[Characterization of cocoa fiber and its effect on the antioxidant capacity of serum in rats].

OBJECTIVES

The aim of this study was to characterize the physico-chemical properties of cocoa fibre (CF), to analyze its polyphenolic content and antioxidant capacity in vitro, and to investigate the effect of the administration of a polyphenolic extract of this cocoa fiber on the antioxidant capacity of the serum in rats.

METHODS AND MATERIALS

Dietary fiber (DF) composition and polyphenolic (PP) content of the cocoa fiber were analyzed. The antioxidant capacity of the CF was determined by means of its reduction power (FRAP) and the capacity to scavenge free radicals (ABTS). To evaluate the bioavailability and the antioxidant capacity in vivo of the phenolic compounds of CF, an extract of these compounds was administred in the stomach of the rats with a gastric probe (100 mg PP/kg), taking blood samples at different time intervals. Sera were analyzed by HPLC to determine the presence/absence of PP or PP-metabolites. In orther to evaluate the antioxidant capacity of the serum FRAP and ABTS methods were used.

RESULTS

Cocoa fiber was an excellent source of DF, with a high content of total dietary fiber (TDF), over 60% of the dry matter, made up mainly of insoluble dietary fiber (IDF; 83% of TDF). This fiber had just 1.15% of polyphenols, with low antioxidant activity. After intragastric administration of the PP-rich fraction a fast and measurable absorption of the CF polyphenols was observed, being epicatechin the main PP in blood. The absorption of this PP confers a significant, although transitory increase of the serum antioxidant capacity 10-45 minutes post-gavage; after this time, the antioxidant capacity progressively decreased reaching basal levels after 6 h.

CONCLUSIONS

Cocoa fiber can be considered as an excellent source of DF, mainly insoluble dietary fiber; therefore, it could be used as an ingredient in fiber-rich functional foods. Besides the benefits derived from its high fiber content, the CF would provide protection against oxidative damage by means of its content in phenolic compounds (epicatechin) wich are absorbed maintaining the antioxidant properties in vivo.