Edible flowers as a new source of natural antioxidants for oxidative protection of cold-pressed oils rich in omega-3 fatty acids

• Published in: Food research international 2020-08, Vol.134, p.109216-109216, Article 109216
• Main Authors: Mikołajczak, Natalia, Sobiechowska, Daria Anna, Tańska, Małgorzata
• Format: Article
• Language: English
• Subjects: Antioxidants - chemistry; Chia seed oil; DPPH radical inhibition; Edible flowers; Fatty Acids, Omega-3 - chemistry; Flavonoids; Flax seed oil; Flowers - chemistry; Food Handling; Food Preservation; Humans; Induction time; Phenolic compounds; Plant Oils - chemistry; Plants, Edible - chemistry; Seeds - chemistry
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2020.109216

[Display omitted] •Lyophilized edible flowers are a valuable source of phenolic compounds.•Extract from 23 lyophilized edible flowers were added to cold-pressed oils.•The flower extracts stabilized more effectively chia seed oil than flax seed oil.•Nasturtium and marigold scattered extracts highly inhibited the oxidation of both oils. This study aimed to evaluate and compare the effect of methanolic extracts from 23 lyophilized Polish edible flowers on the oxidative stability of two cold-pressed oils rich in omega-3 fatty acids. Two popular oils (flax and chia seed oils) were used in the study and characterized for their chemical composition, quality and oxidative stability. Hydro- and lipophilic components, and antioxidant activity were determined in the flower extracts. The effectiveness of the edible flower extracts in oxidative protection of cold-pressed oils was evaluated in the Rancimat test. The edible flower extracts differed significantly in their composition and antioxidant activity. Among the extracts, the richest source of phenolic compounds were those obtained from red begonia (996.80 ppm), red geranium (1028.16 ppm), and small leaved lime (1003.62 ppm) flowers; whereas red begonia and red geranium flower extracts were also found to be valuable sources of flavonoids, 343.70 and 307.34 ppm, respectively. The extracts from lyophilized edible flowers had a low content of lipophilic pigments (0.97–9.01 ppm for chlorophylls and 0.03–12.34 ppm for carotenoids), while the content of tocopherols varied greatly (0.70–193.34 ppm). Most of the analyzed extracts were characterized by a high DPPH radical inhibition value (>10 µM TE/mL). Almost all studied edible flower extracts improved oxidative stability of the cold-pressed flax and chia seed oils. More favorable effects were observed in chia seed oil, in particular after the addition of extracts from nasturtium, marigold scattered, dog rose, and daylilies flowers (the changes were more than 50% higher compared to the control sample).