Optimization of a process for extracting astaxanthin from Phaffia rhodozyma by acidic method was investigated, regarding several extraction factors such as acids, organic solvents, temperature and time. Fractional fac...Optimization of a process for extracting astaxanthin from Phaffia rhodozyma by acidic method was investigated, regarding several extraction factors such as acids, organic solvents, temperature and time. Fractional factorial design, central composite design and response surface methodology were used to derive a statistically optimal model, which corresponded to the following optimal condition： concentration of lactic acid at 5.55 mol/L, ratio of ethanol to yeast dry weight at 20.25 ml/g, temperature for cell-disruption at 30 ℃, and extraction time for 3 min. Under this condition, astaxanthin and the total carotenoids could be extracted in amounts of 1294.7 μg/g and 1516.0 μg/g, respectively. This acidic method has advantages such as high extraction efficiency, low chemical toxicity and no special requirement of instruments. Therefore, it might be a more feasible and practical method for industrial practice.展开更多
method of extracting astaxanthin from Phaffia rhodozyma with various solvents after acid washing was investigated. The extraction efficiency was distinctly increased after acid washing of P. rhodozyma cells. When the ...method of extracting astaxanthin from Phaffia rhodozyma with various solvents after acid washing was investigated. The extraction efficiency was distinctly increased after acid washing of P. rhodozyma cells. When the concentration of HCl was 0.4 mol.L^-1, the highest extraction efficiency of astaxanthin was achieved which was about three times higher than the control. Acetone or benzene as single polar or non-polar solvent was the most ef- fective solvent in our research. With a combination of isopropanol and n-hexane （volume ratio of 2 ： 1）, the maxi- mal extraction efficiency was achieved, approximately 60% higher than that obtained with a single solvent. The liquid-solid ratio and the extracting time were also optimized. Under the optimum extraction conditions, the extraction yield of astaxanthin exceeded 98%.展开更多
Euphausia pacific is an important source of natural astaxanthin. Studies were carried out to assess the extractability of astaxanthin from E. pacific using subcritical 1, 1, 1,2-tetrafluoroethane （R134a）. To examine...Euphausia pacific is an important source of natural astaxanthin. Studies were carried out to assess the extractability of astaxanthin from E. pacific using subcritical 1, 1, 1,2-tetrafluoroethane （R134a）. To examine the effects of multiple process variables on the extraction yield, astaxanthin was extracted under various conditions of pressure （30-150bar）, temperature （303-343 K）, time （10-50rain）, flow rate （2-10gmin-1）, moisture content （5.5%-63.61%）, and particle size （0.25-0.109mm）. The results showed that the extraction yield increased with temperature, pressure, time and flow rate, but decreased with moisture content and particle size. A maximum yield of 87.74% was obtained under conditions of 100bar, 333K, and 30min with a flow rate of 6gmin-1 and a moisture content of 5.5%. The substantial astaxanthin yield obtained under low-pressure conditions demonstrates that subcritical R134a is a good alternative to CO2 for extraction of astaxanthin from E. pacific.展开更多
The influence of alkali on astaxanthin and the optimal working wave length for measurement of astaxanthin from Haematocoecus crude extract were investigated, and a spectrophotometric method for precise quantification ...The influence of alkali on astaxanthin and the optimal working wave length for measurement of astaxanthin from Haematocoecus crude extract were investigated, and a spectrophotometric method for precise quantification of the astaxanthin based on the method of Boussiba et al. was established. According to Boussiba＇s method, alkali treatment destroys chlorophyll. However, we found that： 1） carotenoid content declined for about 25% in Haematococcus fresh cysts and up to 30% in dry powder of Haematococcus broken cysts after alkali treatment; and 2） dimethyl sulfoxide （DMSO）-extracted chlorophyll of green Haematococeus bares little absorption at 520-550 nm. Interestingly, a good linear relationship existed between absorbance at 530 nm and astaxanthin content, while an unknown interference at 540-550 nm was detected in our study. Therefore, with 530 nm as working wavelength, the alkali treatment to destroy chlorophyll was not necessary and the influence of chlorophyll, other carotenoids, and the unknown interference could be avoided. The astaxanthin contents of two samples were measured at 492 nm and 530 nm; the measured values at 530 nm were 2.617 g/100 g and 1.811 g/100 g. When compared with the measured values at 492 nm, the measured values at 530 nm decreased by 6.93% and 11.96%, respectively. The measured values at 530 nm are closer to the true astaxanthin contents in the samples. The data show that 530 nm is the most suitable wave length for spectrophotometric determination to the astaxanthin in Haematococcus crude extract.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 20702019)the Foundation for Young Professors of Jimei University, China
文摘Optimization of a process for extracting astaxanthin from Phaffia rhodozyma by acidic method was investigated, regarding several extraction factors such as acids, organic solvents, temperature and time. Fractional factorial design, central composite design and response surface methodology were used to derive a statistically optimal model, which corresponded to the following optimal condition： concentration of lactic acid at 5.55 mol/L, ratio of ethanol to yeast dry weight at 20.25 ml/g, temperature for cell-disruption at 30 ℃, and extraction time for 3 min. Under this condition, astaxanthin and the total carotenoids could be extracted in amounts of 1294.7 μg/g and 1516.0 μg/g, respectively. This acidic method has advantages such as high extraction efficiency, low chemical toxicity and no special requirement of instruments. Therefore, it might be a more feasible and practical method for industrial practice.
基金Supported by the Fundamental Research Funds for the Central Universities （FRF-AS-10-001B） and the National Natural Science Foundation of China （11071013）.
文摘method of extracting astaxanthin from Phaffia rhodozyma with various solvents after acid washing was investigated. The extraction efficiency was distinctly increased after acid washing of P. rhodozyma cells. When the concentration of HCl was 0.4 mol.L^-1, the highest extraction efficiency of astaxanthin was achieved which was about three times higher than the control. Acetone or benzene as single polar or non-polar solvent was the most ef- fective solvent in our research. With a combination of isopropanol and n-hexane （volume ratio of 2 ： 1）, the maxi- mal extraction efficiency was achieved, approximately 60% higher than that obtained with a single solvent. The liquid-solid ratio and the extracting time were also optimized. Under the optimum extraction conditions, the extraction yield of astaxanthin exceeded 98%.
基金supported by the National Natural Science Foundation of China (No.31071541)
文摘Euphausia pacific is an important source of natural astaxanthin. Studies were carried out to assess the extractability of astaxanthin from E. pacific using subcritical 1, 1, 1,2-tetrafluoroethane （R134a）. To examine the effects of multiple process variables on the extraction yield, astaxanthin was extracted under various conditions of pressure （30-150bar）, temperature （303-343 K）, time （10-50rain）, flow rate （2-10gmin-1）, moisture content （5.5%-63.61%）, and particle size （0.25-0.109mm）. The results showed that the extraction yield increased with temperature, pressure, time and flow rate, but decreased with moisture content and particle size. A maximum yield of 87.74% was obtained under conditions of 100bar, 333K, and 30min with a flow rate of 6gmin-1 and a moisture content of 5.5%. The substantial astaxanthin yield obtained under low-pressure conditions demonstrates that subcritical R134a is a good alternative to CO2 for extraction of astaxanthin from E. pacific.
基金Supported by the Yunnan Provincial Sciences and Technology Department,China (No. 2007AD009)the National Natural Science Foundation of China (No. CNSF30570183)the Knowledge Innovation Program of Chinese Academy of Sciences (No. KSCX2-YW-G-060)
文摘The influence of alkali on astaxanthin and the optimal working wave length for measurement of astaxanthin from Haematocoecus crude extract were investigated, and a spectrophotometric method for precise quantification of the astaxanthin based on the method of Boussiba et al. was established. According to Boussiba＇s method, alkali treatment destroys chlorophyll. However, we found that： 1） carotenoid content declined for about 25% in Haematococcus fresh cysts and up to 30% in dry powder of Haematococcus broken cysts after alkali treatment; and 2） dimethyl sulfoxide （DMSO）-extracted chlorophyll of green Haematococeus bares little absorption at 520-550 nm. Interestingly, a good linear relationship existed between absorbance at 530 nm and astaxanthin content, while an unknown interference at 540-550 nm was detected in our study. Therefore, with 530 nm as working wavelength, the alkali treatment to destroy chlorophyll was not necessary and the influence of chlorophyll, other carotenoids, and the unknown interference could be avoided. The astaxanthin contents of two samples were measured at 492 nm and 530 nm; the measured values at 530 nm were 2.617 g/100 g and 1.811 g/100 g. When compared with the measured values at 492 nm, the measured values at 530 nm decreased by 6.93% and 11.96%, respectively. The measured values at 530 nm are closer to the true astaxanthin contents in the samples. The data show that 530 nm is the most suitable wave length for spectrophotometric determination to the astaxanthin in Haematococcus crude extract.
