Concentration of ergosterol in small-grained naturally contaminated and inoculated cereals

Abstract

Ergosterol (ERG) is a major sterol constituent of most fungi. Its concentration is negligible in higher plants, but can be used as a chemical marker of the presence of fungal contaminations. In this study, ERG concentration was assessed in randomly collected samples of naturally contaminated grain (wheat, barley and oat) and in samples of grain (wheat, barley, triticale and oat) harvested after inoculation of heads with conidia of different Fusarium species. Wheat samples were analysed at three stages of grain development. The lowest ERG concentration was found in non-inoculated samples at the first stage of grain development. This concentration was increasing with grain ripening. In naturally contaminated samples collected after harvest, ERG concentration was lower in wheat than in barley and oat. ERG concentrations in inoculated samples varied significantly, but were always significantly higher than in naturally contaminated samples. In the above cereal samples it was much lower than the levels assayed in laboratory cultures inoculated with fungi from genus Fusarium. The content of ERG was also analyzed in milling products of small-grained cereals and other foodstuffs, where a considerable variation was observed. The lowest ERG amounts were assayed in flours with a high degree of purification, while the highest ones in case of flours and products with a low purification rate. The results indicate the potential application of HPLC combined with microwave-assisted extraction both when assaying samples with low ERG concentrations (naturally contaminated) and those characterized with high contents of fungal biomass (strongly infected, artificially inoculated). It also facilitates analyses of fungal biomass in technological processes, where results may be expected to vary considerably.

Concentrations of ergosterol and trichothecenes in the grains of three Triticum species

“…According to Müller and Schwadorf (1993), ERG levels in wheat grain naturally colonised by fungi are in the range of 4.0 mg/kg to 35.8 mg/kg. Perkowski et al (2008) have argued that the studied metabolite concentrations in grain samples of the type may reach 3.4 mg/kg. Schnürer and Jonsson (1992) claim that ERG concentrations in grain intended for consumption should not exceed 3.0 mg/kg.…”

“…Ergosterol determination. The samples were analysed for the presence of ERG according to Perkowski et al (2008). Briefly, the samples of 100 mg were placed into 17 ml culture tubes, suspended in 1 ml of methanol, treated with 0.1 ml of 2M aqueous NaOH, and tightly sealed.…”

Profile of phenolic and organic acids, antioxidant properties and ergosterol content in cultivated and wild growing species of Agaricus

“…Ergosterol in fruiting bodies of Agaricus species was determine by UPLC according to Perkowski et al [23] with some modifications. Powdered mushroom samples (100 mg), 2 mL of pure methanol and 1 mL of 2 M NaOH were mixed together, irradiated twice in a microwave (2 × 15 s) and cooled.…”

Level of contamination with mycobiota and contents of mycotoxins from the group of trichothecenes in grain of wheat , oats, barley, rye and triticale harvested in Poland in 2006–2008

“…Ergosterol was determined by high-performance liquid chromatography (HPLC) [2]. Samples containing 100 mg of ground grains were placed into 17-ml culture tubes, suspended in 2 ml of methanol, treated with 0.5 ml of 2 M aqueous sodium hydroxide, and tightly sealed.…”

“…The contents of mycotoxins in grain are inseparably connected with the presence of fungal biomass, the presence of which may indicate the occurrence of a fungus, and indirectly also products of its metabolism [2]. Among primary metabolites, ergosterol (ERG), a specific fungal marker, needs to be particularly stressed.…”