Anthocyanin fingerprinting as an authentication testing tool for blueberry, aronia, and pomegranate juices

Systematic study of anthocyanins has been demonstrated as a tool in quality control using typical anthocyanin profiles of berry fruits. High prices of polyphenol rich fruits, such as pomegranate, aronia, and blueberry, often lead to adulteration of their juices with synthetic substitutes and/or cheaper fruits. The main focus of the study was to establish anthocyanin markers and use them to detect potential frauds and as a tool for authentication of commercial juices containing blueberries, aronia, and pomegranates. An HPLC/DAD/MSⁿ for qualitative and quantitative analysis of 18 commercial fruit juices was used. It was found that delphinidin 3,5-diglucoside, cyanidin-3,5-diglucoside, and pelargonidin 3,5-diglucoside can serve as markers for pomegranates, and cyanidin-3-galactoside for aronia, and the content of malvidin and delphinidin derivatives can distinguish blueberries from bilberries. Quantitative data for anthocyanins content were used for establishing the ranges for individual and total anthocyanins content that were used to estimate fruit content. Based on the established markers, the study has revealed that 15 juice samples are authentic, since they contain declared fruits, but six of them have lower total anthocyanin content than expected from the declared fruit content. For juices containing different fruits, it is difficult to distinguish the origin of anthocyanins and correlate to all fruits present, but still the total anthocyanin content can be used to estimate the fruit content and thus for quality control.