Changes in flavonoid and carotenoid profiles alter volatile organic compounds in purple and orange cherry tomatoes obtained by allele introgression.

BACKGROUND: Tomatoes are an important source of human health-promoting compounds, and efforts have been made to enhance their nutritional quality through conventional plant breeding or biotechnology. This study assessed the composition of volatile compounds, phenolics and carotenoids in two allele-introgressed tomato lines, an anthocyanin-rich purple tomato and a β-carotene-rich orange tomato, as well as a red tomato.
RESULTS: The purple tomato peel accumulated a high amount of anthocyanins, mainly petunidin 3-(p-coumaroyl)-rutinoside-5-glucoside, responsible for the purple color, and other flavonoids such as rutin and kaempferol. The orange tomato did not undergo changes in the flavonoid profile but accumulated a high amount of β-carotene, with impairment on lycopene. A total of 27 volatile compounds were detected in purple tomato, 38 in orange tomato and 39 in red tomato. They comprise terpenes, carbonyls, alcohols, esters and hydrocarbons. The difference in the volatile compound profiles of ripe fruits can be related to differences in some precursor contents in the introgression lines. Orange tomato accumulates volatiles from β-carotene cleavage, not detected in the red fruits. Otherwise, volatiles from lycopene were absent in orange tomato as a result of the inhibition on lycopene accumulation. Phenolic volatiles were higher in the purple tomato, which has the highest total phenolic content.
CONCLUSION: The introgessed alleles seem to have a positive effect on the enrichment of ripe tomato in bioactive compounds such as anthocyanins and β-carotene, improving nutritional quality. However, the allele introgression resulted in marked changes in volatile compound profiles, whose impact on tomato flavor and consumer acceptability needs to be evaluated.