Effect of Thermal Processing on Lycopene, Beta-Carotene and Vitamin C Content of Tomato [Var.UC82B]

Abstract

The available lycopene, beta-carotene and vitamin C content of raw, boiled and fried tomato (Var.UC82B) were evaluated. Ripe tomato was purchased from Ogbete main market Enugu-Nigeria and the variety was identified at the Crop Science department, University of Nigeria Nsukka. It was sorted, washed and pulped using a blender. The pulp was divided into seven portions and labeled (A-G) Portion A was raw sample that served as a control since it was neither boiled nor fried. Portions B, C, and D were boiled for 2, 15 and 30minutes respectively. Portions E, F and G were fried in refined bleached and deodourized groundnut oil for 2, 15 and 30 minutes respectively. The seven samples were separately packaged in vial glass tubes and analyzed within three days from the time they were produced. Result shows that the three response variables evaluated were significantly [P < 0.05] affected by either boiling or frying. The lycopene content significantly increased [p < 0.05] as the period of boiling or frying increased between 2 and 30minutes. Boiling the pulp or frying it for 30 minutes increased the lycopene content from 24.2 to 32.9 % respectively. However, both the beta-carotene and the Vitamin C content significantly [p < 0.05] decreased as boiling or frying period increased between 2 and 30 minutes. The beta-carotene content decreased by 61.4 %, while the Vitamin C content decreased by 49.4 % when the tomato pulp was boiled for 30 minutes. When the tomato pulp was fried for 30 minutes, the beta-carotene decreased by 63.6 %, while the vitamin C decreased by 50.0 % [p< 0.05]. It is therefore, advisable to boil or fry tomato before consumption for maximum absorption of its available lycopene. However, excessive heat treatment would have adverse effect on the beta carotene and vitamin C content of the tomato.