Post-harvest technologies applied to edible flowers: A review

Novel strategies for enhancing quality stability of edible flower during processing using efficient physical fields: A review

Edible flowers are an exotic part of the human diet due to their distinct sensorial properties and health benefits. Due to consumers demand edible flowers and their products with natural freshness and high nutritional value, there is increasing research on the application of green and efficient edible flower processing technologies. This paper reviews the application of a number of physical fields including ultrasound, microwave, infrared, ultraviolet, ionizing radiation, pulse electric field, high hydrostatic pressure, and reduced pressure aiming to improve the processing and product quality of edible flowers. The mechanism of action, influencing factors, and status on application of each physical energy field are critically evaluated. In addition, the advantages and disadvantages of each of these energy fields are evaluated, and trends on their future prospects are highlighted. Future research is expected to focus on gaining greater understanding of the mechanism action of physical field-based technologies when applied to processing of edible flowers and to provide the basis for broaden the application of physical field-based technologies in industrial realm.

Flower Species Ingredient Verification Using Orthogonal Molecular Methods

Flowers are gaining considerable interest among consumers as ingredients in food, beverages, cosmetics, and natural health products. The supply chain trades in multiple forms of botanicals, including fresh whole flowers, which are easier to identify than dried flowers or flowers processed as powdered or liquid extracts. There is a gap in the scientific methods available for the verification of flower species ingredients traded in the supply chains of multiple markets. The objective of this paper is to develop methods for flower species ingredient verification using two orthogonal methods. More specifically, the objectives of this study employed both (1) DNA-based molecular diagnostic methods and (2) NMR metabolite fingerprint methods in the identification of 23 common flower species ingredients. NMR data analysis reveals considerable information on the variation in metabolites present in different flower species, including color variants within species. This study provides a comprehensive comparison of two orthogonal methods for verifying flower species ingredient supply chains to ensure the highest quality products. By thoroughly analyzing the benefits and limitations of each approach, this research offers valuable insights to support quality assurance and improve consumer confidence.

Bioactive compounds, nanoparticles synthesis, health benefits and potential utilization of edible flowers for the development of functional dairy products: a review

The food sector faces difficulty meeting the expectations for high-quality food items with safe and clean perceptions in light of customers' increased concern and economic sanctions of synthetic and hazardous chemicals. Besides their widespread use as decoration, flowers are known to be consumed as a traditional food or a component of complementary therapy in many different civilizations worldwide. Because of their nutritional importance as a source of nutrients, proteins, essential amino acids, bioactive compounds, etc., many edible flowers can be viewed as a food source rather than just a delicacy or decoration. Polyphenols, flavonoids, and carotenoids are the phytochemicals that make up the bioactive components of edible flowers. These substances have anti-inflammatory, antibacterial, and antioxidant properties that can improve the nutritional profile of dairy products. Nanoparticles have become a cutting-edge strategy to make use of these advantages. In addition to encapsulating and protecting medicinal substances, nanoparticles made from edible flowers also enable regulated release, increasing bioavailability and durability. Numerous opportunities exist for the addition of edible flower- nanoparticles to dairy products. Their inclusion can add distinctive flavours, colours, and sensations, boosting the consumer's sensory perception. This review quotes the recent studies and discusses different aspects such as nanoparticle synthesis, quantification and characterization, health benefits, novel ingredient for the development of functional food, and the bioactive compounds for different varieties of edible flowers.Kindly check and confirm the edit made in the title.  The final title  is : "Bioactive compounds,nanoparticles synthesis, health benefits andpotential utilization of edible flowers for thedevelopment of functional dairy products: areview".

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Mixed-Mode Solar Drying and its Effect on Physicochemical and Colorimetric Properties of Zompantle (Erythrina Americana)

A mixed-mode solar drying was developed to evaluate the physicochemical and colorimetric properties of Zompantle (Erythrina americana). A 22-factorial design was used; the operation mode (mesh shade and direct) and airflow (natural convection and forced convection) were established as factors in this design. The initial moisture content in the Zompantle flower was reduced from 89.03% (w.b) to values that ranged from 3.84% to 5.84%; depending on the operation mode of the dryer, the final water activity ranged from 0.25 to 0.33. The Zompantle's components as proteins (4.28%), antioxidant activity (18.8%), carbohydrates (4.83%), fat (0.92%), fiber (3.71%), ash (0.94%), and total soluble solids (3°Brix) increased as the water was evaporated during the drying. The increment in the Zompantle's components depends on the operation mode; in direct mode and natural convection, the proteins, antioxidant activity, carbohydrates, fat, fiber, ash, and total soluble solids were 6.99%, 61.69%, 79.05%, 1.20%, 3.84%, 8.70%, and 45 °Brix, respectively. The total drying efficiency was 14.84% with the direct mode and natural convection (DM-NC) and 17.10% with the mesh shade and natural convection (MS-NC). The Hue angle measures the property of the color; the indirect mode and natural convection keep the hue angle close to the initial value (29.2 °). The initial chroma value of the Zompantle flower was 55.07; the indirect mode and natural convection kept high saturation (37.58); these dry conditions ensured a red color in the dehydrated Zompantle. Dehydrated Zompantle's flowers could have several practical applications, such as an additive in traditional Mexican cuisine.

Exploring Plants with Flowers: From Therapeutic Nutritional Benefits to Innovative Sustainable Uses

Flowers have played a significant role in society, focusing on their aesthetic value rather than their food potential. This study's goal was to look into flowering plants for everything from health benefits to other possible applications. This review presents detailed information on 119 species of flowers with agri-food and health relevance. Data were collected on their family, species, common name, commonly used plant part, bioremediation applications, main chemical compounds, medicinal and gastronomic uses, and concentration of bioactive compounds such as carotenoids and phenolic compounds. In this respect, 87% of the floral species studied contain some toxic compounds, sometimes making them inedible, but specific molecules from these species have been used in medicine. Seventy-six percent can be consumed in low doses by infusion. In addition, 97% of the species studied are reported to have medicinal uses (32% immune system), and 63% could be used in the bioremediation of contaminated environments. Significantly, more than 50% of the species were only analysed for total concentrations of carotenoids and phenolic compounds, indicating a significant gap in identifying specific molecules of these bioactive compounds. These potential sources of bioactive compounds could transform the health and nutraceutical industries, offering innovative approaches to combat oxidative stress and promote optimal well-being.

A Review of Sustainable Use of Biogenic Nanoscale Agro-Materials to Enhance Stress Tolerance and Nutritional Value of Plants

Climate change is more likely to have a detrimental effect on the world's productive assets. Several undesirable conditions and practices, including extreme temperature, drought, and uncontrolled use of agrochemicals, result in stresses that strain agriculture. In addition, nutritional inadequacies in food crops are wreaking havoc on human health, especially in rural regions of less developed countries. This could be because plants are unable to absorb the nutrients in conventional fertilizers, or these fertilizers have an inappropriate or unbalanced nutrient composition. Chemical fertilizers have been used for centuries and have considerably increased crop yields. However, they also disrupt soil quality and structure, eventually impacting the entire ecosystem. To address the situation, it is necessary to develop advanced materials that can release nutrients to targeted points in the plant-soil environment or appropriate receptors on the leaf in the case of foliar applications. Recently, nanotechnology-based interventions have been strongly encouraged to meet the world's growing food demand and to promote food security in an environmentally friendly manner. Biological approaches for the synthesis of nanoscale agro-materials have become a promising area of research, with a wide range of product types such as nanopesticides, nanoinsecticides, nanoherbicides, nanobactericides/fungicides, bio-conjugated nanocomplexes, and nanoemulsions emerging therefrom. These materials are more sustainable and target-oriented than conventional agrochemicals. In this paper, we reviewed the literature on major abiotic and biotic stresses that are detrimental to plant growth and productivity. We comprehensively discussed the different forms of nanoscale agro-materials and provided an overview of biological approaches in nano-enabled strategies that can efficiently alleviate plant biotic and abiotic stresses while potentially enhancing the nutritional values of plants.

Evaluation of Radio Frequency-Assisted Enzymatic Extraction of Non-Anthocyanin Polyphenols from Akebia trifoliata Flowers and Their Biological Activities Using UPLC-PDA-TOF-ESI-MS and Chemometrics

A new radio frequency heating-assisted enzymatic extraction (RF-E) method is applied for the determination of phenolic compounds in Akebia trifoliata flowers, compared with hot water, acidified ethanol (EtOH), and enzymatic-assisted (EA) extractions. Non-anthocyanin polyphenol profiles, antibacterial, angiotensin-converting enzyme (ACE) inhibitory, anti-inflammatory activities, and structures of extracts are evaluated. Results show no significant differences in the extraction of total flavonoid content (15.85-16.63 mg QEs/g) and ACE inhibitory activity (51.30-52.86%) between RF-E and EA extracts. RF-E extract shows the highest anti-inflammatory activities. FTIR and UV spectra reveal that acidified EtOH treatment has a significant effect on the structure of the extract due to its highest flavonoid content (20.33 mg QEs/g), thus it has the highest antibacterial activity against Staphylococcus aureus and Escherichia coli. Sixteen non-anthocyanin polyphenols are identified by UPLC-PDA-TOF-ESI-MS and RF pre-treatment did not cause significant compound degradation. The chemometric analysis shows that enzymatic hydrolysis significantly increased biological activities, and the presence of non-anthocyanin polyphenols correlates well with ACE inhibitory and anti-inflammatory activities. Accordingly, A trifoliata flowers have potential as reagents for the food and pharmaceutical industries due to their abundant polyphenols that could be extracted efficiently using RF-E.

Postharvest Treatments on Sensorial and Biochemical Characteristics of Begonia cucullata Willd Edible Flowers

Edible flowers (EFs) are currently consumed as fresh products, but their shelf life can be extended by a suitable drying technique, avoiding the loss of visual quality and valuable nutraceutical properties. Begonia cucullata Willd is a common ornamental bedding plant, and its leaves and flowers are edible. In this work, B. cucullata red flowers were freeze-dried (FD) and hot-air dried (HAD) at different temperatures. To the best of our knowledge, our study is the first one comparing different drying methodologies and different temperatures involving sensory characterization of EFs; therefore, a codified method for the description of the sensory profile of both fresh and dried B. cucullata was developed and validated. Phytochemical analyses highlighted the better preservation of antioxidant compounds (polyphenols, flavonoids and anthocyanins) for flowers dried at 60–70 °C. Visual quality was strongly affected by the drying treatments; in particular the color of the HAD samples significantly turned darker, whereas the FD samples exhibited a marked loss of pigmentation. Although all drying conditions led to a reduction in the hedonic indices if compared with fresh flowers, the best results in terms of organoleptic properties were obtained when the drying temperature was set to 60 or 70 °C.

Impact of Drying Conditions on Antioxidant Activity of Red Clover (Trifolium pratense), Sweet Violet (Viola odorata) and Elderberry Flowers (Sambucus nigra)

Flowers of red clover (Trifolium pratense), sweet violet (Viola odorata) and elderflowers (Sambucus nigra) were dried by means of air drying at 30 °C and 50 °C and by freeze drying. The content of polyphenols was determined using the Folin–Ciocalteu reagent, while anthocyanins were quantified by the pH differential method. Antioxidant activities of aqueous and ethanolic extracts of the dried flowers were measured by the DPPH and ABTS assays, as well as FRAP and reducing power methods. The highest amount of polyphenols was determined in the ethanolic extracts of fresh red clover flowers (854.76 mg/100 g), while the highest concentration of anthocyanins was determined in the aqueous extracts of fresh sweet violet flowers (99.41 mg/100 g). The results showed that, in general, the extracts of red clover flower were characterized by the highest antioxidant activity, while the sweet violet extracts had the poorest antioxidant properties, although these values fluctuated depending on the method used. There was strong correlation between antioxidant activity and TPC (r = 0.9196, FRAP method). In most cases, freeze drying was found to be the best conservation method, retaining well the antioxidant properties of the tested flowers and the compounds determining these properties.

Sensory Profile, Shelf Life, and Dynamics of Bioactive Compounds during Cold Storage of 17 Edible 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.

The Biodiversity of Edible Flowers: Discovering New Tastes and New Health Benefits

Floriculture and horticulture have always been two parallel and very distinct agronomic realities. Floriculture is concerned with meeting the ornamental needs of our urban ecosystems, while horticulture is based on meeting food requirements. These two activities have now converged toward a food chain where flowers are conceived of as a sort of "new vegetable" and one of the most promising novelties to satisfy the growing need for food innovation both in terms of an organoleptic and nutraceutical profile. This novelty has rapidly evolved, especially following the growing scientific evidence of the human health benefits of flowers used as food. The typically high pigment concentration of the corollas (especially flavonoids and carotenoids), which have evolved to chromatically attract pollinators, indicates a marked nutraceutical activity especially in terms of antioxidant power. In this review, we first attempted to explore which species are most promising and which should be avoided due to real or suspected toxicity problems. The nutraceutical virtues were therefore highlighted trying to focus attention on those "functional phytochemicals" capable of counteracting some specific human pathologies. Furthermore, the organoleptic profile of edible flowers was investigated since this is one of the least known aspects. The cropping systems suitable for their cultivation were therefore hypothesized and finally the criticalities of edible flowers were addressed in terms of shelf life and marketing opportunities.

Phytonutritional Content and Aroma Profile Changes During Postharvest Storage of Edible Flowers

Edible flowers are niche horticultural products, routinely used as cooking ingredients in the food industry. Currently, new species are required with the aim of enlarging the number of species with a long shelf-life, healthy nutraceutical compounds, and new fragrance and tastes. Ageratum houstonianum Mill, Tagetes lemmonii A. Gray, Salvia dorisiana Standl, and Pelargonium odoratissimum (L.) L'Hér "Lemon" were selected for their different morphological characteristics and color. Fresh flowers were analyzed to characterize their phytonutritional content and aroma profile. Postharvest was determined up to 6 days of cold storage at 4°C in transparent polypropylene boxes. Visual quality and cellular membrane damage were observed. The relative content of different antioxidant constituents (e.g., polyphenols, flavonoids, anthocyanins, ascorbic acid), nutritional compounds (soluble sugars, crude proteins), the antioxidant scavenging activity, and the volatile profile were determined and correlated to the quality of shelf-life of the different species. The yellow T. lemmonii freshly picked flowers showed the highest ascorbic acid and flavonoids content, which was maintained during the cold storage, as well as the best visual quality. Limited changes in metabolites were detected in the light blue A. houstonianum during postharvest, although the visual quality is severely compromised. Magenta S. dorisiana and light pink P. odoratissimum showed similar changes in antioxidant constituents during cold storage. For the first time, the volatile compounds have been identified in the four species. Sesquiterpene hydrocarbons are the main class in fresh flowers of A. houstonianum, S. dorisiana, and P. odoratissimum, while monoterpene hydrocarbons are abundant in T. lemmonii. The cold storage influenced mainly P. odoratissimum and S. dorisiana flavor initially dominated by the increase in total monoterpenes at 6 days, reaching a relative content of 90%. Both A. houstonianum and T. lemmonii conserved the prevalence of the same class of constituents in all the analyzed conditions, even though the cold storage influenced the major compound abundance. On the basis of the results, T. lemmonii was the most interesting species with the longest shelf-life due to its phytonutritional and aromatic constituents. Results indicated the peculiar metabolic and physiological attitude of flowers species to cold storage.

Effects of infrared freeze drying on volatile profile, FTIR molecular structure profile and nutritional properties of edible rose flower (Rosa rugosa flower)

BACKGROUND

Infrared freeze drying (IRFD) utilizes infrared radiation as a novel heating source in freeze drying (FD), leading to high-quality dehydrated products and less drying time. The present study aimed to investigate the effects of IRFD on the drying characteristics (drying time and energy consumption), volatiles, physical structure and nutritional properties of Rosa rugosa flower. In addition, freeze drying (FD) and hot air drying (HAD) were also evaluated in a comparison with the IFRD drying method with respect to product quality parameters.

RESULTS

Fifty-six volatile compounds were identified in fresh samples, whereas 53, 51 and 46 volatile compounds were identified in FD, IRFD and HAD samples, respectively. FD and IRFD were relatively more effective than HAD for better retention of volatile compounds of Rosa rugose flower. E-nose analysis also exhibited similar flavor properties in FD and IRFD samples. The molecular structure properties of FD and IRFD samples measured by FTIR spectroscopy were also similar. As for nutritional properties, HAD dramatically (P < 0.05) reduced the nutritional values of R. rugosa flower after drying. The content of vitamin C (from 14.83 to 12.15 mg 100 g^-1 ), flavonoids (from 478.00 to 333.33 mg 100 g^-1 ) and anthocyanins (from 220.70 to 196.90 mg 100 g^-1 ) in R. rugosa flower is well retained by IRFD and no significant difference (P < 0.05) was observed between FD and IRFD samples.

CONCLUSION

IRFD was found to be effective in retaining the aroma, structure and nutrition of R. rugosa flower, as well as demonstrating a lower energy consumption and shorter drying time. © 2020 Society of Chemical Industry.

Pre- and Post-harvest Factors Affecting Glucosinolate Content in Broccoli

Owing to several presumed health-promoting biological activities, increased attention is being given to natural plant chemicals, especially those frequently entering the human diet. Glucosinolates (GLs) are the main bioactive compounds found in broccoli (Brassica oleracea L. var. italica Plenck). Their regular dietary assumption has been correlated with reduced risk of various types of neoplasms (lung, colon, pancreatic, breast, bladder, and prostate cancers), some degenerative diseases, such as Alzheimer's, and decreased incidence of cardiovascular pathologies. GL's synthesis pathway and regulation mechanism have been elucidated mainly in Arabidopsis. However, nearly 56 putative genes have been identified as involved in the B. oleracea GL pathway. It is widely recognized that there are several pre-harvest (genotype, growing environment, cultural practices, ripening stage, etc.) and post-harvest (harvesting, post-harvest treatments, packaging, storage, etc.) factors that affect GL synthesis, profiles, and levels in broccoli. Understanding how these factors act and interact in driving GL accumulation in the edible parts is essential for developing new broccoli cultivars with improved health-promoting bioactivity. In this regard, any systematic and comprehensive review outlining the effects of pre- and post-harvest factors on the accumulation of GLs in broccoli is not yet available. Thus, the goal of this paper is to fill this gap by giving a synoptic overview of the most relevant and recent literature. The existence of substantial cultivar-to-cultivar variation in GL content in response to pre-harvest factors and post-harvest manipulations has been highlighted and discussed. The paper also stresses the need for adapting particular pre- and post-harvest procedures for each particular genotype in order to maintain nutritious, fresh-like quality throughout the broccoli value chain.

An update on the health benefits promoted by edible flowers and involved mechanisms

The aim of this review is to provide new findings on health effects of edible flowers since 2015. The antioxidant, anti-inflammatory, anti-cancer, hepatoprotective, neuroprotective, anti-diabetic, anti-osteoporosis, anti-obesity, and anti-hypertensive have been reviewed, and the effective concentrations of flower extracts have been summarized. Among all the health benefits mentioned, anti-osteoporosis, anti-obesity, and anti-hypertensive have rarely been mentioned before 2015. Some health benefits mechanisms of edible flowers were discussed frequently after 2015. Some newly found phytochemicals such as polysaccharides were shown to be beneficial to human health. Species of Rosa, Chrysanthemum, and Osmanthus have been reported to exert different health effects on human. For the toxicity studies, the safe level of flower extracts in cell and animal models were at hundreds of parts per million (ppm) level. In consideration of health promoting effects and toxicities of edible flowers, they could serve as potential natural health products for different health benefits.

Effect of modified atmosphere packaging on overall appearance and nutraceutical quality of pot marigold held at 5 °C

The effectiveness of passive modified atmosphere packaging (MAP) on chemical and quality properties of calendula flowers was studied during ten days of storage at 5 °C. Weight loss of flowers wrapped with continuous and micro-perforated-films (2-3%), was significantly lower than control (unwrapped flowers) (about 30%) and those wrapped with macro-perforated film (about 7%). At the end of storage unwrapped flowers were judged unmarketable being severely wilted and shriveled, while all packaged ones were still fresh and marketable. On day 10, the fructose concentration of control flowers decreased by 74%. Continuous and micro-perforated films delayed the decline of fructose concentration over storage. Sucrose concentration decreased with storage in control flowers, while in continuous film wrapped flowers it increased. After 10 d of storage, the total phenols' concentration of all packaged flowers was significantly higher than control and similar to the initial value (2.58 ± 0.02 g 100 g^-1 d.w.). Thirteen carotenoids were identified by HPLC-MS. The initial β carotene concentration (65.72 ± 0.09 mg 100 g^-1 d.w.) did not change in flowers wrapped with macro- and micro-perforated films, in contrast to the other treatments. Lycopene concentration strongly decreased in control flowers, while minor losses occurred in packaged ones. Laser micro-perforated film, being a good compromise between humidity retention inside the packages and the permeability of the film, seems to be the best choice to extend the storage life of calendula flowers.

Volatilomic Analysis of Four Edible Flowers from Agastache Genus

Volatilomes emitted from edible flowers of two species of Agastache (A. aurantiaca (A.Gray) Lint & Epling, and A. mexicana (Kunth) Lint & Epling) and from two hybrids (Agastache ‘Arcado Pink’ and Agastache ‘Blue Boa’) were investigated using a solid-phase microextraction technique as well as the extraction of its essential oils. Oxygenated monoterpenes were almost always the predominant class (>85%) of volatile organic compounds (VOCs) in each sample of A. aurantiaca, A. ‘Blue Boa’ and A. mexicana, with the exception of A. ‘Arcado Pink’ (38.6%). Pulegone was the main compound in A. aurantiaca (76.7%) and A. ‘Blue Boa’ (82.4%), while geranyl acetate (37.5%) followed by geraniol (16%) and geranial (17%) were the principal ones in A. mexicana. The essential oil composition showed the same behavior as the VOCs both for the main class as well as the major constituent (pulegone) with the same exception for A. mexicana. Total soluble sugars, secondary metabolites (polyphenols, flavonoids and anthocyanins) and antioxidant activity were also investigated to emphasize the nutraceutical properties of these edible flowers.