Nature s Colors Gretchen Goehrend & Associates, Inc.

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1 Nature s Colors 1. What is Color? 2. Color and Food 3. Types of Food Colorants 4. Legislation 5. Natural Colorants 6. Factors Determining Color Choices Primary Information Source: Natural Food Colorants, 2 nd edition, edited by GAF Hendry & JD Houghton, Chapman & Hall, 1996.

2 Color is perceived light. 1. What is Color? White light is made up of varying electromagnetic wave lengths representing colors that are either absorbed or reflected by color pigments. When reflected wave lengths reach our eyes they activate some 3 million color perceiving cone cells on the retina. These cone cells are sensitive to red, yellow, or blue wave lengths that make up the primary colors, and their blends known as secondary colors--green, orange, and violet. The rate of absorption of these wave lengths, measured in nanometers (nm), will result in the perception of an opposite color. For example, a compound with a maximum absorption of 600nm of yellow, will produce a product that will be perceived as deep blue. In other words, our eye perceives only the reflected, not the absorbed color. But not everyone perceives color in the same way. The degree of variation in color perception and its prevalence is unknown, but is believed to be considerable.

3 2. Color and Food Color has everything to do with our expectations of our food s flavor and quality. In tests where the color of food is not matched to its flavor, people have trouble identifying the flavor correctly. Color also affects the apparent level of sweetness, as in a strawberry drink, in which the deeper the color, the sweeter the drink seems to be. For centuries prior to the development of synthetic colors, natural products derived from spices, berries, and herbs were used to enhance the color of food. During the past century, due to ready availability and lower cost, the use of synthetic colors in food has increased. Since 1976, however, there has also been an increase in the use of colors derived from natural sources. It was in 1976 that certain synthetic colors were called into question for health reasons.

4 3. Three Types of Food Colorants 1. Synthetic Colors. These are colorants that do not exist in nature and are produced by chemical synthesis. 2. Nature Identical Colors. These are colorants that are manufactured by chemical synthesis so as to be identical chemically to colorants found in nature, for example beta carotene, riboflavin and canthazanthin. 3. Natural Colors. These are organic colorants that are derived from natural edible sources, for example, curcumin (from turmeric), bixin (from annatto), and anthocyanins (from red fruits and cabbage).

5 4. Legislation Natural colors are widely permitted throughout the world. When considering the use of color, however, it is important not to rely only on a simplified list of permitted colors. There is no universally accepted definition of the term natural colors. The FDA prefers to use the terms certified for approved synthetic colors, and exempt for colors from natural sources. Many countries exclude spices with coloring properties from their list, insisting they be referred to as ingredients rather than colorants. Color usage may be controlled through legislation by stipulating: (1) which colors may be used in food; (2) types of food that may be colored; and (3) maximum quantities of color that can be added to a food. Some colors are considered a quantum satis, that is without restriction. It is unlikely, in the near future, that new colors will be added to the lists since the cost of toxicological testing is extremely high. Future efforts will be aimed at the production of more stable forms of currently permitted colorants.

6 5a. Natural Colorants Factors Blue ( Red Cabbage) Yellow (Turmeric) Red ( Beet Juice) Source Red cabbage is the most common source used for food, while grape is the source used for most beverages. Turmeric is cultivated in many tropical countries Red beets have been cultivated for many including India, China, Pakistan, Haiti, and hundreds of years in temperate climates. It is Peru. the juice of the root that is used as a colorant. Legislation Permitted in USA and in the EU. Curcumin is permitted as a color in the EU; however many countries simply list turmeric without specification to color strength. Permitted universally. Colorant Anthocyanins are the compounds responsible for shades of red to purple in a multitude of fruits and vegetables. There are over 300 different anthocyanins. Curcumin is the principal color present in the Pigments present are called collectively rhizome of the turmeric plant (Curcuma longa). betalains. These are divided into two classes: It is produced by crystallization of the oleoresin red betacyanins and yellow betaxanthins. and has a purity level of 95%. Solubility Water soluble. Ground curcumin is insoluble in water and imparts color either by dispersion throughout the food or by dissolution of the curcumin in vegetable oil. Curcumin must be converted to a convenient application form using an emulsifer/ dilutent, e.g., Polysorbate 80, which is an ideal carrier for curcumin. Very water soluble. ph Anthocyanins are extremely sensitive to ph. In fact, they act as ph indicators. They gradually change from red through blue-red, purple, blue and green to yellow as the ph increases from ph1 through 4, 6, 8, 12, and 13 respectively. Color intensity is also ph dependent being greatest at ph 1.0 and decreasing rapidly as ph rises. Curcumin gives a lemon yellow color in acidic (low ph) media with a distinct green shade. As the ph increases, the green shade fades. In alkaline conditions (above ph 9.0) the color becomes distinctly orange. Greatest stability at ph 4.5. At ph 7.0 betanin degrades more rapidly. Not recommended for alkaline solutions.

7 Oxygen Heat 5b. Natural Colorants Factors Blue ( Red Cabbage) Yellow (Turmeric) Red ( Beet Root) Anthocyanins will slowly oxidize when in aqueous solution. Good stability. The viscosity of liquids and pastes is temperature dependent and their ease of dispersibility into a foodstuff will decrease with decreasing temperatures. Stable to heat and will withstand baking. The viscosity of liquids and pastes is temperature dependent and their ease of dispersibility into a foodstuff will decrease with decreasing temperatures. Light Good stability Sensitivity to light limits curcumin's use in food. Water Activity Susceptible to heat degradation. Rate of loss of color at different temperatures also dependent on several factors including ph and water activity. High temperature for a short time is acceptable, but it is most important to cool the product immediately after processing. Allow the end product to fully equilibrate before evaluating the final color shade and strength. Some degradation will occur. Amount of free water available for dissolution of a color significantly affects stability. In aqueous solution, the higher the solids content, the more stable the color. Applications Blue will be most affected by the ph of the substance to which it is added. Icing and frosting recipes need to be formulated to take into account changes in ph. The effects of fats, cream of tartar, egg whites, etc., are still being tested. Enzymatic degradation and interaction with food components (e.g., ascorbic acid, metal ions, sugars, copigments) may also occur. These various factors are interdependent. Add a small amount of yellow to create various greens. Curcumin is a very intense color with a very bright yellow appearance even at low doses. The color becomes easily saturated and, at levels of 2ppm, it is hard to perceive a small increase in color-dose level. When using curcumin, it is important to determine the minimum dose level required to give the desired color. Dose levels are often very low usually in the range of 5 to 20 ppm. Egg yellow may be achieved as a blend of curcumin and annatto. Beet juice produces very intense colors, generally with a blue caste to them. A small amount of curcumin may to added to achieve a holiday red. More yellow added with create orange.

8 5c. Natural Colorants Factors Blue ( Red Cabbage) Yellow (Turmeric) Red ( Beet Root) Sugar Confectionery Produces purple blues to green blues Acceptable in all sugar confectionery products when added to frostings and icings, not excessively exposed to light. depending on ph and other factors. We are still testing to determine the best recipes in order get the best color. Other uses Sorbets and water ices Ice cream, yoghurt Fondants, sugar strands, sugar coatings and 'cream' fillings are all suitable applications. Microbiological Quality Color Notes Susceptible to yeasts and molds Variations in color due to the age of the colorant and how it has been stored as well as the ingredients in the frosting or icing can be sources of great frustration when working with this color. Because curcumin is such an intense color, when it is mixed with blue to produce green, or with red to produce orange, it may gain the ascendency over the other colors as the product 'cures.' In the case of yellow, less will usually be best. Susceptible to yeasts and molds. Exact color obtained will depend on the variety of beetroot used and the extraction and processing conditions. The difference will be in the degree of blueness. When using 'blue' beetroot juice, it will be necessary to add yellow or orange color to achieve a 'true' red. Primary Information Source: Natural Food Colorants, 2 nd edition, edited by GAF Hendry & JD Houghton, Chapman & Hall, 1996.

9 6. Factors Determining Color Choices Primary Information Source: Natural Food Colorants, 2 nd edition, edited by GAF Hendry & JD Houghton, Chapman & Hall, Shade of color required. 2. Legislation of the countries in which food is to be sold. 3. Physical form: liquid, powder, or gel. 4. Composition of food stuff, in particular whether it is aqueous or contains significant levels of oil or fat. 5. Processing conditions, particularly temperatures and times for which temperatures are held. 6. ph. Stability and color shade of most natural colors are affected by ph. 7. Packaging, which will determine how much oxygen or light will reach the product. 8. Required shelf-life and storage conditions. 9. Colors disperse best at room temperature or above.