Microencapsulated resveratrol (RSV) is a pertinent ingredient in functional foods to be used in the prevention and management of cardiovascular diseases. Gamma-cyclodextrin (γ-CD) was evaluated for its RSV inclusion ability. Fresh lemon juices supplemented with 0.625 mg/mL of RSV in its free (RSV-juice) or complexed (γ-CD·RSV-juice) form were stored along 28 days under dark and room temperature or at 4 ◦C. Initially, the RSV level in γ-CD·RSV-juice was about nine times higher than in RSV-juice (43.1% and 4.8%, respectively), suggesting that the RSV complexation promoted its solubility in the lemon juice, a fact that was still noticed after 28 days of storage. Moreover, regardless the fact that the antioxidant capacity was similar among the juices, the loss of antiradical ABTS•+ capacity in γ-CD·RSV-juice was reduced compared to that of the RSV-juice. Overall, this study allowed concluding that γ-CD can serve as a carrier of RSV, promoting its solubility and eventually protecting its antioxidant stability in lemon juices for at least 28 days.
Among native CDs, γ-CD is considered the most suitable for food applications due to its lower toxicity (lethal dose, 50% > 8000 mg/kg body weight for oral administration in rat) and to the fact that it is the only native CD that undergoes complete digestion in the gastrointestinal tract . There are already a few reports on the formation and use as food fortificants of γ-CD inclusion complexes with bioactive components such as thymol, gingerols and quercetin. While the scarce number of reported studies of complexes with γ-CD in food matrices reflects the slightly high cost of this host, in comparison with β-CD (the most affordable cyclodextrin available), native CDs are considerably more appealing than the modified ones (e.g., the price per ton of HP-β-CD may be from 50 to 200 times that of β-CD). Moreover, relevant for application in liquid foods is the fact that pure aqueous solutions of γ-CD have the particularly of quickly becoming opalescence upon storage, with small visible precipitates. Opalescence may limit the application of γ-CD in some foods but, at the same time, it may be an attractive characteristic in formulations.
Silva, A.F.R.; Monteiro, M.; Resende, D.; Braga, S.S.; Coimbra, M.A.; Silva, A.M.S.; Cardoso, S.M. Inclusion Complex of Resveratrol with γ-Cyclodextrin as a Functional Ingredient for Lemon Juices. Foods 2021, 10, 16. https://dx.doi.org/10.3390/foods10010016