Freezing and air drying determine phytochemical traits and antioxidant potential of selected edible flowers

This study investigated the phytochemical composition and antioxidant potential of edible flower according A factorial experiment on six species (Rosa spp., Calendula officinalis, Viola odorata, Trifolium pratense, Sambucus nigra, and Borago officinalis) using two solvents (aqueous and ethanolic) and four sample states (fresh, freeze-dried, and air-dried at 30 and 50 °C) a. Bioactive compounds were evaluated by total phenolic content (TPC) and monomeric anthocyanin content (MAC), while antioxidant activities were assessed through DPPH, ABTS, FRAP, and reducing power (RP) assays. Results showed that both main factors and their interactions significantly influenced phytochemicals and antioxidant capacity. Fresh and freeze-dried flowers retained the highest levels of phenolics, anthocyanins, and antioxidant activity, whereas hot-air drying at 50 °C caused the greatest losses. Ethanolic extraction consistently outperformed aqueous extraction in recovering bioactive compounds and antioxidant potential. Correlation analysis indicated moderate positive associations between TPC and antioxidant assays, and strong correlations between MAC and RP. The study was limited to six species, selected drying temperatures, and two solvent types. Nevertheless, findings highlight that freeze-drying combined with ethanolic extraction is the most effective method to preserve phytochemical integrity and antioxidant capacity of edible flowers. These insights can guide food and nutraceutical industries in optimizing processing strategies for maintaining the nutritional and functional properties of floral ingredients.