Carotenoid analysis

Schulz, H., Baranska, M., and Baranski, R., Potential of NIR-FT-Raman spectroscopy in natural carotenoid analysis. Biopolymers, 11, 212, 2005. 

Rodriguez-Amaya, D.B. and Kimura, M., Harvest Plus Handbook for Carotenoid Analysis Harvest Plus Technical Monograph 2, Washington, International Food Policy Research Institute and International Center for Tropical Agriculture, 2004. 

Rodriguez- Amaya, DL., A Guide To Carotenoid Analysis in Foods, International Life Sciences Instimte Press, Washington, D.C., 2001. 

Insights into the mechanisms of carotenoid degradation can be followed in model systems that are more easily controlled than foods and the formation of initial, intermediate, and final products can also be more easily monitored. However, extrapolation to foods must be done with caution because simple model systems may not reflect the nature and complexity of a multicomponent food matrix and the interactions that can occur. In addition, even in model systems, one must keep in mind that carotenoid analysis and identification are not easy tasks. 

Deh, J. and Molnar, R, Paprika carotenoids analysis, isolation, structure elucidation, Curr. Org. Chem., 6, 1197, 2002. 

Sandmann, G., Carotenoid analysis in mutants from Escherichia coli transformed with carotenogenic gene cluster and Scenedesmus obliquus mutant C-6D, Meth. Enzymol. 214, 341, 1993. 

Schoefs, B., Chlorophyll and carotenoid analysis in food products. A practical case-by-case view. Trends Anal. Ghent., 22, 335, 2003. 

Alkaline hydrolysis (saponification) has been used to remove contaminating lipids from fat-rich samples (e.g., pahn oil) and hydrolyze chlorophyll (e.g., green vegetables) and carotenoid esters (e.g., fruits). Xanthophylls, both free and with different degrees of esterification with a mixture of different fatty acids, are typically found in fruits, and saponification allows easier chromatographic separation, identification, and quantification. For this reason, most methods for quantitative carotenoid analysis include a saponification step. 

It is recognized that carotenoid analysis is inherently difficult and errors can be introduced in aU steps. Thus continued efforts focusing on analytical refinements are justified so that analytical variability is not mistaken for natural variation of samples. 

Partali, V., Liaaen-Jensen, S., Slagsvold, T., and Lifjeld, J. T. 1987. Carotenoids in food chain studies. II. The food chain of Pams spp. monitored by carotenoid analysis. Comp. Biochem. Physiol. B 87 885-888. 

A Waters 2690 Alliance HPLC equipped with a 996 photodiode array and a 896 IJV/Vis detector was used for carotenoid analysis. The column (Phenomenex, Torrance, CA) was a 250x4.6mm Ultracarb 3 pm C-18 stationary phase and elution was carried out isocratically at a flowrate of l.OmL/min with 85 15 (v v) acetonitrileimethanol (HPLC grade) containing 0.1% triethyl amine to prevent on-column carotenoid decomposition. 

Rodriguez-Amaya D. 2001. A Guide to Carotenoid Analysis in Foods. Washington, DC ILSI Press, International Life Science Institute. 

Eor more comprehensive information, Rodriguez-Bemaldo and Costa [440] have recently made an exhaustive review about carotenoid analysis in vegetable samples. Carotenoids can easily isomer-ize and be oxidized, leading to artifacts in the analysis. Therefore, the extraction must be carried out quickly, avoiding exposure to light, oxygen, and high temperatures. 

DC106 Van Breemen, R. B. Innovations in carotenoid analysis using LC/MS. 

C N.M.R. Spectroscopy. This powerful technique is not yet being used routinely in carotenoid analysis, but the review by Moss " discusses methods and applications and tabulates chemical shift data obtained for a range of carotenoids. Elsewhere the C n.m.r. spectra of (35,3 5)-astaxanthin (60), its 15-cw-isomer, its diacetate, and its 15,15 -didehydro analogue are presented and assigned, along with H n.m.r., u.v., and c.d. data. 

An internal standard is a compound that is not present in the sample, but is chemically and physically similar to the analytes of interest. A fixed quantity is incorporated into the calibration solutions. The same concentration of internal standard is added to the samples during extraction to compensate for analyte recovery and injection variability. As seen in Figure F2.3.I, Echinenone, which is not typically found in foods, is used as the internal standard. Unfortunately, compounds which may be used as internal standards for carotenoid analysis are not readily available commercially. 

S. J. 1992. Applications of fast atom bombardment mass spectrometry (FAB-MS) and continuous-flow FAB-MS to carotenoid analysis. Methods Enzymol. 213 322-336. 

An important early reference describing ionization conditions for carotenoid analysis using electrospray MS. 

Describes the selection and optimization of matrix and mobile-phase conditions for carotenoid analysis using LC-MS/MS with FAB-MS ionization. 

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