Carotenoids extraction method

CO2 extraction has been prevalent for the isolation of essential oils and other natural lipophilic pigments like carotenoids. Hot water and superheated water extraction methods are used for analytical preparation of polar pigments. The technique is commonly referred to as subcritical water extraction because the practitioners of this approach come from SEE backgrounds. 

Matrix solid-phase dispersion (MSPD) is the extraction method of choice for the analysis of solid samples, such as plant material, foodstuffs or tissue samples [26]. This method has been developed especially for solid or viscous matrices. MSPD is preferable to other extraction techniques, because the solid or viscous sample can be directly mixed with the sorbent material of the stationary phase [27]. As the carotenoid stereoisomers stay bound in their biological matrix until the elution step, they are protected against isomerisation and oxidation [28]. The extraction scheme of MSPD is shown in Figure 5.2.1. 

Supercritical fluid extraction (SFE) with carbon dioxide (CO2) has been used as an alternative to the previously mentioned liquid-liquid extraction methods for food samples. One of the main advantages of SFE is that it yields extracts that are free from chemical residues (Spanos et ah, 1993). Where other extraction methods require large amounts of organic solvents that can be costly to purchase and dispose of, SFE is low cost, nontoxic, and environmentally friendly (Marsili and Callahan, 1993). Carbon dioxide is the most commonly used supercritical fluid, as its low critical temperature (31 °C) makes it favorable for the extraction of heat-sensitive carotenoids (Vagi et ah, 2002). 

Howe, J.A. Tanumihardjo, S.A. 2006. Evaluation of analytical methods for carotenoid extraction from biofortified maize (Zea mays sp.). J. Agric. Food Chem. 54 ... 

Taungbodhitham, A.K. Jones, G.P. Wahlqvist, M.L. Briggs, D.R. 1998. Evaluation of extraction method for the analysis of carotenoids in Suits and vegetables. Food Chem. 63 577-584. 

Avocado (Persea americana Mill) is an important tropical fruit and a good source of lipophilic phytochemicals such as monounsaturated fatty acids, carotenoids, vitamin E and sterols [46]. It has several cultivars that present great variation on time of fruit production and oil content in the pulp. Studies have indicated that the avocado oil is similar to olive oil and can be used in cosmetics and also for human consumption [47, 48]. New Zealand, Mexico, Chile United States and South America are among the main avocado oil producers. Avocado oil has the advantage that can be obtained from the fruit by means of a cold extraction methods, which is an easy and low technology that allow maintain in the oil significant amounts of the bioactive phytochemicals present in the fruit [47]. 

The natural ubiquity of carotenoids in both the animal and plant kingdoms means that there is an enormous variety of sources and materials containing them, with very different characteristics. Consequently, no single, universally applicable extraction method can be established. In each case, the extraction system must be adapted to the characteristics of the tissue or source from which the pigments will be extracted. 

Mateos, R. and Garcfa-Mesa, J.A., Rapid and quantitative extraction method for the determination of chlorophylls and carotenoids in olive oil by high-performance hquid chromatography. Anal Bioanal Chem., 385, 1247, 2006. 

Many different methods have been used to evaluate the antioxidant capacities of isolated molecules, carotenoids, and other natural antioxidants and of foods and food extracts containing antioxidants. It is not the purpose of this chaper to review all the methods, but some general points can be made. First, when using only one test to evaluate the antioxidant capacities of carotenoids, one should be very careful in the interpretation of obtained data. Indeed, different results can be obtained with different tests applied to the same molecules. At least two different methods should be used to evaluate the antioxidant activity of a molecule or a food extract. " Second, lipophilicity is an important factor to consider in testing the antioxidant activities... 

Experimental evidence in humans is based upon intervention studies with diets enriched in carotenoids or carotenoid-contaiifing foods. Oxidative stress biomarkers are measured in plasma or urine. The inhibition of low density lipoprotein (LDL) oxidation has been posmlated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Since carotenoids are transported mainly via LDL in blood, testing the susceptibility of carotenoid-loaded LDL to oxidation is a common method of evaluating the antioxidant activities of carotenoids in vivo. This type of smdy is more precisely of the ex vivo type because LDLs are extracted from plasma in order to be tested in vitro for oxidative sensitivity after the subjects are given a special diet. 

High performance liquid chromatography (HPLC) has been by far the most important method for separating chlorophylls. Open column chromatography and thin layer chromatography are still used for clean-up procedures to isolate and separate carotenoids and other lipids from chlorophylls and for preparative applications, but both are losing importance for analytical purposes due to their low resolution and have been replaced by more effective techniques like solid phase, supercritical fluid extraction and counter current chromatography. The whole analysis should be as brief as possible, since each additional step is a potential source of epimers and allomers. 

Carmen Socaciu was bom in Cluj-Napoca, Romania and earned a BSc in chemistry in 1976, an MSc in 1977, and a PhD in 1986 from the University Babes-Bolyai in Cluj-Napoca, an important academic centre located in the Transylvania region. Dr. Socaciu worked as a researcher in medical and cellular biochemistry for more than 10 years, and became a lecturer in 1990 and full professor in 1998 in the Department of Chemistry and Biochemistry of the University of Agricultural Sciences and Veterinary Medicine (USAMV) in Cluj-Napoca. She extended her academic background in pure chemistry (synthesis and instrumental analysis) to the life sciences (agrifood chemistry and cellular biochemistry). Her fields of competence are directed especially toward natural bioactive phytochemicals (carotenoids, phenolics, flavonoids), looking to advanced methods of extraction and analysis and to their in vitro actions on cellular metabolism, their effects as functional food ingredients, and their impacts on health. 

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