Properties of chlorogenic acid quinone: relationship between browning and the formation of hydrogen peroxide from a quinone solution.
Chlorogenic acid is the major polyphenol in foods derived from plants and is a good substrate for polyphenol oxidase. Chlorogenic acid quinone (CQA-Q), which is an oxidative product of chlorogenic acid by polyphenol oxidase, is an important intermediate compound in enzymatic browning. CQA-Q was prepared, and its properties and the relationship with browning were examined. The quinone solution was yellow or orange, and its molecular absorption coefficient was estimated to be 1.7 x 10(3) for 325 nm and 9.7 x 10(2) for 400 nm in an acidic aqueous solution. Chlorogenic acid and H2O2 were spontaneously generated in the CQA-Q solution as the yellowish color of the solution gradually faded. A pale colored polymer was the major product in the reaction solution. Amino acids such as lysine and arginine added to CQA-Q solution did not repress the fading of the yellowish color of the solution. We concluded from these results that CQA-Q itself and a mixture of CQA-Q and amino acids did not form intensive brown pigments in the acidic aqueous solution. H2O2 spontaneously formed in the CQA-Q solution, and other polyphenols might have played an important role in the formation of the brown color by enzymatic browning.
Murata
Masatsune
M
Department of Nutrition and Food Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan. murata@cc.ocha.ac.jp
Sugiura
Makie
M
Sonokawa
Yuko
Y
Shimamura
Tomomi
T
Homma
Seiichi
S
D002726:Chlorogenic Acid / Q000031:analogs & derivatives* / Q000737:chemistry*; D005504:Food Analysis; D006861:Hydrogen Peroxide / Q000737:chemistry*; D015394:Molecular Structure; D010944:Plants / Q000737:chemistry; D011809:Quinones / Q000737:chemistry*
D011809:Quinones; D002726:Chlorogenic Acid; D006861:Hydrogen Peroxide