Dynamic Changes of Carotenoids Contents during Ripening in Tomato Fruit and Regulatory Effect with CEPA

The health promoting and aesthetic qualities of carotenoids have triggered considerable interest in elevating their levels in tomato, which is an important dietary source of lycopene. It was found that lycopene contents increased gradually during tomato ripening, and that the increase in internal parts (columella, locular gel and radical arms) was occurring prior to that of the external part (peripheral pericarp). The maximum lycopene content in mature fruit was in peripheral pericarp (3.33 mg/100 g FW), and the minimum contents were in columella (0.84 mg/100 g FW) and locular gel (0.91 mg/100 g FW). beta-carotene contents decreased in the early ripening stage (breaker stage), then began to increase gradually. The maximum beta-carotene content in mature tomato fruit was in locular gel (1.00 mg/100 g FW), but it changed greatly. Xanthophyll contents decreased at breaker stage, then began to increase gradually. The maximum xanthophyll contents in mature fruits were in locular gel (0.099 mg/100 g FW) and peripheral pericarp (0.095 mg/100 g FW). The CEPA (ethephon, 1 mg/ml) treatment promoted ripening significantly, accelerated the formation and accumulation of lycopene, and the stimulated increase of lycopene content in the external part was prior to that in the internal parts. The absolute amount of lycopene increase was maximum in peripheral pericarp (6.64 mg/100 g FW), and the relative amount of increase (more than 4-fold) was maximum in locular gel. beta-carotene contents were higher in CEPA treatment than that of control that is approximately 2 times as much as that of control. In CEPA treatment, xanthophylls content was higher in the external part and lower in the internal parts comparing with the control. The ripening of fruits was from the inside to the outside in the control treatment, while it was the opposite in the CEPA treatment. The lycopene content, an important factor of nutrient quality, increased significantly with CEPA which would constitute an effective measure for improving the quality of tomato fruits.