Dados do Trabalho

Título

OPTIMIZATION OF EXTRACTION OF BIOACTIVE COMPOUNDS FROM HIBISCUS CALYXES USING SIMPLEX-CENTROID MIXTURE DESIGN

Introdução

The hibiscus calyx (Hibiscus sabdariffa L.) stands out for its high content of anthocyanins, other phenolic compounds, and antioxidant activity. For the correct comparison of data and quantification of these compounds, it is necessary to use extraction conditions that promote maximum recovery of the compounds of interest. Thus, the general objective of this work was to optimize the extraction of phenolic compounds and antioxidants from hibiscus calyxes using simplex-centroid mixture design.

Material e Métodos

To this end, ten tests were carried out using 2% acetic acid, acetone, and ethanol as solvents. The response functions evaluated were the content of phenolic compounds, anthocyanins, and antioxidant activity using the ABTS, FRAP, and DPPH methods. From the results obtained, the equation models were determined with their respective regression coefficients and analysis of variance.

Resultados e Discussão

The content of phenolic compounds in the hibiscus calyx ranged from 12.91 to 17.96 mg AGEq/g sample, while the anthocyanin content ranged from 1.38 to 4.50 (mg dp 3-sam/g). The maximum antioxidant activity for the ABTS method was 128.5 mol TE/g, 146.2 mol TE/g for the DPPH assay and 206.2 mol TE/g for FRAP. The highest levels of phenolic compounds, anthocyanins, and antioxidants were obtained in tests with greater amounts of 2% acetic acid solution; this is because studies show that anthocyanins and phenolic compounds are more soluble in polar solvents.

Conclusão

The addition of acid to the extraction medium promoted the stabilization of anthocyanins, thus increasing extraction efficiency. From the results obtained, it can be determined that the best condition for extracting bioactive compounds from hibiscus calyxes is the combination of the three solvents investigated, in the proportion of 63.3% 2% acetic acid solution, 22.5% ethanol, and 14.2 % acetone.