Berry press residues as a valuable source of polyphenolics: Extraction optimisation and analysis

Vaccinium genus berries (bilberries, blueberries, lingonberries, cranberries) are gathered in the wild as well as cultivated on an industrial scale for use in the food industry. Extraction of juices from these berries produces press residues (pomace) as a waste product. Berry press residues are an excellent source of phenolic compounds and have a potential of use as a polyphenol-rich material. The aim of the present study was to optimise the method of extraction of polyphenols (anthocyanins specifically) from berry press residues of American cranberry using the response surface method and to validate the optimal polyphenol/anthocyanin extraction conditions also for other Vaccinium berries and their press residues. Comparison of whole berry and berry press residue extracts helps to determine the potential berry source materials for further processing and production of products with high antioxidant levels. The composition of anthocyanins was determined in five different berry species of the Vaccinium genus (whole berries and press residues), the results were obtained using the optimised extraction conditions, and the analysis was done by UPLC and LC-TOF/MS.