Thana Praiya, Machmudah Siti, Goto Motonobu, Sasaki Mitsuru, Pavasant Prasert, Shotipruk Artiwan
Department of Chemical Engineering, Chulalongkorn University, Phayathai Rd, Patumwan, Bangkok 10330, Thailand.
Bioresour Technol. 2008 May;99(8):3110-5. doi: 10.1016/j.biortech.2007.05.062. Epub 2007 Jul 20.
Experimental design was used to investigate the effect of operating temperature (40-80 degrees C), operating pressure (30-50 MPa), and extraction time (1-4h) of supercritical carbon dioxide (SC-CO2) extraction on astaxanthin yields and the extract antioxidant activity (IC50). The ranges of the factors investigated were 40-80 degrees C for the operating temperature (X1), 30-50 MPa for the operating pressure (X2), and 1-4h for the extraction time (X3). The statistical analysis of the experiment indicated that pressure, extraction time, and the interaction between temperature and pressure (X1X2) had significant effect on astaxanthin yields. The central composite design showed that polynomial regression models were in good agreement with the experimental results with the coefficients of determination of 0.924 and 0.846 for astaxanthin yield and antioxidant activity, respectively. The optimal condition for astaxanthin yield within the experimental range of the variables studied was at 70 degrees C, 50 MPa, and 4h. At this condition, the predicted amount of astaxanthin extracted was 23.04 mg/g (2.3 wt% or 83.78% recovery). For the effect of experimental extraction conditions on antioxidant activity, IC50 was used as an index, which is the concentration that gives a 50% reduction in the absorbance of the ABTS free radical. The analysis of the results showed that the interaction between the operating temperature and operating pressure (X1X2) was the only significant factor affecting the extract antioxidant activity. The statistical model gave the minimum point for antioxidant activity at 67 degrees C, 40.3 MPa, and 1.86 h of extraction, at which the value for 1/IC50 was 0.39 l/mg (or IC50 was 2.57 mg/l).
采用实验设计方法研究超临界二氧化碳（SC-CO2）萃取的操作温度（40 - 80℃）、操作压力（30 - 50MPa）和萃取时间（1 - 4h）对虾青素产量及提取物抗氧化活性（IC50）的影响。所研究因素的范围为：操作温度（X1）40 - 80℃，操作压力（X2）30 - 50MPa，萃取时间（X3）1 - 4h。实验的统计分析表明，压力、萃取时间以及温度与压力之间的相互作用（X1X2）对虾青素产量有显著影响。中心复合设计表明，多项式回归模型与实验结果吻合良好，虾青素产量和抗氧化活性的决定系数分别为0.924和0.846。在所研究变量的实验范围内，虾青素产量的最佳条件为70℃、50MPa和4h。在此条件下，预测提取的虾青素量为23.04mg/g（2.3wt%或83.78%的回收率）。对于实验萃取条件对抗氧化活性的影响，以IC50作为指标，IC50是使ABTS自由基吸光度降低50%的浓度。结果分析表明，操作温度与操作压力之间的相互作用（X1X2）是影响提取物抗氧化活性的唯一显著因素。统计模型给出抗氧化活性的最低点为67℃、40.3MPa和1.86h的萃取时间，此时1/IC50的值为0.39l/mg（或IC50为2.57mg/l）。
