In a recent study published in the journal Food, researchers examined bioactive compound compositions, aroma profiles, and antioxidant activity levels of four edible flower species. Their findings contribute to the scientific understanding of the nutritional and health benefits of edible flowers.
Study: Phytochemical, nutritional and mineral content of four edible flowers. Image credit: Stephanie Frey / Shutterstock
Record
The Mediterranean diet and other traditional and healthy eating patterns include the consumption of edible flowers that are often rich in micro- and macronutrients and antioxidants while enhancing the taste and texture of dishes.
While some species of edible flowers have been studied to characterize their nutritional properties, others are relatively unknown, including some varieties that are commonly eaten. Analysis of their mineral, nutrient and phytochemical content can lead to the development of new functional foods and natural therapies to improve public health and nutrition.
About the study
In this study, researchers analyzed its flowers Viola cornuta, Fuchsia regia, Dianthus chinensis, and Cucurbita moschata. While C. muscat was grown in an open field in Italy, the other species were grown in a nearby greenhouse.
Viola cornuta. Image credit: joloei / Shutterstock
Organic practices were followed for all plants. Fully open flowers were harvested early in the morning as soon as they were ripe. Flowers were placed in three identical groups or replicates. Half of each replicate was dried under vacuum, while the other half was frozen in liquid nitrogen.
Frozen flowers were used to extract primary metabolites or soluble sugars, namely sucrose, D-fructose, and D-glucose, and secondary metabolites, including polyphenols, flavonoids, carotenoids, and anthocyanins. Radical scavenging activity was also measured from these samples. Freeze-dried flowers were used for the determination of organic nitrogen, phosphorus, other micro- and macro-elements and crude proteins.
In addition, B vitamins (thiamine, riboflavin, niacin and folate) and vitamin C or ascorbic acid were extracted and quantified. Fresh flowers were used to collect volatile organic compounds (VOCs) which were injected into a gas chromatograph to evaluate the aroma profile. Electron impact mass spectrometry was used to analyze compounds after separation.
One-way analysis of variance (ANOVA), statistical test, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to further analyze the biochemical results.
Foundings
D. chinensis had the highest content of soluble sugars while V. cornuta had the least; The latter also showed lower levels of soluble sugars than others Viola kind. Sucrose was not found in C. muscat the F. regia samples and D-glucose was the most abundant sugar in all four species.
C. muscat and V. cornuta showed the highest crude protein content. Macronutrients such as calcium, potassium and phosphorus were abundant, while the most common micronutrients were manganese, zinc and iron.
In particular, the flowers analyzed showed higher levels of calcium than similar species previously studied, suggesting that they could provide a significant part of the daily recommended intake.
Analyzes of antioxidant compounds, including polyphenols, flavonoids, anthocyanins and carotenoids, showed that F. regia showed the highest total polyphenolic content, while V. cornuta had the highest carotenoid content.
F. regia had much higher levels of total phenolic compounds than others known Fuchsia species while V. cornuta was richer in carotenoids than others Viola kind. Analysis of radical scavenging activity validated these results.
C. muscat showed the highest content of all B vitamins except riboflavin, which may help meet daily intake requirements, especially if consumed fresh. This is remarkable as Cucurbita Flowers are often cooked before consumption and usually contain lower levels of niacin, total folate and thiamin. Riboflavin levels were low in all four species.
The content of vitamin C or ascorbic acid was higher in V. cornuta. As this metabolite shows signs of progressive decline after its harvest, the flowers should be consumed shortly after harvest or stored properly so that the necessary levels of vitamin C reach consumers.
VOC analysis revealed distinct aroma profiles. Each species had unique VOC compositions, with D. chinensis and F. regia sharing similar profiles. Especially, C. muscat and V. cornuta they exhibited different compositions, with specific compounds contributing to their aroma. ESPECIALLY, V. cornuta emit high levels of monoterpene hydrocarbons and sesquiterpene hydrocarbons.
Multivariate statistical analyses, including PCA and HCA, distinguished species based on biochemical and volatile compositions. V. cornuta stood out due to its unique VOC profile and higher manganese and zinc content. C. muscat it was notable for its low antioxidant activity and richness in phosphorus and niacin.
In the meantime, F. regia and D. chinensis clustered close to each other, characterized by the emission of cis-geranyl acetone and decanal, while showing higher levels of D-fructose, D-glucose, iron and sodium.
conclusions
Understanding the aroma profiles, antioxidant activity levels, and bioactive compositions of edible flowers is critical to exploiting this relatively underutilized biological resource for the development of new functional foods and natural therapies, with potential applications for creating fragrances as well.
Further research is needed to understand how these compounds can be stabilized and maintained. Meanwhile, many species of edible flowers remain to be characterized and evaluated.
