Effect of catechins on the growth of oxygen-sensitive probiotic bacteria

Oxygen plays a major role in the loss of viability of oxygen-sensitive bacteria. Antioxidant compounds, such as catechins, could be used to limit negative effects of oxygen exposure on bacteria during their growth and storage in food products. The objective of the present study was to measure the effects of different concentrations of (+)-catechin hydrate, green tea epigallocatechin gallate and green tea extracts (GTE) on the growth of probiotic strains with different oxygen sensitivities: Bifidobacterium longum ATCC 15708, B. longum subsp infantis ATCC 15697 and Lactobacillus helveticus R0052. Redox potential (ORP) measurements of the culture medium as well as Fourier-transform infrared (FTIR) spectroscopy analyses on bacterial cells were carried out to evaluate the effects of GTE supplementation. Results obtained showed that medium enrichment with catechins did not stimulate the growth of the two bifidobacteria. However, the growth of L. helveticus was greatly enhanced, under aerobic conditions, by supplementation of the medium with GTE. This growth-promoting effect could be due, in part, by the reduction of the initial ORP value of the medium following addition of GTE. Moreover, the differences in the FTIR spectral region corresponding to fatty acids observed suggest an effect of GTE also on the lipids of the bacterial cell membrane. Thus, GTE supplementation could be used to limit oxygen toxicity on specific probiotic strains but the growth-promoting effect seems to be strain-dependent. © 2012 Elsevier Ltd.