Effect of Capsicum carotenoids on growth and ochratoxin A production by chilli and paprika Aspergillus spp. isolates

Abstract

The aim of this study was to determine the effect of a natural carotenoid mixture (Capsantal FS-30-NT), containing capsanthin and capsorubin, on growth and mycotoxin production of ochratoxin A-producing A. ochraceus, A. westerdijkiae, and A. tubingensis isolates. One isolate of each species, previously isolated from paprika or chilli, was inoculated on Czapek Yeast extract Agar (CYA) medium supplemented with different amounts of capsantal (0 to 1%) and incubated at 10, 15 and 25 °C for 21 days. Growth rates and lag phases were obtained, and OTA production was determined at 7, 14 and 21 days. The taxonomically related A. ochraceus and A. westerdijkiae showed the same behavior at 15 °C, but A. ochraceus was able to grow at 10 °C and had higher growth rates at 25 °C. A. tubingensis had the highest growth rates and lowest OTA production capacity of the assayed isolates, and it was not able to grow at 10 °C. Capsantal addition resulted in increased lag phases at 15 °C for all the strains, while growth rates remained rather constant. At 25 °C capsantal reduced growth rates, with rather constant lag phases. However, the effect of capsantal on OTA production was inconclusive, because it depended on temperature or time, and mostly was not significant. Low temperature has been a crucial factor in OTA production, regardless of the capsantal concentration tested, especially for A. tubingensis and A. westerdijkiae. Industrial storage temperature for paprika and chilli is approximately 10 °C. If this temperature is maintained, mould growth and OTA production should be reduced.