Enhanced stability of natural anthocyanin incorporated in Fe-containing mesoporous silica

Abstract

Anthocyanin is known as a safe coloring material although its poor stability often limits more extended use. In this study, we tried the enhancement of the photostability of the anthocyanin by the incorporation into the pore of HMS type mesoporous silica containing various metal 2 ions. The anthocyanin was adsorbed on the HMS by pouring a highly concentrated anthocyanin solution to the dried HMS, urging the incorporation of the dye into the mesopore by a capillary condensation. Improved stability of the anthocyanin against visible irradiation was achieved by the adsorption onto the HMS containing Fe 3+ , although other metal ions in the HMS showed less effect on the stabilization. From the UV-Vis spectroscopy, the Fe 3+ species effective for the stabilization of the anthocyanin was found to be the tetrahedral one highly dispersed in the silica framework. The decrease in the absorptivity of the anthocyanin on the Fe-HMS compared to other metal-containing HMS suggested that the Fe-HMS promoted the aggregate formation of the anthocyanin molecules. The highly dispersed Fe 3+ species had an ability to gather the anthocyanin molecule close to itself, resulting in tight incorporation of the dye inside the mesopore. The incorporation and aggregate formation of the anthocyanin was expected to contribute to the improvement of the stability against irradiation.

Interaction of Protein Isolate with Anthocyanin Extracted from Black Soybean and Its Effect on the Anthocyanin Stability

“…Recently, studies show that the restrictions can be overcome by developing polyphenol–protein (Chung, Rojanasasithara, Mutilangi, & Mcclements, , ), polyphenol–metal (Kohno et al., ), and polyphenol–phenols complexes (Gordillo et al., ; Qian, Liu, Zhao, Cai, & Jing, ). Until now, these studies were mainly concentrated in grape, red wine, and beverages at pH 3 to 4 (Chung, Rojanasasithara, Mutilangi, & Mcclements, ; Gonçalves, Wessel, Cardoso, Rocha, & Coimbra, ; Rodrigues, Ricardo‐Da‐Silvaa, & Laureano, ), whereas studies at weakly acidic pH and neutral pH were fewer.…”

The effects of selected metal ions on the stability of red cabbage anthocyanins and total phenolic compounds subjected to encapsulation process

“…In one study, red anthocyanins on the surface of thermally processed red pears (D'Anjou) were reportedly stabilized through complexation with stannous ion (Ngo & Zhao, ). Anthocyanin was also found to enhance stability against visible irradiation as it was absorbed onto hexagonal mesoporous silica (HMS) containing Fe 3+ (Kohno et al, ). On the other hand, many authors use encapsulation to enhance the shelf life of the colorant in different environments (Beatus, Raziel, Rosenberg, & Kopelman, ; Desobry, Netto, & Labuza, ; Gradinaru, Biliaderis, Kallithraka, Kefalas, & Garcia‐Viguera, ; Selim, Tsimidou, & Biliaderis, ; Wagner & Warthesen, ).…”

“…In one study, red anthocyanins on the surface of thermally processed red pears (D'Anjou) were reportedly stabilized through complexation with stannous ion (Ngo & Zhao, 2009). Anthocyanin was also found to enhance stability against visible irradiation as it was absorbed onto hexagonal mesoporous silica (HMS) containing Fe 31 (Kohno et al, 2015).…”

Montmorillonite as a reinforcement and color stabilizer of gelatin films containing acerola juice

“…The lowest ΔE* value was presented by the film with 3.9 wt% Mt, and higher Mt concentrations resulted in increased ΔE* values, probably due to some Mt aggregation, which may have impaired Mt-anthocyanin interactions. The color shift (to redder shades) of the films with Mt may be ascribed to electrostatic host-guest interaction (Kohno et al, 2007(Kohno et al, , 2009 and/or the formation of aggregates of anthocyanin molecules near Mt platelets (Gavara et al, 2013;Kohno et al, 2015), while some steric protection by Mt (Kohno et al, 2007(Kohno et al, , 2009 may have also contributed to the color stability of the films throughout storage.…”