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-This article carried out the extraction of sesame oil by using three extraction techniques: supercritical fluid extraction (SFE), Soxhlet and sequential extraction. The SFE was performed using supercritical carbon dioxide (SC-CO 2 ) as solvent and ethanol as cosolvent. Tests were performed at 20 MPa, 35°C and a flow rate of 2.5 g CO 2 /min with a total extraction time of 210 minutes. The Soxhlet extraction was performed for 8 hours, using petroleum ether and ethanol as solvents, until the exhaustion of the oil contained in the seeds. The sequential extraction used ethyl ether, ethanol and water as solvents. The Soxhlet extraction was the most effective (58.93%), while the SFE technique obtained 26.47% as the best result. The antioxidant activity (AA) was determined by the β-carotene/linoleic acid system, with good oxidation inhibition percentages (29.32-83.49%) for all the extracts. The main fatty acids (FA) in sesame oil were oleic and linoleic acids.

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O crescente mercado dos produtos naturais, aliado ao interesse dos consumidores na prevenção de doenças, tem pressionado a indústria alimentícia na busca por produtos mais saudáveis e direcionado pesquisas nesse sentido. Neste contexto, os alimentos funcionais ganharam destaque pelos efeitos bené-ficos que promovem à saúde (ANJO, 2004).Dentre os alimentos funcionais, a linhaça (Linum usitatissimum L.) é reconhecidamente uma das maiores fontes dos ácidos graxos essenciais ω-3 e ω-6, possuindo ainda vários nutrientes como as fibras e os compostos fenólicos, conhecidos por exercerem atividade antioxidante (MAYES, 1994). Para a evolução da indústria alimentícia, o processamento e a conseqüente necessidade de preservação dos alimentos estão intimamente relacionados com o incremento da procura de compostos com propriedades antioxidantes que aumentem o tempo de estocagem dos alimentos, reduzam as perdas nutricionais e que permitam o uso de óleos e gorduras mais suscetíveis à oxidação (BERNARDO-GIL; RIBEIRO;ESQUÍVEL, 2002). Uma vez que a utilização segura de antioxidantes sintéticos como o butil hidroxitolueno (BHT) tem sido questionada, (devido a problemas de solubilidade, aparecimento de sabores estranhos e caráter toxicológico), a investigação da presença de compostos com potencial antioxidante em alimentos como a linhaça desponta como uma alternativa natural contra os efeitos oxidativos dos radicais livres sobre os alimentos.Aliada a isso, a obtenção do óleo da linhaça também é importante. Para tal finalidade são utilizadas técnicas específicas. A extração por solvente orgânico é a mais comumente utilizada para extrair lipídios do óleo de sementes, com um inconveniente: a possibilidade de ocorrer a degradação térmica dos ácidos graxos poliinsaturados, dependendo das condições utilizadas na extração convencional, além da necessidade de eliminação AbstractLinseeds are rich in essential fatty acids, fibers and phenolic compounds, which have antioxidant activity. This work proposed obtaining linseed oil through different extraction methods (organic solvent and sub-critical CO 2 ), observing the presence of compounds with antioxidant potential in the seeds through Thin-Layer Chromatography (TLC) and evaluating the co-oxidation of substrates of the β-carotene/linoleic acid system. For TLC, the detection reagents β-carotene/linoleic acid and ferric chloride/potassium ferricyanide were used. For antioxidant activity, spectrophotometric measurements of solutions containing the oxidant system β-carotene/linoleic acid were made, with readings every 15 minutes/2 hours. The presence of phenolic antioxidant compounds was evidenced in all extracts; however, the aqueous extract presented greater antioxidant activity in the volumes of 100 and 200 mL. The highest extraction yield was obtained through organic solvent extraction, with ethyl ether as solvent (25.89%). Keywords: linseed; extraction methods; antioxidant activity; β-carotene. ResumoAs sementes de linhaça são ricas em ácidos graxos essenciais, fibras e compostos fenólicos, ...

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In this study, research was performed on the interesterification reaction of cotton oil with methyl acetate, using potassium methoxide as catalyst, in the presence of ultrasonic waves. In order to obtain a better understanding of the process variables behavior, a response surface methodology was used along with statistical methods. The experiments were performed with molar ratio varying from 1:8 to 1:24, catalyst percentage of 0.1 to 1.3% (weight), ultrasonic nozzle amplitude varying from 30% to 90% (180 to 540 W) and vibration pulse varying from 50% to 90%. Process variables were optimized with the optimal molar ratio of 1:14.87, catalyst concentration of 1.17%, ultrasonic probe amplitude of 67.64% and vibration pulse of 67.30%. The average conversion of triglycerides was found to be 98.12% at the optimal conditions. The experimental data were adjusted to the second-order irreversible reaction approximation model, under optimized conditions, with temperatures of 30, 40 and 50 ºC. Lastly, in comparison to the conventional methodology, a significant increase of 14% of triglycerides conversion utilizing ultrasonic waves was observed.

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