Color Alteration of Encapsulated Beetroot (Beta vulgaris L.) Extract Upon Dissolving in Various pH Treatment

Abstract

It has been known that most natural pigments are unstable upon exposure against several environmental factors, such as thermal treatment, light, oxidizing or reducing agents, as well as acid or alkaline compounds. Encapsulation procedures is often adopted to adjust the solubility and provide protection to the natural pigments. Here, we prepared an encapsulated beetroot extract as the candidate of red bio-colorant. The primary aim of the present study is to investigate color alteration of encapsulated beetroot (Beta vulgaris L.) extract upon dissolving in various pH adjustment and prolonged storage. The McIllvainne buffer was prepared in various pH range, i.e. from 2 to 11. The encapsulated extract (0.1% w/v) was dissolved and the color of the solutions were measured regularly until 3 days storage under darkness at 200C. Any degradation or structural changes will cause color alteration, which were monitored through L*, a*, b* values, the hue angle (H°), chroma values (C), as well as color difference (DE). The results showed that pH 4 was the most favorable condition that brings least impact to the color alteration, even when the colored solution was kept in prolonged storage until 9 days.

Beta vulgaris L.—A Source with a Great Potential in the Extraction of Natural Dyes Intended for the Sustainable Dyeing of Wool

“…Betanin has no affinity for textile materials, so it does not determine their coloring. Furthermore, together with the other components of betalains, possess a high sensitivity to temperature [ 18 , 19 , 20 ] and pH [ 7 , 21 , 22 ], reason why the stability of betalains must be taken into account both in the extraction and dyeing processes [ 7 ]. The stability of these dyes depends on numerous dye-specific and external factors, as follows: the content of extract, high degree of glycosylation, high degree of acylation, pH, antioxidants, chelating agents, temperature, darkness, nitrogen atmosphere [ 7 , 14 , 15 ].…”