Color extraction/stabilization

Beet extract is also used as a colorant. Extract is sold as either a concentrate prepared by evaporating beet juice under vacuum to a total soHds content of 40—60%, or as a powder made by spray-dryiag the concentrate. Both products usually contain ascorbic or citric acid as a stabilizer, and a preservative such as sodium propionate. On a dry-weight basis, beet extract typically contains between 0.4 and 1.0% betanin, 80% sugar, 8% ash, and 10% cmde proteia. 

The colors and stabilities of anthocyanin extracts from purple- and red-flesh potatoes were less affected by pH and temperature than commercial concentrates of... 

Bautista-Ortin. A.B., Improving color extraction and stability in red wines the use of maceration enzymes and enological taimins, Int. J. Food Sci. Technol., 40, 1, 2005. 

Production of the color involves centrifugal separation of the biomass, cell breakage, and extraction. Use of a salt solution rather than water as an extraction medium increases stability of the color during extraction. Methods for partial exclusion of the polysaccharide from the color extract in order to enhance resolubilization of the dried color were developed. These processes include either microfiltration or co-precipitation of the polysaccharide with an added positively charged polysaccha-... 

Guadalupe, Z., Palacios, A., Ayestaran, B. (2007). Maceration enzymes and mannoproteins a possible strategy to increase colloidal stability and color extraction in red wines.7. Agric. Food Chem., 55, 4854 862. 

Many attempts have been made to reduce the ammoniacal and sulfurous odor of the standard thioglycolate formulations. As the cosmetics market is very sensitive to the presence of impurities, odor, and color, various treatments of purification have been claimed to improve the olfactory properties of thioglycolic acid and its salts, such as distillation (33), stabilization against the formation of H2S using active ingredients (34), extraction with solvents (35), active carbon (36), and chelate resin treatments (37). 

Lube oil extraction plants often use phenol as solvent. Phenol is used because of its solvent power with a wide range of feed stocks and its ease of recovery. Phenol preferentially dissolves aromatic-type hydrocarbons from the feed stock and improves its oxidation stability and to some extent its color. Phenol extraction can be used over the entire viscosity range of lube distillates and deasphalted oils. The phenol solvent extraction separation is primarily by molecular type or composition. In order to accomplish a separation by solvent extraction, it is necessary that two liquid phases be present. In phenol solvent extraction of lubricating oils these two phases are an oil-rich phase and a phenol-rich phase. Tne oil-rich phase or raffinate solution consists of the "treated" oil from which undesirable naphthenic and aromatic components have been removed plus some dissolved phenol. The phenol-rich phase or extract solution consists mainly of the bulk of the phenol plus the undesirable components removed from the oil feed. The oil materials remaining... 

Several techniques can be used to separate phenol. Solvent extraction using gas oil or lube oil (process MSAs Sj and S2, respectively) is a potential option. Besides the purification of wastewater, the transfer of phenol to gas oil and lube oil is a useful process for the oils. Phenol tends to act as an oxidation inhibitor and serves to improve color stability and reduce sediment formation. The data for the waste streams and the process MSAs are given in Tables 3.4 and 3.5, respectively. 

During fermentation, the betacyanins turned out to be more stable than the betaxanthins, which is assumed to be due to their thermal stability rather than different tendencies of pigments toward microbial degradation. Besides these biological tools, beet extracts may also be purified by column chromatographic techniques. After removal of sugars, salts, and phenolics, the nature-derived color preparation will, however, require E number labeling. ... 

Malien-Aubert, C., Dangles, O., and Amiot, M.J., Color stability of commercial anthocyanin-based extracts in relation to phenolic composition protective effects by intra- and intermolecular copigmentation, J. Agric. Food Chem., 49, 170, 2001. 

Plocharski, W., Zbroszczyk, 1., and Lenartowicz, W., Aronia fruit Amnia melano-carpa Elliot) as a natural source of anthocyanin colorants. II. The stability of the color of aronia juices and extracts. Fruit Sci. Rep., 16, 41, 1989. 

High performance spectroscopic methods, like FT-IR and NIR spectrometry and Raman spectroscopy are widely applied to identify non-destructively the specific fingerprint of an extract or check the stability of pure molecules or mixtures by the recognition of different functional groups. Generally, the infrared techniques are more frequently applied in food colorant analysis, as recently reviewed. Mass spectrometry is used as well, either coupled to HPLC for the detection of separated molecules or for the identification of a fingerprint based on fragmentation patterns. ... 

For preparing lakes, a solution of aluminium sulfate (or chloride) is mixed with sodium carbonate, forming fresh alumina Al(OH)3. The colorant is then added and adsorbed on the surface of alumina. Usually the content of colorant in the lake ranges from 10 to 40%." The product is filtered, washed with water, dried, and milled. The product is allowed to contain unreacted alumina but must not contain more than 0.5% HCl-insoluble matter and not more than 0.2 % ether-extractable matter. - Lakes are insoluble in most solvents used for pure dyes, and they have high opacity and better stability to light and heat. Lakes impart their color by dispersion of solid particles in the food. The coloring properties of lakes depend on particles, crystal structures, concentrations of dye, etc. 

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