Methods of phycobiliprotein extraction from Gracilaria crassa and its applications in food colourants

Phycobiliproteins from red seaweeds are pigment-protein complexes constituting three different pigments such as phycocyanin, allophycocyanin and phycoerythrin. The present investigation is focused on phycobiliproteins in red seaweed Gracilaria crassa collected from Pudumadam coast, Rameswaram. Three different solvents such as phosphate buffer, distilled water and seawater were used for extraction of pigments and quantity and purity were compared. Among the three different solvents, distilled water showed better results for phycoerythrin extraction; seawater proved to be a good solvent as well as preservative for all phycobiliproteins. The purity index (PI) was 3.79 for R-phycoerythrin (R-PE), purified by DEAE (Diethylaminoethyl) cellulose 52. The stability of phycobiliproteins was assessed using different preservatives. NaCl at 5% proved to be suitable for long-term preservation of phycoerythrin. Abbreviations * PC, phycocyanin * APC, allophycocyanin * R-PE, R-phycoerythrin * BHT, butyl hydroxyl toluene * DEAE, diethylaminoethyl * FW, fresh weight * TCSPC, time-correlated single photon counting spectrometer.