Estudo dos processos de secagem e de extração para produção do óleo bruto de semente de uva

• Ano de defesa: 2014
• Autor(a) principal: Menezes, Maraísa Lopes de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; Departamento de Engenharia Química; Programa de Pós-Graduação em Engenharia Química; UEM; Maringá, PR; Centro de Tecnologia
• Palavras-chave em Português: Semente de uva; Secagem e extração; Produção do óleo; Óleo bruto; Caracterização físico-química; Brasil.; Grape seed; Physicochemical characterization; Drying; Extraction; Brazil.; Engenharias; Engenharia Química
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/3646

The present study aimed to study and develop a process for the extraction and production of crude oil of Cabernet Sauvignon and Ives grape seeds, that currently are residues from Brazilian wineries. On the characterization tests of the raw material, seeds were used fresh and dried at 105ºC for 24 hours in an oven. To this, were determined the length, width, thickness, specific mass, density, grain size, porosity, sphericity, angle of repose and specific heat. For the chemical characterization, were determined the moisture content, protein, lipids, carbohydrates and mineral profile. By the results, it was found that there was a significant difference in the width, thickness and sphericity among varieties, different from the specific mass. The angle of repose for the seeds was around 30º and the specific heat for both seeds was approximately 1.5 J/gK. The Cabernet Sauvignon and Ives grape seeds were dried in a convective dryer of fixed-bed at temperatures of 30, 40, 50, 60, 70 and 80 ºC and air velocities of 0.8, 1.2 and 1.6 m/s until they rich the equilibrium moisture content. It was The effective diffusivity, activation energy and the surface temperature of the seeds were also determined. Through the results, it was observed that the temperature of the drying air had a direct influence on the process. On the other hand the air speed didn'?t have the same influence, because with its increase, the drying rate, the diffusivity and activation energy also increased, besides the decreasing of the drying time. These results were also verified by analysis of variance and response surface. The equilibrium isotherms were determined by static method at temperatures 25, 35 and 50 ºC, being the models of Modified Henderson and Henderson the best fit to the experimental data. The drying curves and drying rate were adjusted by generalization models and the ones that best fitted the experimental data were the Motta Lima et al. (2002) and Toffoli (2005), respectively, for both grape seeds. For each drying condition. It was also performed adjustments of kinetic models available in the literature . The best models fitted to the experimental data were Verna, Pabis Henderson and Modified-Two Terms. The model parameters were obtained by non-linear regression (Quasi-Newton), with the aid of the Statistica 7.0Òsoftware. Dry seeds in convective dryer of fixed bed at temperatures of 30, 40, 50, 60, 70 and 80 °C and air speed of 0.8 m/s were used for the Cabernet Sauvignon and Ives grape seed oil extraction process,. In addition, the effect of extraction time (4, 8 and 12 hours) and pressure of operation (14, 18 and 22 ton/cm2) were analyzed for the extraction by pressing. In the Soxhlet extraction different solvents (ethyl acetate, dichloromethane and hexane) and extraction times of 4, 8, 16, 24 and 48 horas were evaluated. In the ultrasound extraction the same solvents were used, in the seed/solvent mixture ratio of 1:4, 1:6 and 1:8 and in the extraction times of 30, 60 and 90 minutes. The best condition of extraction based on oil content obtained for each method studied was determined by response surface analysis and analysis of variance, it was also evaluated the influence of the drying temperature of the seed. For the Cabernet Sauvignon and Ives grape seeds, in the pressing, the higher oil content was obtained in 22 ton/cm2 pressure and extraction time of 8h, using dry seeds at 40ºC. In the Soxhlet extraction, the higher oil content was obtained using dry seed at elevated temperatures (80°C), dichloromethane as solvent and a extraction time of 16 hours. With ultrasound, the higher oil content was obtained in extraction time of 90 minutes, using the mixing ratio of 1:8 and dichloromethane as solvent. In these conditions, the oil content obtained were 10, 14 and 20 % for extraction by press, ultrasound and Soxhlet using seeds of Cabernet Sauvignon and 12, 13 and 17 %, using Ives grape seeds. The physicochemical characterization of the oil was performed in these optimum conditions for extraction. For this purpose, the identification and quantification of fatty acids present in oil by gas chromatography, the determining the acid index, peroxide index, saponification number, unsaponifiable matter, iodine index, refractive index, color, chlorophyll, totalphosphorus, as well of specific mass, viscosity, moisture content and antioxidant capacity. were performed. The results showed that the grape seed oil of both varieties is rich in antioxidant compounds in the lipophilic extract and poly-unsaturated fatty acids such as linoleic, whereas the drying temperature of the seeds did not influence significantly the oil quality.