STUDY OF OXIDATIVE HEAT DAMAGE DURING TOMATO DRYING

Ripe, fresh tomatoes of Rita cultivar were dried in a pilot-plant under the following operating conditions: air temperature 80 and 110°C, air flow rate 1.5 m/s, final sample moisture 10%. During drying the variation in loss of weight and temperature of tomatoes was continuously measured, and tomato samples were taken to make a visual evaluation of color and to determine the lycopene. ascorbic acid and HMF contents.

Color, ascorbic acid and HMF contents indicated severe oxidative heat damage during drying.
A 90% decrease of ascorbic acid was observed after drying at 80°C and complete degradation was observed after drying at 110°C. HMF exhibited a maximum of 40 mg/kg TS during drying at 80°C and a maximum of over 500 mg/kg TS at 110°C. Conversely, lycopene had a high stability during drying.
The lycopene content decreased to a maximum of 10% after drying at 110°C and did not change during drying at 80°C.