Anthocyanin recovery

The positions, numbers, and types of sugars on the anthocyanin molecule influence its bioaccessibility. Indeed, a recent human study reported that the acylation of anthocyaifins resulted in a sigififlcant decrease of anthocyanin recoveries in plasma and urine. In addition, anthocyanins form linkages with aromatic acids, aliphatic acids, and methyl ester derivatives, which can also affect their passage through the intestinal barrier. 

The extraction of anthocyanins is the first step in the determination of both total and individual anthocyanins in any type of plant tissue. The choice of an extraction method is of great importance in the analysis of anthocyanins and largely depends on the purpose of the extraction, the nature of the anthocyanins, and the source material. A good extraction procedure should maximize anthocyanin recovery with... 

To obtain anthocyanins closer to their natural state, a number of researchers have used neutral solvents for initial extraction such as 60% methanol, n-butanol, cold acetone, mixtures of acetone, methanol, and water, or simply water. Methanol is the most common solvent used for anthocyanin extraction. Metivier et al. (1980) compared the efficiency of extraction with three different solvents (methanol, ethanol, and water) and different acids, and found that methanol extraction was 20% more effective than ethanol and 73% more effective than water when used for anthocyanin recovery from grape pomace. 

Timberlake and Bridle (1971) and later Wrolstad and Durst (1998) compared the acetone-chloroform method of extraction to acidified methanol and, depending on the material used, the anthocyanin recoveries were comparable or up to 30% higher with the use of acetone. This procedure proved efficient for a wide range of anthocyanin-rich plants to achieve high recoveries with minimal degradation. - ... 

The use of ethyl acetate was suggested by Oszmianski and Lee (1990) to wash out phenolics other than anthocyanins. Finally, a relatively pure anthocyanin extract can be removed from the colnmn with acidified methanol (0.1% HCl). Anthocyanin extracts can be enriched in this way by use of solid phase purification, which is especially helpful for diluted samples such as biological samples. Two factors in the nse of these purification techniques are the stability of anthocyanins to the conditions nsed and the ease of anthocyanin recovery from the column. ... 

Chiriboga, C. and Francis, F.J., Anthocyanin recovery system from cranberry pomace, Proc. Am. Soc. Hortic. Sci., 95, 233, 1970. 

A key factor in the use of these purification techniques is the stability of anthocyanins under the conditions used as well as the ease of anthocyanin recovery from the column (Strack and Wray, 1989). 

Phihp, T., An anthocyanin recovery system from grape wastes, J. Food Sci., 1974, 39, 859. 

DiManro, A. et al.. Recovery of anthocyanins from pulp wash of pigmented oranges by concentration on resins, J. Agric. Food Chem., 50, 5968, 2002. 

Scordino, M. et al., Adsorption and recovery of anthocyanins on resins, m Proceedings of 3rd International Congress on Pigments in Food, Le Berre, Quimper, France, 2004, 78. 

Phenolic compounds are far more stable than vitamin C, showing retention/recovery values of 86-140% of this group, anthocyanins showed the lowest recovery rates. Phenolic compounds are also retained during storage. Odriozola-Serrano and others... 

Hoch, W.A., Singsaas, E.L., and McCown, B.H., Resorption protection. Anthocyanins facilitate nutrient recovery in autumn by shielding leaves from potentially damaging light levels, Plant Physiol, 133, 1, 2003. 

Ethyl acetate is used on the C18-adsorbed anthocyanins to remove polyphenolic compounds. More efficient polyphenolic recovery will be accomplished if residual water is removed from the cartridge with a nitrogen gas stream for 2 to 3 min before application of ethyl acetate. After washing the column with ethyl acetate, water should not be added because some anthocyanins could be eluted and lost. Ethyl acetate removal of polyphenolics is particularly recommended if the anthocyanin fraction is to be subsequently analyzed by electrospray mass spectroscopy. 

The potential impurities will vary according to the plant tissue extracted, and therefore the exact washing volume will vary. It is important to determine the impurities present and their retention properties on the column to minimize impurities in the final proanthocyanidin and maximize proanthocyanidin recovery. For this step, the use of a spectrophotometer is helpful in monitoring the eluate. Some typical impurities and monitoring wavelengths include organic acids (215 nm), flavan-3-ol monomers (280 nm), hydroxycinnamic acids (320 nm), andflavonols (365 nm). Anthocyanins are observable in the visible spectrum. 

However, due to the artifacts resulting from oxidation, hydrolysis of esters or ethers, or isomerization of phenolics during pretreatment of wines, as well as due to the low recovery rates of some phenolics, analysis of wine phenolics via direct injection of the filtered wine into the chromatographic column is often selected (80,82-84). For the red wine and musts (80), which were injected directly into the HPLC without sample preparation, a ternary-gradient system was often employed for phenolic compounds. Twenty-two phenolic compounds, including 10 anthocyanins, were analyzed from red wine. The separation of cinnamic acid derivatives (313 nm),... 

Woodward, G. Kroon, P. Cassidy, A. Kay, C. 2009. Anthocyanin stability and recovery implications for the analysis of clinical and experimental samples. J. Agric. Food Chem. 57 5271-5278. 

Aldehyde-tannin and aldehyde-anthocyanin condensation reactions result in polymer formation (Figure 1). These polymers may be responsible for haze formation in wine and the polymers may eventually precipitate out of solution (26). The polymerized tannins have different flavor properties than the monomeric starting units (21-29) and formation of anthocyanin polymers affects wine color. In addition, these reactions may result in a reduction of aldehyde flavors in the wine. These condensation reactions are discussed more fully in other chapters of this volume. The formation of strong covalent bonds between the aldehyde and the tannin or anthocyanin makes recovery of the bound aldehydes difficult. 

Content and Recovery of Anthocyanins, Chlorogenic Acid, Flavonol Glycosides and Procyanidins in Highbush Blueberries (Vaccinium corymbosum var. Bluecrop) during Juice Processing1... 

---