It is widely accepted that a healthy diet is an important factor in preventing chronic diseases, and in improving energy balance and weight management. Studies have shown strong inverse correlations between tomato consumption and the risk of certain types of cancer, cardiovascular diseases and age-related macular degeneration. Because tomato is the second-most important vegetable in the world after potato, this horticultural crop constitutes an excellent source of health-promoting compounds due to the balanced mixture of minerals and antioxidants including vitamins C and E, lycopene, b-carotene, lutein and flavonoids such as quercetin. Improvement in phytonutrients in tomatoes can be achieved by cultivar selection, environmental factors, agronomic practices, stage of ripeness at harvest, and appropriate handling and conditioning all the way from the field to the consumer. The purpose of this paper is to review the recent literature of the main factors that can improve the nutritional quality of tomato and consequently their beneficial role in human diet. The importance of genotype selection and the optimization of environmental conditions (light, temperature, humidity, atmospheric CO 2 and air pollutants) for high nutritional value is outlined first, followed by the optimization of agricultural practices (soil properties, water quality, mineral nutrition, salinity, grafting, pruning, growing systems, growth promoters, maturity, and mechanical and pest injuries). The review concludes by identifying several prospects for future research such as modelling and genetic engineering of the nutritional value of tomato.

To investigate the effects of low temperature (LT) and weak light (WL) on tomato (Solanum lycopersicum L., cv.) during flowering and fruit-setting periods, a controlled experiment was conducted. Two levels of day/night temperature and PAR were set: S1 (18/8°C, 200 µmol m -2 s -1 ), S2 (12/2°C, 200 µmol m -2 s -1 ), S3 (18/8°C, 80 µmol m -2 s -1 ), and S4 (12/2°C, 80 µmol m -2 s -1 ), taking 28/18°C and 600 µmol m -2 s -1 as control (CK). The results showed that during stress stage, the Chlorophyll (Chl) a, photosynthetic rate at irradiation saturation (Pmax), light saturation point, stomatal conductance, stomatal limitation value, maximal photochemical efficiency of PSII (Fv/Fm), electron transport rate of PSII, and catalase activity of S1, S2, S3, and S4 were lower than that of CK, while the Chl b, carotenoid, light compensation point, superoxide dismutase (SOD), and malondialdehyde (MDA) were opposite. Vitamin C, soluble solid, soluble protein, and lycopene were lower than that of CK, while organic acid was opposite. Plant height and stem diameter significantly correlated with Chl and Pmax. After 25 d of recovery, the Fv/Fm, SOD, and MDA for S1 and S2 almost could recover to CK level, but the values for S3 and S4 could not recover to CK level.

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Measurement of fresh tomato fruit overall quality, and particularly lycopene content, is challenging in the context of high-volume production. An experiment was conducted to simultaneously measure various quality parameters of tomato in a nondestructive manner using vis-NIR reflectance spectroscopy and chemometrics. The sampling set included different cultivars that are obtainable from both retailers' shelves and two greenhouse producers. Results indicate that lycopene content was accurately predicted [r(2) = 0.98; root mean square error of cross-validation (RMSECV) = 3.15 mg/kg], along with color variables such as Hunter a (r(2) = 0.98), L, and b (r(2) = 0.92). Tomato color index (TCI) was better predicted (r(2) = 0.96) than the a/ b ratio (r(2) = 0.89). Firmness prediction, with an r(2) of 0.75, is comparable to what is reported in the literature for other fruits and may have a practical interest. Prediction of internal quality such as pH, soluble solids, titratable acidity, and electrical conductivity was less accurate, partly due to a low variability of these parameters among samples. Predictions were robust with regard to cultivars, except for pink variety tomato. The 400-1000 nm range gave results almost as accurate as the 400-1500 nm range.