fermentation on iridoid and polyphenolic compounds in unripe Cornus mas L. fruits. Fermentation was carried out at room temperature over 6 weeks. Eight versions of the fermentation process were conducted: with inoculation by microflora isolated from black olives, Lb. brevis 18 M, Lb. casei 0919, Lb. paracasei 920, Lb. rhamnosus 0900, Lb. rhamnosus 0908, and spontaneous fermentation with and without summer savory (Satureja hortensis). The polyphenolic compounds, iridoids and antioxidant activities were examined in the products obtained. After fermentation, the polyphenols detected were: gallic acid and one of its derivatives, protocatechuic and ellagic acids, neochlorogenic and chlorogenic acids, and a chlorogenic acid derivative. Loganic acid and cornuside were found to be present in both the fermented fruits and the brines. The tested microorganisms produced varying amounts of lactic acid and had varying degrees of impact on the content of biologically active compounds. Lb. rhamnosus 908 proved to be the most effective strain. Unripe cornelian cherries fermented with probiotic strains could be used as an innovative pro-health product.
Keywords: Cornus mas L.; Iridoids; Lactic acid bacteria; Polyphenols.