Cocoa extracts encapsulations for avoiding polyphenols degradation.

Abstract

Cocoa is highly beneficial for health, because it contains a great deal of polyphenols, which are antioxidants, but also contains arginine, dopamine (neurotransmitter), magnesium, serotonin (neurotransmitter), tryptophan (which is essential to cause the release of the neurotransmitter serotonin), fenilethylamine, and flavones among many others. The term antioxidant is given to a type of molecules that have the ability to retard or even prevent the oxidation caused by oxygen. Oxidation is the transfer of electrons from one substance to another from an oxidizing agent. In consequence of this transfer of electrons, there is a release of radicals causing cell death. Polyphenols contained in food have stability problems, because they are sensitive to sun exposure and other environmental factors, such as high temperature, humidity, etc. Therefore it seems adequate to protect them from degradation. In this work, cocoa extract has been encapsulated into jellified alginate spheres and filaments in order to prevent degradation. However, although this technique has been proposed in the literature as a protection method, there is no published evidence of effective protection of polyphenols against degradation using this type of encapsulation. Therefore, the main aim of this work is to study the protective effect of encapsulation of cocoa extract into alginate gel against degradation, compared with degradation of free cocoa. In order to reach this objective, external gelation was used in order to prepare capsules (an external source of gelling agent, Ca2+, is chosen). A solution of alginate + cocoa was dropped into a conventionally stirred CaCl2 solution or, alternatively, introduced in the solution stirred by ultraturrax. In the first case, spheres were formed. In the second one, filament morphologies, due to the high shear, were found. Samples were subsequently lyophilized. Free cocoa extract was lyophilized for comparison...