Physicochemical factors affecting the stability of two pigments: R-phycoerythrin of Grateloupia turuturu and B-phycoerythrin of Porphyridium cruentum

Phycoerythrin is a major light-harvesting pigment of red algae, which could be used as a natural dye in foods. The stability of R-phycoerythrin of Grateloupia turuturu and B-phycoerythrin of Porphyridium cruentum in relation to different light exposure times, pHs, and temperatures was studied. Regarding the light exposure time, after 48 h, the reduction in concentrations of B-phycoerythrin and R-phycoerythrin were 30 +/- 2.4% and 70 +/- 1%, respectively. Phycoerythrins presented good stability from pH 4 to 10. At pH 2, the reduction in concentration was 90 +/- 4% for B-phycoerythrin and 40 +/- 2.5% for R-phycoerythrin while, at pH 12, the phycoerythrins were degraded. Phycoerythrins showed good stability toward temperature, up to 40 degrees C. At 60 degrees C, the reduction in concentrations of B-phycoerythrin and R-phycoerythrin were 50 +/- 3.4% and 70 +/- 0.18%, respectively. Moreover, the best conditions of storage (-20 degrees C) were determined. (C) 2013 Elsevier Ltd. All rights reserved.