Relation between free amino acids and the biogenic amines contents in green tomatoes inoculated with Lactobacillus plantarum

The aim of the work presented here was the evaluation of the profile of free amino acids as the possible precursors of biogenic amines (BAs) in tomatoes and its changes during tomato ripening. Hygienically significant amounts of BAs can be formed by the action of amino acid decarboxylases provided the tomatoes contain a high enough amount of free amino acids. In view of this, the effect was studied of Lactobacillus plantarum strains 976H and 3626 on the BAs formation in green tomatoes. Homogenates of green tomatoes were adjusted to the model conditions of conservation by the addition of NaCl to the concentration of 1.5% (w/w) and of glucose to the concentration of 2.0% (w/w). The homogenates were subsequently inoculated with the two strains given above. The formation of BAs was monitored for 186 h and compared with that in the control non-inoculated samples. The changes in the BAs content taking place during fermentation were estimated by means of statistical methods. It was found that, during fermentation of green tomatoes with the two strains of Lactobacillus plantarum used, the conditions were not fulfilled that enable BAs formation, i.e. as sufficient amount of free amino acids together with a sufficient production of decarboxylases.