Determination of phycobiliproteins by constant-wavelength synchronous spectrofluorimetry method in red algae

Phycobiliproteins are pigment–protein complexes, brilliant-colored and water soluble, existing in cyanobacteria and red algae. They have a great interest in food technology, food supplements, and pharmaceutical applications. Therefore it is important to have a fast, easy, and reliable method to determine the content of phycoerythrin (PE), phycocyanin (PC), and allophycocyanin (APC) in red algae. The samples are ground, extracted in phosphate buffer (pH 6.8), centrifuged, and the fluorescence scan of the supernatant is recorded. Optimum excitation-emission wavelength intervals (Δλ) for synchronous spectrofluorimetric analysis of the three phycobiliproteins were 10 nm for PE (LD = 10.9 × 10−3 mg/l) and APC (LD = 0.5 mg/l) and 40 nm for PC (LD = 0.77 mg/l). Algae analyzed contain PC and PE.