Increased thermal stability of anthocyanins at pH 4.0 by guar gum in aqueous dispersions and in double emulsions W/O/W

• Published in: International journal of biological macromolecules 2018-10, Vol.117, p.665-672
• Main Authors: de Almeida Paula, Daniele, Mota Ramos, Afonso, Basílio de Oliveira, Eduardo, Maurício Furtado Martins, Eliane, Augusto Ribeiro de Barros, Frederico, Cristina Teixeira Ribeiro Vidigal, Márcia, de Almeida Costa, Nataly, Tatagiba da Rocha, Carolina
• Format: Article
• Language: English
• Subjects: Double emulsion, anthocyanins; Guar gum; Stability
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2018.05.219

This study investigated the potential of guar gum and a double emulsion to increase the thermal stability of anthocyanins. The effect of different guar gum concentrations (0%, 0.25%, 0.50%, 0.75%, 1%, 1.25%, 1.5% and 1.75%) was evaluated in relation to color stability, concentration of anthocyanins and antioxidant capacity under storage for 10 days at 40 °C in the presence of light. The addition of guar gum (0.75–1.75%) significantly increased the color stability and bathochromic displacement of the samples, suggesting the occurrence of a co-pigmentation process. The total anthocyanin content was to 41% after storage in treatments without guar gum, but when using 1.25% guar gum the final concentration was 70% and there was a 2.4 fold increase in the half-life time of anthocyanins. A significant effect of guar gum addition on the antioxidant capacity of the samples was observed. In the second step, the anthocyanins were added together with 1.25% guar gum in the internal aqueous phase of the double emulsion and stored for 10 days at 40 °C in the presence of light. The double emulsion presented high encapsulation efficiency (90.6%) and high kinetic stability under the conditions evaluated, in addition to protecting anthocyanin molecules against degradation.