Distribution of volatile compounds in different fruit structures in four tomato cultivars

Authors: LI, JIAN - Beijing Technology And Business University; DI, TAIJU - Beijing Technology And Business University; Bai, Jinhe

Submitted to: Molecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2019
Publication Date: 7/17/2019
Citation: Li, J., Di, T., Bai, J. 2019. Distribution of volatile compounds in different fruit structures in four tomato cultivars. Molecules. 24, 2594. 10.3390/molecules24142594.
DOI: https://doi.org/10.3390/molecules24142594

Interpretive Summary: Dissatisfaction with the flavor of commercial tomato cultivars has been documented in the past and is still a subject of much attention. Some believe that domestication events in Central America and Europe created genetic bottlenecks resulting in low diversity in the cultivated tomato, including flavor components. In this research we used four tomato cultivars, two common commercial cultivars, ‘Tygress’ and ‘FL 47’, with round shape and firm texture; ‘Tasti-Lee’, a hybrid with high lycopene content due to the crimson gene for the premium tomato market; and ‘Cherokee Purple’, an heirloom cultivar that consistently ranked very high in taste tests. For each cultivar, fruit were divided to four structures, pericarp, septa and columella, locular gel and seeds, and stem end. Volatile analysis based on GC-MS showed that the abundance of total volatile compounds was higher in pericarp associated with higher levels of aromatic proportion and herbaceous series intensity. Thus the sampling methods for molecular biological research, mostly only use pericarp tissue, and for food flavor components research, mostly use whole fruit will not match well. This research provided basic information how to compare the volatile data from two different sampling systems.

Technical Abstract: Distribution of volatile compounds in different fruit structures were analyzed in four tomato cultivars by headspace - solid-phase microextraction (SPME) - gas chromatography-mass spectrometry (GC-MS). A total of 36 volatile compounds was identified in fruit samples, which were primarily aldehydes, hydrocarbons, alcohols, ketones, furans, esters, nitrogen compounds, and sulfur and nitrogen-containing heterocyclic compounds. The volatile compositions in pericarp (PE), septa and columella (SC), locular gel and seeds (LS), and stem end (SE) tissues showed different profiles. The PE tissue showed the highest total volatile concentration due to high abundances of aldehydes especially cis-3-hexenal and benzaldehyde. Meanwhile, it showed higher aromatic proportion and herbaceous series intensity than other tissues. Floral and fruity series showed a higher intensity in SC and LS tissues. The concentration of alcohols in the LS was higher than that in other tissues in association with the higher abundances of 2-methyl propanol, 3-methyl butanol, and 2-methyl butanol. However, the numbers and concentrations of volatile compounds, especially cis-3-hexenal, benzaldehyde and geranyl acetone were lower in SE and it showed less aroma contributions to tomato than the other tissues. Additionally, higher levels of fatty series were shown in SE and the floral and fruity characteristic compounds of geranyl acetone, 1-nitro-pentane, and 1-nitro-2-phenylethane were not identified in SE tissues. ‘FL 47’ contained more volatile compounds than the other three, and the contents of aldehydes, ketones and oxygen-containing heterocyclic compounds in the ‘Tygress’ fruit were higher than the other cultivars. The content of these volatile compounds differed among these four varieties of tomato.