Effect of butylatedhydroxyanisole and propyl paraben on hydrolytic enzyme production by ochratoxigenic Aspergillus section Nigri strains isolated from peanut grains.

BARBERIS C.L.; LANDA F.,; DALCERO A.M,; MAGNOLI C.E.

REVISTA IBEROAMERICANA DE MICOLOGIA

ASOCIACION ESPANOLA MICOLOGIA-AEM

Lugar: Londres; Año: 2014 vol. 30 p. 1 - 8

1130-1406

Background: In the last years, food grade antioxidants are used safely as alternatives at traditional fungicides to control fungal growth in several food and agricultural products. Aims: In this work, the effect of butylated hydroxyanisole (BHA) and propyl paraben (PP) on two hydrolytic enzyme activity (B-d-glucosidase and α-d-galactosidase) by Aspergillus section Nigri species under different water activity conditions (aW; 0.98, 0.95 and 0.93) and incubation time intervals (24, 48, 72 and 96 h) was evaluated on peanut-based medium. Methods: The activity of two glycosidases, B-d-glucosidase and α-d-galactosidase, was assayed using as substrates 4-nitrophenyl-d-glucopyranosido and 4-nitrophenyl-d-galactopyranosido, respectively. The enzyme activity was determined by the increase in optical density at 405 nm caused by the liberation of p-nitrophenol by enzymatic hydrolysis of the substrate. Enzyme activity was expressed as micromoles of p-nitrophenol released per minute. Results: The major inhibition in B-d-glucosidase activity of A. carbonarius and A. niger was found with 20 mmol/l of BHA or PP at 0.98 and 0.95 aW, respectively, whereas for α-d-galactosidase activity a significant decrease in enzyme activity with respect to control was observed in A. carbonarius among 5 to 20 mmol/l of BHA or PP in all conditions assayed. Regarding A. niger, the highest percentages of enzyme inhibition activity were found with 20 mmol/l of BHA or PP at 0.95 aW and 96 h. Conclusions: The results of this work provide information about the capacity of BHA and PP to inhibit in vitro conditions two of the most important hydrolytic enzymes produced by A. carbonarius and A. niger species.