Impact of Frozen Storage on the Anthocyanin and Polyphenol Contents of American Elderberry Fruit Juice

The effects of frozen storage on the anthocyanin and polyphenol content of elderberry fruit juice are investigated. Juice from three genotypes of American elderberry (Adams II, Bob Gordon, and Wyldewood) was screened for total phenolic (TP) and total monomeric anthocyanin (TMA) contents with spectrophotometric methods. The individual anthocyanin content (IAC) of the juice was tested by coupling solid phase extraction with ultraperformance liquid chromatography–tandem mass spectrometry. Juice samples were tested initially upon harvest and then again after 3, 6, and 9 months of frozen storage. Juice from the three different genotypes had significantly different TP, TMA, and IAC profiles initially (p < 0.05). The TP, TMA, and IAC contents of the juice from different genotypes were significantly affected (p < 0.05) by the frozen storage time, suggesting that both genotype and length of frozen storage time can affect the anthocyanin content of elderberry fruit juice.