Content and mean polymerization degree of procyanidins in extracts obtained from clear and cloudy apple juices

Abstract

The polyphenol profile of apples and that of technologically differently treated apple juices has already been studied thoroughly; nevertheless, the content of polymeric procyanidins has not received much attention up to date. Therefore, procyanidins in extracts made from six blended apple juices and two authentic clear as well as cloudy apple juices (Malus domestica cv. Bohnapfel and Bittenfelder) were investigated. Our determinations revealed significant differences in the total procyanidin content between apple juice extracts obtained from clear and the corresponding cloudy juices under study. Depending on the apple cultivars used average amounts of total procyanidin content determined in the extracts made from clear and cloudy juices ranged from 28.4 +/- 4.4% to 49.0 +/- 5.7% and from 48.3 +/- 0.3% to 60.6 +/- 0.3%, respectively. As the mean degree of polymerization (DPm) is supposed to have an influence on bioavailability and toxicity on different cells lines used in in vitro systems, the average degree of polymerization of the juices under examination were determined. Depending on the cultivar used and the technology of juice processing the DPm ranged between 3.0 and 13.4.