Improvement of ginger oil stability by encapsulation in alginate-carrageenan-chitosan blended beads

Abstract

The tendency to create innovative ingredients or new functional foods is growing. Encapsulation is a process aimed at the protection and controlled release of active principles. This study aims to provide better protection for ginger essential oil. It has been based on a preliminary study in which the ginger oil was encapsulated with the Büchi model-390 and where the essential oil coating was a hydrogel consisting of a mixture of sodium alginate with Kappa-carrageenan and with a final chitosan coating, that is, the oil was wrapped in the hydrogel layer. The main conclusion of the previous study was that encapsulation protects ginger oil from oxidation but there is still room for improvement, and a deeper research is required, a part of which is carried out in the present work. In this work, unlike the previous study, the emulsion of ginger oil was encapsulated with the aqueous phase, so that the oil is already trapped in the hydrogel. Three formulations were prepared for the encapsulation of ginger oil, the hydrogel discussed before, the hydrogel with natural reddish tint and the hydrogel with methylene blue, to try to offer a better protection against light. These three formulations were subjected to different storage conditions varying three parameters; temperature, contact with light and contact with air. Contact with the light by placing the samples in the case or, cabinet, temperature by locating them or not in the refrigerator and contact with air by covering or not them. The encapsulated ginger oil gave lower values of oxidation compared to non-encapsulated control oil. The oil extracted from the capsules stored in a refrigerator and covered, showed lower values of oxidation products throughout the storage period. The red dye used in gel capsules provides the best results and improves the protection of ginger oil against unwanted oxidation