Inclusion Complex of Resveratrol with γ-Cyclodextrin as a Functional Ingredient for Lemon Juices.

Andreia F R Silva,Manuel A Coimbra,Artur M S Silva,Susana S Braga,Daniela Resende,Susana M Cardoso,Mariana Monteiro

doi:10.3390/foods10010016

Abstract

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. Inclusion procedures comprised mixing equal concentration of an aqueous solution of γ-CD with an ethanol solution of RSV and freeze-drying to obtain a solid material. Solid-state characterization by vibrational spectroscopy, thermogravimetry, and powder X-ray diffraction (PXRD) confirmed the formation of the γ-CD·RSV complex in a ratio of 1:1. PXRD suggested that cyclodextrin molecules in the complex are stacked in infinite channels holding the RSV inside, with a wide inter-channel space where 14 water molecules are retained. 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.

Highlights

Resveratrol (RSV) is a natural secondary metabolite of the family of stilbenes that is quite valuable as a functional ingredient due to its pleiotropic health beneficial effects as anti-inflammatory, antitumoral, and protecting action on the cardiovascular system [1,2,3]
The present study describes the inclusion of RSV into γ-CD and the isolation of the delayed in γ-CD·RSV-juices, a fact that may have been promoted by the higher amount of RSV dissolved
The present study describes the inclusion of RSV into γ-CD and the isolation of the inclusion complex as a solid product by co-dissolution, using food-safe solvents, and freezedrying

Summary

Introduction

Resveratrol (RSV) is a natural secondary metabolite of the family of stilbenes that is quite valuable as a functional ingredient due to its pleiotropic health beneficial effects as anti-inflammatory, antitumoral, and protecting action on the cardiovascular system [1,2,3]. CDs are approved for use as food additives by the US Food and Drug Administration (FDA) and the World-Health Organization-Food and Agriculture Organization of the United Nations (WHO-FAO) joint committee, having the GRAS status (FDA list of food additives that are generally recognized as safe). Owing to their ring-shaped structure, CDs act as inclusion hosts for a variety of compounds, such as RSV. The resulting inclusion complexes have typically increased aqueous solubility and the included guests are protected from aggressive external conditions such as oxidation and degradation by UV radiation or heat [9]

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Conclusion