Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Changes in the catechin and epicatechin content of grape seeds on storage under different water activity ( a w) conditions
Ist Teil von
Food chemistry, 2007, Vol.105 (4), p.1504-1511
Ort / Verlag
Oxford: Elsevier Ltd
Erscheinungsjahr
2007
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Storage effect on antioxidant content and capacity of grape seeds under different
a
w conditions (
a
w 0.33; 0.53; 0.75/50 days, 25
°C) was examined. Total phenol content (determined by the Folin–Ciocalteu method) decreased during storage though changes were trivial for samples stored at 33% or 53% RH. High level of humidity (75%) accelerated degradation and resulted in a ∼50% reduction of total phenol content. Minor loss of the DPPH radical scavenging activity (%RSA) of the extracts was observed. Catechin and epicatechin content monitored by RP-HPLC was reduced during storage, particularly at 75% RH. Epicatechin content proved to be less sensitive to water activity conditions than catechin content. Results of various
in vitro assays (Folin–Ciocalteu, FRAP, DPPH, ABTS, CBA, ORAC and copper induced liposome oxidation) did not support difference in terms of resistance to oxidation. Based on the continuous release of gallic acid, our finding was related to hydrolytic reactions. Control of
a
w of grape seeds can be of practical importance for the wine industry.