Optimization of Microwave-Assisted Extraction of Astaxanthin from Haematococcus Pluvialis by Response Surface Methodology and Antioxidant Activities of the Extracts

Abstract

Microwave-assisted extraction (MAE) was applied for the extraction of astaxanthin from Haematococcus pluvialis and response surface methodology (RSM) was used to optimize extraction parameters to the content of astaxanthin. Four independent variables such as microwave power (W), extraction time (sec), solvent volume (mL), and the number of extraction were optimized in this paper. The optimal conditions were determined and tri-dimensional response surfaces were plotted from the mathematical models. The F-test and p-value indicated that microwave power, extraction time, the number of extraction, and their quadratic had a highly significant effect on the response value (p <0.01), then the solvent volume and the interaction effects of microwave power and the number of extraction also displayed significant effect (p <0.05). Considering the extraction efficiency, the optimized conditions of MAE were as follows: microwave power was 141 W, extraction time 83 sec, solvent volume 9.8 mL, the number of extraction four times. About 594 ± 3.02 µg astaxanthin was extracted from Haematococcus pluvialis the dried powders (100 mg) under the optimal conditions, and it close to the predicted contents (592 µg). The antioxidant activities of the extracts obtained under optimal conditions were analyzed, and the results showed that the extracts presented strong ability of inhibiting the peroxidantion of linoleic acid, exhibited strong radical-scavenging properties against the DPPH, as well as strong reducing power.

Keywords:

• Antioxidant activities
• astaxanthin
• haematococcus pluvialis
• microwave-assisted extraction (MAE)
• response surface methodology

ACKNOWLEDGEMENT

This project was supported by Program for New Century Excellent Talents in University (NCET-04-0134), and the National Natural Science Foundation of China (30570181).

Notes

^a Date expressed in above table is the mean of triplicate analyses. And the unit of data in the last column is micrograms of astaxanthin equivalents per 100 mg dried powder of Haematococcus pluvialis.

^a The effects marked “ + ” were used in optimizing the response.

^a Mean ± standard deviation of triplicate determinations.