Extractability of C-Phycocyanin from Limnospira platensis and Its Antioxidant Capacity Using Spark Discharge Plasma

Phycocyanin as water-soluble, accessory pigment is commonly extracted from Limnospira platensis (L. platensis). The pigment is often used as natural food colourant and is a potential antioxidant. Usually, the pigment is extracted with several freeze–thawing cycles with subsequent purification steps. The cell disintegration with physical plasma (here spark discharges) is already described for microalgae and was tested for the extraction of phycocyanin from L. platensis. Moreover, calcium chloride was examined as a non-toxic and inexpensive precipitator in the purification step. Samples were treated with water as solvent alone or precipitated with calcium chloride. Also, samples were divided for immediate analysis after extraction and 24 h incubation after the respective cell wall rupture method with subsequent analysis. The extracts were tested for C-phycocyanin (C-PC) concentration, content, selectivity, and radical scavenging activity. Spark discharges were administered with 4 Hz, 100 ns high-voltage pulses of 35 kV, resulting in a pulse energy of ca. 0.2 J/pulse. For freeze–thawing, a maximum yield of 2.75 mg/mL was obtained, for spark discharges, max. 0.24 mg/mL. However, despite a lower concentration, a remarkable purity was found for plasma-treated samples. In addition, radical scavenging activity was not influenced by the spark discharge exposure.