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The objective of this study was to maximize the ultrasonic‐assisted extraction (UAE) of β‐carotene for sunflower oil, by adjusting the combinations of the operational variables: temperature, time, and oil to carrot ratio, as well as obtaining extraction kinetics. Enriched sunflower oil and commercial sunflower oil was characterized. A polynomial model was developed to describe the β‐carotene content as a function of operating parameters and the results indicated that all variables had an influence on the β‐carotene extraction. The maximum values of temperature (55°C), time (60 min), and oil to carrot ratio (30 ml/g) promoted the highest removal of β‐carotene. UAE was endothermic, irreversible, and the increase in temperature favored the viability and spontaneity of the process. The oils presented linoleic and oleic acid as the main fatty acids and the enrichment of sunflower oil did not affect the fatty acid profile and the contents of phytosterols and tocopherols. Practical applications The demand for functional foods and the minimization of synthetic additives have stimulated the application of natural active compounds to products, such as β‐carotene, which is known for its antioxidant properties. To investigate the extraction of β‐carotene, it is important to use efficient technologies that maintain the characteristics of the extract and that overcome the disadvantages of conventional techniques, such as longer extraction time and high solvent consumption. In this context, the enrichment of the sunflower oil with β‐carotene from the ultrasound‐assisted extraction is highlighted. In addition, optimization studies and thermodynamic analysis contribute to the improvement in the process performance, through the systematic selection of the operational variables, and to the understanding of the behavior of the active compound with the interfaces of the extraction, respectively.

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A interesterificação permite a obtenção de ésteres livre de glicerol, com a produção da triacetina, que pode ainda ser utilizada como aditivo ao biocombustível. A fim de potencializar a produção de ésteres e triacetina a inserção de aditivos a reação tem sido abordada. O presente estudo teve como objetivo avaliar o efeito de adicionar solução aquosa de ácido acético 26% (SA26%) em 5 e 10% (em relação a massa de óleo) sobre o rendimento em ésteres e teor de triacetina, bem como verificar seu efeito sobre os ésteres individuais, variando a temperatura da reação de 300 a 325 °C e tempo de residência entre 10 a 30 minutos. Para a maioria das reações conduzidas com SA(26%) a 300 °C houve maior produção de ésteres, se comparadas as reações sem o aditivo (p<0,05). Os resultados demonstraram que as reações conduzidas com SA26% permitiram elevar os rendimentos de ésteres em até 45%. Foi possível constatar ainda conversão completa dos triglicerídeos em ésteres com apenas 20 min de reação, com 10% de SA(26%)  300 °C. O aumento da temperatura resultou em maior rendimento inicial (10 min), contudo foi observada redução dos ésteres individuais analisados, sendo que, dentre estes o linoleato se mostrou mais susceptível a decomposição térmica. AbstractThe interesterification allows the production of esters free of glycerol, with the production of triacetin, which can still be used as an additive to biofuel. In order to potentiate the esters and triacetin production the insertion of additives into the reaction has been approached. The present study aimed to evaluate the effect of adding aqueous solution of acetic acid 26% (SA26%) in 5 and 10% (relative to oil mass) on the ester yield and triacetin content, as well as to verify its effect on obtaining the individual esters, varying the reaction temperature from 300 to 325 °C and residence time between 10 to 30 minutes. For the majority of the reactions conducted with SA26% at 300 °C there was higher ester production, when compared with the reactions without the additive (p<0.05). The results showed that the reactions conducted with SA26% allowed to raise ester yields by up to 45%. It was also possible to verify complete conversion of the triglycerides to esters with only 20 min of reaction, with 10% of SA26% at 300 °C. The increase in temperature resulted in a higher initial yield (10 min), however, a reduction of the individual esters analyzed was observed, with linoleate being more susceptible to thermal decomposition.

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