Glucosinolates in Brassica vegetables. Analysis of twenty-seven cauliflower cultivars (Brassica oleracea L. var. botrytis subvar. cauliflora DC)

The glucosinolate content of 27 cultivars of commercially grown cauliflower have been determined. The levels of total glucosinolates (<120 mg 100 g^?1 fresh wt) were comparable with those previously reported for cabbage, but much lower than those found in Brussels sprouts. The major individual glucosinolates were identified as those possessing prop-2-enyl-, 3-methylsulphinylpropyl-, 3-indolylmethyl- and 1-methoxy-3-indolylmethyl- side chains. Smaller amounts of but-3-enyl-, 2-hydroxybut-3-enyl-, 3-methylthiopropyl-, 4-methylthiobutyl-, 2-phenylethyl-, pent-4-enyl-, 2-hydroxypent-4-enyl- and 5-methylthiopentyl-glucosinolates were also measured in some cultivars, the last three compounds not previously having been reported in cauliflower. Environmental effects, determined for the cultivars Wallaby, Coolabah, Barrier Reef and Snowy River were much less than previously found in Brussels sprouts.     

Potential bioactive compounds in health promotion from broccoli cultivars grown in Spain

Glucosinolates, phenolic compounds and vitamin C were evaluated in two commercial and 12 experimental cultivars of broccoli (Brassica oleracea L var italica) grown under uniform cultural conditions. The predominant glucosinolates in all broccoli cultivars were 4‐methylsulphinylbutyl glucosinolate (glucoraphanin) and 3‐indolylmethyl glucosinolate (glucobrassicin). Other glucosinolates such as 4‐OH‐glucobrassicin and N‐methoxyglucobrassicin were detected in lower amounts. The total glucosinolate concentration ranged from 3.0 µmol g^?1 dw (dry weight) in Pentathlon (experimental cultivar) to 28.3 µmol g^?1 dw in I‐9905 (experimental cultivar). Flavonoids, caffeic acid derivatives and sinapic acid derivatives were quantified in methanol extracts. The largest content of flavonoids was found in the commercial cultivars Marathon and Lord, around 60 mg kg^?1 fw (fresh weight). The vitamin C content of broccoli ranged from 43.1 mg per 100 g fw in Lord (commercial cultivar) to 146.3 mg per 100 g fw in SG‐4515 (experimental cultivar). © 2002 Society of Chemical Industry     

The effect of light and temperature on glucosinolate concentration in the leaves and roots of cabbage seedlings

In previous studies it was shown that the concentration of total and individual glucosinolates in brassicaceous plants can vary significantly over a 24-h period grown either in the field or under controlled conditions. The present study shows total and individual glucosinolate variation during a single day. Seedlings of cabbage grown under controlled conditions and at 14 and 15 days after emergence were moved to 20°C (Exp A) and 30°C (Exp B), with a constant photosynthetic photon flux density of 480 μmol m⁻² s⁻¹ and 75% relative humidity, over a 2-day period, during which time aerial parts and roots were sampled at regular intervals. Whilst the glucosinolate patterns of the aerial part of the plant and of the roots remained the same, the levels of major glucosinolates in the aerial part, averaged over all sampling times and 2 days, were 233 ± 60 μmol 100 g⁻¹ DW for 3-methylsulphinylpropyl and 72 ± 22 for 2-propenyl; in the roots, 2-phenylethyl and 1-methoxyindol-3-ylmethyl showed the highest average concentrations, with 678 ± 355 μmol 100 g⁻¹ DW and 411 ± 122, respectively. Total and individual glucosinolate levels showed very high significant differences between the two plant parts. Despite the constant temperature, light and relative humidity, glucosinolates varied within a 24-h period, showing ultradian rhythms that are common to several metabolic processes in plants. The results confirm previous observations that at a temperature of 20°C, close to the optimum for growth and development, the diurnal variation in glucosinolate concentration, was smaller than at 30°C. © 1998 Society of Chemical Industry     

Glucosinolates in Rutabaga Grown in Soil Capped over Coal Fly Ash

Nine glucosinolates were measured by HPLC analysis in rutabaga grown on soil capped over a coal fly ash landfill or on normal clay and silt loam soil. Progoitrin (2-hydroxybut-3-enyl glucosinolate) and neoglucobrassicin (1-methoxy-3-indolylmethyl glucosinolate) were the most abundant glucosinolates found. Progoitrin and three other minor glucosinolates were present in the natural soil-grown rutabaga in greater amounts than in that grown in fly-ash soil. However, fly ash grown rutabaga contained comparatively greater levels of glucobrassicin (3-indolylmethyl glucosinolate) and neoglucobrassicin, the major glucosinolate present.     

Daily Variation in Glucosinolate Concentrations in the Leaves and Roots of Cabbage Seedlings in Two Constant Temperature Regimes

Limited information is available on the glucosinolate variation within the Brassica plant and the relationship between the pattern and concentration of glucosinolates in the aerial parts and the roots has received little attention. Early studies carried out under field conditions have shown that glucosinolate levels may vary considerably throughout a 24 h period. The purpose of the present study was to show whether, under controlled conditions, temperature was a factor in glucosinolate variation and to determine whether such variation might be due to translocation of glucosinolates between the aerial parts of the plant and its roots. Cabbage seedlings were maintained at 20 and 30°C over 2 days and leaves and roots sampled at 02:00 h, 06:00 h, 10:00 h, 14:00 h, 18:00 h and 22:00 h. The glucosinolates 2-propenyl- and 3-methylsulphinylpropyl- with an average of 261 and 167 μmol 100 g^-1 DW, respectively, were the two main glucosinolates in the aerial part of the plant whilst in the roots 1-methoxyindol-3-ylmethyl-, 2-phenylethyl- and 3-methylsulphinylpropyl, with 495, 495 and 385 μmol 100 g^-1 DW respectively, showed the highest average concentrations. Total and individual glucosinolates in the roots and in the aerial part of the plant showed the highest concentrations in the dark cycle, at 02:00 h and 22:00 h, respectively, whilst the lowest levels were during the light cycle, mainly at 18:00 h. The results suggest that temperature was not a major factor in the short-term variation in glucosinolate levels. Although there was a very high significant difference between the total glucosinolate levels in the aerial part of the plant (581 μmol 100 g^-1 DW) and roots (2124 μmol 100 g^-1 DW), the results of the present study do not support the concept of translocation between aerial part and roots, suggesting that other factors may be involved. © 1997 SCI.     

Determination of total glucosinolates in oilseed rape by X-ray spectrometric analysis for oxidised sulphur (S6+)

A rapid X-ray spectrometric (XRS) method has been developed for the determination of the total glucosinolate content of oilseed rape and other Brassica oilseeds. The method is based on analysis for fully oxidised sulphur (S⁶⁺), which includes half the sulphur (S) in the glucosinolate molecule, and the S in sulphate. Results are highly correlated with glucosinolate content determined by glucose release, a standard method widely used in Australia. The relationship is total glucosinolates = (23·97 S⁶⁺ -9·43) r² = 0·987, where the glucosinolate content is expressed as μmol g^?1 and the S⁶⁺ content in mg g^?1. The relationship is applicable to seed of any glucosinolate content and to meal, and is unaffected by changes in protein sulphur content. The correlation of glucosinolates with S⁶⁺ is shown to be closer than the correlation with total S. The latter correlation forms the basis of the existing XRS method, used within the European Community in recent years. The advantages of S⁶⁺ derive from the linearity of the regression and the elimination of errors caused by variation in protein content. The method should be valuable to the Australian oilseed industry because it allows the rapid screening of breeding lines to ensure low glucosinolate content and the assessment of deliveries for crushing and of meal.     

The Nutritive Value of Mango Seed Kernels for Starting Chicks

Raw mango ( Mangifera indica L) seed kernels were found to contain tannins (56·5 g kg⁻¹ DM), cyanogenic glucosides (64 mg kg⁻¹ DM), oxalates (42 mg kg⁻¹ DM) and trypsin inhibitory activity (20 TIU g⁻¹ DM). The contents of these anti-nutritive factors were lowered by both soaking and boiling treatments, but boiling was more effective. The in vitro protein digestibility (26·3%) and apparent metabolisable energy (7·88 MJ kg⁻¹ DM) values of raw kernels were low, and these parameters were improved by soaking and boiling. The observed improvements paralleled reductions in tannin contents, indicating that tannins are largely responsible for the poor nutritive value of raw kernels. In experiment 1, diets containing 0, 50, 100, 150 and 200 g kg⁻¹ raw mango seed kernels that replaced maize were fed to 7-day-old White Leghorn cockerels for 14 days. Inclusion of more than 50 g kg⁻¹ raw kernels lowered ( P< 0·05) the weight gains, feed intake and feed efficiency of chicks. High level inclusion of raw kernels had toxic effects, as evidenced by increased mortality. In experiment 2, soaking and boiling treatments improved ( P< 0·05) feed intake of chicks fed on diets containing 100 g kg⁻¹ kernels and reduced mortality. Feed/gain was unaffected by processing. Soaking had no effect, whereas boiling of kernels improved the weight gains. However, weight gains of chicks receiving diets containing 100 g kg⁻¹ boiled kernels were numerically, though non-significantly, lower than those of the maize-control group. It is concluded that raw mango seed kernels are unsuitable as a feed ingredient in chick diets and, that soaking and boiling do not completely overcome the anti-nutritive effects of raw kernels.     

Sulfate determines the glucosinolate concentration of horseradish in vitro plants (Armoracia rusticana Gaertn., Mey. & Scherb.)

BACKGROUND: Horseradish plants (Armoracia rusticana) contain high concentrations of glucosinolates. Former studies have revealed that Armoracia plants cultivated in vitro have markedly lower glucosinolate concentrations than those grown in soils. Yet, these studies neglected that the sulfate concentration in the growth medium may have had a strong impact on glucosinolate metabolism. Accordingly, in this study horseradish in vitro plants were cultivated with differing sulfate concentrations and the glucosinolate concentrations were quantified by ion pair HPLC. RESULTS: Cultivation in 1.7 mmol L^?1 sulfate (as used in the prior studies) resulted in the accumulation of 16.2 µmol g^?1 DW glucosinolates, while the glucosinolate concentration increased to more than 23 µmol g^?1 DW when 23.5 mmol L^?1 sulfate was used in the medium. Correspondingly, the glucosinolate concentration decreased to 1.6 µmol g^?1 DW when sulfate concentration was lowered to 0.2 mmol L^?1. CONCLUSION: Since the glucosinolate accumulation in relation to the sulfate concentration follows a typical saturation curve, we deduce that the availability of sulfate determines the glucosinolate concentration in horseradish in vitro plants. © 2012 Society of Chemical Industry     

Rapeseed Meals,Methimazole, Thiocyanate and Iodine Affect Growth and Thyroid. Investigations into Glucosinolate Tolerance in the Pig

In two factorial experiments with a total of 81 growing pigs, the effects of antithyroid compounds and rapeseed meal (RSM) diets differing in glucosino-late content were tested without or with supplementary iodine. In Experiment 1, a 4×3 factorial arrangement was used to investigate the effects of antithyroid compound inclusion and supplementary iodine. Pigs received a grain–soya bean meal diet (control) or this diet with 250 mg kg^-1 methimazole (MMI), 1000 mg kg^-1 thiocyanate (SCN^- as KSCN) or 80 g kg^-1 high glucosinolate RSM (9·5 mmol glucosinolates kg^-1), each diet supplemented without or with iodine; 0, 125 μg kg^-1 (requirement) or 500 μg kg^-1. In Experiment 2, a 5×3 factorial arrangement was used to study the effects of dietary glucosinolate content and iodine supplementation. Pigs received a grain–soya bean meal diet or four diets with 160 g kg^-1 RSM differing in glucosinolate content (0·6, 2·4, 6 or 19 mmol kg^-1 diet), each diet supplemented with iodine: 62·5 μg kg^-1, 125 μg kg^-1 (requirement) or 250 μg kg^-1. Irrespective of the iodine dosage, MMI suppressed production of thyroxine and resulted in goitre, myxoedema and cretinism. SCN^- induced clinical hypothyroidism when there was no supple-mental iodine. Despite high iodine supplementation, glucosinolate load (19 mmol kg^-1 diet) decreased growth, feed intake, iodine store of the thyroid and serum concentration of thyroid hormone and resulted in goitre formation. In the case of diets with ⩽6 mmol glucosinolates kg^-1, iodine prevented antithyroid effects. However, more iodine was required by these pigs than by control animals to a high T₄ serum concentration. The lowest glucosinolate level tested (0·6 mmol kg^-1 diet) yielded the same thyroid hormone status and thyroid weight as the control, however, the iodine content of thyroid gland was decreased. In conclusion, iodine administration prevents the effects of a low glucosinolate intake only, by overcoming the depressed thyroxine released of the thyroid, resulting in regression of goitre. © 1997 SCI.     

CHEMICAL AND SENSORY QUALITY OF BROCCOLI (BRASSICA OLERACEA L. VAR ITALICA)

Five cultivars of broccoli (Brassica oleracea L. var. italica) were analyzed for individual glucosinolates, S-methylcysteine sulfoxide (SMCSO), aroma volatiles and sensory quality. Total glucosinolate content ranged from 47 to 93 μmol μmol·g dry weight¹, and SMCSO ranged from 22 to 57 μmol μmol·g dry weight¹. A total of 11 glucosinolates were identified in the broccoli cultivars. The major glucosinolates were: progoitrin, glucoiberin, glucoraphanin, glucobrassicin and neo-glucobrassicin and they accounted for more than 95% of the total content. Glucoiberin was only found in appreciable amounts in purple-headed broccoli. Pentanol, pentanal, hexanal, heptanal and nonanal were the most abundant higher boiling volatiles isolated from cooked broccoli using dynamic headspace trapping on Porapak and solvent desorption with diethyl ether. Sensory analysis by a trained panel showed that scores for cooked vegetable odor (‘hay’ and ‘green peapod’) were significantly different between cultivars. In contrast, scores related to Brassica odor (‘cauliflower’ and ‘mustard’) were not significantly different. The content of individual glucosinolates, SMCSO and higher boiling volatiles in the cultivars is discussed in relation to the sensory quality of the cooked product.     

An estimate of the mean daily intake of glucosinolates from cruciferous vegetables in the UK

Samples (174) of cabbage, Brussels sprouts, cauliflower and swede-turnip have been analysed for total and individual glucosinolate content in both the fresh and cooked form. Using data from the 1980 National Food Survey, the national mean daily intake is calculated to be 46.1 mg in fresh material, and 29.4 mg in cooked. There are large variations within the UK (for example in Scotland it is less than half that in south-west of England), between income groups and over the year. National mean daily intake figures for the glucosinolates yielding goitrogenic products such as oxazolidine-2-thiones and thiocyanate ion are 6.7 and 14.7 mg respectively; the former figure is approximately doubled in the winter months. Based upon the above variations, arising from eating habits in the UK, together with the known large variation in glucosinolate content in cruciferous plants because of agronomic and environmental effects, it is likely that certain individuals will consume more than 300 mg total glucosinolates per day. The nutritional and toxicological consequences of such an intake are unknown at present.     

Effect of post‐harvest treatments on the level of glucosinolates in broccoli

Broccoli is a very perishable vegetable with a high water content (around 88%) which leads to rapid dehydration and probably to an alteration in composition if conditions after harvest are not controlled. This study evaluates the glucosinolate pattern and glucosinolate levels in the principal and secondary inflorescences of fresh broccoli cv ‘Tokyodome’, and after being submitted to some situations which are likely to occur during or after harvest: room temperature (±20 °C) for 5 days, kept in the fridge at 4 °C for 5 days, and frozen after blanching. Another set of material was harvested 5 days later, simulating a post‐maturation stage, and analysed. The highest total glucosinolate content was found at commercial maturation with 20 888 and 20 355 µmoles kg⁻¹ DW in the principal and secondary inflorescences, respectively. Keeping the inflorescences at room temperature caused the most significant (P < 0.05) reductions in total and individual glucosinolates, except for 4‐hydroxyindol‐3‐ylmethyl‐, 2‐hydroxy‐2‐phenylethyl‐ and 2‐phenylethyl‐, when compared to the other situations. The highest levels (10 925 µmoles kg⁻¹ DW) of 4‐methylsulphinylbutyl‐, the precursor of the anti‐cancer isothiocyanate sulphoraphane, were found in the inflorescences freshly harvested at commercial stage. Refrigeration at 4 °C and freezing were shown to be the best preservation processes for maintaining high levels of these and other glucosinolates in contrast with the other situations. © 1999 Society of Chemical Industry     

INDIVIDUAL GLUCOSINOLATES IN SIX CANOLA VARIETIES

The glucosinolate composition of canola varieties ofAltex, Candle, Regent, Tower, Triton and Westar were determined by gas chromatography (GC) and high-performance liquid chromatography (HPLC). Twelve glucosinolates were detected and their identities confirmed by comparison with the retention times of known glucosinolates and by mass spectrometry (MS). The major glucosinolates present in canola meals were gluconapin (3-butenyl), progoitrin (2-hydroxy-3-butenyl), glucobrassicanapin (4-pentenyl), glucobrassicin (3-indolylmethyl) and 4-hydroxyglucobrassicin (4-hydroxy-3-indolylmethyl). Indole glucosinolates were quantified better by HPLC than GC method of analysis. Sulphinyl glucosinolates were determined only by the HPLC methodology due to the yield of multiple peaks by GC.     

Glucosinolate content and myrosinase activity evolution in three maca (Lepidium meyenii Walp.) ecotypes during preharvest,harvest and postharvest drying

Glucosinolate profiles, glucosinolate contents and myrosinase activity were evaluated in yellow, red and black hypocotyls of maca during pre-harvest, at harvest and during post-harvest drying. At harvest, six glucosinolates (GLs) were identified: 5-methylsulfinylpentyl, 4-hydroxybenzyl, benzyl, 3-methoxybenzyl, 4-hydroxy-3-indolylmethyl and 4-methoxy-3-indolylmethyl, of which benzyl glucosinolate was the most abundant in the three ecotypes, representing 80% of the total GLs. A significant increase in GLs was observed for the three ecotypes during the 90 days before harvest and during the 15–30 days of post-harvest drying. This was followed by an important decrease of GLs during the 30–45 day period, which was attributed to cell breakdown, due to fluctuations in temperatures during the drying process, and was correlated with a high myrosinase action. During the last period of post-harvest drying, GLs were much lower and correlated to lower myrosinase activity and lower maca hypocotyl humidity. A combination of artisanal and other processing techniques should be utilised, in order to best preserve maca glucosinolates.     

Composition and content of flavonol glycosides in broccoli florets (Brassica olearacea) and their fate during cooking

The two main flavonol glycosides present in broccoli florets were identified as quercetin 3-O-sophoroside and kaempferol 3-O-sophoroside. Three minor glucosides of quercetin and kaempferol were also detected, namely isoquercitrin, kaempferol 3-O-glucoside and a kaempferol diglucoside. The sophorosides of quercetin and kaempferol were present in raw florets at a level of 65 mg kg⁻¹ and 166 mg kg⁻¹ fresh weight, respectively. The total content of quercetin and kaempferol glycosides expressed as aglycone was 43 and 94 μg g⁻¹ fresh weight, respectively, and these agree with other recently published data. During the cooking process only 14–28% of the individual glucosides were retained in the cooked tissue, the remainder being largely leached into the cooking water with only a small loss attributed to the formation of the respective aglycones. © 1998 SCI.     

Effect of processing on the antinutrient content of rapeseed

The effects of dry extrusion of mixtures of rapeseed and soya bean on total and individual glucosinolates, selected glucosinolate hydrolysis products, myrosinase, sinapine and tannins have been compared with those of more conventional processing, e.g. lime treatment, micronisation and ammoniation. Extrusion at 150°C effectively inactivated myrosinase but had relatively little effect on glucosinolate content unless chemicals were added before extrusion; the most effective combination, 5% alkali+1% ferrous sulphate, reduced the total glucosinolate content by 80%. Under the latter conditions very high (>30 μmol g^?1 defatted meal) levels of nitriles were produced, leading to the suggestion that nitriles in addition to oxazolidine-2-thione and isothiocyanates be used to monitor the effectiveness of processing techniques. None of the extrusion conditions showed any significant effect on reducing sinapine or tannin contents. In view of the chemical data presented, and the probable adverse effects which the processing conditions selected have on the nutritional value of the processed meal it seems unlikely that extrusion will play a significant role in rapeseed detoxification.     

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     

Comparative assessment of soybean meal with high and low glucosinolate rapeseed–mustard cake as protein supplement on performance of growing crossbred calves

BACKGROUND: Feeding of high glucosinolate rapeseed–mustard cakes (RMCs) imparts adverse effects on dry matter (DM) intake, health and overall performance of animals. Recently, plant breeding efforts have resulted in many cultivars of RMCs containing low to moderate levels of glucosinolate in India. The feeding value of RMC cultivars with high and low glucosinolate was evaluated relative to commonly used soybean meal as a protein supplement in growing crossbred calves. RESULTS: Eighteen growing crossbred calves (62.9 ± 3.8 kg body weight) were randomly allocated to three dietary treatments SBM, LG and HG containing soybean meal, low glucosinolate B. napus (15 µmol glucosinolates g^?1) and high glucosinolate B. juncea (135 µmol glucosinolates g^?1), respectively. Although daily intake of total DM and wheat straw did not differ (P > 0.05) among the dietary treatments, intake (g/kgW^0.75) of concentrate moiety decreased quadratically (P < 0.01) with increasing glucosinolate levels in diets. Nutrient digestibility and balances of N, Ca and P by calves were similar (P > 0.05) among dietary treatments. However, average daily gain (g) decreased and feed conversion ratio values increased quadratically (P < 0.05) with increasing glucosinolate levels. Serum metabolic profile and triiodothyronine remained within the normal range; however, thyroxine changed quadratically. CONCLUSION: The results suggested that while high glucosinolate RMCs may reduce the palatability and consequently growth rate in crossbred calves, SBM can be replaced completely by low glucosinolate rapeseed without compromising their performance. Copyright © 2008 Society of Chemical Industry     

Total phenol,flavonoid, proanthocyanidin and vitamin C levels and antioxidant activities of Mauritian vegetables

Ten Mauritian vegetables, broccoli, cauliflower, white cabbage, lettuce, Chinese cabbage, mugwort, carrot, onion, tomato and chilli pepper, were analysed for their total phenol, flavonoid, proanthocyanidin and vitamin C contents and antioxidant capacity. Antioxidant activities of the vegetables ranged from 0.43 to 3.68 µmol g^?1 fresh weight Trolox equivalent antioxidant capacity (TEAC) and from 0.60 to 8.47 µmol g^?1 fresh weight ferric reducing antioxidant power (FRAP). Levels of total phenols in the vegetables varied between 132 and 1189 µg g^?1 fresh weight and those of total flavonoids between 45 and 944 µg g^?1 fresh weight, while proanthocyanidins were detected at very low levels in only a few vegetables. Vitamin C contents varied between 25 and 748 µg g^?1 fresh weight. Quercetin was the dominant flavonoid aglycone in the hydrolysed vegetable extracts, with values in the range of 15–390 µg g^?1 fresh weight. There were strong correlations between antioxidant capacity and total phenols (TEAC, r = 0.91; FRAP, r = 0.83) and total flavonoids (TEAC, r = 0.89; FRAP, r = 0.82). Vitamin C contents showed poor correlation with TEAC values (r = 0.33), while no correlation was observed with FRAP values. Highest antioxidant capacities were observed in Chinese cabbage (Brassica chinensis L), onion (Allium cepa L), mugwort (Artemisia vulgaris Cantley) and broccoli (Brassica oleracea L var botrytis L subvar cymosa). Mauritian vegetables therefore represent a significant source of phenolic antioxidants, with quercetin derivatives being most abundant, and this may contribute to their potential health benefits. Copyright © 2004 Society of Chemical Industry     

Variation of glucosinolates in three edible parts of Chinese kale (Brassica alboglabra Bailey) varieties

Glucosinolates in Chinese kale (Brassica alboglabra Bailey) were analysed by liquid chromatography–mass spectrometry (LC–MS), and the variation of glucosinolates in three edible parts (sprout, rosette leaf and bolting stem) of 27 Chinese kale varieties was investigated. Thirteen glucosinolates, including eight aliphatic glucosinolates, four indole glucosinolates and one aromatic glucosinolate, were identified in Chinese kale. The contents of total glucosinolate varied extensively among the different edible parts, and the total glucosinolate contents in the sprouts were obviously higher than those in rosette leaves and bolting stems. Obvious differences in the total and individual glucosinolate contents were also observed in each edible part among the different varieties. Gluconapin was the most abundant glucosinolate among all the edible parts of the 27 varieties except for the sprout of JL-26. The JL-26, JL-25 and JL-16 varieties are good candidates for future breeding programs since they contain high levels of methylsulphinylalkyl glucosinolates (glucoiberin and glucoraphanin) in certain edible parts.