Anthocyanin composition of cauliflower (Brassica oleracea L. var. botrytis) and cabbage (B. oleracea L. var. capitata) and its stability in relation to thermal treatments

Violet cauliflower and red cabbage were analysed for their anthocyanin profiles before and after thermal treatments. Anthocyanins are well-noted as healthy compounds due to their antioxidant properties. Samples were analysed for total anthocyanin content by using a spectrophotometric differential pH method. An MS-based method, combining high-performance liquid chromatography (HPLC) with quadrupole tandem mass spectrometry (HPLC–MS/MS) was developed, aimed to separate, identify and quantify the main anthocyanin forms. The procedure involves a rapid and efficient pre-treatment of the samples by solid-phase extraction, followed by selective determination of all compounds in a single run analysis using HPLC–MS/MS. Structural information for the identification of compounds was obtained from their fragmentation patterns (MS/MS spectra). The compounds were separated by HPLC and detected in the multiple reaction monitoring mode (MRM), which provides a high level of selectivity for targeting the analytes in vegetables. Cauliflower and red cabbage showed differences in their anthocyanin profiles: cyanidin-3,5-diglucoside was absent in cauliflower, while it was well represented in red cabbage, together with the characteristic anthocyanin of Brassica genus, cyanidin-3-sophoroside-5-glucoside. The p-coumaryl and feruloyl esterified forms of cyanidin-3-sophoroside-5-glucoside were predominant in cauliflower, while the sinapyl one was mostly present in red cabbage. Besides, the stability of cauliflower’s anthocyanin profile was evaluated in relation to thermal pre-treatments. All thermal treatments, except microwave heating, drastically reduced total cauliflower anthocyanin content. The amount of individual anthocyanins was expressed as the percentage with respect to total anthocyanin amount, spectrophotometrically measured. Significant individual changes were observed after different thermal treatment with an isomer formation.     

Variation in the content of glucosinolates,hydroxycinnamic acids,carotenoids, total antioxidant capacity and low‐molecular‐weight carbohydrates in Brassica vegetables

Bioactive compounds were investigated in genotypes (cauliflower 10, white cabbage 10, curly kale 1) and plant parts of the three crops. The content of most of the major glucosinolates glucobrassicin, sinigrin and glucoiberin differed significantly between cultivars. Samples harvested in 2000 had higher amounts of several glucosinolates than samples from 1999. Within cauliflower the buds of the floret had 1.5 to 2.5‐fold higher concentration of glucobrassicin and 4‐methoxyglucobrassicin than the stalk. In white cabbage several glucosinolates had their highest content in the outer leaves (up to 2‐fold higher). Upper leaves of curly kale contained 5‐fold more of total glucosinolates than lower leaves. Chlorogenic acid was the dominating hydroxycinnamate in curly kale, which also contained at least ten times more of carotenoids (mainly lutein) than white cabbage. Total antioxidant capacity (TAC) assayed with the FRAP method was 0.76 (0.06) µmol/g fw (mean (SD)) in water‐soluble and 0.32 (0.04) in water‐insoluble extracts of cauliflower which was 62–68% higher than in white cabbage. Curly kale contained 6.4 and 6.1 µmol/g fw TAC in water‐soluble and water‐insoluble extracts. TAC did not differ between plant parts. Progoitrin and 4‐hydroxyglucobrassicin were correlated to water‐soluble TAC in white cabbage, probably reflecting a variation in other compounds. Cauliflower contained less glucose, fructose and sorbitol but more sucrose than white cabbage. Curly kale had lower contents of glucose (～2 times), fructose (～4–5 times) and sucrose (20 and 36 times, respectively) than cauliflower and white cabbage, while inositol was only found in curly kale. Storage of white cabbage reduced the amount of sorbitol and sucrose. The study shows that cultivar, plant part and storage affect the content of bioactive compounds in Brassica vegetables. The variation between years, as in cauliflower, is due to environmental factors. Since the cultivar ranking order was rather stable for several components the data could provide a basis for the selection of cultivars optimised for valuable health components for fresh market consumption. Copyright © 2005 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     

Analysis of the isothiocyanates present in three Chinese Brassica vegetable seeds and their potential anticancer bioactivities

Epidemiological studies give evidence that high dietary intake of cruciferous vegetables has been associated with lower risk of cancer, this activity due to their content in glucosinolates (GL), which upon myrosinase hydrolysis release the corresponding isothiocyanates (ITCs). In this study, the isothiocyanates contents and the anticancer activity of ethyl acetate extracts from three kinds of Chinese Brassica vegetable seeds have been examined and analyzed. A correlation was found between the potency of anticancer activity and the amount of isothiocyanates in their extracts. Extracts followed by GC–MS analysis revealed that 3-BITC (3-butenyl isothiocyanate) was mainly found in Chinese kale contained 77.58 ± 7.28 mg/g (dry weight); AITC (allyl isothiocyanate), 3-BITC and iberverin were the predominant isothiocyanates in Oxheart cabbage contained 33.57 ± 3.94, 26.50 ± 1.92 and 22.77 ± 0.00 mg/g, respectively; 3-BITC and sulforaphane were found as the major isothiocyanates in broccoli contained 138.52 ± 3.42 and 49.77 ± 0.18 mg/g, respectively. The amount of total isothiocyanates in broccoli was twice higher than that in other two species. The anticancer activity of broccoli was the highest, and the IC₅₀ value of the extract inhibiting on the growth of A549, LAC, HELA and HepG₂ were 14.38 ± 0.35, 10.38 ± 0.34, 19.45 ± 1.72 and 26.75 ± 0.82 mg/g, respectively. The extracts of Chinese Brassica vegetable seeds have the potential in inducing cancer cells apoptosis by morphology observation. The results of this study got a new kind of Brassica vegetable seeds that could produce high content of isothiocyanates, which is important to preparation of anticancer food additives.     

ANTIMICROBIAL ACTIVITIES OF SULFUR COMPOUNDS DERIVED FROM S-ALK (EN) YL-L-CYSTEINE SULFOXIDES IN ALLIUM AND BRASSICA

Allium and Brassica vegetables have long been known for their antimicrobial activity against various microorganisms, including Gram-positive and Gram-negative bacteria and fungi. Most microorganisms tested were sensitive to extracts of the Allium and Brassica vegetables and the degree of sensitivity varied depending on the strain under study and test conditions. Among the vegetables, garlic showed the most potent activity, followed by onion. Brassica, including cabbage, showed the least potent activity. The principal antimicrobial compounds of Allium and Brassica have been elucidated as allicin (S-allyl-L-propenethiosulfinate) and methyl methanethiosulfinate, respectively. Both compounds belong to the same chemical group, thiosulfinate, generated from S-allyl and S-methyl derivatives of L-cysteine sulfoxide, respectively, existing in Allium and Brassica as major non-protein sulfur-containing amino acids. There have been only few applications of garlic as a natural food preservative, in spite of numerous studies on antimicrobial activity of the vegetables. Relative instability of the antimicrobial compounds and the strong odor of their mother plants seem to limit the use of them as a practical food preservative.     

Quality maintenance of minimally processed Chinese cabbage with low temperature and citric acid dip

Chinese cabbage (Brassica campestris L pekinensis group) was minimally processed using best preparation techniques and stored at 0 and at 5°C with and without dips in either citric acid, calcium chloride or ascorbic acid, all at 10 g litre⁻¹. The visual quality, degree of chilling injury, pH and taste were evaluated. The most deleterious effects on quality were produced by black speck (gomasho) and browning. Citric acid inhibited the development of black speck and extended storage life from 10 days of the control to 14 days at 5°C. At 0°C the storage life was not extended by any dip, but citric acid improved quality by reducing black speck. Minimally processed Chinese cabbage treated with citric acid showed only a slight reduction of pH from 6·3 of the control to 6·1 (P⩽0·05) and taste was not significantly affected (P>0·05). Microbial spoilage was not apparent during storage at 0°C for 35 days and 5°C for 21 days under any treatment. © 1997 SCI.     

Simultaneous determination of pyrimethanil,cyprodinil, mepanipyrim and its metabolite in fresh and home-processed fruit and vegetables by a QuEChERS method coupled with UPLC-MS/MS

A QuEChERS procedure for the simultaneous determination of pyrimethanil, cyprodinil, mepanipyrim and its metabolite (M31) in fresh and processed fruit and vegetables was developed using ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). The determination of the four target compounds was achieved in less than 6.0 min using an electrospray ionisation source in positive mode. The limits of detection (LODs) were below 0.4 μg?kg^?1, while the limits of quantification (LOQs) did not exceed 1.5 μg?kg^?1 for all studied matrices. Good linearity of the calibration curves was obtained over the range from 0.002 to 2 mg?kg^?1, with correlation coefficients higher than 0.999. The average recoveries of this method in apple, peach, cabbage and tomato at the five spiked levels (0.002, 0.01, 0.05, 0.20 and 2.0 mg?kg^?1) ranged from 81.5% to 107.3% with relative standard deviations (RSDs) in the range of 1.5–13.9% (n = 5) for all analytes. Residue levels of anilinopyrimidine fungicides in fresh and home-processed apple, peach, cabbage and tomato were also studied. The results indicate that residue levels are significantly reduced following washing, peeling and boiling, and there is no toxic metabolite of mepanipyrim (M31) which is detected during boiling. This study provides a theoretical basis for China to draw up maximum residue limits (MRLs) and protect consumers from the negative health effects of pesticide residues detected in fruit and vegetables.     

Comparison of multiple methods for the determination of sulphite in Allium and Brassica vegetables

Sulphites are a family of additives regulated for use worldwide in food products. They must be declared on the label if they are present in concentrations greater than 10 mg kg^–1, determined as sulphur dioxide (SO₂). The current US regulatory method for sulphites, the optimised Monier–Williams method (OMW), produces false-positive results with vegetables from the Allium (garlic) and Brassica (cabbage) genera due to extraction conditions that are thought to cause endogenous sulphur compounds to release SO₂. Recently, modifications to the OMW method (2x MW) were published that reportedly reduced this false-positive in garlic. However, no other vegetables from these genera have been investigated. In addition, an LC-MS/MS method was developed for sulphite analysis, but it has not yet been tested with these problematic matrices. Ten vegetable species were analysed using these sulphite methods (OMW titration, OMW gravimetric, 2x MW and LC-MS/MS) to determine the false-positive rate. Sulphite concentrations > 10 mg kg^–1 SO₂ were observed with the OMW analyses. The 2x MW method reduced the measured concentration in unsulphited samples to ≤ 10 mg kg^–1 SO₂ for all matrices analysed. The LC-MS/MS method showed concentrations < 10 mg kg^–1 for the Brassica samples, but only displayed a slight reduction in the Allium matrices. Spiked recovery studies were conducted to determine if these methods can detect added sulphite. The 2x MW had recoveries of 17% and 42% for water and fresh garlic, respectively, and the LC-MS/MS had recoveries of 108%, 125%, 116% and 107% for water, fresh garlic, roasted garlic, and hummus, respectively. The low recoveries of the 2x MW may indicate that sulphur compounds cannot be properly quantified with this method. The ability to eliminate false-positives will enable accurate determination of added sulphite to ensure compliance with sulphite labelling requirements.     

Stabilization of Refrigerated Avocado Pulp: Chemometrics-Assessed Antibrowning Allium and Brassica Extracts as Effective Lipid Oxidation Retardants

The effectiveness of Allium and Brassica extracts to inhibit the evolution of lipids oxidation in avocado pulp under refrigeration (storage at 4 °C) was studied. Onion, garlic, scallion, white cabbage, cauliflower, and Brussels sprouts extract were tested as preserving agents in refrigerated avocado pulp. Allium extracts promoted almost a 60% retention of the intrinsic anti-radical capacity of the pulps. Considering secondary oxidation effects, extinction coefficient at 270 nm shows that all treated pulps (except those with scallion addition) were acceptable at the 30th storage day (K ₂₇₀ < 0.22), but they were all significantly less oxidized than the untreated samples (K ₂₇₀ = 1.8) (P < 0.05). Garlic-treated avocado showed the highest antioxidant effectiveness, based on C=CH cis proportion (I _cis = 108.3), while samples with white cabbage extract presented the highest C=CH trans (I _trans = 5.7) proportion after 30 days. The PCA method was discriminant enough since 83.6% of the variance was explained by the first two principal components, allowing the samples to be grouped according to storage time and extract type. This study confirmed that the addition of garlic, onion, and cauliflower extracts enhanced lipid antioxidant properties in refrigerated avocado pulps.     

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.     

Glucose,fructose and sucrose content in broccoli,white cabbage and Portuguese cabbage grown in early and late seasons

Consumption of Portuguese cabbage and white cabbage is very high in Portugal, but diets including broccoli have been highly recommended owing to recognition of the health‐protective effects of secondary plant metabolites. Broccoli production is generally concentrated in the summer/winter season, but the demand for a fresh product throughout the year requires production in other seasons. Sugars might affect flavour and the acceptance of broccoli by consumers. This study reports the free fructose, glucose and sucrose content in primary and secondary inflorescences of 11 cultivars of broccoli, one white cabbage and four Portuguese cabbages grown in early (March–July) and late (August–January) seasons in the northern region of Portugal. On average the results show that the total free sugar content in the broccoli cultivars, except for cv Marathon, is significantly (P < 0.05) lower than in the other cabbages. Fructose was the major sugar in the three types of Brassica, representing between 48.8 and 56.9% of the total sugar content in broccoli cvs Marathon and Senshi respectively and between 48.7% (cv Mirandela) and 53.8% (cv Murciana) in the other cabbages. Glucose was the second major sugar, while sucrose represented a maximum of 20.5% in broccoli cv Shogun and 11.1% in cv Murciana. The growing season influenced the free sugar content, with generally higher levels in the spring/summer than in the summer/winter season in broccoli, while an opposite tendency was noted in the other Brassica species. In broccoli the sugar levels in the primary inflorescences were generally lower than in the secondary inflorescences, except for sucrose. © 2001 Society of Chemical Industry     

Development of Specific LC-ESI-MS/MS Methods to Determine Bifenthrin, Lufenuron, and Iprodione Residue Levels in Green Beans, Peas, and Chili Peppers Under Egyptian Field Conditions

The dissipation of bifenthrin, lufenuron, and iprodione was studied in green beans, peas, and chilli peppers under Egyptian field conditions. For this purpose, three specific and one multi-analyte liquid chromatography-electrospray ionization-tandem mass spectrometry methods were developed and validated according to SANCO guidelines for the determination of bifenthrin, iprodione, and lufenuron residues in the selected commodities. Sample preparation was carried out by the QuEChERs approach, and determination was performed in positive ionization mode for iprodione and bifenthrin and in negative mode for lufenuron. Optimization of the ionization parameters and the chromatographic conditions was performed for each method developed. All methods showed satisfactory performance criteria. Linear dynamic range, limits of detection (LOD) and quantification (LOQ), precision, recovery, and matrix effects were estimated, and the calculated LODs were in the micrograms-per-kilogram range, namely 0.14, 0.61, and 1.4 μg/kg for bifenthrin, lufenuron, and iprodione, respectively. Field trials were carried out in one of the biggest farms in Egypt (Blue Nile) that exports significant quantities of vegetables to the European Union (EU) countries. All the examined pesticides showed high degradation rates. The t _1/2 values for bifenthrin were 3.3, 2.1, and 9.6 days in green beans, peas, and chili peppers, respectively. For iprodione, they reached 2.4 and 14.4 days in green beans and peppers. Furthermore, the calculated pre-harvest interval (PHI) values, according to the maximum residue limits set by EU, were 0, 4, and 0 days for bifenthrin in green beans, peas, and peppers, respectively, and for iprodione, 2 days in green beans and 0 days in peppers. In case of lufenuron, no t _1/2 and PHI were estimated as no residues were found in all pea samples.     

Investigation of ascorbigen as a breakdown product of glucobrassicin autolysis in Brassica vegetables

The formation of ascorbigen (ABG), one of the major indole-derived compound of Brassica vegetables, has been studied. An HPLC method developed previously in our laboratory was used to determine ABG precursors, glucobrassicin (GB) and L-ascorbic acid (AA), in intact plant tissues of four nutritionally important vegetable crops belonging to the genus Brassica - white cabbage, cauliflower, Chinese cabbage, and broccoli. The levels of GB varied within the range 25-142 mg kg^-1 and AA contents varied within the range 110-840 mg kg^-1. The amounts of ABG in homogenized Brassica vegetables was found to be between 7 mg kg^-1 and 18 mg kg^-1. The level of GB in the plant material was shown to be the limiting factor in the process of ABG formation. Calculated conversion values expressing the conversion of GB into ABG revealed that only 20-46% of GB present in intact plant tissues was employed in the process of ABG formation. The conversion values increased with decreasing pH values of the vegetable homogenates.     

Evolution of anticarcinogenic substance in dietary fibre powder from cabbage outer leaves during drying

White cabbage (Brassica oleracea L. var. capitata) is an important source of dietary fibre (DF) and various bioactive compounds, which are claimed to possess antioxidant and anticarcinogenic activities. Sulforaphane, one of the most potent food-derived anticarcinogens, is a hydrolysis product of glucosinolates, which are abundant in Brassica vegetables. As the formation of sulforaphane is via enzymatic reactions and since the compound is heat sensitive, processing temperature is of importance. In this study the effect of hot air drying temperature (40–70 °C) on the evolution of sulforaphane in cabbage during drying was investigated; outer leaves of cabbage, which are discarded and normally considered as waste, were used. The retention of sulforaphane in the finally dried DF powder was also determined. The results showed that the formation of sulforaphane occurred when the cabbage temperature during drying was in the range of 25–53.5 °C and thermal degradation took place once the cabbage temperature exceeded this range. A semi-empirical heat transfer and kinetic model was proposed to predict the evolution of sulforaphane during drying. Drying at 60 °C was suggested as an optimum condition to obtain the highest retention of sulforaphane in cabbage DF powder.     

In vitro calcium availability from brassica vegetables (Brassica oleracea L.) and as consumed in composite dishes

In vitro calcium availability from four varieties of Brassica oleracea L. (broccoli, cauliflower, green cabbage and kale) was evaluated. The effect of including some brassica vegetables in composite dishes (macaroni and broccoli, macaroni and cauliflower) was also studied. Brassica vegetables were rich in calcium (20.6–35.3 mg/100 g) and in organic acids. Dietary fibre content in brassica vegetables (2.4 g/100 g) was lower than in composite dishes, the latter having a higher content of the soluble fraction. Uronic acids represented 50% of the soluble fibre fraction of brassica vegetables and only 24% of that of composite dishes. Approximately 25% of the total calcium of brassica vegetables was dialysable; ionic dialysable calcium was about 7% of the total calcium. The addition of macaroni to vegetables significantly lowered only calcium dialysability (p<0.001). Unlike vegetables, composite dishes had a percentage of soluble calcium higher (p<0.001) than that of dialysable calcium. The presence in dialysates of higher amounts of bound calcium compared to free ionic calcium implies that most of the absorbable calcium was bound to low molecular weight compounds. Organic acids might constitute the main association of calcium in brassica vegetables. Brassicaceae can be regarded as a good source of available calcium; their consumption in the diet may contribute to an adequate calcium nutriture.     

Myrosinase activity and total glucosinolate content of cruciferous vegetables,and some properties of cabbage myrosinase in Taiwan

The myrosinase activity and total glucosinolates of 10 different cruciferous vegetables and some properties of cabbage (Brassica oleracea L var capitata L) myrosinase were investigated. Radish, cabbage and broccoli showed higher myrosinase activity than other samples. No correlation (P > 0–05) was found between myrosinase activity and total glucosinolates of cruciferous vegetables tested. Myrosinase activity for white cabbage was higher than red cabbage. An optimal pH of myrosinase activity was observed at pH 8–0 for both white and red cabbages. The myrosinase extracted from cabbage was more stable in neutral or alkaline pH. The optimal temperature of myrosinase activity for both cabbages was about 60°C, but the myrosinase activity was destroyed after heating at 70°C for 30 min. The myrosinase activities of both white and red cabbages were activated by 10 mM and 5 mM ascorbic acid, respectively.     

Stereoselective behaviour of diclofop-methyl and diclofop during cabbage pickling

This experiment studied the behaviour of diclofop-methyl (DM) and its main metabolite, diclofop (DC), during the pickling process. DM showed obvious enantioselective degradation in the pickled cabbage in the pickling process, with a half-life of 4.95 days for (+)-(R)-DM but less than 12 h for (−)-(S)-DM. In addition, the stereoselective degradation of DM also led to the enantioselective formation of DC. Therefore, (−)-(S)-DC showed a higher residue level than (+)-(R)-DC in both pickled cabbage and its brine. Rac-DC was added into the cabbage used for pickling to study the behaviour of the enantiomers of DC; no enantioselective degradation was observed either in the pickled cabbage or in the brine. DM and DC were configurationally stable in the process, showing no interconversion of (−)-(S)- to (+)-(R)- enantiomer, or vice versa. This research provides information for evaluating the risk of food safety and environmental pollution at the enantiomer level.     

Heavy metals in vegetables sold in the local market in Jordan

Heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in various vegetables (cabbage, green onion, lettuce, parsley, rocket, spinach, carrot, onion, potato and cauliflower) from the market in Jordan were measured using inductively coupled plasma-mass spectrometry. As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn ranged from 0.009–0.275 mg kg^?1 wet weight, 0.004–0.060 mg kg^?1, 0.003–0.401 mg kg^?1, 0.105–3.51 mg kg^?1, 0.15–1.15 mg kg^?1, 0.93–14.39 mg kg^?1, 0.044–0.702 mg kg^?1, 0.072–0.289 mg kg^?1 and 2.23–6.65 mg kg^?1, respectively. Parsley, followed by spinach, contained the highest concentration of heavy metals. Onion contained high levels of toxic heavy metals. The content of Cu in parsley and spinach and Pb in onion exceeded the Codex limits. However, the daily intake of heavy metals from the tested vegetables was lower than the maximum limits for allowable intake.     

Effect of different blanching times on antioxidant properties in selected cruciferous vegetables

This study aimed to evaluate the effect of different blanching times on the antioxidant properties (antioxidant and free radical scavenging activities) and phenolic content of selected cruciferous vegetables. The study revealed that a 10‐min blanching time had a significant effect (p < 0.05) on the antioxidant properties and phenolic content of all the vegetables except for cabbage and mustard cabbage. The loss of antioxidant activity was highest in Chinese cabbage (40%) after 15 min of blanching, followed by cabbage (27%), Chinese white cabbage (19%), mustard cabbage (9%) and red cabbage (4%). Red cabbage had lost a total of 40% scavenging activity after 15 min of blanching followed by Chinese cabbage (38%), cabbage (36%), mustard cabbage (23%) and Chinese white cabbage (11%). Only Chinese cabbage showed an increase (p < 0.05) in total phenolic content after 15 min of blanching compared with other vegetables. Minimal heat treatment through blanching process is recommended to prevent the major loss of antioxidant properties and phenolic content in selected cruciferous vegetables. Copyright © 2005 Society of Chemical Industry     

Thermal and high hydrostatic pressure inactivation of myrosinase from green cabbage: A kinetic study

Myrosinase, a family of enzymes which coexist with glucosinolates in all Brassica vegetables, catalyses the hydrolysis of glucosinolates to yield compounds that can have beneficial effects on human health. In this study, the thermal and pressure inactivation of myrosinase from green cabbage was kinetically investigated. Thermal inactivation started at 35 °C and inactivation kinetics was studied in the temperature range 35-55 °C. Thermal inactivation of green cabbage myrosinase followed the well known consecutive step model. Pressure inactivation started at 300 MPa, even at 10 °C, and the consecutive step model effectively described pressure inactivation in the range 300-450 MPa at 10 °C. The combined effects of applying various pressures and temperatures on myrosinase inactivation kinetics were studied in the ranges 35-50 °C and, 100-400 MPa. The inactivation followed first-order kinetics at all of the applied combinations. This study demonstrates that myrosinase from green cabbage is highly susceptible to both thermal and high pressure processing. Furthermore, it is also noted that myrosinase stability during processing appears to vary widely between different Brassica species.