The effect of temperature and moderate electric field pre-treatment on carotenoid extraction from Heterochlorella luteoviridis

Moderate electric field (MEF) was evaluated as a pre-treatment (0-180 V) to carotenoid extraction at four different temperatures (30, 40, 50 and 60 degrees C) followed by a extraction step using ethanol/water as solvent (75% of ethanol, v/v). During the extraction step, samples were collected at 1, 5, 30, 40 and 50 min. Results showed that MEF allowed higher carotenoid concentration at the beginning of the extraction step at 30, 40 and 50 degrees C, leading to better extraction results along the extraction time. A different behaviour was observed at 60 degrees C probably due to the thermal effects on the cell and to carotenoids thermal degradation. The highest extraction yield, 86% of the total carotenoid content (compared to exhaustive extraction), was achieved at both 40 and 50 degrees C with the MEF pre-treatment, indicating that a high extraction yield can be obtained even at relatively low temperatures (40 degrees C).