Encapsulation, Properties, and Thermal Study of Red Biocolorant from Selected Plants Obtained Through Physical Extraction

Abstract

The human perception on food is closely associated with its color. Since the standard manufacturing procedure often causes partial even total degradation of natural pigments, resulting in color fading, the addition of colorants becomes necessary. Natural colorant, produced from plants or animals, has health promoting effects, better safety, and need not any specific toxicity evaluation. However, the extraction method will be crucial in determining the properties of this biocolorant. In the present study, red biocolorant was prepared from selected local plants i.e., red spinach, red cabbage, beetroot, and dragon fruit, through physical extraction in order to avoid the using of organic solvents. Then, we applied the encapsulation technique and evaluated its coloring and antioxidant properties, as well as its stability against thermal treatment. The results showed that the encapsulated biocolorant of red spinach and beetroot exhibited red hue at pH range 2-11, whereas those of red cabbage and dragon fruit indicated color alteration at different pH. The prominent red hue intensity was found at pH 4 for encapsulated beetroot extract, which endured up to 10 days at aqueous buffered solution when stored in the dark at 200 C. In addition, it underwent merely low degradation (∼30%) during incubation at 600 C for 30 minutes. The antioxidant activity of encapsulated biocolorant of beetroot was comparable to that of red cabbage, being higher than the others.