Determinação de compostos fenólicos e carotenoides do óleo de sementes de uva (Cabernet Sauvignon e Bordô) extraído por ultrassom

• Autor(a) principal: Diório, Alexande
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/3729
• topic: Semente de uva; Produção do óleo; Óleo bruto; Produção; Característica química; Ultrassom; Teor de óleo; Compostos fenólicos; Beta caroteno; Brasil.; Ultrasound; Oil content; Grape seeds; Phenolic compounds; Beta carotene; Brazil.; Engenharias; Engenharia Química

The present dissertation aimed the application of analytical techniques for the determination of carotenoid and phenolic compounds presents in grapeseed oil of Cabernet Sauvignon and Bordô varieties, since this kind of product is currently imported from Europe at a high cost and, in Brazil, grapesseds are discarded from wineries as a residue. It was necessary, thus, to chemicaly characterize the extracts obtained through ultrasound. The seeds were dried at 80 oC, a temperature previously determined as to obtain an optimum oil content. Furthermore, the dried seeds were grinded and the granulometric analysis indicated a medium Sauter diameter of 0,08 mm for both varieties. Extractions were carried out in duplicates by both the Soxhlet technique and ultrasound one. Hexane was the solvent employed and its boiling temperature (68 oC) was the Soxhlet extraction working temperature with 02, 06, 10, 20 and 48 hours of extractions. Oil content raging from 13 14 % was achieved for both especies of grapeseeds. The extractions employing ultrasound waves were carried out accordingly a Box-Behnken design of experiments aiming minimize the numbers of runs and the statistical properties were analysed by means of ANOVA and Response Surface Methodology (RSM). The analysis of variances indicated that the three evaluated factors of this study, i.e., time, temperature and mass ratio of seeds/hexane, were statisticaly significant in the extraction process. The response surfaces and the equations adequately described the experimental data showing acceptables adjusted determination coefficients of 0,995 and 0,871 for Cabernet Sauvignon and Bordô , respectively. Regarding to the chemical analysis, this paper employed spectrophotometric tests for the quantification of β-carotene, phenolic and carotenoid compounds. In adition, the organic chemicals structures were characterized by means of infrared Fourier transform spectroscopy and the fatty acids composition using gas chromatography derivatized in metil esters with intern padronization. The FTIR analysis resulted in very similar profiles for the Cabernet Sauvignon and Bordô extracts inferring, thus, the characteristic band waves of C-H, C=O and carboxylic bonds present in fatty acids and, moreover, C-OH and C=O characteristics of polyphenolic molecules and antioxidant phytochemicals, e.g., vitamin E and carotenoids. The gas chromatography of the Cabernet Sauvignon and Bordô extracts had a similar profile in fatty acids being, in decrescent order of content, linoleic, oleic, palmitic and stearic acid, thus being both rich in polyunsaturated acids. In fewer concentrations were observed acids such as α-linolenic, arachidonic, eicosenoic, palmitoleic, myristic, behenic and lignoceric being the latter only found in Bordô extract. The quantification of Soxhlet oil samples accordingly to carotenoids compounds revealed concentrations of 0,0625 mg and 0,0369 mg per 100 grams of oil for Cabernet Sauvignon and Bordô , respectively. However, only for β-carotene compound around ten times more were observed: 0,37 and 0,26 mgβ-carotene per 100 grams of oil respectively, thus revealing, that the spectrophotometric analysis was not efficient in the determination of others kind of carotenoids compounds. The total polyphenolic compounds quantification showed that high temperatures during the extraction might oxidate the molecules causing, therefore, the loss of bioavailability in the oil samples. The samples obtained through ultrasound revealed greater concentrations of β-carotene, carotenoid and phenolic compounds evidencing, therefore, the effectiveness of this technique in the obtaining phytochemicals with benefits for the human body. The kinetic and thermodynamic properties of the extraction were determined and can be seen throughout the dissertation. The phenomenological modeling of the extraction process was carried out fundamentally by means of mass balances in each phase of the system by applying concentrated parameters model. Low values for the desorption constant indicating that the velocity in the variation of the oil concentration in the pores is greater than the extraction in the fluid phase. The m parameter indicated 50 70 % of oil in the pores at initial ultrasonic extraction moments and 86 88 % for the Soxhlet ones. Finally, it was concluded that the use of ultrasound waves revealed satisfactory efficiency for the oil extraction for Cabernet Sauvignon and Bordô grapeseeds and, besides that, the sonic waves improved the extraction of phytochemicals when compared with Soxhlet extraction. The chemical characterization of these extracts were important due to the accentuated presence of compounds, which are able to improve human health and prevent cardiovascular diseases.