Vedecký časopis

46 2007

Journal of Food and Nutrition Research
Súhrny čísla 1 / 2007

Differentiation of coffee varieties according to their sterolic profile
Journal of Food and Nutrition Research, 46, 2007, č. 1, s. 28-34

Helena Čížková, Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Technická 5, CZ-160 00 Prague 6, Czech Republic. E-mail: helena.cizkova@vscht.cz

Súhrn: The aim of the presented work was to differentiate between two important coffee varieties – arabica and robusta by means of chemical analyses of sterolic fraction of 13 model and 14 commercial roasted coffee samples. After the extraction of the coffee oil, the lipids have been saponified and sterols converted into trimethyl silyl derivatives and analysed by gas chromatography with mass spectrometric detection. For the evaluation of authenticity of coffee samples several statistical approaches, such as multilinear regression, principal component analyses and cluster analysis were used. ?5-avenasterol was found to be the chemical descriptor with the highest contribution to the model and the following correlation equation was achieved: percentage of arabica in coffee = 117 – 11.1 × percentage of ?5-avenasterol in total sterols, with a high correlation coefficient (R2 = 0.98) and precision (RSD = 7.9%). The method was applied to the determination of the arabica/robusta composition of commercial roasted coffee samples.

Kľúčové slová: coffee; arabica; robusta; authenticity; sterols, gas chromatography, multilinear regression, principal component analysis, cluster analysis

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