Synthetic colorants stability

Candy starch jellies include sugar and (modilied) starch boiled to a certain viscosity and poured into a starch mold to form semi-solid jelly. Water-soluble synthetic colorants are generally added at concentrations of approximately 6% before the mixture is placed in gel-forming blocks. The shape and thickness of the final semi-transparent gel and subsequent coating with sugar sand may cause the color to become shaded. Natoal colorants are rarely used for such applications due to their low stability to temperature and pH. 

Freedom from toxicity is clearly the primary consideration for dyes used in foods, drugs and cosmetics, followed by high solubility and chemical stability in the appropriate medium of incorporation. The possibility that they may affect consumers adversely has caused growing concern [59,60]. Legislation over many years has increasingly restricted the usage of synthetic colorants to certain permitted products that have shown no harmful effects when tested rigorously. 

Mazza, G. and Brouillard, R., Color stability and structural transformations of cyanidin 3,5-diglucoside and four deoxyanthocyanins in aqueous solutions. J. Agric. Food Chem. 35, 1987. Roehri-Stoeckel, C. et al.. Synthetic dyes simple and original ways to 4-substituted flavylium salts and their corresponding vitisin derivatives. Can. J. Chem. 79, 1173, 2001. 

Colorants can be natural or synthetic. Natural colorants or pigments will be described in Chapter 20. Synthetic colorants are attractive to the food industry because they are superior to natural colorants in tinctorial strength, hue, and stability. Synthetic colorants provide a larger spectrum of colors. Their colors are strong therefore, very small amounts are required. They are also lower in cost and are more readily available (129,130,132-134). 

In mixed pigmentations, lecithin additives help to maintain a uniform mixmre in both alkyd and latex paints, ensuring uniform settling in storage. Latex paint redispersion is also made more effective with a water-dispersible lecithin additive than with a synthetic surfactant. Paint specimens with lecithin additives, remixed after 28 months of storage, maintained a very high level of uniform color stability (434). 

The synthetic color industry dates back to the accidental discovery of the first synthetic organic dye (mauve) in 1856. Sir William Henry Perkin, in an unsuccessful attempt to synthesize quinine, succeeded in obtaining a violet dye by the oxidation of aniline. This led other scientists to experiment and discover many new colors with superior properties to the natural pigments and extracts. The use of these new and different colors in foods, drugs, and cosmetics began almost immediately because of their tinctorial value, stability, and the many shades in which they were available. 

Butylated hydroxytoluene is also used at 0.5-1.0% w/w concentration in natural or synthetic rubber to provide enhanced color stability. 

Food additives are chemical substances, other than basic foods, used in commercial food preparation to achieve preservative, flavor, color, stability, and aesthetic effects. Though some of the chemicals used are derived naturally, most of the additives used in food production are synthetic and with little or no nutritional value.i22>23] A glance at almost any cookbook shows that chemical additives are not necessary for food preparation. Their use allows inferior ingredients to be used, extends the shelf lives of many products, and exposes people to toxic chemicals. 

The synthetic organic dyes are superior to the natural colorants in consistency of strength, range and brilliance of shade, stability, ease of application, and cost-effectiveness. However, the manner in which synthetic colorants are employed, from a safety viewpoint, has much to be desired. Therefore, regulations were introduced to control the use of these added food colorants. 

Acrylic resins are the materials of choice for almost all dental applications wherever synthetic plastics are favored for the restoration of missing teeth or tooth structures. This is not surprising because polymers derived from methacrylate esters fulfill most requisites of a restorative adequate strength, resilience and abrasion resistance dimensional stability during processing and subsequent use translucency or transparency simulating the visual appearance of the oral tissue that it replaces satisfactory color stability after fabrication resistance to oral fluids, food or other substances with which it may come Into contact satisfactory tissue tolerance low toxicity, and ease of fabrication into a dental appliance. 

Anthocyanins have a considerable potential in the food industry as safe and effective food additives. Their annual world production has been estimated to reach 10,000 tons from grapes alone. However, compared with synthetic colorants they have not been extensively used because of their instability towards a variety of chemical and physical factors. Notwithstanding, polyacylated anthocyanins display a marked stability which may prove to be of particular importance for food technology [33],... 

E252 Potassium nitrate Natural salt or synthetic Preservative, color stabilizer... 

Roy, G. Berardi, R. Chan, W. Lee, X. Prevention of synthetic color fading in beverages nsing botanically derived color stabilizers such as phenylpropenoic carbonyl compounds. U.S. Pat. Appl. Publ. US 2004091589, 2004 Chem. Abstr. 2004, 140, 405940. 

Stannic chloride is also used widely as a catalyst in Eriedel-Crafts acylation, alkylation and cycHzation reactions, esterifications, halogenations, and curing and other polymerization reactions. Minor uses are as a stabilizer for colors in soap (19), as a mordant in the dyeing of silks, in the manufacture of blueprint and other sensitized paper, and as an antistatic agent for synthetic fibers (see Dyes, application and evaluation Antistatic agents). 

Plastics and Synthetic Products. To prevent degradation of plastics at elevated processing temperatures, it is necessary to use suitable heat stabilizers. Eor example, flexible poly(vinyl chloride) (PVC) manifests uncontroUed color development in the absence of stabilizers. Accordingly, cadmium salts of organic acids are typically used in a synergistic combination with corresponding barium salts, in about a 1 3 cadmium barium ratio, to provide a cost-competitive heat stabilizer for flexible PVC. 

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