Ácidos graxos e compostos fenólicos como substâncias fitotóxicas nos resíduos agroindustriais: vinhaça, torta de filtro e bagaço
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Data
2018-02-16
Autores
Luz, Dandara Alves
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Universidade Federal do Espírito Santo
Resumo
The residues of agroindustry from sugar cane vinasse, filter cake and bagasse are abundant in Brazil, a leading country in the production of sugar and alcohol. The use of this waste solves problems related to waste and environmental pollution. Extracts were produced by solvent maceration, some of them were submitted to liquid / liquid partitions and others were saponified, resulting in numerous samples that were tested for phytotoxic activity and analyzed by GC-MS, by ESI (-) FT-ICR-MS and ESI (-) MS / MS leading to the identification of 22 substances, among them ten fatty acids and twelve phenolic compounds. The DIC experiments of the pseudomolecular ions [MH] –327,21796 (C18H32O5) and 329,23355 (C18H34O5) led to the proposition of the polyhydroxylated unsaturated fatty acids, 9,12,13-trihydroxy-10,15-octadecadienoic, for the first and the isomers 9 , 12,13-trihydroxy-10-octadecenoic acid / 9,10,13-trihydroxy-12-octadecenoic acid for the second, which have not been described so far in Saccharumssp. GC-MS analyzes corroborated the chemical profile already observed by the FT-ICR-MS technique. In the phytotoxicity bioassay in Lactuca sativa, the most active fractions were the dichloromethane partition of vinasse (IC50 = 168.4 ppm) and ethyl acetate of vinasse (IC50 = 262.3 ppm). The FT-ICR-MS and CG-EM analyzes demonstrated that the VDiCl sample consists of a proportionally similar mixture of fatty acids and phenolic acids, whereas VAcOEt is formed in a higher proportion by a mixture of phenolic compounds. In the bioassays with Ipomoea purpurea(weed), the dichloromethane partition of vinasse was also more active, inhibiting root growth by 52% (IC 50 = 344 ppm). At the same concentration, the ethyl acetate partition inhibited only 25.74% root growth. It has been suggested that the interaction between fatty acids and phenolic compounds is important for a higher rate of inhibition and that the presence of oxilipins (polyhydroxylated unsaturated fatty acids)is essential for the more marked phytotoxicity of this sample. This work demonstrated the potentiality of fatty acids and phenolic compounds present in the agroindustrial residues regarding phytotoxicity, indicating that these can be used as raw materials in the elaboration of innovative products for the control of weeds, minimizing the risks that the incorrect disposal to the environment.
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Filter cake , Phytotoxicity , Saccharum ssp , Fitotoxicidade , Vinhaça , Torta de filtro
Citação
LUZ, Dandara Alves. Ácidos graxos e compostos fenólicos como substâncias fitotóxicas nos resíduos agroindustriais: vinhaça, torta de filtro e bagaço. 2018. Dissertação (Mestrado em Química) – Universidade Federal do Espírito Santo, Vitória, 2018.