Article ID Journal Published Year Pages File Type
5133023 Food Chemistry 2018 10 Pages PDF
Abstract

•The colour of phycocyanin (PC) is stabilised by interaction with micelles formed from SDS.•Micelles stabilise PC as well as the purified chromophore, phycocyanobilin (PCB).•The stabilisation could be related to conformational stabilisation of PCB.

Phycocyanins are pigment-protein complexes with potential application as natural food colourants. The perceived colour of phycocyanins varies with pH, and a method to stabilise the colour over a broad range of pH values is requested by the food industry. In this work, the stabilising effect of sodium dodecyl sulphate (SDS) micelles on pH-induced colour variations of phycocyanin was examined. SDS was shown to stabilise the blue conformation of phycocyanin, preventing formation of the green conformation, which is prevalent at low pH. The studies indicated that the stabilising effect occurred through interaction or entrapment of the non-protonated, circular helical (blue) structure of phycocyanin and the anionic SDS micelles. The interaction prevented conversion into protonated, partially unfolded (green) phycocyanin species. This information opens for new possibilities to stabilise the blue conformation of phycocyanin and to apply the stabilised form in food products as a natural blue food colourant.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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