Dados do Trabalho

Título

OPTIMIZATION AND KINETIC STUDY OF ULTRASOUND-ASSISTED EXTRACTION OF CAROTENOIDS PRODUCED BY THE YEAST Rhodotorula glutinis

Introdução

Carotenoids have been the subject of many studies due to their important biological functions in humans, as well as their role as natural pigments ranging from providing color and flavor to preserving nutrient stability. Carotenoids can be produced via fermentation, offering advantages such as scalability, controlled growth conditions, and reduced environmental impact. Green extraction techniques, such as ultrasound-assisted extraction (UAE), are effective for obtaining carotenoids, providing high extraction efficiency, reduced solvent usage, and the possibility of using non-toxic solvents.

Material e Métodos

In this context, the objective of the study was to optimize the UAE of carotenoids from the yeast Rodotorula glutinis. The optimization of the extraction process was carried out using a DCCR 22 experimental design. Power (100 to 450 W) and solvent (ethanol)/biomass ratio (30:1 to 70:1 v/w) were evaluated. The extraction volume and time were fixed at 30 mL and 10 min, respectively. Kinetic assays were performed in the region of the highest yield, and the results were adjusted to a spline model to determine the best extraction time.

Resultados e Discussão

The extracts were evaluated for total carotenoid content (TC) and antioxidant activity. TC ranged from 7.10 (150 W and 36:1 v/w) to 31.77 (450 W and 50:1 v/w) µg β-carotene/g dw biomass. The quadratic model generated by the response surface methodology showed a good coefficient of determination (R2 = 0.83). The variable power exerted the highest influence on the total carotenoid content. According to the model, the region with the highest yield was >450 W and between 45-55:1 v/w. Despite this, it was observed that extracts with higher antioxidant activity were obtained at lower powers (100 W and 150 W) as these powers reached lower extraction temperatures (T < 20 °C), thus providing greater stability to the extracts. Kinetic assays demonstrated that after 6.4 minutes, the extraction process reached the diffusion period (extraction rate = 0).

Conclusão

Thus, UAE demonstrated significant results in the recovery of carotenoids produced by Rodotorula glutinis. The UAE achieves a yield of around 77% when compared to the traditional method of extraction using exhaustive maceration with organic solvents.