Betanin

 ( Biological Pigments ) 

Betanin, or beetroot red, is a red glycoside food dye obtained from ; its aglycone, obtained by hydrolyzing the glucose molecule, is betanidin. As a food additive, its E number is E162. As a food additive, betanin has no safety concerns.

The color of betanin depends on pH; between pH four and five, it is bright bluish-red, becoming blue-violet as the pH increases. Once the pH reaches alkaline levels, betanin degrades by hydrolysis, resulting in a yellow-brown color.

Betanin is a betalain pigment, together with isobetanin and other betacyanins.

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Sources Betanin is usually obtained from the extract of beet juice; the concentration of betanin in red beet can reach 300–600 mg/kg. Other dietary sources of betanin and other betalains include the Opuntia cactus, Swiss chard, and the leaves of some strains of amaranth.

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Uses The most common uses of betanins are in coloring ice cream and powdered soft drink beverages; other uses are in some sugar confectionery, e.g. Fondant icing, sugar strands, sugar coatings, and fruit or cream fillings. In hot processed candies, it can be used if added at the final part of the processing. Betanin is also used in soups as well as tomato and bacon products. Betanin has "not been implicated as causing clinical food allergy when used as a coloring agent".Dean D. Metcalfe, Hugh A. Sampson, Ronald A. Simon: Food Allergy: Adverse Reactions to Foods and Food Additives. 4th Ed., Blackwell Publishing, 2009, , p. 416.

Betanin has also shown to have antimicrobial activity and can be used as a natural antimicrobial agent in food preservation.

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Photophysics and photoprotection Betanin exhibits very weak fluorescence, with a quantum yield typically much lower than 1%. The lifetime of the first excited state of betanin, formed after photon absorption depends strongly on the environment's viscosity. In low-viscosity solvents, the excited-state relaxation pathway is enhanced, resulting in a shortened lifetime and reduced fluorescence intensity. Short excited state lifetime makes betanin an excellent dissipator of light energy. It was demonstrated that more betanin is accumulated in Mesembryanthemum crystallinum L. leaves when the plant is exposed to strong light or UV light. It was proposed that betanin can perform Photoprotection in plants by shielding them from excessive light conditions.

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Degradation and stability

Betanin degrades when subjected to light, heat, and oxygen; therefore, it is used in frozen products, products with a short shelf life, or products sold in dry state. Betanin can survive pasteurization when in products with high sugar content. Its sensitivity to oxygen is highest in products with a high water content and/or containing metal cations (e.g. iron and copper); like ascorbic acid and can slow this process down, together with suitable packaging. In dry form betanin is stable in the presence of oxygen.

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Safety

Use of betanin and other betacyanins as food coloring has a long history in Europe. A scientific panel for the European Food Safety Authority found that acute or chronic toxicity and carcinogenicity studies were too limited to make conclusive safety evaluations, and that the amounts food additive were similar to those with naturally occurring betanin. The panel also concluded that there was insufficient information to assign an acceptable daily intake level for beetroot red.

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See also

• Betalain

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Further reading

Categories: Biological Pigments, Food Colorings, Glucosides, Betalains, Indoles, E-number Additives, Enoic Acids

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