PRODUCTION OF BIOGENIC AMINES BY WINE MICRORGANISMS

ABSTRACT: In order to evaluate the role of different microorganisms potentially involved in the production of biogenic amines (BAs) in wine, studies were performed both during wine laboratory fermentations and during vinifications at industrial level. Fermentations were carried out in sterilized grape must by inoculating different yeast species (Saccharomyces cerevisiae, Kloeckera apiculata, Candida stellata, Metschnikowia pulcherrima and Brettanomyces bruxellensis) and BA concentrations were determined by HPLC analysis after the carbon dioxide evolution ceased. The highest concentration of total BAs was formed by B. bruxellensis, with an average value of 20 mgL -1 , followed by S. cerevisiae and M. pulcherrima with an average of about 13 mgL -1 ; the other yeast species formed less than 10 mgL -1 . Moreover, a qualitative method using a plate medium for a rapid detection of BA producer yeasts was applied to check 100 strains of S. cerevisiae. Similarly, several strains of Oenococcus oeni were characterized for their capability to produce biogenic amines both in synthetic media and in wine. Under optimal growth conditions more than 60% of the bacterial strains tested were able to produce histamine at concentrations ranging from 1 to 33 mgL -1 , and about 16% showed the additional capability to form putrescine and cadaverine to different extents. The behaviour of the different O. oeni was confirmed in ethanol-containing medium while they were performing malolactic fermentation. In wine, the formation of putrescine from arginine and ornithine by single O. oeni strain culture and by a metabiotic association between strains showing different metabolic capabilities was also demonstrated. Finally, to examine the potentially evolution of BA contents during the whole winemaking process, two vinifications at industrial level were studied by determining dynamics of different yeast populations as well of O. oeni during the alcoholic and malolactic fermentations. Independently of the vinification, the content of BAs reached significant values only after the occurrence of the malolactic fermentation. Hence, BA formation and accumulation in wine seems to be a phenomenon that can be reduced or avoided only by eliminating lactic acid bacteria suddendly after the completion of malolactic fermentation.