A novel yellow pigment, furpipate, derived from lysine and furfural

Furfural is an important intermediate compound of the Maillard reaction of pentose or ascorbic acid. We examined the browning of furfural and lysine by heating these compounds in solution and found two yellow compounds. The first, furpipate, is a novel pipecolic acid derivative and was (Z)-3-(2-furylmethylidene)-3H, 4H, 5H, 6H-pyridine-2-carboxylic acid. The second was decarboxylated-furpipate. Furpipate shows absorption maxima at 370 nm and 310 nm under acidic and alkaline conditions, respectively. This compound was the major colored compound of the heated solution containing lysine and furfural.