Content of carotenoids and physical properties of tomatoes harvested at different ripening stages.

The aim of the research was to investigate dynamics of variations of carotenoids content (lycopene and β-carotene) and physical parameters (colour and texture) in two tomato hybrids 'Admiro' and 'Kassa' and one Lithuanian tomato cultivar 'Rutuliai' during the ripening process. Investigated tomatoes were grown in the greenhouses of Lithuanian Institute of Horticulture. During the ripening process the amount of carotenoids, especially lycopene, in fruits increased. The highest lycopene and β-carotene content was determined in red-ripe fruits of cv. 'Rutuliai', 10.44 and 1.22 mg 100g respectively. Lycopene content was 1.6 times higher in red-ripe fruits of 'Rutuliai' than in fruits of ‘Admiro F1 and 2 times higher than in fruits of 'Kassa' F1 at the same ripening stage. The colour of tomato fruits was evaluated by the CIE L*a*b* system. The ratio of colour coordinates a* and b*, which is indicative of the red colour development in tomatoes, increased with maturity. The highest a*/b* value of 0.99 was determined in red-ripe fruits of cv. 'Rutuliai'. Strong positive correlation (r=0.86) was found between a*/b* and lycopene content in the present study. The firmness of fruits was influenced by the degree of tomato ripeness. Turning stage tomatoes of Dutch selection 'Admiro' F1 and 'Kassa' F1 were the firmest, while fruit firmness of turning stage tomatoes 'Rutuliai' was less than that of Dutch selection tomato hybrids at the same ripening stage.