Effect of light combined with heat treatment on colour development and fruit quality of cherry tomato (Solanum lycopersicum)

Cherry tomatoes have become popular worldwide as fruit vegetables. It is rich in various carotenoids particularly lycopene and beta-carotene. Carotenoids in tomato play a significant role in the prevention of various diseases. The first characteristic that determines the degree of consumer's acceptance is colour, while the final quality parameter consumers judge tomatoes on is firmness. Mature green cherry tomatoes (Solanum lycopersicum) were harvested from the polyethylene-covered tunnel. The following treatments were administered before the storage: light treatment (LT) for 24 h, hot water treatment (HWT), a combination of light and hot water (LT + HWT) for 30 s, 1 min and 2 min; all fruits were packed with modified atmospheric packaging. A hot water treatment was applied to the selected batch by dipping fruit into hot water at 48 degrees C for 30 s. One batch was subjected to white LEDs for 24h, a further batch to a combination of white LED light (LT) and hot water treatment (HWT) for 30 s, 1 min or 2 min. All fruit were stored for 25 days at 21 degrees C. Fruit mass, colour, firmness and pigment concentrations were monitored in 7-day intervals over the 25-day experimental period. The present study showed that cherry tomatoes treated with light plus hot water for 1 min did not have a negative effect on mass loss and firmness; however, the treatment significantly enhanced colour development and the production of beta-carotene and lycopene. It was also observed that light treatment 'alone' and light combined with hot water treatment at 2 min did not have a significant effect on colour and carotenoids. Even though the mechanisms involved are yet unknown, it can be concluded that combined effects of white LED light and HWT for 1 min (LT + HWT for 1 min) is a promising post-harvest treatment to improve quality of cherry tomatoes.