Anthocyanin-rich edible flowers - Impact of food matrix on anthocyanin stability, digestion and absorption: the case of wild pansy, cosmos and cornflower.

Several commercial berries have been examined for anthocyanin composition, bioaccessibility, and bioactive effects, while Brazilian berries remain underexplored. This study aimed to access the effect of in vitro gastrointestinal digestion on anthocyanin bioaccessibility, stability, and antioxidant potential in black pitanga (Eugenia uniflora var. rubra Mattos), grumixama (Eugenia brasiliensis), nhamburi (Rubus urticaefolius), and barapiroca (Eugenia involucrata) - also called Rio Grande cherry - and explore its link with the food matrix composition. The INFOGEST in vitro digestion model was applied to these berries, and anthocyanin were quantified using ultra-high-performance liquid chromatography-electrospray ionization-triple-quadrupole-tandem mass spectrometry. Antioxidant potential, polyphenols, flavonoids, anthocyanins, and proximate composition were analyzed by conventional protocols. The results were used in performing analysis of variance, Pearson's R correlations, and multivariate principal component analysis to explore the food matrix key roles. Brazilian native berries, particularly black pitanga, nhamburi, and grumixama, were found to be rich sources of anthocyanins. Stability during in vitro digestion oscillated between berries and anthocyanin type, besides remaining over 40%. Bioaccessibility highlights are the cyanindin-3-glucoside and malvidin-3,5-diglucoside, which had the highest bioaccessibilities (between 45% and 68%). Black pitanga and nhamburi were able to provide the highest amounts of bioaccessible anthocyanins (477 and 1172 mg g-1, respectively). Black pitanga presented the highest ferric reducing antioxidant power and oxygen radical absorbance capacity in bioaccessible fractions. Multivariate statistics showed a clear correlation between centesimal composition and anthocyanin stability. The findings reveal complex interactions between food matrices, anthocyanin stability and bioaccessibility, and effective antioxidant potential for human health. This research emphasizes the use of Brazilian berries as good anthocyanin sources, highlighting black pitanga and nhamburi, while fostering consumer health and conservation of natural resources. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Anthocyanins have attracted a lot of attention in the fields of natural pigments, food packaging, and functional foods due to their color, antioxidant, and nutraceutical properties. However, the poor chemical stability and low bioavailability of anthocyanins currently limit their application in the food industry. Various methods can be used to modify the structure of anthocyanins and thus improve their stability and bioavailability characteristics under food processing, storage, and gastrointestinal conditions. This paper aims to review in vitro modification methods for altering the molecular structure of anthocyanins, as well as their resulting improved properties such as color, stability, solubility, and antioxidant properties, and functional applications as pigments, sensors and functional foods. In industrial production, by mixing co-pigments with anthocyanins in food systems, the color and stability of anthocyanins can be improved by using non-covalent co-pigmentation. By acylation of fatty acids and aromatic acids with anthocyanins before incorporation into food systems, the surface activity of anthocyanins can be activated and their antioxidant and bioactivity can be improved. Various other chemical modification methods, such as methylation, glycosylation, and the formation of pyranoanthocyanins, can also be utilized to tailor the molecular properties of anthocyanins expanding their range of applications in the food industry.

Red cabbage is, among different vegetables, one of the major sources of anthocyanins. In the present study an in vitro digestion method has been used to assay the influence of the physiological conditions in the stomach and small intestine, as well as faecal microflora on anthocyanins stability in red cabbage and anthocyanin-rich extract. The recovery of anthocyanins during in vitro gastrointestinal digestion was strongly influenced by food matrix. The results showed that other constituents present in cabbage enhanced the stability of anthocyanins during the digestion. The amount of anthocyanins (HPLC method) and antioxidant capacity (ABTS and FRAP assays) strongly decreased after pancreatic-bile digestion in both matrices but total phenolics content (Folin-Ciocalteu assay) in these digestions was higher than in initial samples. Incubation with human faecal microflora caused further decline in anthocyanins content. The results obtained suggest that intact anthocyanins in gastric and products of their decomposition in small and large intestine may be mainly responsible for the antioxidant activity and other physiological effects after consumption of red cabbage.

Anthocyanins are phenolic compounds present in many natural products and known for their health benefits. These benefits are directly related to their bioaccessibility, which is, the ability of those substances to reach the intestine after the digestive process, being absorbed and used by the organism. In this context, this thesis aims to investigate strategies to increase the bioaccessibility of anthocyanins for human consumption. The first article consists of a comprehensive review of technological tools and strategies to improve the stability, bioaccessibility and bioavailability of anthocyanins in food systems. Additionally, we highlight methodologies for evaluating their bioaccessibility and bioavailability, which vary between in vitro and in vivo approaches. We observed that in vitro methodologies are the most widely used due to their relative financial accessibility, lower complexity, and ability to provide rapid results. Among the most used strategies to increase the stability of anthocyanins during the digestion process, microencapsulation stands out. This technique proved to be effective in protecting against pH variations and enzymatic action, resulting in a general improvement in the in vitro bioaccessibility. The review also addresses the influence of the food matrix and types of processing over those parameters, indicating that these strategies can have positive or negative impacts on bioaccessibility and bioavailability. Therefore, more studies are needed to delve on how such strategies, as fermentation, for example, effectively assist in the formulation of functional foods. Thus, in the second chapter we detailed the evaluation of three types of fermentation (spontaneous, lactic, and alcoholic) on the bioaccessibility of anthocyanins from açai. Furthermore, we evaluated the cytotoxic effect of fermented açai extracts before and after simulated gastrointestinal digestion (SD) in three cell lines. Dried açai extracts produced from spontaneous fermentation (SF) for 24 h presented greater bioaccessibility of phenolics (52.68%) and cyanidin-3 glycoside (27.01%) compared to unfermented açai. Similarly, lactic acid fermentation (LF) for 72 hours improved the bioavailability of phenolics (64.49%) and cyanidin-3-rutinoside (20.00%). The fermented extracts did not presented cytotoxicity in the cell lines A549 (lung adenocarcinoma epithelial cells), HCT8 (human colon carcinoma) and IMR90 (normal human lung fibroblast), while extracts derived from 24-h alcoholic fermentation presented antioxidant and antimutagenic effects in vitro, reducing around 40% of chromosomal aberrations. This thesis highlights the relevance of processes such as microencapsulation and fermentation to increase the stability and bioaccessibility of anthocyanins, providing relevant information for the development of more effective functional foods. Keywords: Açai. Phenolic compounds. Bioaccessibility. Fermentation.

Edible flowers have been gaining popularity among researchers, nutritionists and chefs all around the world. Nowadays, flowers are used to make food look and/or taste better; however, they are also a very good source of valuable nutrients (antioxidants, vitamins, proteins, fats, carbohydrates, macro and microelements). The aim of our study was to determine the content of dietary fibre and total protein in selected edible flowers; we also compared the nutritional content of petals, differentiating between the representatives of the Oleaceae and Asteraceae families, as well as herbaceous vs. woody plants. The study material consisted of petals of 12 edible flower species (Magnolia × soulangeana, Sambucus nigra L., Syringa vulgaris L. (white and violet flowers), Robinia pseudoacacia, Forsythia × intermedia, Cichorium intybus L., Bellis perennis, Tussilago farfara L., Taraxacum officinale F.H. Wiggers coll., Centaurea cyanus L., Calendula officinalis). Dietary fibre content was determined by the enzymatic-gravimetric method and ranged from 13.22 (Magnolia × soulangeana) to 62.33 (Calendula officinalis L.) g/100 g. For insoluble dietary fibre (IDF), the values ranged from 8.69 (Magnolia × soulangeana) to 57.54 (Calendula officinalis L.) g/100 g, and the content of soluble dietary fibre (SDF) was between 1.35 (Syringa vulgaris L.-white flowers) and 7.46 (Centaurea cyanus L) g/100 g. Flowers were also shown to be a good, though underappreciated, source of plant protein, with content ranging from 8.70 (Calendula officinalis L.) to 21.61 (Magnolia × soulangeana) g/100 g dry matter (Kjeldahl method). Considerable amounts of protein were found in the flowers of the olive family (Oleaceae) and woody plants, which can enrich the daily diet, especially vegan and vegetarian. Edible flowers of the Asteraceae family, especially the herbaceous representatives, contained high levels of both total dietary fibre and its insoluble fraction; therefore, they can be a rich source of these nutrients in the daily diet of athletes, which would perform a prebiotic function for gut bacteria.

The aim of the present work was to study the main volatile and bioactive compounds (monomeric anthocyanins, hydrolysable tannins, total flavonoids, and total reducing capacity) of five edible flowers: borage (Borage officinalis), calendula (Calendula arvensis), cosmos (Cosmos bipinnatus), Johnny Jump up (Viola tricolor), and pansies (Viola × wittrockiana), together with their sensory attributes. The sensory analysis (10 panelists) indicated different floral, fruity, and herbal odors and taste. From a total of 117 volatile compounds (SPME–GC–MS), esters were most abundant in borage, sesquiterpenes in calendula, and terpenes in cosmos, Johnny Jump up, and pansies. Some bioactive and volatile compounds influence the sensory perception. For example, the highest content of total monomeric anthocyanins (cosmos and pansies) was associated with the highest scores of colors intensity, while the floral and green fragrances detected in borage may be due to the presence of ethyl octanoate and 1-hexanol. Therefore, the presence of some volatiles and bioactive compounds affects the sensory perception of the flowers.

In this study, 17 edible flowers (Allium ursinum L., Borago officinalis L., Calendula officinalis L., Centaurea cyanus L., Cichorium intybus L., Dianthus carthusianorum L., Lavandula angustifolia Mill., Leucanthemum vulgare (Vaill.) Lam., Paeonia officinalis L., Primula veris L., Robinia pseudoacacia L., Rosa canina L., Rosa pendulina L., Salvia pratensis L., Sambucus nigra L., Taraxacum officinale Weber, and Tropaeolum majus L.) were investigated to assess their sensory profile at harvest and their shelf life and bioactive compounds dynamics during cold storage. The emerging market of edible flowers lacks this information; thus, the characteristics and requirements of different flower species were provided. In detail, a quantitative descriptive analysis was performed by trained panelists at flower harvest, evaluating 10 sensory descriptors (intensity of sweet, sour, bitter, salt, smell, specific flower aroma, and herbaceous aroma; spiciness, chewiness, and astringency). Flower visual quality, biologically active compounds content (total polyphenols and anthocyanins), and antioxidant activity (FRAP, DPPH, and ABTS assays) were evaluated both at harvest and during storage at 4 °C for 14 days to assess their shelf life. Generally, species had a wide range of peculiar sensory and phytochemical characteristics at harvest, as well as shelf life and bioactive compounds dynamics during postharvest. A strong aroma was indicated for A. ursinum, D. carthusianorum, L. angustifolia, and L. vulgare, while B. officinalis and C. officinalis had very low values for all aroma and taste descriptors, resulting in poor sensory profiles. At harvest, P. officinalis, R. canina, and R. pendulina exhibited the highest values of polyphenols (884–1271 mg of gallic acid equivalents per 100 g) and antioxidant activity (204–274 mmol Fe2+/kg for FRAP, 132–232 and 43–58 µmol of Trolox equivalent per g for DPPH and ABTS). The species with the longest shelf life in terms of acceptable visual quality was R. pendulina (14 days), followed by R. canina (10 days). All the other species lasted seven days, except for C. intybus and T. officinale that did not reach day 3. During cold storage, the content of bioactive compounds differed, as total phenolics followed a different trend according to the species and anthocyanins remained almost unaltered for 14 days. Considering antioxidant activity, ABTS values were the least variable, varying in only four species (A. ursinum, D. carthusianorum, L. angustifolia, and P. officinalis), while both DPPH and FRAP values varied in eight species. Taken together, the knowledge of sensory profiles, phytochemical characteristics and shelf life can provide information to select suitable species for the emerging edible flower market.

What Nutritional Contribution Do Edible Flowers Make?

In recent years, a new trend in the food industry is the use of flowers in food production. Although currently consumed on a relatively small scale around the world, edible flowers have been a source of nutritional diets since ancient times due to their aesthetic appeal and desirable aroma. The importance of color acceptability and the need to meet and attract more consumers to market have led to the development of new pigments for industrial products. The stability of anthocyanin is influenced by a number of factors such as pH, temperature, oxygen as well as the presence of co-pigments and metallic ions. It can also easily degraded by oxidase. Several preservation methods can improve the stability of anthocyanin, phytochemicals, nutrients and other functional properties of edible flowers. This article comprehensively reviewed the recently developed processing and preservation technologies for color retention, anthocyanin degradation, and anthocyanin-related enzyme inactivation as well as various methodologies for the extraction of anthocyanins from edible flowers. It should be noted that not all flowers are safe to consume due to potential presence of natural toxins. Practical applications The synergistic effect of novel treatments could maintain anthocyanins degradation, color, nutrients, and bioactive compounds as well as the novel extraction techniques were also expressed to extract the anthocyanins of edible flowers. The anthocyanins pigments have been traditionally used as a natural colorant nowadays. Besides being used as natural colorants, some of the anthocyanin-rich flowers and fruits have been used as medicine to treat various diseases.

The edible flowers have been used since ancient times at traditional cuisine or alternative medicine, for their nutritional and health benefits. These benefits are attributed to their phenolic acids, organic acids and flavonoids (anthocyanins). Edible flower has great importance, due to the presence of bioactive compounds with antioxidant. Therefore, the present study determine the phenolic composition and antioxidant capacity of six different edible flowers, namely Viola tricolor, Rosa, Pelargonium graveolens and two different species of Calendula officinalis L.. For each edible flower, the goal was to evaluate the phenolic composition and antioxidant capacity, and for that we performed the determination of the total polyphenolic, ortho-diphenols and flavonoids contents, as well as an accurate quantitative and qualitative determination of phenolic compounds by HPLC-DAD. The results showed that there were significant differences in the content of phenolic compounds and antioxidant capacity of the analyzed edible flowers. The total phenolic content, ortho-diphenols, and flavonoids ranged 12.28 ± 0.29 to 82.06 ± 1.28 mg GA/g; between 0.89 ± 0.00 and 222.67 ± 0.02 mg GA/g and 5.53 ± 0.38 to 12.97 ± 0.71 mg CAT/g, respectively. For the antioxidant capacity, Rosa and Pelargonium graveolens was the flowers that presented the highest antioxidant capacity for the three methods. Regarding the determination of phenolic compounds by HPLC-DAD, 17 compounds belonging to flavonoids (flavonols and anthocyanins) and non-flavonoids (phenolic acids) groups were identified. Thus, this study revealed the possibility to use edible flowers with objective to replace synthetic antioxidants.

Edible flowers with the common name “marigold”: Their therapeutic values and processing

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Recently, there has been a considerable interest in finding natural antioxidants from plant materials to replace the synthetic ones. The edible flowers represent a valuable alternative source of bioactive compounds and have been used as food and herbs with increasing interest. The antioxidant properties of 7 edible flowers of the South Bulgaria, including Viola tricolor L., Cucurbita pepo L., Sambucus nigra L., Calendula officinalis L., Hibiscus rosa-sinensis L., Rosa damascena Mill., and Allium ursinum L. were evaluated. The contents of flower chemicals, such as total phenolics and total flavonoids content, were determined as well. By comparing decoction and infusion as methods of extraction, the decoction ones revealed to be the most appropriate in respect of the evaluated compounds. The results showed that the highest antioxidant activity was found in the Rosa damascena and Viola tricolor ones. The established total polyphenol content and total flavonoids in the decocts of Rosa damascena and Viola tricolor were 56.66 ± 0.48 and 135.82 ± 1.50 mg GAE/g dw and 28.60 ± 0.43 and 15.87± 0.52 mg QЕ/g dw, respectively. The present research extends the traditional knowledge and revealed an opportunity to obtain biological active substances of the nature and edible flowers in particular.

Edible flowers are a new gourmet product; however, they are not always available all years. Thus, it is essential to find out technologies to guarantee this product for a longer time. Flowers of four species (borage [Borago officinalis], heartsease [Viola tricolor], kalanchoe [Kalanchoe blossfeldiana], and dandelion [Taraxacum officinale]) were subjected to freezing (in their natural form and in ice cubes) and analyzed in terms of visual appearance, the content of flavonoids, hydrolysable tannins, phenolics, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power), and microbial quality after storage for 1 and 3 months. Flowers in ice cubes showed similar appearance to fresh ones during the 3 months of storage, whereas frozen flowers were only equivalent up to 1 month with the exception of kalanchoe. Even though flowers in ice cubes showed good appearance after 3 months of storage, they had the lowest values of bioactive compounds and antioxidant activity. On the contrary, when frozen, the content of bioactive compounds maintained or even increased up to 1 month of storage compared to fresh flowers, except for borage. Furthermore, in both freezing treatments, the microorganisms' counts decreased or maintained when compared to fresh samples, except in dandelion. In general, both treatments may allow keeping the flowers after their flowering times. PRACTICAL APPLICATION: The market of edible flowers is increasing, although they are a very perishable product with short shelf-life. Edible flowers are stored in the cold (frozen or in ice cubes); however, the effect on the bioactive compounds and microbial quality that this treatment may have on borage (Borago officinalis), heartsease (Viola tricolor), kalanchoe (Kalanchoe blossfeldiana), and dandelion (Taraxacum officinale) flowers is unknown. So, the present study was conducted to increase the knowledge about the changes that freezing treatments may have in different edible flowers. The results of the present study underline that each flower has different behavior at frozen and ice cubes storage. However, freezing flowers maintain/increase the contents of bioactive compounds, while ice cubes not. Both treatments are effective in protecting flowers from microorganism growth. So, suggesting that both freezing treatments can be used as a preservative method and may allow keeping the flowers after their flowering times.

Two identical surveys were conducted with separate samples to determine consumer perceptions of the quality of five edible flower species. Participants were either members of a class that reviewed the history and uses of edible flowers at an annual, 1-day event (Garden Days) or Michigan Master Gardeners who attended a similar class. Participants were shown a randomized series of projected photographic slides of five edible flower species and asked to indicate whether they found the flower quality acceptable. The slides depicted a range of ratings of mechanical damage, insect damage, or flower senescence on a Likert reference scale (1 through 5) developed by the researchers. A flower rated 5 was flawless, while a flower rated 1 had substantial damage. Nearly one-half of all participants had eaten edible flowers before the study, and 57% to 59% had grown them for their own consumption, indicating many individuals had previous experience. Both samples rated flower quality equally and found pansy ( Viola × wittrockiana `Accord Banner Clear Mixture'), tuberous begonia ( Begonia × tuberhybrida `Ornament Pink'), and viola ( Viola tricolor `Helen Mount') acceptable from stage 5 to 3. Both groups found the nasturtium ( Tropaeolum majus `Jewel Mix') flowers acceptable at only rating 5. Garden Days participants rated borage ( Borago officinalis ) acceptable from ratings 5 to 3, while the Master Gardeners rated their acceptability from only 5 to 4. Participants also rated flower color (yellow, orange, and blue) as equally acceptable.