Abstract
Introduction:Hibiscus calyces are important sources from anthocyanins and pigments. The recovery of these bioactive compounds using non-organic solvents becomes very attractive for the food industry.Methods:For this reason, the separation of phenolic compounds by acidified aqueous extraction from hibiscus calyces was studied. The experiments were conducted by a fractional factorial design.Result and Conclusion:Four factors were evaluated: temperature, time, stirring speed and enzyme concentration. The extracts produced were subjected to analysis of color (L*,a*,b*andChroma), total monomeric anthocyanins, antioxidant capacity by ABTS and fourteen phenolic compounds were quantified. The results showed that the best condition to obtain hibiscus calyces extract was using an enzyme concentration of 50 µL/1000 g hibiscus extract, 400 rpm of stirring speed at 55 ºC by 4 hours of extraction, that corresponded to concentrations of 17595, 7516, 2568 μg/g, expressed on a dry basis, for total phenolic compounds, delphinidin 3-sambubioside and cyanidin 3-sambubioside, respectively, and antioxidant capacity measured by ABTS of 7.8 µmol of Trolox equivalent per gram.
Highlights
Hibiscus calyces are important sources from anthocyanins and pigments
Regarding the anthocyanins of hibiscus extract, two anthocyanins, highlighting the delphinidin 3-sambubioside as the main anthocyanin of the hibiscus were identified and quantified, followed by cyanidin-3-sambubioside, which is found to be in agreement with the results obtained by Ramirez-Rodrigues et al [31] and Christian et al [39], who reported delphinidin and cyanidin sambubiosides as the anthocyanins in hibiscus aqueous extracts
T8 provided the highest extraction of phenolic compounds (17595 μg/g extract on dry basis), followed by T7 (16656 μg/g extract on dry basis), showing a positive effect mainly of the temperature and stirring speed in the extraction of phenolic compounds
Summary
Hibiscus calyces are important sources from anthocyanins and pigments. The recovery of these bioactive compounds using non-organic solvents becomes very attractive for the food industry. Hibiscus is a native plant from Africa and Asia, belonging to Malvaceae family. Hibiscus calyx is widely used to make infusions or teas, as well as in the preparation of jellies and/or as a natural dye source [3]. Natural antioxidants from plant sources have had special importance, especially compounds, such as polyphenols and flavonoids (anthocyanins) [1]. The compounds responsible for these effects are the molecules of phenolic and anthocyanins present in hibiscus [6, 16]
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