Evaluation of hemicellulose as a coating material with gum arabic for food microencapsulation

Abstract

In this study, hemicellulose-based coatings were assessed for use in microencapsulated fish oil. The fish oil emulsions were prepared using the solutions of gum arabic (GA), gum arabic-hemicellulose (GA-HC) and hemicellulose (HC) as the coating materials, amended with maltodextrin as a cheap filler material. The fish oil was then encapsulated with these emulsions using the spray drying method. The effects of the hemicelluloses on the emulsions and the formed microcapsules were evaluated by physical and chemical tests. Although the GA-HC and HC emulsions showed higher creaming index and apparent viscosity values than that of the GA samples, all emulsions showed shear-thinning behavior. The oil particle size of the emulsions was found to be affected by the apparent viscosity. The HC emulsions contained oil particles with the largest size among all samples (p < 0.05). On the other hand, oil particle sizes of the reconstituted microcapsules were not significantly different (p > 0.05). Scanning electron microscope (SEM) was also used to visualize the morphological characteristics of all microcapsules. The hemicellulose microcapsules (GA-HC and HC) had fewer dents than the GA microcapsules. The micro-encapsulating efficiency (MEE) of the GA microcapsules was found higher than that of the GA-HC and HC microcapsules. The HC microcapsules had the lowest water activity (0.049 a(w),). The wetting time of GA and GA-HC microcapsules were not significantly different (p > 0.05). As a result, this study showed that hemicelluloses can be used as the coating material with gum arabic for food microencapsulation. (C) 2014 Elsevier Ltd. All rights reserved.