Effect of grafting on biochemical and nutritional traits of 'Cuore di Bue' tomatoes harvested at different ripening stages.

摘要

In the last years, 'Cuore di Bue' tomato has been one of the most important types requested from the market because of its special flesh texture and flavour, which is very pleasing to the consumer. The present study aims to verify if rootstock affects some specific qualitative traits of this tomato fruits during ripening process. The main quality traits during ripening of tomato fruits of cultivar 'Profitto' ungrafted and grafted on 'Beaufort' and 'Big Power' rootstocks were determined. Results showed that different ripening stages and grafting combinations affected, sometimes strongly, tomato fruits' quality. Among phenolics, gallic, cinnamic and p-coumaric acids declined during ripening, whereas chlorogenic, caffeic and ferulic acids increased in the last ripening stages. The quality of tomato fruits was also influenced by grafting. As far as quality parameters (colour, degrees Brix, electrical conductivity, pH, titratable acidity) and sugar content are concerned, there were significant differences. Strong differences are attributable also to the contents of phenolic acids. In particular, ungrafted Profitto plants showed more p-coumaric and caffeic acid content than the other two grafted treatments. Profitto and Profitto x Beaufort showed more chlorogenic and cinnamic acid than Profitto x Big Power variety. The last one variety showed a completely different chlorogenic acid accumulation pattern and contained more gallic and ferulic acid than the other two. The nutritional value of grape tomatoes 'Cuore di Bue' considerably increased with ripening stage. Grafting has a significant effect on various biochemical and nutritional properties in tomato fruit. Many chemical compounds related to the antioxidants group have been involved in these changes showing a significant decrease in grafted fruits. Concerning other parameters such as pH, EC and Brix, the graft leads to very small changes.