Abstract
Synthetic model systems of single strength normal local lemon juice were prepared with different contents of some compounds ( ascorbic acid, reducing sugar, and amino acids ) that may play an important role in brown pigments (Melanoidins) formation samples were stored at 25 and 35 °C for 12 weeks. Results showed that the main brown pigment formation pathway in these highly acidic synthetic model systems (pH < 2.5) was ascorbic acid decomposition aerobic (oxidation) and anaerobic (acid catalysis) pathways rather than reducing sugar degradation by acid catalysis and Strecker decomposition of amino acids .The results showed that the highest rate of brown pigments formation was in synthetic model system which contain all components with similar ratio of model systems contain ascorbic acid .
