Production of phenolic compounds and biosugars from flower resources via several extraction processes

Abstract Edible flowers are abundant sources of bioactive compounds that provide substantial health benefits due to the antioxidant, anti-inflammatory, antimicrobial, anticancer, and neuroprotective agents that they contain. In the current study, the potential production of phenolic molecules by environmentally friendly extraction processes from camellia, rose, and roselle flowers was investigated. Rose showed the highest content of phenolic compounds (129.0–198.4 mg gallic acid equivalents (GAE)/g dry weigh (DW)), followed by camellia (56.7–107.6 mg GAE/g DW) and roselle (28.9–43.1 mg GAE/g DW). The antioxidant capacities of the extracts were correlated with their total phenolic contents, and were 898.4–1635.6 μmol Trolox equivalents (TE)/g for rose, 410.8–768.6 μmol TE/g DW for camellia, and 88.7–155.4 μmol TE/g for roselle. Significant improvements in the phenolic content were observed for the process using hydrolytic enzymes, which released 3940.9, 1623.3, and 81.4 mg/100 g of gallic acid from rose, camellia, and roselle flower, respectively. Rose and camellia flowers were found to be promising sources of natural gallic acid. Extraction with aqueous ethanol at 180 °C was the most effective method for achieving high total phenolic contents, antioxidant activities, and protocatechuic acid content. The highest levels of protocatechuic acid were 163.2 mg/100 g for roselle flowers and 84.7 mg/100 g for camellia flowers. The maximum sugar production was obtained by enzymatic hydrolysis, which yielded 596, 585, and 380 mg/g for rose, camellia, and roselle flowers, respectively. These results demonstrate that edible flowers can be exploited as potential sources of phenolic compounds and biosugars for functional foods and pharmaceutical applications.