Recovery and characterisation of coloured phenolic preparations from apple seeds.

The aim of this study was to investigate whether complexly constituted phenolic extracts from apple seeds may be utilised for the recovery of natural coloured antioxidant preparations, which might serve as potential food or cosmetic ingredients. In a first step, the recovery of phenolic compounds was optimised by varying crucial extraction parameters. A single extraction step at 25°C using an acetone-water mixture (60:40, v/v) and a solid-to-solvent ratio of 1:8 (w/v) for 1 h was found to be appropriate to achieve both high phenolic yields and antioxidant activities. In a second step, differently produced apple seed extracts and a phloridzin model solution were enzymatically treated by mushroom polyphenol oxidase to investigate the rate of pigment synthesis. Depending on the extraction procedure applied, synthesis rates, pigment yields and colour properties significantly differed. Compared to the phloridzin model solution, extracts recovered from the seeds showed comparable and even better results, thus indicating such preparations to be a promising alternative to synthetic yellow dyes.