title: Inhibition of enzymatic browning in actual food systems by the Maillard reaction products.
abstract: BACKGROUND
  The Maillard reaction occurring between amino acids and sugars produces neo-formed compounds having certain levels of antioxidant activity depending on the reaction conditions and the type of reactants. The objective of this study was to investigate enzymatic browning inhibition capacity of Maillard reaction products (MRPs) formed from different amino acids including arginine (Arg), histidine (His), lysine (Lys) and proline (Pro).
  
  
  RESULTS
  The inhibitory effects of the MRPs on polyphenol oxidase (PPO) were determined. The total antioxidant capacity (TAC) of MRPs derived from different amino acids were in the order Arg > His > Lys > Pro. The TAC and PPO inhibition of MRPs were evaluated as a function of temperature (80-120 °C), time (1-6 h) and pH (2-12). Arg-Glc and His-Glc MRPs exhibited strong TAC and PPO inhibition. Increasing temperature (up to 100 °C) and time also increased TAC and PPO inhibition. Kinetics analysis indicated a mixed type inhibition of PPO by MRPs.
  
  
  CONCLUSIONS
  The results indicate that the MRPs derived from Arg and His under certain reaction conditions significantly prevent enzymatic browning in actual food systems. The intermediate compounds capable of preventing enzymatic browning are reductones and dehydroreductones, as confirmed by liquid chromatographic-mass spectrometric analyses.
authors.affiliation: Department of Food Engineering, Hacettepe University, Ankara, Turkey.
authors.forename: Burçe Ataç
authors.initials: BA
authors.lastname: Mogol
authors.forename: Asli
authors.initials: A
authors.lastname: Yildirim
authors.forename: Vural
authors.initials: V
authors.lastname: Gökmen
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism*; D004156:Catechol Oxidase / Q000037:antagonists & inhibitors; D005638:Fruit / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D015416:Maillard Reaction; D027845:Malus / Q000201:enzymology*; D013696:Temperature; D013997:Time Factors
chemical_list: D000596:Amino Acids; D000975:Antioxidants; D004156:Catechol Oxidase