Evaluation of the pH and thermal stabilities of rosella anthocyanin extracts under solar light

Abstract

Available online A B S T R A C TAnthocyanin is considered as an unstable pigment, undergoes gradual degradation processes throughout the storage or use. The degradation of Rosella anthocyanin extract (RAE) in different pH solutions was studied under solar light and compared with solutions kept in the dark. It appears that RAE solutions under solar light were suffering rapid degradation than those kept in the dark. Moreover, RAE samples at higher pH values showed faster rates of degradation than those with lower pH values. A mechanism for degradation was suggested through the formation of hydroxyl radical which is responsible for demineralization process. It is also appears that as the initial concentration of the dye increases, the requirement needed for degradation increased as well. The thermal degradation behavior of RAE at temperature range 25-60°C under solar light showed first order kinetics with low activation energies. © 2015 Production and hosting by Elsevier B.V. on behalf of Beni-Suef University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Stability and Quality of Anthocyanin in Purple Sweet Potato Extracts

“…Concluded from different research which associated with various natural agricultural foods processing product, anthocyanin is recommend to be preserved under pH 3. This phenomenon may relate to the production of hydrogen peroxide, which could induce and accelerate the degradation anthocyanin [52]. In addition, some of the natural organic acid in the foods, like ascorbic acid, could protect anthocyanin from degradation by hydrogen peroxide [53].…”

Optimizing a Simple Natural Dye Production Method for Dye-Sensitized Solar Cells: Examples for Betalain (Bougainvillea and Beetroot Extracts) and Anthocyanin Dyes

“…Anthocyanins can be affected by age, sugars, organic acids, co-pigments, etc. These molecules are susceptible to degradation under the influence of many factors, including temperature or basic pH in the presence of oxygen [2,80,81]. For example, Askar and col. [80] find degradation of the extract in 3 h of about 5% for the most stable extract or 20% for the less one.…”

“…UV-Vis spectra of the extracts showed an increase in the wavelength of the maximum absorbance peak with increasing pH (also found in Refs. [80,83]), and the highest conversion efficiency was obtained using a pH 4 dye solution. Suyitno and col. studied papaya-leaf dye and the influence of pH, finding the most efficient and stable cell for pH 3.5 [70].…”

Stability of Anthocyanin During Processing, Storage and Simulated Digestion of Purple Sweet Potato Pasta

“…Anthocyanin of PSP primarily exists as an acylated form of phenolic acids having some advantages in pH and heat resistance, light sensitivity, and overall sensitivity (Xu et al 2015). The stability of anthocyanin and its color are correlated with anthocyanin structure and affected by heat, pH, light, and the presence of enzymes, phenolic acids, oxygen, sugar, sulfur dioxide and a metal ion (Askar et al 2015). Besides, color stability depends on the concentration of anthocyanin (Durge et al 2013).…”