Scientific Publications by FDA Staff

Food Addit Contam Part A 2016 Mar;33(3):560-73

Targeted and non-targeted detection of lemon juice adulteration by LC-MS and chemometrics.

Wang Z, Jablonski JE

Economically motivated adulteration (EMA) of lemon juice was detected by LC-MS and principal component analysis (PCA). Twenty-two batches of freshly-squeezed lemon juices were adulterated by adding an aqueous solution containing 5% citric acid and 6% sucrose to pure lemon juices, to obtain 30%, 60%, and 100% lemon juice samples. Their total titratable acidities, degrees Brix, and pH values were measured and then all the lemon juice samples were subject to LC-MS analysis. Concentrations of hesperidin and eriocitrin, major phenolic components of lemon juice, were quantified. The PCA score plots for LC-MS data sets were used to preview the classification of pure and adulterated lemon juice samples. Results showed a large inherent variability in the chemical properties among 22 batches of 100% lemon juice samples. Measurement or quantitation of one or several chemical properties (targeted detection) was not effective in detecting lemon juice adulteration. However, by using the LC-MS data sets, including both chromatographic and mass spectrometric information, 100% lemon juice samples were successfully differentiated from adulterated samples containing 30% lemon juices in the principal component analysis score plot. LC-MS coupled with chemometric analysis can be a complement to existing methods for detecting juice adulteration.