News

This peer-reviewed pre-print (open access) reports a classification model for different Greek olive oil cultivars using combined data from two analytical techniques: volatile component analysis (6 marker compounds) by solid phase microextraction – gas chromatography (SPME-GC-MS) and spectral analysis by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR)

The model was built to differentiate Greek oils from 3 cultivars: Koroneiki, Megaritiki and Amfissis.  The reference database was constructed from samples collected over 3 harvest seasons.  The authors report that application of the supervised methods of linear and quadratic discriminant cross-validation analysis, based on volatile component data, provided a correct classification score of 97.4 and 100.0%, respectively. The corresponding statistical analyses were used in the mid-infrared spectra where the 96.1% of samples were discriminated correctly.

The authors conclude that ATR-FTIR and SPME-GC-MS, in conjunction with the appropriate feature selection algorithm and classification methods, are powerful tools for the authentication of Greek olive oil. They consider that the proposed methodology could be used in industrial settings for the determination of Greek olive oil botanical origin.

Differentiating gelatin species is an analytical challenge because of a lack of intact DNA.  Most speciation methods therefore target the profile of proteins.  Proteins are difficult to analyse - they are too large to measure directly by techniques such as LC-MS, without  prior breaking down, and their folded structure is also an important diagnostic parameter.  This structure is disrupted by many of the sampling and extraction procedures used in analytical method. Analysis of mixed gelatins is particularly difficult.

This method (open access) used a new approach based on the interaction of ethanol with amino acids inside a protein. Ethanol can denature globular proteins by disrupting intraprotein hydrogen bonds due to hydrophobic interactions. However, when added to solutions having proteins with considerable number of α-helices, ethanol can stabilize the protein structure and prevent aggregation. The specific effects of ethanol on protein structure and function can vary depending on the protein's composition and environment.

Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy was used to leverage ethanol's differential effects on gelatin's amide bands for quantifying pork gelatin contamination in bovine gelatin.

The authors report that the method showed a strong linear correlation between contamination levels and amide band transmission, with detection and quantification limits of 0.85 and 2.85 mg/100 mg (pork in bovine), respectively. It effectively identified pork gelatin in halal candy, with recovery rates from 50.05 % to 103.69 %.