Chokeberries are a rich source of anthocyanins and procyanidins, but these compounds are unstable during juice processing and storage. Losses are accompanied by increased polymeric color values, indicating anthocyanins react with procyanidins to form polymeric pigments. In this study, polymeric pigments in samples at various stages of juice processing and pasteurized juices stored over six months at 25oC were measured by MALDI-TOF-MS in linear mode. Monomeric anthocyanins were analyzed by HPLC.  Polymeric pigment signal intensities were strongest in the protonated molecular ion form [M+].  Cyanidin 3-galactoside with one (m/z 737) up to 12 (m/z 3903) flavan-3-ol units was present in all samples during processing and storage.  The largest increase in polymeric pigments occurred following pasteurization, coinciding with a marked loss of monomeric anthocyanins. Polymeric pigments changed little over six months of storage despite a linear decline in monomeric anthocyanins.  Thermal treatment appears to promote the formation of polymeric pigments in chokeberry juice.

Formation of polymeric pigments during chokeberry juice processing and storage

246th National Meeting (2013)

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