Forskning

February 20, 2017

Positive and negative aspects of green coffee consumption – antioxidant activity vs. mycotoxins

M Jeszka-Skowron et al, 2017. Positive and negative aspects of green coffee consumption – antioxidant activity vs. mycotoxins

ABSTRACT:

BACKGROUND: The quality of coffee depends not only on the contents of healthy compounds but also on its contamination with microorganisms which can produce mycotoxins during development, harvesting, preparation, transport and storage.

RESULTS: Antioxidant activity of green coffee brews measured in this study by ABTS, DPPH and Folin-Ciocalteu assays showed that coffee extracts from Robusta beans possessed highest activity in all assays than extracts from Arabica coffee. The occurrence of ochratoxin A and aflatoxins (B1, B2, G1, G2) in green coffee beans was studied, using liquid chromatography-mass spectrometry. Apart from mycotoxins, content of ergosterol as a marker indicating fungal occurrence was also determined. Among aflatoxins, aflatoxin B1 was dominant mycotoxin in coffee bean samples with the highest level at 17.45 ng g-1 . Ochratoxin A was detected in four samples in the range of 1.27 to 4.34 ng g-1 and fungi (potentially producing this toxin): Aspergillus oryzae, Alternaria sp., Aspergillus foetidus, Aspergillus tamarii and Penicillium citrinum were isolated.

CONCLUSIONS: Steaming and decaffeination of coffee beans increased antioxidant activities of brews in comparison to those prepared from unprocessed beans. Although toxins can be quantified in green coffee beans and novel fungi were isolated, their concentrations are acceptable according to law limits.