Quantification and in vitro bioaccessibility of glucosinolates and trace elements in Brassicaceae leafy vegetables

Improving benzyl - isothiocyanate bioaccessibility in white mustard (Sinapis alba) sauce through spray - drying microencapsulation and Pickering emulsions

This study compared the bioaccessibility and behaviour of different formulations of benzyl - isothiocyanate (benzyl - ITC) prepared using different approaches and the INFOGEST in vitro digestion protocol. The aim was to improve the low bioaccessibility of this bioactive compound caused by its lipophilic properties. Spray-dried microparticles were prepared using a matrix of either mannitol or maltodextrin, and compared with Pickering emulsions produced with cellulose nanofibres. The different systems were characterised and their ability to associate benzyl - ITC determined. The in vitro digestion characteristics provided by the different systems was evaluated. Microencapsulation of benzyl-ITC by spray-drying was not successful when mannitol was used as excipient, while maltodextrin resulted in a production yield around 70 % with an ITC association efficiency up to 75 %. Nevertheless, significant improvement of benzyl - ITC bioaccessibility in a mustard sauce was not achieved. In contrast, the formulation of benzyl - ITC in a Pickering emulsion prepared with cellulose nanofibres showed an association efficiency of around 100 % and high bioaccessibility with values up to 77 %. The chemical similarity between the mixed micelles formed for lipid absorption in the small intestine, and the structure of cellulose nanofibre emulsion could justify the observed improvement.

The Influence of Different Hydrothermal Processes Used in the Preparation of Brussels Sprouts on the Availability of Glucosinolates to Humans

Cruciferous vegetables represent a valuable source of bioactive compounds. However, there is currently a deficiency of information regarding the extent to which these compounds remain bioaccessible to the body following thermal treatment and digestion processes within the digestive tract. Accordingly, the aim of this study was to evaluate the impact of heat treatment and in vitro digestion on the level of selected bioactive compounds in Brussels sprouts. The Brussels sprouts samples were subjected to a range of thermal processing techniques, which were then followed by a simulated in vitro digestion. The investigated compounds were analyzed using UV-Vis spectrometry and liquid chromatography coupled with mass spectrometry (LC-MS). The findings revealed that the sous-vide method of cooking Brussels sprouts resulted in significantly higher losses of glucosinolates (GLS) in comparison to conventional cooking methods. No significant differences were observed with regard to isothiocyanates and indoles. The analysis of GLS following digestion revealed that the process was more effective after sous vide and traditional cooking, and slightly less effective after steam cooking. With regard to individual compounds, glucoraphanin (GRA), glucoraphenin (GIV), and gluconasturtiin (GNS) were found to be completely degraded, whereas methoxyglucobrassicin (metGBS) was the most resistant to digestion in both the sous vide and steamed Brussels sprouts. The results indicated that the process of simulating digestion had no significant impact on isothiocyanates and indoles. This suggests that, if present in the heat-treated samples, these compounds remained stable during the in vitro digestion procedure.

Influence of Dietary Fibre and Protein Fractions on the Trace Element Bioaccessibility of Turnip Tops (Brassica rapa) Growing under Mediterranean Conditions

The objective of this work was to study the influence of three dietary fibre fractions (pectin, gum arabic and cellulose) and three protein fractions (casein, lactalbumin and soy) on the trace element bioaccessibility (Fe, Mn, Ni, Se and Zn) of turnip tops (B. rapa subsp. Rapa) growing under Mediterranean conditions. Then, it aimed to promote the use of this vegetable not only for direct fresh consumption but also as a main ingredient in the development of food mixtures. The results showed that soluble fibre fractions, such as pectin and gum arabic, can enhance the bioaccessibility of trace elements, such as Fe, Mn, Se and Zn. This effect was not proved for cellulose (an insoluble fibre fraction), in which, at best, no bioaccessibility effect was observed. Regarding the protein fractions, with the exception of Se, caseins and lactalbumin had a neutral effect on improving the trace element bioaccessibility. This did not hold true for soy protein, in which a considerable improvement in the bioaccessibility of Fe, Mn, Se and Zn was determined.

Bioaccessible Organosulfur Compounds in Broccoli Stalks Modulate the Inflammatory Mediators Involved in Inflammatory Bowel Disease

Inflammatory diseases are strongly associated with global morbidity and mortality. Several mediators are involved in this process, including proinflammatory interleukins and cytokines produced by damaged tissues that, somehow, act as initiators of the autoreactive immune response. Bioactive compounds present in plant-based foods and byproducts have been largely considered active agents with the potential to treat or prevent inflammatory diseases, being a valuable alternative to traditional therapeutic agents used nowadays, which present several side effects. In this regard, the present research uncovers the anti-inflammatory activity of the bioaccessible fraction of broccoli stalks processed, by applying different conditions that render specific concentrations of bioactive sulforaphane (SFN). The raw materials' extracts exhibited significantly different contents of total glucosinolates (GSLs) that ranged between 3993.29 and 12,296.48 mg/kg dry weight (dw), with glucoraphanin as the most abundant one, followed by GI and GE. The indolic GSLs were represented by hydroxy-glucobrassicin, glucobrassicin, methoxy-glucobrassicin, and neo-glucobrassicin, with the two latter as the most abundant. Additionally, SFN and indole-3-carbinol were found in lower concentrations than the corresponding GSL precursors in the raw materials. When exploring the bioaccessibility of these organosulfur compounds, the GSL of all matrices remained at levels lower than the limit of detection, while SFN was the only breakdown product that remained stable and at quantifiable concentrations. The highest concentration of bioaccessible SFN was provided by the high-ITC materials (~4.00 mg/kg dw). The results retrieved on the cytotoxicity of the referred extracts evidenced that the range of supplementation of growth media tested (0.002-430.400 µg of organosulfur compounds/mL) did not display cytotoxic effects on Caco-2 cells. The obtained extracts were assessed based on their capacity to reduce the production of key proinflammatory cytokines (interleukin 6 (IL-6), IL-8, and TNF-α) by the intestinal epithelium. Most of the tested processing conditions provided plant material with significant anti-inflammatory activity and the absence of cytotoxic effects. These data confirm that SFN from broccoli stalks, processed to optimize the bioaccessible concentration of SFN, may be potential therapeutic leads to treat or prevent human intestinal inflammation.

Selenium in plant-based beverages: Total content, estimated bioaccessibility and contribution to daily intake

BACKGROUND

The search for alternative protein sources has increased the consumption and commercialization of plant-based beverages (PBBs). This study aimed to determine the total Se content, estimate the bioaccessibility of selenium (Se) in commercial PBBs derived from different raw materials, and evaluate their contribution to the reference daily intake (RDI).

METHODS

An ultrasound assisted acid digestion method and ICP-MS was used to determine Se, and the INFOGEST method to estimate the bioaccessible percentages. Validation of this method was also performed, and the parameters obtained were: LOD and LOQ were 2.1 and 4.0 µg/kg, respectively. For accuracy, recovery percentages ranged from 99 % and 111 % (certified reference materials), and 95 % and 101 % (spiked experiments for bioaccessible extracts as recoveries).

RESULTS

The PBBs presented total Se content between 4 and 226 µg/kg. Bioaccessible percentages ranged from 63.5 % (mix of plant sources) to 95.9 % (produced with organic cashew nuts). Only one cashew nut PBBs supplied the daily demand of Se, representing 64.6 %, 75.3 % and 82.2 % of the RDI; for lactating and pregnant women, children (≥ 4 years) and adults, respectively.

CONCLUSIONS

The Se determination method through acid digestion assisted by ultrasound and ICP-MS was considered adequate for the PBBs samples. Se content varied according to the raw material used in sample preparation. High percentages (> 60 %) of bioaccessibility were observed and only one PBBs derived from organic cashew nuts supplied the recommended Se demand for different groups of individuals.

Chemical Profile of Turnip According to the Plant Part and the Cultivar: A Multivariate Approach

Turnip (Brassica rapa subsp. rapa) is a cruciferous plant cultivated worldwide that serves as a source of nutrients and bioactive compounds. Most turnip studies have focused on a few compounds or on part of the plant. The establishment of a complete chemical profile of different plant parts would facilitate its use for nutritional and medicinal purposes. In the current study, mineral elements, soluble sugars, free amino acids (FAA), total phenols (TP), total flavonoids (TF), and glucosinolates (GS) were quantified in the leaves, stems, and roots. Results were compared for 20 strains of turnip. The outcomes showed significant differences between parts of the plant and strains. The leaves exhibited the highest TF, TP, indispensable FAA, and microelement levels, and they showed a higher GS. Moreover, the stems had a high content of GS and macroelements. Furthermore, the roots showed high levels of free sugars and total FAA. The findings of this work provide the basis for utilizing each part of the turnip plant based on its chemical composition.

Anticancer activity of broccoli, its organosulfur and polyphenolic compounds

The use of natural bioactive constituents from various food sources for anticancer purposes has become increasingly popular worldwide. Broccoli (Brassica oleracea var. italica) is on the top of the consumed vegetables by the masses. Its raw matrix contains a plethora of phytochemicals, such as glucosinolates and phenolic compounds, along with rich amounts of vitamins, and minerals. Consumption of broccoli-derived phytochemicals provides strong antioxidant effects, particularly due to its sulforaphane content, while modulating numerous molecules involved in cell cycle regulation, control of apoptosis, and tuning enzyme activity. Thus, the inclusion of broccoli in the daily diet lowers the susceptibility to developing cancers. Numerous studies have underlined the undisputable role of broccoli in the diet as a chemopreventive raw food, owing to the content in sulforaphane, an isothiocyanate produced as a result of hydrolysis of precursor glucosinolates called glucoraphanin. This review will provide evidence supporting the specific role of fresh florets and sprouts of broccoli and its key bioactive constituents in the prevention and treatment of different cancers; a number of studies carried out in the in vitro and in vivo conditions as well as clinical trials were analyzed.

Use of granules and free salts for Fe and Zn fortification of leafy vegetables: Improvements in trace element bioaccessibility and fulfillment of Dietary Reference Intakes

BACKGROUND

Leafy vegetables represent an excellent dietary source of trace elements such as Fe and Zn. Nevertheless, Fe and Zn bioaccessibility can lessen due to a high concentration of anti-nutritional compounds. The encapsulation of Fe and Zn salts as granules could be used to fortify these leafy vegetables.

METHOD

Three leafy vegetables, spinach, Swiss chard and Ethiopian mustard were fortified with iron sulfate and zinc sulfate as granules and free salts in order to test the improvements in the bioaccessibility and fulfillments of DRIs. Fe and Zn granules were prepared in a fluidized bed granulator. A probabilistic analysis was performed, using experimental data, to assess bioaccessible intake and fulfillments of DRIs in European populations.

RESULTS

Fe contents ranged between 4.8 mg/100 g of Ethiopian mustard to 157.4 mg/100 g of spinach. Fe and Zn bioaccessibility percentages were low for Swiss chard and spinach without fortification. Fortification with granules improved Fe bioaccessibility of these latter vegetables (196 and 223 mg/100 g). Zn contents in samples without fortification ranged between 2.3 mg/100 g for Ethiopian mustard and 7.4 mg/100 g for spinach. Zn fortification as granules improved Zn bioaccessibility for the three vegetables studied. Thus, Zn bioccessible concentrations ranged between 17.4 and 108 mg/100 g for the solubility assay and between 5.9 and 31.1 mg/100 g for the dialyzability assay. Besides, the probability analysis showed that fortification had a better performance in meeting DRIs for those populations with higher consumption levels of leafy vegetables.

CONCLUSIONS

The probability analysis demonstrated that fortification can be a suitable strategy to meet DRIs for both trace elements, which was especially remarkable for Fe. Fortification with granule was more effective in most the cases, although for Ethiopian mustard, free salt of Fe showed a better performance.

Bioaccessibility of glucosinolates, isothiocyanates and inorganic micronutrients in cruciferous vegetables through INFOGEST static in vitro digestion model

Green tissues and seeds from cruciferous vegetables growing in conventional and ecological conditions (Brassica carinata; Brassica rapa; Eruca vesicaria and Sinapis alba) were analyzed to determine their contents of glucosinolates, isotihiocyanates (ITCs) and inorganic micronutrients (Ca, Cr, Cu, Fe, Mn, Ni, Se and Zn), and the bioaccessibility of these compounds. Regarding total contents and bioaccessibility values of these compounds, no clear difference was found between the organic and conventional systems. Glucosinolates bioaccessibility present in green tissues were high, with values around 60-78%. In additon, it was quantified in bioaccessible fraction ITCs concentrations such as Allyl - ITC; 3 - Buten - 1 - yl - ITC and 4 - Penten - 1 - yl - ITC. Trace elements bioaccessibility in green tissues was also high for Ca (2.26-7.66 mg/g), Cu (0.60-2.78 µg/g), Se (9.93-74.71 µg/Kg) and Zn (12.98-20.15 µg/g). By contrast, the bioaccessibility of glucosinolates and trace elements in cruciferous seeds was extremely low. With the exception of Cu, these bioaccessibility percentages did not exceed 1% in most cases.

The Combination of Monochromatic LEDs and Elicitation with Stressors Enhances the Accumulation of Glucosinolates in Mustard Sprouts with Species-Dependency

This work studies the enhancement of glucosinolates (GSLs) in mustard sprouts as health promoters. Sprouts of Sinapis alba, Brassica nigra, and B. carinata were grown under broad-spectrum, monochromatic blue or red light-emitting diode (LED) lamps, irrigated with 0-100 mM sodium chloride (NaCl), and sprayed with 0-250 µM methyl jasmonate (MeJA) as elicitor. The use of LEDs did not result in increased sprout biomass in any case. The effect of the applied treatments on the GSLs depended on the species and were restricted to Brassica spp. The red LEDs produced an overall increase in GSLs over 500% in B. carinata (from 12 to 81 mg 100 g^-1 F.W.), compared to the white broad-spectrum lights, although the highest increase in content was obtained in treated sprouts with 250 µM MeJA (104 an 105 mg 101 g^-1 F.W., under the red and blue LEDs, respectively). The combination of blue LEDs, 100 mM NaCl, and 250 µM MeJA enhanced the levels of GLSs in B. nigra to the maximum (81 mg 100 g^-1 F.W.). Overall, these results indicate that by modifying the growing conditions for a given sprout, enhancement in the accumulation of GSLs as health promoters is possible. The use of these treatments is a sustainable alternative to genetic modification when looking for bioactive-enriched foods, delivering natural plant foods rich in bioactive ingredients (e.g., glucosinolates). Nevertheless, the response to the treatments varies among species, indicating that treatments will require adjustment across sprouts. Further research continues with producing cruciferous sprouts to obtain GSL-enriched formulas for further studying the effects of their bioavailability and bioactivity on health-promotion.

Traditional uses, phytochemistry, transformation of ingredients and pharmacology of the dried seeds of Raphanus sativus L. (Raphani Semen), A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Raphani Semen (Lai Fu-zi in Chinese, RS), the dried seeds of Raphanus sativus L., is a traditional Chinese herbal medicine. RS has long been used for eliminating bloating and digestion, antitussive, expectorant and anti-asthmatic in clinical treatment of traditional Chinese medicine.

AIM OF THE STUDY

This review provides a critical and comprehensive summary of traditional uses, phytochemistry, transformation of ingredients and pharmacology of RS based on research data that have been reported, aiming at providing a basis for further study on RS.

MATERIALS AND METHODS

The search terms "Raphani Semen", "the seeds of Raphanus sativus L." and "radish seed" were used to obtain the information from electronic databases such as Web of Science, China National Knowledge Infrastructure, PubMed and other web search instruments. Traditional uses, phytochemistry, transformation of ingredients and pharmacology of RS were summarized.

RESULTS

RS has been traditionally used to treat food dyspeptic retention, distending pain in the epigastrium and abdomen, constipation, diarrhea and dysentery, panting, and cough with phlegm congestion in the clinical practice. The chemical constituents of RS include glucosinolates and sulfur-containing derivatives, phenylpropanoid sucrosides, small organic acids and derivatives, flavone glycosides, alkaloids, terpenoids, steroids, oligosaccharides and others. Among them, glucosinolates can be transformated to isothiocyanates by plant myrosinase or the intestinal flora, which display a variety of activities, such as anti-tumor, anti-inflammatory, antioxidant, antibacterial, treatment of metabolic diseases, central nervous system protection, anti-osteoporosis. RS has a variety of pharmacological activities, including treatment of metabolic diseases, anti-inflammatory, anti-tumor, antioxidant, antibacterial, antihypertensive, central nervous system protection, anti-osteoporosis, etc. This review will provide useful insight for exploration, further study and precise medication of RS in the future.

CONCLUSIONS

According to its traditional uses, phytochemistry, transformation of ingredients and pharmacology, RS is regarded as a promising medical plant with various chemical compounds and numerous pharmacological activities. However, the material bases and mechanisms of traditional effect of RS need further study.

Transcriptome Analysis of Glutathione Response: RNA-Seq Provides Insights into Balance between Antioxidant Response and Glucosinolate Metabolism

When being stressed, plants require a balance between the resistance pathway and metabolism. Glucosinolates (GS) are secondary metabolics that widely exist in Brassicaceae. Glutathione (GSH) not only participates in plant processing reactive oxygen species (ROS) but also directly participates in GS synthesis as a sulfur donor. Therefore, we used transcriptomic to identify antioxidant and GS metabolism responses in GSH-treated pakchoi. Our study elucidated that GSH can be used as priming to improve oxidative resistance and preferentially stimulate the expression of resistance genes such as CAT1. The reduction in transcription factor expression inhibits the key steps of the GS synthesis pathway. When ROS returned to normal level, the resistance gene decreased and returned to normal level, while GSH restored the gene expression of GS biosynthesis. This work puts forward the mechanism of GSH in regulating the antioxidant system and glucosinolate metabolic pathway, which provides a basis for further study on the relationship between environmental signals and plant metabolism and provides ideas for follow-up research.

Glucosinolates, Ca, Se Contents, and Bioaccessibility in Brassica rapa Vegetables Obtained by Organic and Conventional Cropping Systems

In northwest Spain and Portugal, there is a long tradition of cultivating B. rapa subsp. rapa to obtain turnip greens and turnip tops. Brassica rapa L. subsp. rapa (turnip greens and turnip tops) were grown under conventional and organic conditions in two Farms in southern Spain. Glucosinolatescontents were higher in Brassicas grown under conventional conditions than those grown under organic ones. Average Ca total and bioaccessible contents ranged between 14.6–23.4 mg/g; 8.9–12.0 mg/g for turnip greens and 6.4–8.9 mg/g; 4.3–4.8 mg/g for turnip tops. According to these concentrations, an intake of 100–200 g (fresh weight) of the studied Brassica rapa fulfills Ca dietary reference intakes (DRI) (considering the total content data) and complies with 72–100% Ca DRI percentage (considering the bioaccessible data). Se concentrations ranged between 0.061–0.073 µg/g and 0.039–0.053 µg/g for turnip greens and turnip tops respectively. Se bioaccessibility values were high, with percentages of around 90%. Finally, the total glucosinolate content ranged between 13.23–21.28 µmol/g for turnip greens and 13.36–20.20 µmol/g for turnip tops. In general, the bioaccessibility of the total glucosinolates analyzed in this study was high, with mean values of around 73% and 66% for turnip greens and turnip tops, respectively. Brassica rapa vegetables grown under both organic and conventional conditions in southern Spain are an excellent dietary source of Ca, Se, and glucosinolates with a high bioaccessibility.

Role of Glucosinolates in the Nutraceutical Potential of Selected Cultivars of Brassica rapa

Brassica rapa L. subsp. rapa (turnip greens), a traditionally consumed vegetable, is well-known due to its high content of glucosinolates, which are secondary metabolites with a positive biological activity for human health. Our hypothesis has been based on the relation between B. rapa glucosinolate content and its healthy properties, and our aim is to establish guidelines for safe B. rapa vegetable consumption. Three B. rapa cultivars (143N5, 143N7 and 163N7) have been characterized by HPLC analysis of purified extracts from leaf samples in order to determine their glucosinolate content and to relate this content to beneficial effects on DNA protection, lifespan extension and chemoprevention. In order to ascertain the heath properties in vitro and in vivo, toxicity activities were assayed in the Drosophila melanogaster and leukaemia cell models; genomic safety was also assessed in both models using genotoxicity, fragmentation and comet assay. The Drosophila model has also been used to study the antioxidative activity and the longevity induction. Our results showed a relationship between B. rapa glucosinolate content and its safety and benefices in its consumption. Gluconapin, the main B. rapa glucosinolate, was directly related with these wholesome effects. The relevant conclusion in the present research is focused on B. rapa cultivar 163N7 due to its high gluconapin content and low progoitrin content, which exert anti-cancer and DNA protection properties and could be recommended as being safe and healthy for human consumption.

Evidence on the Bioaccessibility of Glucosinolates and Breakdown Products of Cruciferous Sprouts by Simulated In Vitro Gastrointestinal Digestion

Cruciferous vegetables are gaining importance as nutritious and sustainable foods, rich in phytochemical compounds such as glucosinolates (GSLs). However, the breakdown products of these sulfur-based compounds, mainly represented by isothiocyanates (ITC) and indoles, can contribute to human health. In the human digestive system, the formation of these compounds continues to varying extents in the different stages of digestion, due to the contact of GSLs with different gastric fluids and enzymes under the physicochemical conditions of the gastrointestinal tract. Therefore, the aim of the present work was to uncover the effect of gastrointestinal digestion on the release of glucosinolates and their transformation into their bioactive counterparts by applying a simulated in vitro static model on a range of brassica (red radish, red cabbage, broccoli, and mustard) sprouts. In this sense, significantly higher bioaccessibility of ITC and indoles from GSLs of red cabbage sprouts was observed in comparison with broccoli, red radish, and mustard sprouts, due to the aliphatic GSLs proportion present in the different sprouts. This indicates that the bioaccessibility of GSLs from Brasicaceae sprouts is not exclusively associated with the initial content of these compounds in the plant material (almost negligible), but also with the release of GSLs and the ongoing breakdown reactions during the gastric and intestinal phases of digestion, respectively. Additionally, aliphatic GSLs provided higher bioaccessibility of their corresponding ITC in comparison to indolic and aromatic GSLs.

Agronomic and Metabolomic Side-Effects of a Divergent Selection for Indol-3-Ylmethylglucosinolate Content in Kale (Brassica oleracea var. acephala)

Brassica oleracea var. acephala (kale) is a cruciferous vegetable widely cultivated for its leaves and flower buds in Europe and a food of global interest as a “superfood”. Brassica crops accumulate phytochemicals called glucosinolates (GSLs) which play an important role in plant defense against biotic stresses. Studies carried out to date suggest that GSLs may have a role in the adaptation of plants to different environments, but direct evidence is lacking. We grew two kale populations divergently selected for high and low indol-3-ylmethylGSL (IM) content (H-IM and L-IM, respectively) in different environments and analyzed agronomic parameters, GSL profiles and metabolomic profile. We found a significant increase in fresh and dry foliar weight in H-IM kale populations compared to L-IM in addition to a greater accumulation of total GSLs, indole GSLs and, specifically, IM and 1-methoxyindol-3-ylmethylGSL (1MeOIM). Metabolomic analysis revealed a significant different concentration of 44 metabolites in H-IM kale populations compared to L-IM. According to tentative peak identification from MS interpretation, 80% were phenolics, including flavonoids (kaempferol, quercetin and anthocyanin derivates, including acyl flavonoids), chlorogenic acids (esters of hydroxycinnamic acids and quinic acid), hydroxycinnamic acids (ferulic acid and p-coumaric acid) and coumarins. H-IM kale populations could be more tolerant to diverse environmental conditions, possibly due to GSLs and the associated metabolites with predicted antioxidant potential.

Metabolomic insight into the profile, in vitro bioaccessibility and bioactive properties of polyphenols and glucosinolates from four Brassicaceae microgreens

In this study, four Brassicaceae microgreens species, namely kale, red cabbage, kohlrabi, and radish, were evaluated for their phytochemical compositions using spectrophotometric assays and untargeted metabolomics before and after in vitro gastrointestinal digestion. According to the in vitro spectrophotometric results, significant amounts of phenolics could be detected in each studied species, thus supporting the total antioxidant capacities recorded. Overall, metabolomics allowed annotating a total of 470 phytochemicals across the four Brassicaceae microgreens, either fresh or digested. Among polyphenols, flavonoids were the most represented class (180 compounds, including anthocyanins, flavones, flavonols, and other flavonoids), followed by phenolic acids (68 compounds, mainly hydroxycinnamic and hydroxybenzoic acids), non-flavonoid or phenolic acid-based structures (i.e., alkyl- and alkylmethoxy-phenols and tyrosol derivatives), and lignans. Also, 22 glucosinolates were annotated, including gluconapin glucoraphanin, glucobrassicin, and 4-hydroxyglucobrassicin. Noteworthy, significant differences could be observed in terms of bioaccessibility as a function of the phenolic class and the species considered. Overall, lignans exhibited the highest bioaccessibility values (14%), followed by tyrosol derivatives and flavonoids (on average, 9% and 8%, respectively). However, differences could be evidenced as a function of the species, with red cabbage having comparatively lower bioaccessibility values irrespective of the chemical class of bioactive considered. Similarly, bioaccessibility of glucosinolates significantly differed across species, ranging from 2% in kale to 43% in kohlrabi microgreens.

Comparative Effects of Organic and Conventional Cropping Systems on Trace Elements Contents in Vegetable Brassicaceae: Risk Assessment

Genotypes selected from 3 plant species (Brassica rapa, Eruca vesicaria and Sinapis alba) belonging to the Brassicaceae family were chosen to compare the concentrations of 9 inorganic elements (Cd, Co, Cr, Cu, Fe, Ni, Mn, Pb and Zn) in these varieties, that were grown under both conventional and organic conditions during two agricultural seasons (2018/2019 and 2019/2020) on two different experimental farms (Farm I and Farm II). We found that, together with agriculture practices, the inorganic element concentrations in Brassicas depended on many other factors, including soil characteristics. However, there were no conclusive results indicating a lower heavy metal content or a higher nutritionally beneficial trace elements content in vegetables grown under organic agriculture. Finally, a probabilistic assessment (@Risk) derived from the consumption of 150–200 g of these vegetables showed that organic Brassicas fulfill in comparison with the conventional ones, similar Dietary Reference Intakes (DRI) percentages for Co, Cr, Cu, Fe, Mn and Zn. Regarding heavy metals (Cd, Ni and Pb), we only found slight differences (mainly in the case of Pb) in the Tolerable Intakes (TI) between both cropping systems.