Microencapsulation of polyphenolic compounds recovered from red wine lees: Process optimization and nutraceutical study

Bioactive polyphenolic compounds, recovered by nanofiltration of Cabernet Sauvignon wine lees were encapsulated with maltodextrin to obtain a spray dried micro powder with enhanced nutritional value. A Central Composite Design allowed setting up optimal spray-drying conditions using a commercial grape extract-polyphenol as the reference polyphenolic source and considering maltodextrin concentration and the inlet temperature as independent variables. The optimized spray-drying conditions were: maltodextrin 7 g/100 mL, inlet temperature 110 degrees C. These conditions were then applied to lees nanofiltrates and retentate. The obtained microcapsules were characterized according to the drying yield (62.9-82.0%), moisture (0.81-1.52%), total bioactive compounds (0.08-0.57 mg GAE/100 mg dw), surface bioactive compounds (5.8-34.5%), microencapsulation efficiency (65.5-94.2%), polyphenols recovery (57.4-82.7%), and antioxidant activity (0.27-0.36%). The microcapsules showed high stability and durability when subjected to accelerated aging using the stress-heat test, as evaluated by calculating first-order rate constants of degradation of the encapsulated polyphenols and the reduction of radical scavenging capacity; stability over time was further confirmed by the reduced water activity of the micro powders (ranged 0.27-0.36). Lastly, an in-vitro simulated digestion was performed under physiological conditions evidencing a different bioaccessibility of polyphenols among samples (ranged 50-78%) and suggesting potential for the encapsulated polyphenols to be absorbed at gastrointestinal level. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

This study focused on the encapsulation of bioactive polyphenolic compounds from Cabernet Sauvignon wine lees using nanofiltration and spray drying techniques. The optimized microcapsules exhibited high stability and durability, and showed potential for gastrointestinal absorption.