Inflorescences of Brassicacea species as source of bioactive compounds: A comparative study

Two Brassica oleracea varieties (B. oleracea L. var. costata DC and B. oleracea L. var. acephala) and Brassica rapa L. var. rapa inflorescences were studied for their chemical composition and antioxidant capacity. Phenolic compounds and organic acids profiles were determined by HPLC–DAD and HPLC–UV, respectively. B. oleracea var. costata and B. oleracea L. var. acephala inflorescences presented a similar qualitative phenolic composition, exhibiting several complex kaempferol derivatives and 3-p-coumaroylquinic acid, while B. rapa var. rapa was characterized by kaempferol and isorhamnetin glycosides and several phenolic acids derivatives. B. oleracea L. var. costata and B. rapa var. rapa showed the highest phenolics content. The three Brassica exhibited the same six organic acids (aconitic, citric, pyruvic, malic, shikimic and fumaric acids), but B. oleracea L. var. acephala presented a considerably higher amount. Each inflorescence was investigated for its capacity to act as a scavenger of DPPH radical and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid), exhibiting antioxidant capacity in a concentration dependent manner against all radicals. These samples were also studied for its antimicrobial potential against Gram-positive and Gram-negative bacteria and fungi, displaying antimicrobial capacity only against Gram-positive bacteria.     

The Glucosinolate Content of Some Fodder Brassicas

The glucosinolate contents of six kales and five cabbages (Brassica oleracea L.), four stubble turnips and six turnips (B. campestris L.), and six swedes and six fodder rapes (B. napus L.) were determined. As fodder brassica breeders wish to reduce the goitrogenicity of these crops, the concentrations of 2-hydroxybut-3-enylglucosinolate (5-vinyloxazolidine-2-thione is the goitrogenic hydrolysis product) and 3-indolylmethylglucosinolate (the thiocyanate ion is the goitrogenic hydrolysis product) were of particular interest. High concentrations (mmol kg^?1 dry matter) of 2-hydroxybut-3-enylglucosinolate were found in stubble turnip leaf (8.12) and bulb (9.20), turnip bulb (9.97), swede bulb (5.66), and rape leaf (8.99) and stem (21.81) but not in kale or cabbage. In contrast, the concentration of 3-indolylmethylglucosinolate was relatively high in cabbage head (6.39) and kale leaf (3.25) but not in the other crops.     

Protein,amino acid,ash and mineral contents in Brassica spp. grown in Northwest Spain

The protein, amino acid, ash, and mineral composition of different Brassica spp. grown in several areas of Galicia (Northwest Spain) were studied. The highest protein values were observed in Galega kales (crude protein: 29.66 g per 100 g) and turnip greens and turnip tops (27.74–31.46 g per 100 g), whereas the leaves showed higher protein contents than the stems. Glutamic acid was the most abundant amino acid present (14.53% in turnip greens to 18.45% in white cabbage). Other amino acids such as arginine, aspartic acid, lysine, alanine and glycine were also observed in higher quantities. The stems contained the same amino acid as the leaves but at a lower level. Furthermore, differences in amino acid contents were observed among varieties. The proportion of essential amino acids was high (41% in leaves of turnip top to 47% in external leaves of oxheart cabbage). The studied varieties are also a good source of some minerals, which include as main element potassium (27.24–37.57 mg g^?1 in whole plants), followed by calcium (4.27–17.48 mg g^?1 in whole plants) and magnesium (1.62–2.92 mg g^?1 in whole plants). Significant differences among varieties and edible portions were found concerning ash and mineral contents.     

Relationship of climate and genotype to seasonal variation in the glucosinolate–myrosinase system. II. Myrosinase activity in ten cultivars of Brassica oleracea grown in fall and spring seasons

Myrosinase catalyzes the hydrolysis of glucosinolates found in the Brassicaceae, generating a variety of bioactive reaction products that may aid in the prevention of some cancers and that are suppressive to soil‐borne plant pathogens. Two cultivars each of broccoli (Brassica oleracea L var italica), Brussels sprouts (B oleracea var gemmifera), cabbage (B oleracea var capitata), cauliflower (B oleracea var botrytis), and kale (B oleracea var acephala) were grown during two fall seasons and two spring seasons to determine if myrosinase activity varied by season. Regression models that included mean temperature and photosynthetic photon flux (PPF) during the growing seasons showed that climatic variables explained seasonal differences for myrosinase activity. Activity‐FW (FW = fresh weight; U g^?1) and specific activity (U mg^?1) were significantly (p ≤ 0.05) affected by season, botanical group and group × season. Activity‐FW had a negative linear relationship with temperature, and a positive linear but negative quadratic relationship with PPF. Specific activity had a positive linear and a negative quadratic relationship with both temperature and PPF. Therefore the influence of climatic factors on myrosinase activity in Brassica species may affect the potential benefits of the glucosinolate–myrosinase system. Copyright © 2004 Society of Chemical Industry     

Myrosinase activity of cruciferous vegetables

Myrosinase activity in partially purified extracts of 12 cruciferous vegetables and an acetone powder preparation of Sinapis alba L. (white mustard) was determined by the initial rate of glucose formation from glucosinolate hydrolysis using a coupled assay. Of the species studied Raphanus sativus L. (radish, 12.8±0.7 μmol min^?1g^?1 powdered tissue) had the greatest myrosinase activity, and Brassica campestris L. ssp. rapifera (turnip) and Nasturtium officinalis R.Br. (watercress) (0.6±0.1 and 0.8±0.03 μmol min^?1g^?1 powdered tissue respectively) the least. The sub-species of Brassica oleracea studied all had similar myrosinase activity (ca 2.5±0.2μmolmin^?1g^?1 powdered tissue) except B. oleracea L. var. gemmifera D.C. (Brussels sprouts) and B. oleracea L. var. capitata L. (white cabbage) which had higher activities (7.6±0.1 and 5.2±0.2μmol min^?1g^?1 powdered tissue respectively). The effect of ascorbate concentration upon the myrosinase activity of six of the crucifers studied and the white mustard preparation, revealed that the ascorbate concentration necessary to promote maximal activity varied with species. A concentration of 0.9mM ascorbate maximally activated radish and turnip myrosinase, while red cabbage, watercress, white mustard and Brussels sprouts were maximally activated at 2.0, 3.0, 5.0 and 0.7–1.0mM ascorbate respectively. Two peaks of maximal myrosinase activity, occurring between 0.9 and 1.0mM and at 3.0mM ascorbate, were found for B. oleracea L. var. botrytis L. subvar. cauliflora D.C. (cauliflower).     

Effects of different cooking methods on some chemical and sensory properties of Galega kale

Kale (Brassica oleracea L. var. acephala) is rich in bioactive phytochemicals such as phenolic compounds and vitamins. However, cooking the plants can cause important changes in composition. The objective of this study was to investigate the effect of some domestic cooking processes (boiling, steaming, microwaving and pressure cooking) on several quality parameters of Galega kale. Boiling had the strongest effect on the antioxidant capacity (the IC₅₀ was four times higher than in the fresh sample), total phenolics (losses of 76.4–77.9%) and colour (ΔE = 17.79–19.12). Microwaving caused the greatest loss of soluble solids (80.8–82.2%). Steaming seems to be the best method for retaining the nutrient and antioxidant capacity of kale (100% ash, 71–77.5% soluble solids, 100% antioxidant capacity, 67–71% total phenolics, 62–71% chlorophyll). However, steamed kale was awarded the lowest sensory scores, indicating the difficulty in reconciling nutritional value and sensorial quality. Use of discriminant statistical techniques enabled the classification of 100% of samples.     

Sensory quality of turnip greens and turnip tops grown in northwestern Spain

In Galicia (northwestern Spain), Brassica rapa var. rapa L. includes turnip greens and turnip tops as vegetable products that are characterized by a particular sulfurous aroma, pungent flavor, and a bitter taste. In this work, 12 local varieties grown as turnip greens and turnip tops were evaluated to define the sensory attributes, to relate them with secondary metabolites, and to select those sensorial traits that better describe these crops. Results showed differences in the sensory profiles of B. rapa varieties. Turnip greens were significantly different regarding aroma intensity, leaf color, and salty taste, while turnip tops were for color and firmness of leaves, moistness and fibrosity in mouth, sharpness, and bitter taste. Secondary metabolites as glucosinolates in turnip greens and phenolic compounds in turnip tops were highly correlated with texture and flavor. Glucosinolates, especially progoitrin (in turnip greens) and gluconapin (in turnip tops), showed correlation with bitter taste and aftertaste persistence. Correlation between sensory traits showed highest values between leaf firmness and stalk firmness (R = 0.94**), leaf firmness and fibrosity (R = 0.92**), aftertaste persistence and bitterness (R = 0.91**), and between bitterness and moistness (R = −0.89**).     

Relationship of climate and genotype to seasonal variation in the glucosinolate–myrosinase system. I. Glucosinolate content in ten cultivars of Brassica oleracea grown in fall and spring seasons

Two cultivars each of broccoli (Brassica oleracea L var italica), Brussels sprouts (B oleracea var gemmifera), cabbage (B oleracea var capitata), cauliflower (B oleracea var botrytis) and kale (B oleracea var acephala) were grown during two fall seasons and two spring seasons to determine whether significant seasonal effects on glucosinolate (GS) concentrations could be explained by mean temperature, photosynthetic photon flux (PPF) and daylength during the growing seasons. Concentrations of total GSs, indole GSs and glucoraphanin differed by genotype and season. Total GS concentrations at harvest had a negative linear but positive quadratic relationship with temperature and daylength over the 2 weeks preceding harvest and a positive linear but negative quadratic relationship with PPF over the same 2 weeks. The regression model for indole GS concentrations similarly varied with mean temperature, daylength and PPF over the 4 weeks prior to harvest. Glucoraphanin concentrations at harvest decreased linearly with mean PPF from transplanting to harvest and had a negative linear but positive quadratic relationship with daylength from transplanting to harvest. Because glucoraphanin and other GSs in cruciferous crops are important for cancer chemoprotection, climatic conditions should be considered when planning planting dates or when making breeding selections for GS concentration. Copyright © 2004 Society of Chemical Industry     

Cooking methods of Brassica rapa affect the preservation of glucosinolates,phenolics and vitamin C

Cooking Brassica vegetables as a domestic processing method has a great impact on health-promoting bioactive compounds: glucosinolates (GLS), flavonoids, hydroxycinnamic acids, and vitamin C. In Galicia (NorthWestern Spain), one of the most consumed horticultural crops is Brassica rapa, by using the leaves (turnip greens) and the young sprouting shoots (turnip tops) in different culinary preparations. In order to determine the effect of cooking, on turnip greens and turnip tops, bioactive GLS, flavonoids, hydroxycinnamic acids and vitamin C were analysed and simultaneously determined. The level of retention of each individual compound after cooking procedures was evaluated in the edible organs, and also in the cooking water, in order to compare their composition to a fresh uncooked control. Steaming, conventional boiling, and high-pressure cooking, traditional processing methods of this kind of vegetables, were the three domestic processing methods used in this work. Results showed that total GLS and phenolics were significantly affected by the cooking procedure and the loss rate varied among individual compounds. Steaming was the method that better preserved GLS and phenolic compounds. Conventional boiling and high-pressure cooking methods presented similar rate of losses of total GLS content (64%) and total phenolic content (more than 70%). Degradation among glucosinolate classes, aliphatic or indolic, was similar. The total flavonoids lost in turnip greens were 64% and 67% for conventional boiling and high-pressure, respectively. The main losses were caused by leaching into the cooking water. The concentration of vitamin C suffered a drastic loss in the process of sample handling and after cooking. Despite the fact that any cooking procedure affected negatively the nutritional composition of the turnip greens and tops, our results showed high retentions of individual compounds in steaming, and the lowest retentions were obtained in the traditional high-pressure cooking. High retention of health-promoting compounds in the cooking water should be considered for increasing the intake of properties of B. rapa.     

Oil Content and Fatty Acids Composition in Brassica Species

Seeds of 20 accessions of six Brassica species including cultivated and five wild relatives were analyzed for oil and fatty acid composition. The results showed that oil content varied from 21 (B. nigra) to 46% (B. napus). Among wild species, B. rapa and B. oleracea had highest oil content (31 and 28%, respectively). The main fatty acids of oleic, linoleic, linolenic, erucic, palmitic, and stearic acids accounted for 89–94% of the total fatty acids in all species. Cultivated species of B. napus had highest oleic acid (61%) and lowest erucic acid (1%) content compared to other studied species. Brassica rapa and B. oleracea had the highest content of erucic acid (41 and 46%, respectively). The highest content of linolenic (20%) and linoleic (19%) acid was observed for B. juncea. The results showed that there was high genetic variation among the studied species for oil content and fatty acids composition. This indicates that seed oil of these species is possibly suitable for both human consumption and industrial purposes.     

HPLC screening of anti-cancer sulforaphane from important European Brassica species

Natural sulforaphane has been of increasing interest for nutraceutical and pharmaceutical industries due to its anti-cancer effect. The sulforaphane contents of 14 different major European Brassica oleracea L. varieties (cauliflower Alverda, cauliflower di Jesi, cauliflower Minaret, broccoli Ramoso calabrese, white cabbage, palm cabbage Cuor di Bue, broccoli Primor, savoy cabbage riccio d’Asti, broccoli Eolo, Delicato, cauliflower Nuvola, cauliflower Palla di neve, San martino, Velox) and four different Brassica rapa L. varieties (turnip Senza Testa, cima di rapa 40, cima di rapa 90, cima di rapa 120) which are cultivated in Italy, were analysed during two different developmental stages (3rd and 9th day after germination) of the seedlings. A quantitative determination of sulforaphane in Brassica species seedlings was established by HPLC. The highest amount of sulforaphane (2.21 mg/g d w) was found in San martino 3-day old seedlings. Seedlings of this European Brassica variety may be considered as a potential new source of natural sulforaphane.     

Glucosinolates profile of Brassica rapa L. subsp. Sylvestris L. Janch. var. esculenta Hort

Glucosinolates in different ecotypes of Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort. widely distributed in Southern Italy and locally known as “friariello” and “cima di rapa”, were characterized and their glucosinolate composition was compared with that of broccoli (Brassica oleracea L. var. italica).     

Chemical and antioxidative assessment of dietary turnip (Brassica rapa var. rapa L.)

The phenolic compounds and organic acids of turnip (Brassica rapa var. rapa L.) edible parts (leaves and stems, flower buds and roots) were determined by HPLC–DAD and HPLC–UV, respectively. The results revealed a profile composed of 14 phenolics (3-p-coumaroylquinic, caffeic, ferulic and sinapic acids, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-sophoroside-7-O-sophoroside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, kaempferol 3,7-O-diglucoside, isorhamnetin 3,7-O-diglucoside, kaempferol 3-O-sophoroside, 1,2-disinapoylgentiobiose, 1,2′-disinapoyl-2-feruloylgentiobiose, kaempferol 3-O-glucoside and isorhamnetin 3-O-glucoside) and six organic acids (aconitic, citric, ketoglutaric, malic, shikimic and fumaric acids). The quantification of the identified compounds showed kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, isorhamnetin 3,7-O-diglucoside and isorhamnetin 3-O-glucoside as the main phenolics, and malic acid as the organic acid present in highest amounts. A screening of the antioxidative potential was also performed by means of the DPPH radical scavenging assay. Turnip flower buds exhibited the strongest antioxidant capacity.     

Phytochemical and Health‐Beneficial Progress of Turnip (Brassica rapa)

Despite the advancement of medical science, diseases are part‐and‐parcel of human life. Plants have provided humans with medicines since time immemorial, and are still one of the primary sources for drug discovery. Brassica rapa L., commonly known as turnip, is one of the world's oldest cultivated vegetables. Besides being an important vegetable and source of oil, turnip is also used as a traditional medicine for the treatment of headaches, chest complaints, rheumatisms, oedemas, gonorrhoea, syphilis, and rabies. Glucosinolates and isothiocyanates (mainly 2‐phenylethyl, 4‐pentenyl, and 3‐butenyl derivatives) are the main constituents of turnip with diverse bioactivities, especially for the protective effect against cancers. Besides, flavonoids, phenolics, indoles and volatiles are also concomitant in this plant. Pharmacological investigation on turnip revealed the antitumor, antihypertensive, antidiabetic, antioxidant, antiinflammatory, hepatoprotective, and nephroprotective effects. The anticancer property was found to be the most promising biological activity of turnip with 2‐phenylethyl isothiocyanate, phenylpropionitrile, brassicaphenanthrene A, 6‐paradol, and trans‐6‐shogaol as the major active constituents. Flavonoids and phenolics with high free radical scavenging activity should be corresponding to the antioxidant effects. Arvelexin, an indole derivative in turnip, was reported with various effects involving antiinflamatory, antihypertensive and hypolipidemic potency. In spite of many studies concerning either the chemical constituents or the biological activities of turnip, only a few cases disclosed the active ingredients responsible for diverse bioactivities. This review summarizes the research progress on the chemistry and health‐benefits of turnip over the past 20 years to provide a reference for the further investigation.     

Changes in the dry matter,sugar, plant fibre and lignin contents of swede,rape and kale roots in response to turnip root fly (Delia floralis) larval damage

Plants from two genotypes of swede (Brassica napus var napobrassica), kale (B oleracea var. acephala) and rape (B napus var napus) were each inoculated at the three to four true leaf stage with 10 eggs of the turnip root fly, Delia floralis. After 8 weeks the damage caused by the resultant larvae significantly reduced the weight of leaves, stems and roots compared with uninoculated plants, with the greatest reduction (26–46%) being found in the roots. Dry matter content, which did not differ between either crop type or cultivar, was unaffected by larval damage. Ethanol-soluble sugar content was reduced in all cases by larval damage, but only significantly in one rape and one swede cultivar. The effect of D floralis damage on the concentrations of individual sugars (glucose, fructose and sucrose) was crop type and cultivar dependent. The neutral detergent fibre and lignin contents of the undamaged swede roots were significantly lower than in either the undamaged kale or rape cultivars studied. In all crop types the neutral detergent fibre and lignin content significantly increased following D floralis damage. The six Brassica genotypes studied fell into two groups on the basis of host status for D floralis. The two kale cultivars and the forage rape Hobson were considered poor hosts for D floralis, with low percent age pupation (38–41%) and low pupae weight (12.5–14.4 mg). The two swedes and the oilseed rape Ariana were considered good host for D floralis, with both higher percentage pupation (51–59%) and pupae weights (19.8–20.0 mg). The possible relationships between the root composition of undamaged and attacked roots, and D floralis resistance are discussed.     

Sulphur- and nitrogen-containing volatile components of kohlrabi (Brassica oleracea var.gongylodes L.)

Summary Volatiles from the edible part of kohlrabi (Brassica oleracea var.gongylodes) were isolated by means of a dynamic headspace sampling device and separated by capillary gas chromatography. For identification samples were subjected to element-specific detection (Flame photometric and nitrogen-phosphorus detectors) and mass spectral analyses. Major volatile products are: 3-methylthiopropyl, 4-methylthiobutyl and allyl isothiocyanate. The two corresponding organic cyanides 3-methylthiopropyl and 4-methylthiobutyl cyanides and dimethyl, trimethyl and tetramethyl disulphides are also present in higher amounts.n-Nonenal, (E)-2-hexenal, (E,E)-2,4-heptadienal and some isothiocyanates of unknown structure appear in the volatile fraction as minor constituents. The sulphur- and nitrogen-containing components could be related to the enzymic cleavage (myrosinase) of glucosinolates, naturally occurring precursors in brassica plants. Some of the volatile products possess antimicrobial and antithyroid effects and have been identified in different plants of the cruciferae family. The possible role of the isothiocyanates, cyanides, sulphides and aldehydes to the flavour of kohlrabi is discussed.

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Flüchtige schwefel- und stickstoffhaltige Komponenten in Kohlrabi (Brassica oleracea var.gongylodes L.)

Zusammenfassung Die flüchtigen Inhaltsstoffe des Kohlrabi (Brassica oleracea var.gongylodes L.) wurden mittels der dynamischen Kopfraum-Technik isoliert und anschligßend gaschromatographisch aufgetrennt. Unter Anwendung elementspezifischer Detektoren (FPD, NPD) und Massenspektrometrie erfolgte deren Identifizierung. Zu den Hauptkomponenten gehören: 3-Methylthiopropyl-,4-Methylthiobutyl- und Allyrisothiocyanat. Die beiden korrespondierenden organischen Cyanide 3-Methylthiopropyl- und 4-Methylthiobutyl-cyanid sowie Dimethyldisulfid, Dimethyltrisulfid und Dimethyl-tetrasulfid erscheinen ebenfalls in gröBeren Mengen. In geringerer Konzentration treten nochn-Nonenal, (E)-2-Hexenal, (E,E)-2,4-Heptadienal und einige Isothiocyanate unbekannter Struktur in den Extrakten auf. Die schwefel- und stickstoffhaltigen Komponenten sind auf die enzymatische Spaltung (Myrosinase) der inBrassica-Arten vorhandenen Glucosinolate zurückzuführen. Einige der identifizierten Stoffe zeigen antimikrobielle und antithyroide Eigenschaften und wurden in verschiedenen Cruziferenarten nachgewiesen. Die mögliche Bedeutung der Isothiocyanate, Cyanide, Sulfide und Aldehyde für das Kohlrabiaroma wird diskutiert.

     

Effect of Fermentation on Antioxidant Properties of Red Cabbages

The influence of fermentation, natural and inoculated by two types of lactic acid bacteria (Lactobacillus plantarum ATCC 8014 and Lactobacillus acidophilus, NCFM), on antioxidant properties of red cabbages was determined and compared with those of their unfermented counterparts. Fermentation led to increased antioxidant activity, which was measured by using DPPH and TEAC method. Highest antioxidant activity was observed in red cabbages fermented with L. plantarum. The total content of phenolic compounds increased upon natural fermentation and was determined by the Folin–Ciocalteu method. Interestingly, in contrast to natural fermentation, for the red cabbages inoculated with L. plantarum and L. acidophilus, the total amount of phenolics increased slightly until day 7 of fermentation and gradually decreased for longer time of fermentation. Fermentation appears to decrease the level of total anthocyanins for all type of fermentation. Additionally, results of the HPLC analysis indicated the metabolism of phenolic compounds during the fermentation of red cabbages. Thus fermentation offers a tool to further increase the antioxidant potential of red cabbages.     

Free Radical Scavenging Activity of Aqueous and Ethanolic Extract of Brassica oleracea L. var. italica

In this study, antioxidant activities of aqueous and ethanolic extracts of Brassica oleracea L. var. italica were investigated. The antioxidant properties of both extracts of Brassica oleracea L. var. italica were evaluated using different antioxidant tests, including 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, superoxide radical scavenging, inhibition of microsomal lipid peroxidation, reduction of power, and metal ion chelating activities. Inhibition of superoxide scavenging by aqueous and ethanolic extracts showed an IC₅₀ of 0.93 and 0.25 mg/ml, respectively. Metal ion chelation showed an IC₅₀ of 0.35 mg/ml of both the extracts and was equipotent to positive control, ethylenediamine tetra-acetic acid. The ethanolic extract of Brassica oleracea L. var. italica exhibited higher antioxidant activity in DPPH radical and superoxide anion scavenging than that of aqueous extract. The results obtained in the in vitro models clearly suggest that, Brassica oleracea L. var. italica is a natural source for antioxidants, which could serve as a nutraceutical with potential applications in reducing the level of oxidative stress and related health benefits. However, comprehensive studies need to be conducted to ascertain the in vivo safety of such extracts in experimental animal models.     

Total and individual glucosinolate contents in inflorescences of eight broccoli cultivars grown under various climatic and fertilisation conditions

Total aliphatic, indolic and aromatic glucosinolates were evaluated in the edible portions of fresh harvested inflorescences of five commercial and three experimental broccoli (Brassica oleracea L var italica) cultivars grown under various climatic and agronomic conditions, ie early (winter) or late (spring) season with poor (15 kg ha^?1) or rich (150 kg ha^?1) sulphur fertilisation, in an attempt to identify differences due to genetic and agronomic factors. The predominant glucosinolates in all broccoli cultivars were 4‐methylsulphinylbutyl‐glucosinolate (glucoraphanin), 3‐indolylmethyl‐glucosinolate (glucobrassicin) and 1‐methoxy‐3‐indolylmethyl‐glucosinolate (neoglucobrassicin). The results showed no significance differences in total glucosinolates between rich and poor fertilisation, whereas total glucosinolates were detected more significantly in the late than in the early season. All broccoli cultivars showed a higher content of indolic glucosinolates than aliphatic glucosinolates. Clear advantages were detected in the analysed commercial cultivars, as the experimental cultivars yielded lower concentrations of these compounds. © 2003 Society of Chemical Industry     

Volatile Flavor Sulfur and Nitrogen Constituents of Brassica rapa L.

The volatile flavor constituents of Brassica rapa L. var laciniitolia Kitamura and Brassica rapa L. subvar Hiroshimana Kitamura have been investigated by a combination of chromatographic and spectioscopic methods. These volatile oils possess a characteristic pungent odor and taste. A total of 14 sulfur and nitrogen compounds were identified positively, including 4 isothiocyanates, 3 nitriles, 2 methylthio isothiocyanates, 4 methylthio nitriles and 1 sulfide.