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Extracting phenolic compounds from Hibiscus sabdariffa L. calyx using microwave assisted extraction

Cassol, Liliana, Rodrigues, Eliseu, Zapata Noreña, Caciano Pelayo
Industrial crops and products 2019 v.133 pp. 168-177
Hibiscus sabdariffa, anthocyanins, antioxidant activity, aqueous solutions, bioactive compounds, calyx, chlorogenic acid, citric acid, edible flowers, kaempferol, methanol, microwave treatment, myricetin, phenolic acids, quercetin
Hibiscus is an edible flower with great industrial potential due to the presence of bioactive compounds. The aim of this study was to compare three extraction procedures of phenolic compounds from the calyx of hibiscus using only microwave assisted extraction (MAE), using a solution of citric acid followed by MAE, and MAE followed by extraction using a solution of citric acid. The results indicated that the best extraction condition was the combined extraction of 700 W for 8 min and subsequent extraction in acidic aqueous solution for 6 h, with the contents of 1.63 mg g−1, 29.62 mg g−1, 133.25 μmol g−1 for anthocyanins, total phenolics, and antioxidant activity, respectively. In extractions obtained by exhaustive extraction with methanol for 25 min and MAE at 700 W and 8 min, 13 compounds were found: six phenolic acids, two anthocyanins, and five flavonoids derived from quercetin, kaempferol, and myricetin. The major phenolic compounds were 3-caffeoylquinic acid (2.58 and 1.32 mg g−1) and 5-caffeoylquinic acid (1.71 and 0.90 mg g−1) for exhaustive extraction and MAE, respectively. The results suggest that MAE followed by extraction in acidic aqueous solution was the best alternative to recovery of phenolic compounds from hibiscus.