Use of FTIR and Raman spectroscopy for the study of lactic acid bacteria

A GOMEZ ZAVAGLIA

Tucumán

Congreso; IV Simposio Internacional de Bacterias Lácticas (SIBAL). Alimentos, Salud y Aplicaciones. 16-18/10/2013. Tucumán (Argentina).; 2013

CERELA

Methods based on vibrational spectroscopy (in particular infrared and Raman spectroscopies) are widely extended among microbiologists. Vibrational spectra allow obtaining a global picture of the microbial molecular composition (i.e.: nucleic acids, proteins, lipids and cell wall components). For this reason, spectroscopic based methods have been used for many different purposes including taxonomy, production of metabolites, diagnostics, bacteria structural analysis, etc. As a result of the huge amount of information contained in the spectra, bands become broad and most of the times require the use of powerful mathematical techniques (known collectively as chemometrics) for the analysis. Chemometric methods allow the extraction of valuable information from large and complex data sets (the spectra), supporting the application of both infrared and Raman spectroscopies in many different fields, including Food Microbiology. In this presentation the following applications of Raman and infrared spectroscopies will be exposed: a) implementation of Raman spectroscopy for the quantification of metal ions attached to the bacterial surface of two Lactobacillus kefir strains; b) use of near infrared spectroscopy (NIR) to determine the efficiency of three cryoprotectants; c) use of NIR to monitor the growth of bacterial starters. Considering the amount of chemical and physical information that can be obtained from the spectra with no extensive preparation of samples and without using chemical reagents, it is not surprising the increasing interest of food microbiologists in vibrational spectroscopic methods.