Influence of Cultivar and Industrial Processing on Polyphenols in Concentrated Sour Cherry (Prunus cerasus L.) Juice

Abstract

The objective of this study is to investigate the infl uence of cultivar and industrial processing on total polyphenols, anthocyanins, hydroxycinnamic acids and antioxidant activity in concentrated sour cherry (Prunus cerasus L., cvs. Marasca and Oblačinska) juices. Samples were collected during four processing steps: from fresh fruit prior to processing, then from pressed, fi ltered and concentrated juices. The content of total phenols was the same in both cultivars, but antioxidant activity (Oblačinska>Marasca) and total monomeric anthocyanins (Marasca>Oblačinska) diff ered. All processing steps significantly influenced the content of total phenols, total monomeric anthocyanins and antioxidant activity. In all samples four major anthocyanins were identifi ed by HPLC with UV/VIS PDA detector, listed in the descending order based on their abundance: cyanidin-3-glucosylrutinoside, cyanidin-3-rutinoside, cyanidin-3-sophoroside and cyanidin-3-glucoside. Marasca cv. contained more total anthocyanins, and contents of cyanidin-3-sophoroside and cyanidin-3-glucosylrutinoside. The content of total hydroxycinnamic acids was also higher in Marasca than Oblačinska cv. Aft er processing, the concentration of all identifi ed anthocyanins increased in both cultivars. Majority of the highest values of polyphenols were detected in the juice aft er pressing. The content of polyphenols and their antioxidant activity were considerably stable during industrial processing to concentrated juice. Although Marasca had higher polyphenolic content than Oblačinska, both cultivars showed promising industrial potential for processing to concentrated juice.

Keywords

• sour cherry
• Marasca cv.
• Oblačinska cv.
• juice concentrate processing
• polyphenolic content and anthocyanins
• antioxidant activity