102(2)_str24

 

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 102, No. 2 (2015), p. 185–192
DOI 10.13080/z-a.2015.102.024

Stability of tomato lycopene under thermal- and light-irradiation treatments in an oil-based model system

Dalia URBONAVIČIENĖ, Pranas VIŠKELIS, Jonas VIŠKELIS, Česlovas BOBINAS

Abstract

The lycopene content in food may be increased by thermal and mechanical processing. Food processing is beneficial because it disrupts food matrices facilitating the release and solubilisation of lycopene resulting in increased carotenoid bioavailability for the formation of cis-isomers. A lycopene-rich and β-carotene oil-based system was used in this study. High-performance liquid chromatography (HPLC) and colour coordinates analyses were employed to analyse lycopene, its cis-isomers and β-carotene stability of the following sample set after 28 days of storage: fridge temperature at 1 ± 1°C in absence of light (FT dark), ambient temperature at 20 ± 1°C in natural light with different day and night illumination (AT light), ambient temperature at 20 ± 1°C in absence of light (AT dark ), thermostatically controlled temperature at 37 ± 1°C in UV irradiation (TT UV) and thermostatically controlled temperature at 37 ± 1°C in absence of light (TT dark). The control sample in our study was lycopene enriched oil stored in the dark at 1 ± 1°C on day zero (0). The aim of this study was to create lycopene-enriched oil from tomato to investigate its stability and to prepare the recommendations to consumers for the storage conditions of this functional food. The results indicated that the trans-lycopene amount changed from 76.6% to 61.0% at ambient temperature (AT light and AT dark sample), and from 76.6% to 46.8% (TT dark) and 44.4% (TT UV) at 37 ± 1°C. According to our investigation, the highest percentage of 5-cis-lycopene isomer in all samples was found after 28 days of storage. The TT UV samples had the most colour changes. Vegetable oil enriched with lycopene from tomatoes is a high quality food product that can supplement daily diet and enhance absorption of lycopene from the intestine.

Key words: β-carotene, degradation rate constant, isomerisation, lycopene, Lycopersicon esculentum.

Full text:  102_2_str24.pdf