Changes in the free amino acids and the biogenic amine contents during lactic acid fermentation of different lupin species

The aim of the work was to evaluate the profile of free amino acids (FAA) as the possible precursors of biogenic amines (BAs) in different varieties and hybrid lines of Lupinus luteus and Lupinus angustifolius and its changes during fermentation. Lupins have high amounts of FAA, and therefore, significant contents of BAs by the action of bacterial amino acid decarboxylases can be formed. In view of this, the effect of three Pediococcus pentosaceus strains KTU05-8, KTU05-9 and KTU05-10 on BA formation during lupin fermentation was studied. The formation of BAs was monitored during 48-h fermentation at solid-state conditions and compared with that in samples after submerged fermentation and in the control nonfermented samples. The lupin variety, fermentation conditions and the Pediococcus strain were found to have the significant effect on the FAA profile and BA contents in fermented lupin; the interaction between analysed factors was F(5.989)=1755.321 (P<0.0001) and F(5.660)=130.736 (P<0.0001), respectively. A weak correlation was found between amino acid His and histamine (r=0.3709; P=0.0005) and between Phe and phenylethylamine (r=0.3914, P=0.0002) in lupin samples, but the significant correlations between amino acid Tyr and tyramine and between Lys and cadaverine were not found. By optimising the fermentation technology, it is possible to increase the nutritional value and functionality of lupin.