%0 Journal Article
%T Cin¨¦tica do escurecimeno n o-enzim¨¢tico com solu  es modelo de a ¨²cares e amino¨¢cidos em pH neutro e ¨¢cido = Kinetic of non-enzimatic browning with model solutions of sugar and aminoacids in neutral and acid pH
%A Vandr¨¦ Barbosa Bri£¿o
%A L¨ªgia Follmer
%A Mar¨ªlia de Souza
%A Vera Maria Rodrigues
%J Acta Scientiarum : Technology
%D 2011
%I Editora da Universidade Estadual de Maring¨¢
%X A cor dos alimentos ¨¦ um importante atributo para a escolha do consumidor. O escurecimento ¨¦ desej¨¢vel em alguns alimentos pela cor e pelo aroma produzidos (como nos casos do p o e carne assada), mas, ¨¦ indesej¨¢vel em outros (como no tratamento t¨¦rmico de leite). A rea  o de Maillard ¨¦ influenciada pela natureza dos a ¨²cares e amino¨¢cidos envolvidos, bem como pelo pH e temperatura do processo. O objetivo do trabalho foi avaliar o escurecimento de solu  es modelo contendo a ¨²cares e amino¨¢cidos pela rea  o de Maillard em pH neutro e ¨¢cido, obtendo as taxas de rea  o e avaliando a cin¨¦tica dela. Doistipos de a ¨²cares (glicose e lactose) foram misturados com dois tipos de amino¨¢cidos (glicina ou glutamato de s¨®dio) em pH 7,0 e pH 5,1. As solu  es (2 mol L-1) foram aquecidas em ¨¢gua fervente (97oC), e a absorbancia medida (420 nm) em intervalos de tempo. A glicose apresentou maior taxa de rea  o que a lactose, enquanto que entre os amino¨¢cidos a glicina reagiu com intensidade semelhante ao glutamato. A redu  o do pH do meio retarda a rea  o, e o escurecimento demonstrou menor taxa de rea  o em pH ¨¢cido. The color of food is an important attribute for consumer choice. Browning is desirable in some foods due to the color and flavor itproduces (such as in bread and roasted meat), but is undesirable for others (such as heattreated milk). The Maillard reaction is influenced by the nature of the sugars and amino acids involved, as well as the pH and temperature of the process. The aim of this work was to evaluate the browning of model solutions containing sugars and amino acids due to the Maillard reaction in neutral and acid pH, and to calculate the reaction rate and the kinetics of the reaction. Two types of sugars (glucose or lactose) were mixed with amino acids(glycine or sodium glutamate) in pH 7.0 or pH 5.1. The solutions (2 mol L-1) were heated in boiling water (97oC), and the absorbance was measured (420 nm) at time intervals. The glucose showed a higher reaction rate than lactose, whilst glycine reacted with the sameintensity as glutamate. The reduction in pH of the medium delays the reaction, and browning showed a slower reaction rate in acid pH.
%K rea  o de Maillard
%K cin¨¦tica de rea  o
%K taxa de rea  o
%K Maillard reaction
%K reaction kinetics
%K reaction rate
%U periodicos.uem.br/ojs/index.php/ActaSciTechnol/article/view/8360/8360