Riboflavin-5'-Phosphate
The short version
The phosphate ester of vitamin B2 — a more water-soluble form for fortification and yellow coloring.
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Where it comes from
Manufactured by chemical phosphorylation of riboflavin (E101) followed by neutralization. The phosphate group dramatically improves water solubility (~80× plain riboflavin), making it the preferred form for clear and lightly colored beverages.
How it's used
Used as a yellow-orange colorant and B2 vitamin source in fortified beverages, yogurts, dietary supplements, and egg-substitute products. Provides natural yellow tones without the cloudiness or sedimentation of plain riboflavin.
Safety profile
ADI not specified — considered safe. Hydrolyzed in digestion to riboflavin and phosphate, both essential nutrients. Excess water-soluble vitamins are excreted in urine (sometimes producing the bright-yellow urine color associated with B-complex supplements).
Physical & chemical properties
Yellow-orange crystalline powder. Highly soluble in water (much more than plain riboflavin). Sensitive to light — degrades in transparent packaging.
Regulation worldwide
Permitted globally without restrictive limits.
Educational information only. Not medical or dietary advice.