Detection of OTA contaminated dried vine fruit by FTIR-ATR infrared spectroscopy
Résumé
A methodology for screening contaminated sultanas by ochratoxin A (OTA) using mid-infrared spectroscopy/one single reflection ATR Golden Gate is described. A preliminary study comprehends the acquisition and analysis of the spectra of sultanas from different origins allowing the identification of their principal spectra characteristics. After spectra were recorded, they were subject to principal component analysis (PCA), which showed that sample from the various origins had different spectra characteristics, especially in the water content and in the fingerprint region. Samples of sultanas from a specific origin were split into small sub samples and then were analysed along various days. The repeatability of the spectra was highly improved when sample's water activity was set at 0.62. A calibration curve of OTA was built in a range of 10–40 µg OTA kg-1. Concentrations of OTA higher than 20 µg OTA kg-1 were separated from samples contaminated with a lower concentration (10 µg OTA kg-1) and from no contaminated samples. The methodology reported here opens the possibility of the application of a reliable and simple methodology for screening contaminated dried vine fruit.
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