Issn: 1579 4377

ISSN: 1579-4377

EXTRACTION OF NATURAL ANTIOXIDANTS USING SUPERCRITICAL CARBON DIOXIDE AND HYDROTHERMAL

CONDITION

1Motonobu Goto, 2, 3Siti Machmudah, 3Mitsuru Sasaki

1Bioelectric Research Center, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555, JAPAN [email protected]

2Chemical Engineering Department, Sepuluh Nopember Institute of Technology, Kampus ITS Keputih –

Sukolilo, Surabaya, 60111, INDONESIA [email protected]; [email protected]

3Graduate School of Science and Technology, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555,

JAPAN [email protected]

ABSTRACT Supercritical CO2 and subcritical water are attractive solvents, particularly for the extraction of valuable bioactive natural compounds with application in food, cosmetics and pharmaceutical industries. The extraction of carotenoids from microalgae and food products and byproducts with clean extraction technologies is revised. Particular attention was paid to the optimization of the extraction and recovery operational conditions and to the development of suited mathematical models. KEYWORDS Natural antioxidants, supercritical carbon dioxide, hydrothermal.

Goto et al. EJEAFChe, 7 (8), 2008. [3250-3253]

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INTRODUCTION

Valuable compounds (mainly antioxidants) extraction from biological materials has paid much attention on food, cosmetic and pharmaceutical industries. Valuable compounds with antioxidant and antimicrobial properties, such as tocopherols, carotenoids and polyphenols, have been extracted from biological materials using supercritical carbon dioxide (SC-CO2) and hydrothermal condition in our group. Carbon dioxide (CO2) is the best supercritical fluid in the field of extraction of heat-sensitive components mainly destined for human nutrition (i.e., antioxidants) due to its chemical and physical properties and its low critical temperature and pressure values (31oC and 74 bar). Recently, water has also been used as subcritical solvent for extraction, especially in the field of food application. Water is a polar environmentally friendly solvent, especially for non heat-sensitive compounds.

Carotenoids, such as β-carotene, lycopene, lutein and astaxanthin, are the most famous one of the nutraceuticals. Carotenoids are a family of compounds that possess antioxidant and colouring properties for food, cosmetic and medical applications. They can be obtained in a large variety of natural sources, such as vegetables, animals, yeasts and microalgae. Carotenoids are traditionally extracted using organic solvents with the well-known problems of selectivity and organic solvents usage and pollution. Pretreatment of the raw materials should be taken into account in the efficiency of the extraction process, since carotenoids are frequently located inside complex cellular structures and can also be linked to the solid matrix. Carotenoids have very low or moderate solubilities in SC-CO2. Therefore, in several cases SC-CO2 has been added with a co-solvent. The most frequently used co-solvent is ethanol since its presence in the extracts does not compromise the use in food applications. However, it is better, when it is possible, to avoid the use of a co-solvent that tends to regenerate the problem of solvent elimination from the extracts.

Our group has extensively evaluated SC-CO2 extraction performance including optimization of the process on the antioxidant compounds (especially carotenoids) extracted from microalgae, fruit products and by products (seed and pulp or skin). SC-CO2 extractions were conducted with or without co-solvent to obtain high yield of astaxanthin from Haematococcus pluvialis [1], lycopene from tomato skin [2], carotenoids (β-carotene, lycopene and lutein) from rosehip fruit [3] and antioxidants from Nigella sativa seed [4]. Moreover, extraction of antioxidant component from Chlorella vulgaris using water in hydrothermal condition was also developed. Antioxidant activity of extract was also determined using DPPH method to evaluate the effect of extraction conditions on the extract. Figure 1 showed the effect of extraction pressure on the astaxanthin extracted. Higher extraction pressure caused decreasing the antioxidant activity, however higher yield of extracted antioxidants could be obtained at higher pressure Figure 2 as well as at higher temperature.

In addition, our group also developed mathematical model for evaluating SC-CO2 extraction process. Our group’s members conducted research on the field of sub and supercritical fluids for extraction, separation, reaction and material processing.


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Figure 1.- Antioxidant activity of astaxanthin extracted at various extraction pressures.

Figure 2.- Astaxanthin extracted at various extraction pressures.


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REFERENCES

[1] Machmudah, S.; Shotipruk, A.; Goto, M.; Sasaki, M.; Hirose, T. Extraction of astaxanthin from Haematococcus pluvialis using supercritical CO2 and ethanol as entrainer. Ind. Eng. Chem. Res., 2006, 45, 3652-3657.

[2] Topal, U.; Sasaki, M.; Goto, M.; Hayakawa, K. Extraction of lycopene from tomato skin with supercritical carbon dioxide: Effect of operating conditions and solubility analysis. J. Agric. Food Chem., 2006, 54, 5604-5610.

[3] Machmudah, S.; Kawahito, Y.; Sasaki M.; Goto, M. Process optimization and extraction rate analysis of carotenoids extraction from rosehip fruit using supercritical CO2. J. Supercrit. Fluids ., 2008, 44, 308-314.

[4] Machmudah, S.; Shiramizu, Y.; Goto, M.; Sasaki M.; Hirose, T. Extraction of Nigella sativa L. using supercritical CO2: A study of antioxidant activity of the extract. Sep. Sci. Technol., 2005, 40, 1267-1275.

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Issn: 1579 4377