IN VITRO ZEARALENONE REMOVAL BY BAKER’S YEAST

Zearalenone (ZEA), a lactone of β-resorcylic acid, is a mycotoxin produced mainly by Fusarium graminearum commonly detected in wheat and corn. The toxicity of zearalenone and its metabolites is related to their estrogenic properties such as infertility, vulvovaginitis and rectal and vaginal prolapse. Considering the serious economic losses and the health hazards caused by natural occurrence of ZEA, the objective of this study was to evaluate the ability of Saccharomyces cerevisiae strains isolated from baker's to remove ZEA in vitro. Five yeast strains were obtained from fresh baker's yeast, purchased in the markets of Londrina, Paraná, Brazil, called ScA, ScB, ScC, ScD and ScE. Yeast strains were grown in YPD (yeast, peptone, dextrose) broth and incubated at 25 ± 1 °C, 250 rpm for 24 h. The experiments were divided into two groups: no heat (viable cells) and treatment (120 °C for 15 min). The yeast suspension was standardized at 108 cells/mL. This suspension was centrifuged, the pellet was suspended in 10 mL PBS ( pH 7.4) to a ZEA final concentration of 500 ng/mL. The assays were then incubated at 37 °C, 250 rpm for 1 h. The experiment was stopped by centrifugation (8379 x g at 0 °C for 15 min). The supernatant was used to determine the ZEA adsorbed. In vitro ZEA removal by viable yeast cells ranged from 70 to 78 %. The ScA yeast showed the highest ZEA removal rate (78 %), but did not differ significantly (p > 0.05) from ScB (77 %), ScC (76 %) and ScD (73 %). Unviable cells showed ZEA removal ranging from 78 (ScE) to 87% (ScD). Comparing the ZEA removal (%) by the same strain, unviable cells of ScC and ScD strains showed higher adsorption (p< 0.05) than the viable cells. Other strains showed no significant difference (p > 0.05) in mean ZEA removal (%) between viable and heat inactivated cells. All the Saccharomyces cerevisiae strains showed potential for in vitro ZEA removal. Saccharomyces cerevisiae is Generally Recognized as Safe (GRAS), therefore there is no risk for its application in food and feed. They have potential to be included in a new product for animal feed, reducing economic losses and minimizing risk of ZEA carry-over to human food.