LC-MS/MS-Based Metabolomics for Authenticity Assessment of Fruit Juices
The production of fruit juices represents an important branch of the beverage industry. Besides orange juice, which is produced and consumed in the largest volume worldwide, other fruit juice types, such as those obtained from pomegranate or various types of berries have become popular presumably due to their high levels of antioxidants resulting in positive health effects. Similarly to other highly prized food commodities, the economic value and large-scale production of orange juice and other valuable fruit juices have made them a likely target for adulteration and fraud. The most frequent profit-driven fraudulent procedures applied either alone or in combination, employ dilution with water, addition of sugars or pulp wash, and extension of authentic juice with cheaper alternatives. As the adulteration of fruit juices represents an ongoing problem, suitable analytical methods are needed to control authenticity parameters.
LC-MS/MS technique, employing a 4000 QTRAP® system, was used for comprehensive metabolomic fingerprinting of several fruit juices, prepared from both expensive (orange, pomegranate, blueberry, and cranberry) and relatively low-priced (apple, grapefruit) fruits. Following the automated data mining, the suitability of the statistical data processing for classification of fruit juice and adulteration detection, was assessed with the use of advanced chemometric tools (principal component analysis with principal component variable grouping PCA-PCVG). In the final stage of this study, AB SCIEX TripleTOF® 5600 system measurements were performed in order to obtain data for identification of pre-selected marker compounds using elemental formula calculation and online databases search.