Polyphenols and Antioxidant Activity of Citrus Fiber/Blackberry Juice Complexes

The objective of this study was to investigate the use of citrus fiber as a carrier of blackberry juice polyphenols. For that purpose, freeze-dried complexes with blackberry juice and different amounts of citrus fiber (1%, 2% and 4%) were prepared. Complexes were evaluated spectrophotometrically for total polyphenols, proanthocyanidins and antioxidant activity. Analyses of individual polyphenols were performed using high-performance liquid chromatography. IR spectra were recorded to confirm encapsulation. All analyses were performed after preparation and after eight months of storage, in order to examine the stability of formed complexes. The obtained results indicated that increasing the amount of fiber led to a decrease in the concentration of polyphenols and the antioxidant activity of complexes. Cyanidin 3-glucoside was the prevalent anthocyanin in complexes (138.32-246.45 mg/100 g), while cyanidin 3-dioxalylglucoside was present at lower concentrations (22.19-31.45 mg/100 g). The other identified and quantified polyphenols were hesperidin (from citrus fiber), ellagic acid and quercetin (1317.59-1571.65 mg/100 g, 31.94-50.11 mg/100 g and 20.11-33.77 mg/100 g, respectively). Degradation of polyphenols occurred during storage. Results obtained in this study confirmed that citrus fiber could be used for the formulation of novel bioactive additives. Such additives could enhance the antioxidant potential of products to which they are added, such as baked goods, dairy, or fruit products.

Automated summary

The study found that increasing the amount of citrus fiber decreased the concentration of polyphenols and antioxidant activity in the complexes, which degraded during storage. This suggests that citrus fiber could be used as a carrier for blackberry juice polyphenols to enhance the antioxidant potential of food products.