Quality of processed tomatoes in response to water stress

Tomato (<em>Solanum lycopersicum</em> L.) is one of the largest horticultural crops in the world with more than 160 million tons produced per year. A large proportion of tomatoes is processed and represents important sources of phytonutrients in the human diet. Processed tomatoes require a lot of water, and therefore, in the context of global climate changes, constitute a valuable target for water saving strategies in agriculture. However, reducing water may impact not only yield, but also modify the reactivity of tomato to the process by modifying fruit tissues structures or soluble and structural component. Therefore, we design a study to evaluating the effects of two water irrigation treatments on tomato production and fresh fruit quality, also including strategic industrial quality attributes of processed tomatoes, i.e. puree viscosity, dry mater content and colour after processing. The objective was also to investigate the putative crosstalk betweenquality parameters of fresh cut tomatoes and processed tomatoes. Two industry-type-tomato genotypes differing in fruit color, dry weight and soluble material content and over a period of 55 days were grown in a glasshouse with 100% of replacement of evapotranspiration. After 56 days, the irrigation was reduced to only a replacement of 60% of the ETP for the stressed plant while irrigation remains constant for controls. From the anthesis of the first flowers, soil humidity, leaf water potential, leaf conductance and fruit growth were monitored on control and stressed plants. Then after, 12 fruits per genotype and water treatment were collected, evaluated for their colour, fresh and dry weight, and processed in a hot break way. Colour, soluble solids, treatable acidity, viscosity and dry weight of purees were then evaluated. We found that the water stress impacted significantly all quality parameters of fresh or processed tomatoes whereas the genotype only affected the colour parameters and the percentage of dry weight of fruits and purees. Interestingly, the water stress increased the a* value, the viscosity, and the soluble solids of the purees by 69.06%, 106.97% and 105.65% respectively. In addition our results revealed that the a* value of purees and the treatable acidity were linked to the a* value of fresh fruit. The percentage of dry weight of fruit was a good indicator of puree viscosity in our study. The results indicate that a reduction of in water can bring increases in desirable characteristics sought by the industry and contribute to a rational use of water source.