Kinetic Degradation and Storage Stability of β-Carotene Encapsulated by Freeze-Drying Using Almond Gum and Gum Arabic as Wall Materials

Abstract

The purpose of this study was to evaluate almond gum as an encapsulation material for β-carotene in comparison with gum arabic and to assess the functionality of the obtained powders applying them in cake as colorant. β-carotene gum powders were prepared by freeze-drying, then the kinetic degradation as well as the surface color changes of the powders, during a storage period of 70 days, under three relative humidities (RHs): 10, 45 and 80% were studied. The degradation rate of β-carotene and the decrease in the red color were described using a first-order kinetic model. The rate of degradation of β-carotene as well as that of the red color increased as increasing RH until a value at which the samples collapsed (80% RH). Results showed that microencapsulation with almond gum offered greater protection to β-carotene compared to gum arabic, and it was observed that the powders were able to color the studied food system (cake) in a homogenous manner. Practical Applications In recent years, a growing interest was observed for new sources of biopolymers to be used in the food industry. In this work, a novel gum exudate, almond gum from Prunus dulcis, is compared with the well-established gum arabic, an exudate from Acacia senegal trees, in terms of their encapsulation abilities. Almond gum is a gum copiously exuded from the trunk, branches and fruits of P. dulcis trees, after mechanical injury and/or infection by microorganisms. It has been proved in the present study that almond gum could be used successfully as a wall material to encapsulate β-carotene by freeze-drying. Moreover, the results suggest that almond gum could be explored as a novel and potential natural wall material for use in encapsulation of active ingredients to substitute many other wall materials which are not all the time evident.