Food Coloring and color

Food Coloring and color

Food color is any substance that is added to food or drink to change its color. Food coloring is used in both in commercial food production and in domestic cooking. Due to its safety and general availability, food coloring is also used in a variety of non-food applications. Organic molecules are the cause of color in food colorings. The objective of adding color to foods is to make them appealing, augment the loss of color during processing, to improve the quality and also to influence the consumer to buy a product. Sometimes, the aim is to simulate a color that is perceived by the consumer as natural, such as adding red coloring to glace cherries which would otherwise be beige.

Due to the increased awareness on therapeutic and medicinal properties, the demand of natural dyes is increasing worldwide. Natural dyes are those derived from naturally occurring sources such as plants, insects, animals and minerals. Among all the natural dyes, plant-based pigments have medicinal values so are mostly preferred.

Food colorings are tested for safety by various bodies around the world and sometimes different bodies have different views on food color safety. In the United States, FD&C numbers are given to approve synthetic food dyes that do not exist in nature, while in the European Union, E numbers are used for all additives, both synthetic and natural, which are approved in food applications.

There are three major categories of food colors;                                                                   1)Natural colors                                                                                                                           2)Synthetic colors                                                                                                                       3)Lakes and dyes

1.   Natural Food color

Natural Food Color is any dye, pigment or any other substance obtained from vegetable, animal, mineral, or source capable of coloring food drug, cosmetic or any part of human body, colors come from variety of sources such as seeds, fruits, vegetables, algae & insect. Natural food colors have taken on an added importance for many food manufacturers as the public demand for more products made from all natural ingredients grows.

The following table outlines the ranges of colors available. Many of these colors are available in different strengths, bases and shades.

Carmine:

Carmine also called Crimson Lake, Cochineal, Natural Red 4, C.I. 75470, or E120, is

a pigment of a bright red color obtained from the carminic acid produced by some scale insects, such as the cochineal and the Polish cochineal, and is used as a general term for a particularly deep red color of the same name. Carmine is used in the manufacture of artificial flowers, paints, crimson ink, rouge, and other cosmetics, and is routinely added to food products such as yogurt and certain brands of juice, most notably those of the ruby-red variety.

Production

Carmine may be prepared from cochineal, by boiling dried insects in water to extract the carminic acid and then treating the clear solution with alum, cream of tartar, stannous chloride, or potassium hydrogen oxalate; the coloring and animal matters present in the liquid are thus precipitated. Other methods are in use in which egg white, fish glue, or gelatin are sometimes added before the precipitation.

PAPRIKA:-

Paprika is a spice made from the grinding of dried fruits of Capsicum annuum (e.g., bell peppers or chili peppers). In many European languages, the word paprika refers to bell peppers themselves. The seasoning is used in many cuisines to add color and flavor to dishes. Paprika can range from sweet (mild, not hot) to spicy (hot). Flavors also vary from country to country.

The pigments of importance present in paprika are a mixture of capsanthin and capsorubin, both are carotenoids, responsible for the red color of the dye. This dye is used in cosmetics and in medicine

 

Carotenoids

The term carotene is used for several related hydrocarbon substances having the formula C40Hx, which are synthesized by plants but cannot be made by animals. Carotene is an orange photosynthetic pigment important for photosynthesis. Carotenes are all colored to the human eye. They are responsible for the orange color of the carrot, for which this class of chemicals is named, and for the colours of many other fruits and vegetables (for example, sweet potatoes and orange cantaloupe melon). Carotenes are also responsible for the orange (but not all of the yellow) colours in dry foliage.

The two primary isomers of carotene, α-carotene and β-carotene, differ in the position of double bonds in the cyclic group at the end.

α-carotene

β-carotene

Curcumin

Curcumin is the principal curcuminoid of the popular Indian spice turmeric, which is a member of the ginger family (Zingiberaceae). The other two curcuminoids are desmethoxycurcumin and bis-desmethoxycurcumin. The curcuminoids are polyphenols and are responsible for the yellow color of turmeric. Curcumin can exist in at least two tautomeric forms, keto and enol. The enol form is more energetically stable in the solid phase and in solution.

Curcumin incorporates several functional groups. The aromatic ring systems, which are polyphenols are connected by two α,β-unsaturated carbonyl groups. The two carbonyl groups form a diketone. The diketone form stable enols or are easily deprotonated and form enolates, while the α,β-unsaturated carbonyl is a good Michael acceptor and undergoes nucleophilic addition.

Chlorophyll

Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. Its name is derived from the Greek (chloros "green") and (phyllon "leaf"). Chlorophyll absorbs light most strongly in the blue portion of the electromagnetic spectrum, followed by the red portion. However, it is a poor absorber of green and near-green portions of the spectrum, hence the green color of chlorophyll-containing tissues. Chlorophyll was first isolated by Joseph Bienaime Caventou and Pierre Joseph Pelletier in 1817.

http://www.youtube.com/watch?v=Q0dhvWA5iq4

                

2.   Synthetic colors

Synthetic food colors are used widely in the food industry and despite the recent emphasis on natural colors continue to be the number one source of color. Synthetic colors are stable, economical and safe.

Typical applications are:

·         Beverages

·         Jams and Jellies

·         Desserts

·         Confections

·         Cakes and Cookies

·         Ready to eat Cereal

·         Pet foods

·         Pharmaceuticals

3.   Lakes and dyes

Food color lakes are the pigment form of the food color dyes. Lakes are used in applications when there is limited moisture or where a surface coating is required.

Typical applications for lakes and lake dispersions include:

·        Pan coated confections

·        Compound coatings

·        Pharmaceutical tablets and coatings

·        Dry powder blends

·        Snack foods

Color of Meat

There are two types of meat: red and white. Red meat contains a highly pigmented protein called myoglobin that stores oxygen in the muscle cells. More the myoglobin in the cells, the redder is the meat. However, as meat is heated, the proteins break down and shrink in size. When the interior of the meat reaches 170° F, hemichrome (a tan colored compound) levels rise, and the myoglobin becomes metmyoglobin, which gives well-done meat its brown-gray shade. White meat contains glycogen, which has a translucent "glassy" quality when it is raw. When it's cooked, the proteins recombine, or coagulate, and the meat becomes opaque and whitish. Myoglobin forms pigments responsible for making meat red. The color that meat takes is partly determined by the charge of the iron atom in myoglobin and the oxygen attached to it. When meat is in its raw state, the iron atom is in the +2 oxidation state, and is bound to a dioxygen molecule (O2). Meat cooked well done is brown because the iron atom is now in the +3 oxidation state, having lost an electron, and is now coordinated by a water molecule. Under some conditions, meat can also remain pink all through cooking, despite being heated to high temperatures. If meat has been exposed to nitrites, it will remain pink because the iron atom is bound to NO, nitric oxide (true of, e.g., corned beef or cured hams). Grilled meats can also take on a pink "smoke ring" that comes from the iron binding a molecule of carbon monoxide to give metmyoglobin. Raw meat packed in a carbon monoxide atmosphere also shows this same pink "smoke ring" due to the same coordination chemistry. Notably, the surface of the raw meat also displays the pink color, which is usually associated in consumers' minds with fresh meat. This artificially-induced pink color can persist in the meat for a very long time, reportedly up to one year. Hormel and Cargill are both reported to use this meat-packing process, and meat treated this way has been in the consumer market since 2003. Myoglobin is found in Type I muscle, Type II A and Type II B, but most texts consider myoglobin not to be found in smooth muscle.

Apples Turning Brown

Apples contain an enzyme called polyphenol oxidase (PPO), also known as tyrosinase. Cutting an apple exposes its cells to the atmospheric oxygen and oxidizes the phenolic compounds present in apples. This is called the enzymatic browning that turns a cut apple brown. In addition to apples, enzymatic browning is also evident in bananas, pears, avocados and even potatoes.

Ripening of Fruits

A simple hydrocarbon gas ethylene switches on the necessary genes that stimulate the secretion of the ripening enzymes which catalyze reactions to change the properties of the fruit. Ethylene channelizes the action of several other chemicals called hydrolase, amylase, kinase and pectinase. These enzymes convert starch to sugar, alter the cell walls to make them softer, neutralize acids and cause the fruit to emit an aroma.