FNH 303: Food Colorants

Food Colorant

Food additive used to color food; alongside it’s usual uses of bringing back color to natural or degrading colors, it can also be used for flavor and characteristic identification, vitamin protection, and minor component addition

Visible Spectrum

Portion of the electromagnetic spectrum where light is visible; ranges from 400-700 nanometers

Conjugated Bonds

Alternating single and double or triple bonds. The length of these typically determine the color of organic compounds

Structural Modifications

Changes in molecular design, such as carbon chain branching, nitrogen or oxygen double bonds, and transition metals; all of which can affect color perception

Color Labelling

A recent law passed in ingredient labels were food colors must be declared by their common name.

Synthetic Colors

Colors that come from synthetic sources. While they have their benefits (cheap, stable, uniform quality, high strength, and lack of taste, among others), a lot of them have unforeseen health risks. Note that almost all of these have a natural counterpart.

Water-Soluble Colors

Type of synthetic color that is water soluble thanks to having a full or partial charge. Can be charged, anionic or cationic, or zwitterionic.

Lake Colors

Type of synthetic color that is water insoluble by precipitating with a metal. Generally used in low-moisture products for dispersion in oils or water thanks to their low color bleeding.

Azo

Synthetic color group that include a double-bonded nitrogen pair. Contains a variety of color ranges, from red to orange to yellow.

Triarylmethane

Synthetic group that include three aromatic rings bonded to a central carbon atom. Contains mostly green and blue hues.

Xanthene

Synthetic group that contain iodine and oxygen atoms branching from chained aromatic rings. Creates a bright red color seen in maraschino cherries.

Indigotine

Synthetic group derived from the indigo family, made up of nitrogen-containing groups joined by double bonds. Soluble in ethanol, serves as a pH and ozone indicator, and forms blue colors.

Natural Colors

Colors that come from natural sources. Oftentimes have other functional properties such as being antioxidants or vitamins, but have cost, stability, or availability issues

Anthocyanin

Largest group of natural food colors formed by combining anthocyanidins with sugars. Water-soluble, widely distributed in plants, and come in red, pink, purple, and blue colors. Note that they are only colored at low pHs and heats.

Sulphur Dioxide

A common gas added to preserve fruit pulp or juices. However, adding it will degrade anthocyanins and cause them to lose colors.

Self Association

The stacking of anthocyanin molecules on top of each other, allowing for the stabilization of AH+; this allows them to preserve the color and increases light absorption.

Co-Pigmentation

The stacking of anthocyanin molecules on top with other colorless molecules, serving as a shield that stabilizes AH+ or quinoidal and increases their intensity.

Metal Complexation

The act of anthocyanin molecules grabbing onto metal ions, shifting the color blue or purple but stabilizing it in the process.

Betalain

Natural food color group formed by combining betalamic acids with amino acids or amino acid derivatives. Water-soluble, widely distributed in plants, and come in yellow, red, and purple colors. Note that they are only colored at high pHs and heats.

Cochineal

Natural red dye that comes from the bodies of insects. Water-soluble, can go from orange to red to purple depending on pH. Highly heat and light stable, and is found in juices, ice creams, yogurts, and candies.

Carotenoids

Natural dye that comes in orange, red, yellow, and purple hues. Soluble in CHCl3, minimal solubility in oil, stable in high heat (but lowers vitamin A activity) and alkaline conditions. Found in corn, red pepper, eggs, and carrots, and used for processed food fortification, supplementation alongside colorings

Bleaching

The whitening of carotenoids via light, metals, peroxides, or enzymes. Desirable in some foods, but undesirable in others.

Porphyrins

Natural dye created from four pyrole rings. Soluble in water or CHCl3, forms ring structure with metals and non-covalently links to proteins. Comes in green, blue, red, and brown hues.

Chlorophyll

Green porphyrin found in nettles, parsley, and alfalfa. Quality indicator due to it degrading with acid, heat, enzymes, and maturation.

Phycocyanin

Blue porphyrin found in spirulina and cyanobacteria. Water-soluble, only colored in lightly acidic or alkaline solutions.

Hemoglobin

Water soluble porphyrin made of a tetrapyrrole and four polypeptide chains. Makes up the red and brown color in dehydrated blood.

Myoglobin

Water soluble porphyrin made of a tetrapyrrole and a single polypeptide chain. Color is determined by various factors such as iron state, 6th site, and chemical modification, with colors such as blue, red, brown, pink, and green.

Leghemoglobin

Water soluble porphyrin found in legume roots. Has a red color similar to hemoglobin, allowing for its use in vegan burgers.

Caramel and Melanoidin

Natural brown hues made up of a complex mixture of chemicals. Can either be created from caramelization or the maillard reaction.