In the present study the anthocyanin content of commercially available bilberry juices and fresh fruits were quantified by using 15 authentic anthocyanin standards via high performance liquid chromatography with an ultra-violet detector (HPLC-UV/VIS). Delphinidin-3-O-glucopyranoside, delphinidin-3-O-galactopyranoside, and cyanidin-3-O-arabinopyranoside were the major anthocyanins found in juices, nectar, and fresh bilberries. In contrast, fresh blueberries had higher concentrations of malvidin-3-O-arabinopyranoside and petunidin-3-O-galactopyranoside. Up to 438 mg anthocyanins per 100 g fresh weight (2762 mg/100 g dry weight (DW)) were detected in blueberries from various sources, whereas bilberries contained a maximum of 1017 mg anthocyanins per 100 g fresh weight (7465 mg/100 g DW). Commercially available bilberry and blueberry juices (n= 9) as well as nectars (n= 4) were also analyzed. Anthocyanin concentrations of juices (1610 mg/L to 5963 mg/L) and nectar from bilberries (656 mg/L to 1529 mg/L) were higher than those of blueberry juices (417 mg/L) and nectar (258 mg/L to 386 mg/L). We conclude that using several authentic anthocyanin references to quantify anthocyanin contents indicated them to be up to 53% and 64% higher in fresh bilberries and blueberries, respectively, than previously reported using cyanidin-3-O-glucoside. This study has also demonstrated that commercially available juices produced from bilberries contain much higher anthocyanin concentrations than those from blueberries.
Practical application: We have investigated the contents of a special class of antioxidants, namely anthocyanins in blueberry and billberry fruits and juices commercially available in Germany. To achieve reliable data we have used authentic standards for the first time. We think that our results are important in the field of nutritional intake of this important class of polyphenols and fruit juice companies get a closer insight in the occurrence of these antioxidants in market samples to be used in food composition databases and for nutritional survey.
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