This research paper examines three commonly-used food coloring substances: annatto, cochineal and saffron. Topics addressed include the sources of the colorings (geographic and in nature), how they are used (with which foods), and how they are affected, e.g. by cooking or by acidity when used.
Annato is a naturally-occurring dye, ranging in color from a “bright yellow to deep orange” (“What is Annatto?” n.d.). The seeds of the achiote tree – indigenous to Central and Southern America – are the source of the dye, which in those regions is not only used as food coloring but simply as a dyestuff and for medicinal purposes, too. In terms of its use as food coloring, it is used widely; for example providing the yellow coloring in butter, margarines and cheeses, to give them a richer yellow hue. In order to produce the food coloring, the seeds are ground into a powder, or can be made into a paste or infused into an oil. Commercially, it is also used as a coloring in other food products such as meats and fish and other packaged foods including beverages. According to the same article, it is also called “poor man’s saffron” because it can produce a yellow color without paying the high cost of saffron.
Naz (2010), reports that annatto contains chemical elements bixin and norbixin. The more bixin it contains, the yellower it is; the more norbixin, the more red in the color. Naz notes that unless an acid-proof type is used, it turns somewhat pink at low levels of pH.
Bhasin and De La Cruz (2012) provide details of the process via which cochineal – a bright red food dye – is produced from the dried bodies of the females of the cochineal scale insects, which are indigenous to Mexico and countries in South America, living on the leaves and fruit of cactus, commonly the prickly pear. Farmers harvest the insects from the cactus, kill them by shaking, baking, or immersing them in hot water, then dry them in the sun. Around 70,000 insect bodies are used to make just one pound of the cochineal red dye. According to Bhasin and De La Cruz, about 200 tons of it are produced in Peru annually. It is used as a coloring in wide range of foods including various drinks, ice creams, yoghurts, canned fruits, jams, ketchup and even in soups.
Senese (updated 2010) reports that cochineal comprises about 10 percent carminic acid, and turns yellow in an acidic solution, or a deep violet color in an alkaline solution, though in present times is not often used as an acid/base indicator.
Saffron is a natural source of yellow coloring, well known for its use in Mediterranean cooking, particularly to color rice dishes like paella. It is the dried “threads” of parts of the flowers of a member of the crocus family (Crocus Sativus Linnaeus) and is cultivated primarily in Spain, although it is also produced in other countries including China, England, India, Iran and Turkey (Gaifyllia, n.d.). Good quality saffron has an aroma and flavor similar to that of honey and is used in only small amounts to produce the required color and flavor.
It is said to be the most expensive spice (by weight) in the world, although fortunately needs only a very small quantity to provide the wanted coloring. Using more than is needed can give the food a somewhat medicinal flavor. The main reason for its high cost is that the crocus stigmas must be hand-picked, and there are just three of them in each flower. They then have to be sorted and dried (“Saffron Price” n.d.).
Apart from its use in coloring rice, it is also used in stews and in fish dishes. Although the natural saffron threads are a red color, the effect on the cooked food is to give it a yellow shade (“What Is Saffron?” n.d.).
Bhasin, Kim and De La Cruz, Noelia. (2012). “Here’s What You Need To Know About The Ground-Up Insects Starbucks Puts In Your Frappuccino.” Business Insider. Retrieved from: http://www.businessinsider.com/how-cochineal-insects-color-your-food-and-drinks-2012-3?op=1
Gaifyllia, Nancy. (n.d.). “Saffron – Greek Herbs and Spices.” About.com. Greek Food. Retrieved from: http://greekfood.about.com/od/herbsspices/p/saffron.htm
Naz, Kiran. (2010). “Chemistry of food colors.” Feingold.org. Retrieved from: http://www.feingold.org/Research/PDFstudies/colors.pdf
“Saffron Price.” (n.d.). Saffron Spices. Retrieved from: http://www.saffronspices.co.uk/saffron-price
Senese, Fred. (updated 2010). “What are some natural acid/base indicators?” Frostburg State University. Retrieved from: http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/natural-indicators.shtml
“What is Annatto?” (n.d.). About.com Food Reference. Retrieved from: http://foodreference.about.com/od/Food-Additives/a/What-Is-Annatto.htm