Inhibition of browning by antibrowning agents and phenolic acids or cinnamic acid in the glucose-lysine model

The effects of antibrowning agents and phenolic acids or cinnamic acid on the inhibition of browning were investigated with a glucose-lysine model. Six antibrowning agents (cysteine, glutathione, sodium sulfite, pentasodium tripolyphosphate, citric acid and oxalic acid) and four phenolic acids (ferulic, hydroxybenzoic, syringic and vanillic acids) were used. In order to investigate the antibrowning capacity of these agents, model solutions containing glucose, lysine and an antibrowning agent were heated at 50 degrees C in the presence of FeCl2, before being stored in nitrogen or air at VC or 30 degrees C. Browning was accelerated to some degree during storage in air at 30 degrees C. In the case of storage at VC, however, no browning was detected in nitrogen after four weeks. Citric acid was the most efficient antibrowning agent during storage in air at 30 degrees C and inhibited browning to 36% after four weeks. However, its antibrowning capacity was increased by 8-15% in the presence of any of the phenolic acids or cinnamic acid, essentially independently of concentration in the range 10 mu M to 10 mM or the type of phenolic acid. (c) 2005 Society of Chemical Industry.