Studies on Browning Mechanism of Tomato Products

Part II. Browning velocity of tomato serum

Abstract

An investigation was carried out on the factors affecting on the browning of tomato serum which is possibly caused by the reaction between amino acids and sugars as well as the oxidation of ascorbic acid.
Browning velocity was raised at higher temperature in the absence of oxygen, and in the presence of oxygen by 3 times at 100°C and 11 times at 40°C in the comparison with that proceeded in a closed vessel. Browning velocity was also increased by 3.5-4 times when tomato serum of double concentration was used, but was not affected remarkably by the presence of oxygen. Browning velocity was accelerated more than 5 times by copper than by iron ion, being affected greatly by oxygen and temperature. Browning velocity was increased at higher pH value in a closed vessel, but not in the presence of oxygen when oxidative browning was proceeded. Browning velocity was accelerated by the addition of sugars but not accelerated remarkably by the presence of oxygen.
Tomato variety and its maturity did not give significant effect on the browning.