COMPARATIVE SCRENNENING OF BIOGENIC AMINES PRODUCTION BY LACTIC ACID BACTERIA OF INTEREST ISOLATED FROM FRUIT JUICES

SAVINO MARIA JULIETA ; PEREZ MARIA BELEN; MATURANO CARMEN; SAGUIR, FABIANA MAR¨ªA

Mar del Plata

Congreso; SAMIGE VIII CONGRESO DE MICROGIOLOBIA GENERAL; 2012

Sociedad Argentina de Microbiologia General

 Amine biogenic (BA) are nitrogen basic compounds mainly formed by decarboxilation of precursor amino acid through microbial enzymes in foods. Their presence can affect the sanitary quality of final product.  In fruits and derived products, studies on BA formation by lactic acid bacteria (LAB) are still relatively scarce. In this work we investigated comparatively the potential to produce the BA histamine, tyramine, agmatine, cadaverine or putrescine in LAB isolated from grape (GJ), apple (AJ) and orange (OJ) juices after selecting by their ability to produce the aroma compounds diacetyl, acetoin and 2,3 butilenglicol (GJ), to utilize arginine via arginine dihydrolase pathway (ADI) (AJ) and to inhibit the pathogenic microorganism growth (OJ). Aroma compounds and  ammonia and citrulline production was measured spectrophotometrically at the end of exponential growth in MRS medium plus L-malic acid (0.25 %) and minimum medium containing arginine (0.1%), both at pH 4.5, respectively. Antibacterial activity (OJ) was explored in an agar spot test utilizing Escherichia coli ATTC35218 as indicator. BA production was evaluated in decarboxylase agar medium containing pyridoxal-phosphate (0.005%) as cofactor, bromocresol purple (0.006%) as pH indicator and the precursor amino acid (1%), pH 4.5. A positive result was indicated by a change of the medium colour in response of the indicator to a pH shift, except for tyrosine (precipitate disappearance around the colony). Production of the aroma compounds by Oenococcus oeni strains (8, GJ) varied from 0.44 to 12 mg/l. Four strains forming lower concentrations than 5 mg/l were selected for BA screening since low diacetyl appears to be important to determine wine style. Six from a total of 11 tested strains (AJ) belonging to Lactobacillus plantarum and Lactobacillus brevis species were tested for BA production by utilizing arginine via ADI pathway. Analysis of citrulline production indicated that it was maxima in  Lact.brevis M15 (0.07 mM). Three strains of Lact. plantarum (2) and Lact. brevis of eight analyzed resulted positive for antibacterial activity (inhibition halo ¡Ý 5 mm), so they were screened for BA. None of the selected strains showed potential to produce histamine, tyramine or cadaverine, even when the decarboxylase medium efficiently supported their growth. In presence of agmatine Lact. brevis M15 (AJ) and JNB23 (OJ), gave positive results indicating that it was decarboxylated to putrescine. In addition they and other two apples strains gave a weak positive reaction in presence of ornithine. In conclusion, the majority of tested strains did not show potential to synthesize BA, indicating that this property might not be mainly relevant for growth in their acid natural environmental, despite encouraging an protection against acid. This fact warrant further investigations to explore their potential biotechnological application. Lact. brevis strains independently of origin (AJ, OJ) were able to produce putrescine. Thus, their growth in fresh juice could affect the final product safety.