Five Edible Flowers – Valuable Source of Antioxidants in Human Nutrition

Consumption of the edible flowers forms new trend in human nutrition, especially in Bulgaria. Therefore, the determination of bioactive compounds content in their petals presents important tasks for their evaluation as natural source of antioxidants for human diet. In this study the quantity of natural pigments, total phenolic content and total flavonoids content, as well the antioxidant capacities in 95 % (v/v) ethanol, 70 % (v/v) ethanol, 80 % (v/v) methanol and distilled water extracts obtained from five edible flowers targets (Tagetes erecta L.), marigold (Calendula officinalis L.), geranium (Geranium macrorrhizum L.), bougainvillea (Bougainvillea spectabilis Willd.), Jerusalem artichoke (Helinathus tuberous L.) were invastigated. Total phenols and flavonoid quantification of the extracts was achieved by using Folin–Ciocalteau and AlCl3 reagents, respectively. Geranium 95 % ethanol extracts were evaluated as the richest source of total phenols -19.79 mg GAE/g fw, while 80% methanol extracts of Helinathus tuberous L. showed the highest values of total flavonoids content 8.89 mg QE/g fw. The highest antioxidant capacities using two methods, DPPH and FRAP assays were obtained for 95% ethanol geranium (Geranium macrorrhizum L.) extracts 242.9 and 106 mM TE/g fw, respectively. There was positive linear correlation between antioxidant activity and total phenolic content for all investigated edible flower extracts. All studied flowers could be a valuable source of antioxidants for addition to dishes or fresh consumption for preventing diets. These findings showed that the tested flowers could be considered as new sources of safe natural antioxidants and colorants for food industry.