Substances (such as sugars1 acidity, minerals, free amino acids, peptides and proteins) affected on the taste of tomato juice and its products were investigated. Results revealed that total solids of tomato juice gradually increased by heat treatment. Whereas, total solids of tomato paste was significantly higher than that pasteurized juice and the latter was higher than that of non-pasteurized one. Total reducing sugars of tomato non-pasteurized juice, pasteurized juice and paste, made up mainly from glucose and fructose which they occurred in a ratio near to 1:1. A slight decrease in the reducing sugars content was observed in tomato paste. The titratable acidity of pasteurized juice was (12.22g as citric acid 1100g SS) slightly higher than that of non-pasteurized one (11 .99g as citric acid /1 00g SS), while the lowest titratable acidity (1.29 g as citric acid ¡100g SS) was detected ¡n tomato paste. At the same time, pH vaLues of their serum were mostly identical. Soluble mineral content of tomato products slightly increased as a result of heat treatment (pasteurization and concentration). Total mineral content (6.OOg/lOOg SS) consisted of potassium (4.8lgIlOOg SS), magnesium (0.321g/lOOg SS), calcium (0.17 g/lOOg SS), sodium (0.07 g/tOOg SS) and phosphorus (0.591g/lOOg SS). More than 80 % of the nitrogen content could be derived from soluble compounds present in the serum. The percentage of nitrogenous constituents increased ¡n the paste comparing with both non - pasteunzed and pasteurized juices. Glutamic, glutamine, y- amino butyric and asparatic acids made up 72 % of the total free amino acids in non-pasteurized juice. Threonine, lysine and phenylalanine were the main essential amino acids in non-pasteurized tomato juice. Which increased ¡n tomato products due to heat treatment. Nevertheless, peptide content of non-pasteurized juice was 8.5 g/lOOg SS increased to 10.1 g/lOOg SS in tomato paste.