The Compositional Aspects of Edible Flowers as an Emerging Horticultural Product.

Edible flowers are becoming very popular, as consumers are seeking healthier and more attractive food products that can improve their diet aesthetics and diversify their dietary sources of micronutrients. The great variety of flowers that can be eaten is also associated with high variability in chemical composition, especially in bioactive compounds content that may significantly contribute to human health. The advanced analytical techniques allowed us to reveal the chemical composition of edible flowers and identify new compounds and effects that were not known until recently. Considering the numerous species of edible flowers, the present review aims to categorize the various species depending on their chemical composition and also to present the main groups of compounds that are usually present in the species that are most commonly used for culinary purposes. Moreover, special attention is given to those species that contain potentially toxic or poisonous compounds as their integration in human diets should be carefully considered. In conclusion, the present review provides useful information regarding the chemical composition and the main groups of chemical compounds that are present in the flowers of the most common species.

Chemical composition and bioactive properties of Cichorium spinosum L. in relation to nitrate/ammonium nitrogen ratio.

BACKGROUND: Nitrogenous fertilizers may affect the yield and quality of leafy vegetables via the application rate and nitrogen form. In the present study, the effect of the nitrate:ammonium nitrogen ratio in the nutrient solution on the chemical composition and bioactive properties of Cichorium spinosum leaves was evaluated. For this purpose, C. spinosum plants were fertigated with nutrient solution containing different ratios of nitrate: ammonium nitrogen: (i) 100:0 NO3 -N:NH4 -N; (ii) 75:25 NO3 -N:NH4 -N; (iii) 50:50 NO3 -N:NH4 -N; (iv) 25:75 NO3 -N:NH4 -N; and (v) 0:100 NO3 -N:NH4 -N of total nitrogen; as well as (vi) 100% ureic nitrogen. RESULTS: The only detected tocopherol isoforms were α- and δ-tocopherol, which were positively affected by nitrate nitrogen (100:0 NO3 -N:NH4 -N). Similar results were observed for individual and total organic acids. The main detected sugars were fructose, glucose and sucrose, with a varied effect of nutrient solution composition on their content, whereas total sugar concentration was positively affected by a balanced or a slightly increased proportion of NH4 -N (50:50 and 25:75 NO3 -N:NH4 -N). The fatty acids profile was beneficially affected by the highest NH4 -N ratio (0:100 NO3 -N:NH4 -N), whereas higher amounts of NO3 - than NH4 + nitrogen (75:25 NO3 -N:NH4 -N) resulted in a higher content of total phenolic compounds. Finally, no cytotoxic effects were observed against non-tumor (PLP2, HeLa) and tumor (HepG2, MCF-7, NCI-H460) cell lines for any of the studied nutrient solutions. CONCLUSION: The modulation of NO3 -N:NH4 -N ratio in the nutrient solution supplied to C. spinosum may enhance the content of desirable health-promoting compounds and reduce the content of antinutrients, thus increasing the overall quality of the final product without compromising yield. © 2019 Society of Chemical Industry.

Physicochemical, agronomical and microbiological evaluation of alternative growing media for the production of rapini (Brassica rapa L.) microgreens.

BACKGROUND: Peat-based mixes and synthetic mats are the main substrates used for microgreens production. However, both are expensive and non-renewable. Recycled fibrous materials may represent low-cost and renewable alternative substrates. Recycled textile-fiber (TF; polyester, cotton and polyurethane traces) and jute-kenaf-fiber (JKF; 85% jute, 15% kenaf-fibers) mats were characterized and compared with peat and Sure to Grow® (Sure to Grow, Beachwood, OH, USA; http://suretogrow.com) (STG; 100% polyethylene-terephthalate) for the production of rapini (Brassica rapa L.; Broccoletto group) microgreens. RESULTS: All substrates had suitable physicochemical properties for the production of microgreens. On average, microgreens fresh yield was 1502 g m-2 in peat, TF and JKF, and was 13.1% lower with STG. Peat-grown microgreen shoots had a higher concentration of K+ and SO42- and a two-fold higher NO3- concentration [1959 versus 940 mg kg-1 fresh weight (FW)] than those grown on STG, TF and JKF. At harvest, substrates did not influence microgreens aerobic bacterial populations (log 6.48 CFU g-1 FW). Peat- and JKF-grown microgreens had higher yeast-mould counts than TF- and STG microgreens (log 2.64 versus 1.80 CFU g-1 FW). Peat-grown microgreens had the highest population of Enterobacteriaceae (log 5.46 ± 0.82 CFU g-1 ) and Escherichia coli (log 1.46 ± 0.15 CFU g-1 ). Escherichia coli was not detected in microgreens grown on other media. CONCLUSION: TF and JKF may be valid alternatives to peat and STG because both ensured a competitive yield, low nitrate content and a similar or higher microbiological quality. © 2016 Society of Chemical Industry.

Nutritional properties of raw and cooked Azolla caroliniana Willd., an aquatic wild edible plant.

Azolla caroliniana Willd. is an understudied wild edible plant native to the Eastern United States. Other species of Azolla have been used across the world for several thousand years as a livestock feed and as "green manure." The use of Azolla for human consumption is thought to be limited by its high total polyphenolic content (TPC). However, the TPC and nutritional content of A. caroliniana has not been thoroughly studied. We measured TPC and other nutrients before and after cooking methods designed to lower TPC. We found that TPC was 4.26 g gallic acid equivalent (GAE) kg-1 DW in raw A. caroliniana. All cooking methods significantly lowered TPC. Protein content was 19% DW, and the apparent protein digestibility was 78.45%. Our yield was 173 g FW m-2 day-1 and 5.53 g DW m-2 day-1. Azolla caroliniana is a high-yielding plant with great potential for cultivation and domestication.

Effect of cooking methods on antioxidant activity and nitrate content of selected wild Mediterranean plants.

Wild edible plants (WEP), traditionally consumed in the Mediterranean diet, are considered a rich source of natural antioxidants but can also accumulate significant amount of nitrates. Most WEP are cooked before consumption, therefore, a study was conducted to evaluate the effects of boiling, steaming and microwave cooking processes on the total antioxidant activity (TAA) and nitrate content of eight common WEP. Boiling caused the highest losses of TAA, resulting in a reduction of the TAA on dry weight (DW) basis ranging from 5.5% in Beta vulgaris up to 100% in Urtica dioica. Steaming and microwaving produced the highest increase of TAA on DW basis in Helminthotheca echioides (249.7%) and Taraxacum officinale (60.7%). Boiling caused the highest reduction of nitrate content in all species excluding Asparagus acutifolius that maintained almost unvaried its already low nitrate content. These results suggest that cooking has not always negative effect on product quality, since in certain cases, it may even enhance the nutritional value of WEP by increasing their TAA and reducing the nitrate content.

Organic waste compost and spent mushroom compost as potential growing media components for the sustainable production of microgreens.

Microgreens are emerging specialty crops becoming increasingly popular for their rich nutrient profile and variety of colors, flavors, and textures. The growing medium is a significant key factor in microgreen yield, quality, and sustainability. The widespread use of peat-based media raises questions regarding the environmental sustainability of microgreens production, and new substrates that are more sustainable are required. To this purpose, a study was designed with the objective of comparing eight alternative growing media evaluating their physicochemical properties and effect on yield, mineral profile, and nutritional quality of peas and radish microgreens. Tested substrates included a standard peat and perlite mixture (PP), coconut coir (CC), spent mushroom compost (SMC), organic waste compost (CMP), and 50:50 (v:v) mixes of PP and SMC, PP and CMP, CC and SMC, and CC and CMP. The physicochemical properties widely differed among the alternative substrates tested. SMC had high electrical conductivity and salt concentration, which resulted in poor seed germination. Growing media tested significantly influenced the production and nutritional quality of both microgreen species and variations were modulated by the species. With a 39.8% fresh yield increase or a small yield decrease (-14.9%) in radish and peas, respectively, PP+CMP (50:50, v/v) mix provided microgreens of similar or higher nutritional quality than PP, suggesting the potential of substituting at least in part peat with CMP. Using locally available CMP in mix with PP could reduce the microgreens industry reliance on peat while reducing costs and improving the sustainability of the production of microgreens. Further research is needed to evaluate also the potential economic and environmental benefits of using locally available organic materials like CMP as alternative growing media and peat-substitute to produce microgreens.

Zinc biofortification through seed nutri-priming using alternative zinc sources and concentration levels in pea and sunflower microgreens.

Micronutrient deficiencies caused by malnutrition and hidden hunger are a growing concern worldwide, exacerbated by climate change, COVID-19, and conflicts. A potentially sustainable way to mitigate such challenges is the production of nutrient-dense crops through agronomic biofortification techniques. Among several potential target crops, microgreens are considered suitable for mineral biofortification because of their short growth cycle, high content of nutrients, and low level of anti-nutritional factors. A study was conducted to evaluate the potential of zinc (Zn) biofortification of pea and sunflower microgreens via seed nutri-priming, examining the effect of different Zn sources (Zn sulfate, Zn-EDTA, and Zn oxide nanoparticles) and concentrations (0, 25, 50, 100, and 200 ppm) on microgreen yield components; mineral content; phytochemical constituents such as total chlorophyll, carotenoids, flavonoids, anthocyanin, and total phenolic compounds; antioxidant activity; and antinutrient factors like phytic acid. Treatments were arranged in a completely randomized factorial block design with three replications. Seed soaked in a 200 ppm ZnSO4 solution resulted in higher Zn accumulation in both peas (126.1%) and sunflower microgreens (229.8%). However, an antagonistic effect on the accumulation of other micronutrients (Fe, Mn, and Cu) was seen only in pea microgreens. Even at high concentrations, seed soaking in Zn-EDTA did not effectively accumulate Zn in both microgreens' species. ZnO increased the chlorophyll, total phenols, and antioxidant activities compared to Zn-EDTA. Seed soaking in ZnSO4 and ZnO solutions at higher concentrations resulted in a lower phytic acid/Zn molar ratio, suggesting the higher bioaccessibility of the biofortified Zn in both pea and sunflower microgreens. These results suggest that seed nutrient priming is feasible for enriching pea and sunflower microgreens with Zn. The most effective Zn source was ZnSO4, followed by ZnO. The optimal concentration of Zn fertilizer solution should be selected based on fertilizer source, target species, and desired Zn-enrichment level.

Yield performance, mineral profile, and nitrate content in a selection of seventeen microgreen species.

Introduction: Originally regarded as garnish greens, microgreens are increasingly valued for their nutritional profile, including their mineral content. Methods: A study was conducted under controlled environmental conditions utilizing a selection of seventeen microgreen species belonging to seven different botanical families to investigate the genetic variation of macro- and micro-minerals and nitrate (NO3 -) content. Plants were grown in a soilless system using a natural fiber mat as the substrate. After germination, microgreens were fertigated with a modified half-strength Hoagland solution prepared using deionized water and without adding microelements. At harvest (10 to 19 days after sowing, based on the species), yield components were measured and dry tissue samples were analyzed for the concentration of total nitrogen (N), NO3 -, P, K, Ca, Mg, S, Na, Fe, Zn, Mn, Cu, and B. Results and discussion: Genotypic variations were observed for all of the examined parameters. Nitrogen and K were the principal macronutrients accounting for 38.4% and 33.8% of the total macro-minerals concentration, respectively, followed in order by Ca, P, S, and Mg. Except for sunflower (Helianthus annuus L.), all the tested species accumulated high (1,000-2,500 mg kg-1 FW) or very high (>2,500 mg kg-1 FW) NO3 - levels. Eight of the studied species had a K concentration above 300 mg 100 g-1 FW and could be considered as a good dietary source of K. On the other hand, scallion (Allium fistulosum L.), red cabbage (Brassica oleracea L. var. capitata), amaranth (Amaranthus tricolor L.), and Genovese basil (Ocinum basilicum L.) microgreens were a good source of Ca. Among micro-minerals, the most abundant was Fe followed by Zn, Mn, B, and Cu. Sunflower, scallion, and shiso (Perilla frutescens (L.) Britton) were a good source of Cu. Moreover, sunflower was a good source of Zn, whereas none of the other species examined could be considered a good source of Fe and Zn, suggesting that supplementary fertilization may be required to biofortify microgreens with essential microminerals. In conclusion, the tested microgreens can be a good source of minerals showing a high potential to address different dietary needs; however, their yield potential and mineral profile are largely determined by the genotype.

Enhancing crop resilience by harnessing the synergistic effects of biostimulants against abiotic stress.

Plants experience constant exposed to diverse abiotic stresses throughout their growth and development stages. Given the burgeoning world population, abiotic stresses pose significant challenges to food and nutritional security. These stresses are complex and influenced by both genetic networks and environmental factors, often resulting in significant crop losses, which can reach as high as fifty percent. To mitigate the effects of abiotic stresses on crops, various strategies rooted in crop improvement and genomics are being explored. In particular, the utilization of biostimulants, including bio-based compounds derived from plants and beneficial microbes, has garnered considerable attention. Biostimulants offer the potential to reduce reliance on artificial chemical agents while enhancing nutritional efficiency and promoting plant growth under abiotic stress condition. Commonly used biostimulants, which are friendly to ecology and human health, encompass inorganic substances (e.g., zinc oxide and silicon) and natural substances (e.g., seaweed extracts, humic substances, chitosan, exudates, and microbes). Notably, prioritizing environmentally friendly biostimulants is crucial to prevent issues such as soil degradation, air and water pollution. In recent years, several studies have explored the biological role of biostimulants in plant production, focusing particularly on their mechanisms of effectiveness in horticulture. In this context, we conducted a comprehensive review of the existing scientific literature to analyze the current status and future research directions concerning the use of various biostimulants, such as plant-based zinc oxide, silicon, selenium and aminobutyric acid, seaweed extracts, humic acids, and chitosan for enhancing abiotic stress tolerance in crop plants. Furthermore, we correlated the molecular modifications induced by these biostimulants with different physiological pathways and assessed their impact on plant performance in response to abiotic stresses, which can provide valuable insights.

Quantifying the effects of anaerobic soil disinfestation and other biological soil management strategies on nitrous oxide emissions from raised bed plasticulture tomato production.

Soilborne pests are a major obstacle that must be overcome for the production of horticultural crops. Methyl bromide (MBr) was an effective preplanting soil broad-spectrum biocide, but its use has been banned due to its role in depleting the ozone layer. As a result, sustainable alternative methods for controlling soilborne pathogens and pests are needed. Nitrous oxide (N2 O) emissions are of concern in crop production due to the role of N2 O as a greenhouse gas. Agricultural lands are known sources for emission of N2 O into the atmosphere. Emissions are related to many environmental factors as well as fertilization and fumigation practices. This study evaluated the influence of different alternatives to MBr on N2 O emissions throughout a tomato production season in two locations representative of southern and northern Florida. We evaluated eight soil management practices, including (a) untreated controls; (b) chemical soil fumigation; (c) anaerobic soil disinfestation using molasses (M) + composted poultry litter and (d and e) M + composted yard waste (CYW, at two rates); (f) Soil Symphony Amendment (SSA), a commercially available mix of microbes and nutrients; (g) CYW alone; and (h) CYW + SSA. Nitrous oxide emissions were measured throughout the cropping season. Emissions were highest on the day of planting (Day 21), ranging from 213 to 1,878 µg m-2 h-1 , likely due to the release of N2 O that had accumulated under the totally impermeable film when it was punctured for planting. However, statistical significance varied between sites. Estimated cumulative emissions of N2 O throughout the production season ranged from 1.3 to 4.8 kg N2 O-N ha-1 .

Natural Antioxidants, Health Effects and Bioactive Properties of Wild Allium Species.

BACKGROUND: There is an increasing interest from the pharmaceutical and food industry in natural antioxidant and bioactive compounds derived from plants as substitutes for synthetic compounds. The genus Allium is one of the largest genera, with more than 900 species, including important cultivated and wild species, having beneficial health effects. OBJECTIVE: The present review aims to unravel the chemical composition of wild Allium species and their healthrelated effects, focusing on the main antioxidant compounds. For this purpose, a thorough study of the literature was carried out to compile reports related to health effects and the principal bioactive compounds. Considering the vast number of species, this review is divided into subsections where the most studied species are presented, namely Allium ampeloprasum, A. flavum, A. hookeri, A. jesdianum, A. neapolitanum, A. roseum, A. stipitatum, A. tricoccum, and A. ursinum, with an additional composite section for less studied species. METHODS: The information presented in this review was obtained from worldwide accepted databases such as Scopus, ScienceDirect, PubMed, Google Scholar and Researchgate, using as keywords the respective names of the studied species (both common and Latin names) and the additional terms of"antioxidants" "health effects" and "bioactive properties". CONCLUSION: The genus Allium includes several wild species, many of which are commonly used in traditional and folklore medicine while others are lesser known or are of regional interest. These species can be used as sources of natural bioactive compounds with remarkable health benefits. Several studies have reported these effects and confirmed the mechanisms of action in several cases, although more research is needed in this field. Moreover, considering that most of the studies refer to the results obtained from species collected in the wild under uncontrolled conditions, further research is needed to elucidate the effects of growing conditions on bioactive compounds and to promote the exploitation of this invaluable genetic material.

Organic Amendments for Pathogen and Nematode Control.

The loss of methyl bromide as a soil fumigant and minimal advances in the development and registration of new chemical fumigants has resulted in a resurgence of interest in the application of organic amendments (OAs) for soilborne plant pathogen and plant-parasitic nematode management. Significant progress has been made in the characterization of OAs, application of strategies for their use, and elucidation of mechanisms by which they suppress soilborne pests. Nonetheless, their utility is limited by the variability of disease control, expense, and the logistics of introducing them into crop production systems. Recent advances in molecular techniques have led to significant progress in the elucidation of the role of bacteria and fungi and their metabolic products on disease suppression with the addition of OAs. Biosolarization and anaerobic soil disinfestation, developed to manipulate systems and favor beneficial microorganisms to maximize their impact on plant pathogens, are built on a strong historical research foundation in OAs and the physical, chemical, and biological characteristics of disease-suppressive soils. This review focuses on recent applications of OAs and their potential for the management of soilborne plant pathogens and plant-parasitic nematodes, with emphasis primarily on annual fruit and vegetable production systems.

Grown to be Blue-Antioxidant Properties and Health Effects of Colored Vegetables. Part II: Leafy, Fruit, and Other Vegetables.

The current trend for substituting synthetic compounds with natural ones in the design and production of functional and healthy foods has increased the research interest about natural colorants. Although coloring agents from plant origin are already used in the food and beverage industry, the market and consumer demands for novel and diverse food products are increasing and new plant sources are explored. Fresh vegetables are considered a good source of such compounds, especially when considering the great color diversity that exists among the various species or even the cultivars within the same species. In the present review we aim to present the most common species of colored vegetables, focusing on leafy and fruit vegetables, as well as on vegetables where other plant parts are commercially used, with special attention to blue color. The compounds that are responsible for the uncommon colors will be also presented and their beneficial health effects and antioxidant properties will be unraveled.

The Effect of Nitrogen Input on Chemical Profile and Bioactive Properties of Green- and Red-Colored Basil Cultivars.

In the present study, three red-colored (Dark Opal, Basilico Rosso, and Red Basil) and one green-colored landrace (Mitikas) of basil (Ocimum basilicum L.) were grown under four nitrogen regimes, namely Control (no fertilizer added), 200 ppm, 400 ppm, and 600 ppm of nitrogen (N). Fresh yield varied depending on N input following a quadratic function in all four genotypes, and green basil performed better compared to the red cultivars. A significant interaction of genotype × N input was recorded for most of the chemical parameters measured. Tocopherols contents of leaves were consistently higher in plants that received 200 ppm of N and lower in those receiving 600 ppm of N, especially in Dark Opal and Red Basil cultivars. Polyunsaturated fatty acids (PUFA) were the major category of fatty acids and Red Basil had the lowest ratio of omega-6/omega 3 (0.29) and thus the best fatty acid profile. Polyphenols content was the highest in Red Basil and Dark Opal (25 mg/g of extract on average) and the lowest in Mitikas and decreased with increasing N input. Similarly, antioxidant activity was the highest in Dark Opal and Red Basil fertigated with 200 ppm of N, whereas all the leaf extracts tested had good antibacterial and antifungal activity. In conclusion, basil chemical and bioactive profile was significantly influenced by both genotype and N input. Red-colored basil, although less productive, had the best chemical profile, and moderate levels of N input may provide the best compromise between yield, nutritional value, and bioactivity for the species.

Dissipation of fomesafen in fumigated, anaerobic soil disinfestation-treated, and organic-amended soil in Florida tomato production systems.

BACKGROUND: Fumigated, anaerobic soil disinfestation-treated (ASD), and organic-amended soil management strategies have been investigated as potential methyl bromide (MBr) alternatives for controlling diseases, nematodes, and weeds in soil. Nutsedge and broadleaf weed control using fomesafen has been reported to be comparable to MBr in normal cropping systems. There is no information on the fate of fomesafen used in combination with alternative practices. In this study, the fate of fomesafen in these alternative systems was measured by liquid chromatography-tandem mass spectrometry (LC/MS-MS) following extraction using a modified Quick Easy Cheap Effective Safe (QuEChERS) method. RESULTS: The reported half-life (DT50 ) values for fomesafen in the top 15 cm of soil were from 62.9 to 107.3 days. The DT50 values in organic-amended soil were higher than in ASD-treated soil in the top 15 cm. For all treatments, reductions in concentrations were positively correlated with lower redox potentials and organic matter content. Some leaching of fomesafen into the 16-30 cm zone was observed in all treatments. CONCLUSIONS: The DT50 values in this study were generally higher than those reported in previous studies performed at different locations. Due to increased losses of the herbicide and subsequent reduction in weed control, fomesafen is likely not to be suitable for effective weed control in systems using ASD techniques employing composted poultry litter and molasses. Integration of fomesafen using composted yard waste 1 (CYW1) and Soil Symphony Amendment (SSA) may result in acceptable weed control. Given that the soil was very sandy and the pH was higher than the pKa, fomesafen might leach deeper than 30 cm, particularly with the use of chemical soil fumigants (CSFs). © 2019 Society of Chemical Industry.

Phytoestrogens, phytosteroids and saponins in vegetables: Biosynthesis, functions, health effects and practical applications.

Phytoestrogens are non-steroidal secondary metabolites with similarities in structure and biological activities with human estrogens divided into various classes of compounds, including lignans, isoflavones, ellagitannins, coumestans and stilbenes. Similarly, phytosteroids are steroidal compounds of plant origin which have estrogenic effects and can act as agonists, antagonists, or have a mixed agonistic/antagonistic activity to animal steroid receptors. On the other hand, saponins are widely distributed plant glucosides divided into triterpenoid and steroidal saponins that contribute to plant defense mechanism against herbivores. They present a great variation from a structural point of view, including compounds from different classes. In this chapter, the main vegetable sources of these compounds will be presented, while details regarding their biosynthesis and plant functions will be also discussed. Moreover, considering the significant bioactive properties that these compounds exhibit, special focus will be given on their health effects, either beneficial or adverse. The practical applications of these compounds in agriculture and phytomedicine will be also demonstrated, as well as the future prospects for related research.

Vegetable Organosulfur Compounds and their Health Promoting Effects.

BACKGROUND: Trends in modern pharmaceutical science show an increase in demand for new drugs and diet supplements derived from natural products, while during the last decades, great research is conducted regarding the natural compounds and their medicinal and bioactive properties. Organosulfur compounds are present in many plants and their bioactive properties have been used in folk and traditional medicine throughout the centuries. Not until recently, modern science confirmed and revealed the chemical compounds that are responsible for these properties, the chemistry involved in their biosynthesis and the main mechanisms of action. OBJECTIVE: In the present review, the organosulfur compounds of vegetable origin and their health effects are presented, focusing on the chemical composition of their main compounds, their biosynthesis and the mechanisms involved in their health effects. Sulfur compound sources presented include mainly vegetable species belonging to Allium genus and Brassicaceae family. CONCLUSION: Organosulfur compounds of vegetable sources are very important in human diet, and their regular consumption has a beneficial contribution to health and well-being. Moreover, their medicinal properties and therapeutic effects have been described thousands of years ago, while they constitute an important ingredient in traditional medicines and preparations. However, not until recently, the mechanisms of action of organosulfur compounds have started to unravel, with promising results for further exploitation of these significant bioactive compounds in drug development and novel nutraceutical products. This review reveals the numerous biological activities of organosulfur compounds of vegetable origin, while it also presents the results of recent clinical studies and trials.