Influence of pre- and post-harvest treatments on metabolite profiling of tomato fruit (Solanum lycopersicum) during ripening

• Autor(a) principal: Meza, Silvia Leticia Rivero
• Data de Publicação: 2021
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/9/9131/tde-05082021-102520/
• topic: Amadurecimento; Estresse salino; Fitohormonios; Fruit quality; Fruit ripening; Metabolitos primários e secundários; Phytohormones; Pre- and post-harvest treatments; Primary and secondary metabolites; Qualidade do fruto; Salinity stress; Solanum lycopersicum; Solanum lycopersicum; Tratamentos pré- e pós-colheita

During fruit ripening, sensory changes occur, such as in color, texture and aroma, as well as the production of beneficial compounds for health. Thus, changes in primary and secondary metabolites were analyzed in fruits, which were exposed to pre- and post-harvest treatments as well as salinity stress and hormonal treatment, respectively, aiming to improve the sensory and nutritional quality of the fruit. Salinity treatment was applied in two Mediterranean traditional tomato varieties named \'Tomate Pimiento\' (TP) and \'Muchamiel Aperado\' (MA), using as reference the commercial cultivar \'Moneymaker\' (MM). Hormonal treatments (ethylene, methyl jasmonate, 1-methylcyclopropene, and both 1-methylcyclopropene and methyl jasmonate) were applied in Grape tomato fruits, using as control the no-treated fruits. Concerning pre-harvest treatment, plants were grown without salt (control) and with moderate salt stress (50 mM NaCl), which did not affect fruit yield in any variety. The variety TP is of great interest because of its high soluble solids content (SSC) in control, which is even higher in salt, while MA is very attractive because of its high Brix yield index (SSC x fruit yield), which has been used as overall fruit quality measure. Similitude between both traditional varieties were found for primary metabolism, as they significantly increased their sucrose contents with respect to MM in red ripe fruits from plants grown in control and, especially, salt stress conditions. The most remarkable difference was observed in the high constitutive levels of total amino acids in TP fruits, including the three major free amino acids found in tomato fruit, GABA, glutamate and glutamine, which even increased under salinity. On the subject of secondary metabolites, the most interesting change induced by salinity was the increase in α-tocopherol found in red ripe fruits of both tomato varieties. Regarding post-harvest treatment, ethylene increased fructose, sucrose and glucose, while methyl jasmonate increased organic acids such as citric and malic acids and amino acids such as glutamic acid, GABA and phenylalanine at 10 DAH; and fatty acids at 4 DAH. Both treatments induced the accumulation of tocopherols and phytosterols at 10 DAH, and carotenoids (mostly lycopene) at 10 and 21 DAH. Fruits treated with only 1-methylcyclopropene presented significant reduction in the levels of metabolites mainly at 4 and 10 DAH. Fruits treated with both 1-methylcyclopropene and methyl jasmonate exhibited a lower impact on delayed of metabolite production than treatment with 1-methylcyclopropene. In addition, it showed a tendency to improve the levels of sugars (glucose, glucaric acid and mannose) at 10 DAH and organic acids (propanoic and butanoic acids), carotenoids (lycopene, β-carotene, lutein), tocopherols (α-tocopherol, β-tocopherol, γ-tocopherol) and phytosterols (β-sitosterol, stigmasterol and stigmastadienol) at 21 DAH. Most of the changes in the metabolites profiling are related to the organoleptic and nutritional value of the fruits, proposing that the pre- and post-harvest treatments can be applied as tools to improve the nutritional and sensory value of tomato.