Bixins

Annatto is a colored pigment that is extracted from the Central and South American plant Bixa orellana. The color comes from the resinous outer covering of the seeds of the plant, which is composed of the carotenoid pigments bixin and norbixin and their esters. The central portion of those molecules is the same as that of the molecule beta-carotene, and the yellow-orange color of annatto comes from the same physical chemistry origins as the orange color of beta-carotene. 

GA is mainly used for fat microencapsulation because it produces stable emulsions in the case of most oils in a wide pH range, and it has the ability to form films (Kenyon, 1995). Barbosa et al., 2005 studied the photostability of the microencapsulated carotenoid bixin in different edible polysaccharide. They found out that microencapsulated bixin in GA was three to four times more stable than the one microencapsulated with maltodextrin, and about ten-fold than in homogeneous solvents. 

Barbosa, M.I. Borsarelli, C.D. Mercadante, A. Z. (2005). Light Stability of Spray-Dried Bixin Encapsulated with Different Edible Polysaccharide Preparations. Food Research International,Vol. 38, No. 8-9, (October-November 2005), pp 989-994, ISSN 0963-9969. 

Bixa Orellana seeds Bixin, norbixin (annatto) Food colouring... 

Carotenoids are also present in animal products such as eggs, lobsters, greyflsh, and various types of hsh. In higher plants, they occur in photosynthetic tissues and choloroplasts where their color is masked by that of the more predominant green chlorophyll. The best known are P-carotene and lycopene but others are also used as food colorants a-carotene, y-carotene, bixin, norbixin, capsanthin, lycopene, and P-apo-8 -carotenal, the ethyl ester of P-apo-8-carotenic acid. These are Upid-soluble compounds, but the chemical industry manufactures water-dispersible preparations by formulating coUoid suspensions by emulsifying the carotenoids or by dispersing them in appropriate colloids. ... 

FIGURE 4.2.2 Structures of carotenoids found in paprika (capsanthin and capsombin), saffron and gardenia (crocetin derivatives), and annatto (bixin and norbixin). 

Bixin, a diapocarotenoid with a cis configuration at the carbon 9 and two carboxylic groups (one methylated), accounts for more than 80% of the total carotenoid content in annatto seeds, and has only been encountered to date in these seeds. The amount of red pigments in annatto seeds varies from 1.5 to 4%, depending on the variety. Bixin is the main pigment in commercial annatto powder... 

FIGURE 4.2.3 UV-vis spectral changes and AAbs obtained by heating bixin in water ethanol (8 2) at 92°C. Inset shows kinetic profile at several wavelengths, with the solid lines representing the fitting of experimental data from the sum of two exponential functions. From Rios, A.O., Borsarelli, C.D., and Mercadante, A.Z., J. Agric. Food Chem., 53, 2307, 2005. With permission. 

Therefore no trustworthy results for kinetic analysis conld be obtained from the UV-vis absorption spectra due to the formation of bixin isomers and degradation products at different rate constants. " ... 

Degradation of bixin dissolved in a water medium with 0.2% Tween 80 followed first-order rate, either in the dark or under fluorescent light (700 lux), both at 21°C. As expected, degradation was much higher under light (ko, s = 3.79 x KTVmin) than in dark conditions = 7.25 x lO Vmin). ... 

Tocchini, L. and Mercadante, A.Z., Extraction and determination of bixin and nor-bixin, by HPLC, in aimatto spice ( colorifico ), Cienc. Tecnol. Aliment., 21, 310, 2001. 

Rios, A.O., Borsarelli, C.D., and Mercadante, A.Z., Thermal degradation kinetics of bixin in an aqneons model system, J. Agric. Food Chem., 53, 2307, 2005. 

Scotter, M.J., Characterization of the coloured thermal degradation products of bixin from annatto and a revised mechanism for their formation, Food Chem., 53, 111, 1995. Zechmeister, L., Cis-trans isomerization and stereochemistry of carotenoids and diphenylpolyenes, Chem. Rev., 34, 267, 1944. 

Fujii, R. et al., Cis-to-trans isomerization of spheroidene in the triplet state as detected by time-resolved absorption spectroscopy, J. Phys. Chem. A, 106, 2410, 2002. Montenegro, M.A. et al., Model studies on the photosensitized isomerization of bixin, J. Agric. Food Chem., 52, 367, 2004. 

Barbosa, M.I.M.J., BorsareUi C.D., and Mercadante, A.Z. Light stability of spray-dried bixin encapsulated with different edible polysaccharide preparations, Food Res. Int., 38, 989, 2005. 

E 100 1% bixin propylene glycol, potassium hydroxide, mono- and diglycerides Annatto extract in vegetable oil. Yellow-orange beverages Butter, oils, margarines, processed... 

The longest lifetime, highest incorporation yield (74%), and stabilization were observed for a fraction of bound bixin in 95% Arabic gum plus 5% sucrose as the matrix. The minor fraction of bixin, non-encapsulated, showed a short lifetime. When encapsulated in Arabic gum or in p-cyclodextrin compared with DE-20 and... 

DE-10 maltodextrin encapsulation, the best stability was obtained in the first case, the optimal bixin-to-matrix ratio being 1 3. 

Constant, P.B.L. et al.. Spray drying microencapsnlation of the bixin natural colorant. Proceedings of 3rd International Congress on Pigments in Food, Le Berre, Quimper, France, 2004, 154. 

FIGURE 5.3.4A Proposed biosynthetic pathway to bixin. Enzyme abbreviations and enzyme activities are defined in Table 5.3.1. 

Bouvier, R, Dogbo, O., and Camara, B., Biosynthesis of the food and cosmetic plant pigment bixin (annatto). Science 300, 2089, 2003. 

Dried or freeze dried samples can be extracted with water-immiscible solvents such as EtOAc or diethyl ether. For quantitative extraction, dried samples are preferably rehydrated at different times for example, 5 to 10 min for dried mangoes, 30 min for lyophihzed red peppers and pasta. Rehydration is followed by extraction with acetone or MeOH. Bixin and norbixin from a mix dry powder of annatto and com can quantitatively be extracted with MeOH followed by acetone. In order to improve pigment recovery, extruded foods require pre-digestion with enzymes to liberate the pigment from the matrix. ... 

More severe conditions, 35 ml of 35% methanolic KOH added to 10 mL extract in EtOAc and shaken for 20 min at 50°C, are necessary for the total conversion of bixin, an ester of a carotenoid acid, to norbixin in snacks. Since saponification yields the norbixin salt (K or Na, depending on the alkali) that is soluble in the aqueous phase, the pH should be decreased to 3.5 or even lower to allow extraction of the protonated norbixin by EtOAc and diethyl ether. ... 

The simplest and cheapest procedure to obtain standards is based on selective extraction followed by crystallization. A method developed to obtain lycopene from tomato residue using factorial experimental design consisted of a preliminary water removal with ethanol, followed by extraction with EtOAc and two successive crys-talhzation processes using dichloromethane and ethanol (1 4), producing lycopene crystals with 98% purity, measured by HPLC-PDA. Using this approach, bixin was extracted with EtOAc from annatto seeds that were previously washed with... 

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