Encapsulated Proanthocyanidins as Novel Ingredients

Abstract

Proanthocyanidins (OPC) are polyphenolic compounds, derivatives of flavan-3-ol flavonoids. They are abundant in grape seeds and skins, and contribute to most of the polyphenols in red wine. Proanthocyanidins from grape seed have been reported to show various health as well as technological properties.
Aim of the study was to investigate the coating efficiency of maltodextrin (MD) in different molecular ratios with arabic gum (AG) on encapsulation of phenolic compounds extracted from grape pomace.
The present study was planned to examine the contributions of MD, AG and OPC to the structural architecture of encapsulated OPC by means of scanning electron microscopy (SEM), their encapsulation efficiency and their functionality (antioxidant activity and bioavailability) by spectrophotometric assays and mass spectrometry analysis (MALDI-TOF-MS). The effect of encapsulated OPC on in vitro polyphenol digestibility was also evaluated according to the Infogest protocol.
Encapsulated products were obtained by a mild ultrasonication method in controlled conditions based on the phenomenon of acoustic cavitation, and then freeze-dried. The content of coating material had significant (p>0.05) impact on particle morphology of spray-dried suspensions. SEM analysis of samples of AG/MD and AG/MD/OPC were similar and exhibited cracks and sharp edges, but samples with OPC showed a more enclosed structure. Total and Surface phenolic content of microcapsules showed the best encapsulation efficiency for samples with 4% of AG and 12% of MD. MALDI-TOF-MS characterization of encapsulated samples showed integrity of OPC components in the microcapsules with no changes with respect to original OPC. The in vitro digestion experiments showed also that composition and functionality of encapsulated OPC were better preserved along gastrointestinal digestion process.
In conclusion, OPC microcapsules could be utilized both as nutraceuticals and additives in various food applications.