EVALUATION OF THE ABILITY OF FERMENTED CACTUS PEAR JUICE TO IMPROVE OXIDATIVE STRESS TOLERANCE IN YEAST

ISLA,MI; FERNADEZ-ESPINAR, MT; TORRES, S; GAUFFIN CANO, PAOLA; GIL PONCE, J.V.; VERON, H; DANTUR, K

ANNALS OF NUTRITION AND METABOLISM

KARGER

Lugar: Basel; Año: 2017 vol. 71 p. 1210 - 1211

0250-6807

Background and objectives: Cactus pears from Opuntia ficus-indica are strongly recommended in the human diet since their nutritional and health-promoting features. Scientific evidence has demonstrated the benefits from cactus pear ingestion with special consideration about potentially active antioxidant phytochemicals. However, long-term storage represents the main drawback to the commercialization of this fruit. Since in many places cactus pears are consumed as juice, different procedures were developed to prevent its spoilage. Lactic acid fermentation of cactus pear juice (CPJ) using autochthonous bacteria constitutes an important biotechnology for the exploitation of this fruit. The aim of this study was to evaluate the effect of fermented CPJ (F-CPJ) on oxidative stress tolerance of Saccharomyces cerevisiae.Methods: Lactobacillus plantarum S-811, an autochthonous lactic acid bacteria strain isolated from O. ficus-indica fruits from Northwest Argentina was used to fermented the juice. To evaluate the antioxidant response induced by CPJ and F-CPJ, cultures of S. cerevisiae were incubated with the juices (amounts equivalent to 50, 250 and 500 mg/L of phenolics) during 18 h at 28 °C. Cells were then exposed to sub-lethal oxidative stress, using 0.5 or 4 mM H2O2. After stress treatments, cells were cultured in YPD medium and incubated for 18 h at 28 °C. To evaluate the oxidant effect in each culture, growth-ratio curves (GRC) and effect curves (EC) were constructed as follows: RC = quotient between the growth curve (GC) of the culture exposed to oxidant and the GC of the non-exposed culture; EC = GRC for the culture pre-incubated with the juice was divided by the GRC for the culture pre-incubated without juice.Results: Against a final concentration of 0.5 mM H2O2 there was not observed a significant protective effect by any of the evaluated juices. However, against 4 mM H2O2, CPJ and F-CPJ showed a significant protective effect, that was much higher with the F-CPJ (up to 15 times protection) than CPJ (up to 4 times protection).Conclusions: These results suggest that F-CPJ with L. plantarum S-811 could be a suitable choice for the development of a CPJ with improved functional properties.