High-performance liquid chromatography for the analytical characterization of anthocyanins in Vaccinium myrtillus L. (bilberry) fruit and food products

Anthocyanins represent the most abundant class of bioactive compounds present in Vaccinium myrtillus L. (bilberry) fruit, conferring it several health-promoting properties. The content of anthocyanins in food products produced from bilberries can be affected by many parameters, making the study of their composition a critical issue. In this ambit, this work was aimed at a comprehensive profiling of anthocyanins in bilberry fruit and derivatives from the Italian Northern Apennines, including jam, juice, and liqueur ("Mirtillino"). Anthocyanins were extracted from the jams by means of a dynamic maceration with acidified methanol, while juice and liqueurs were directly analyzed. The analysis of anthocyanins in the extracts was carried out by means of HPLC-UV/DAD, HPLC-ESI-MS, and MS2, under gradient elution. As a comparison, authentic bilberry fruits were analyzed. The total anthocyanin content was in the range 582.4-795.2 mg/100 g (FW) for the fruit, 2.3-234.5 mg/100 g for the jams, 109.2-2252.2 mg/L for the juice, and 27.9-759.3 mg/L for the liqueurs. To deeper investigate the anthocyanin profile of the liqueurs that exhibited a remarkably different composition in comparison with the other products, an authentic bilberry liqueur was prepared in the lab, following a traditional recipe, and monitored weakly by HPLC. The percentage of degradation of 3-O-galactosides and 3-O-arabinosides of bilberry anthocyanidins was found to be higher than that of 3-O-glucosides. The results of this work demonstrated the importance of a suitable and reliable analysis of bilberry fruit and related food products to ensure their genuineness and quality.