Glucosinolate content of Brassica vegetables-Chinese cabbages Pe-tsai (Brassica pekinensis) and Pak-choi (Brassica chinensis)

The glucosinolate content of 19 cultivars of pe-tsai and three cultivars of pak-choi Chinese cabbage (Brassica pekinensis Lour) Rupr and (Brassica chinensis L, respectively) has been determined using high performance liquid chromatography. The levels of total glucosinolates were 0.097-0.337 g kg^?1 fresh weight (mean 0.198) in pe-tsai and 0.39-0.704 g kg^?1 (mean 0.534) in pak-choi. The main components present were (2-hydroxybut-3-enyl-progoitrin), but-3-enyl- (gluconapin), 5-methylsulphinylpentyl- (glucoalyssin) and pent-4-enyl (glucobrassicanapin) glucosinolates, respectively. In comparison with other UK brassicas and American cultivars of Chinese cabbage, both the UK-grown pak-choi and pe-tsai are low in glucosinolates.     

Aflatoxin contamination in mustard (Brassica juncea) in relation to agronomic practices

Aflatoxin contamination in two varieties of mustard (Brassica juncea L), Varuna and BR-40, sown on three planting dates (1, 15 and 30 November) under two different cropping patterns, viz monocropping and mixed cropping (along with the UP-262 variety of wheat), was examined in rabi (winter) crops of 1987–1988 and 1988–1989. Analysis of variance showed a significant effect of planting date and cropping pattern as well as a combined effect of planting date × cropping pattern. Delayed planting (30 November) resulted in a very high level of aflatoxin contamination. The level of aflatoxin was low when mustard was cultivated along with wheat (mixed cropping). Varuna was more susceptible to aflatoxin than BR-40. The maximum number of fungi was recorded in mixed cropping samples.     

Capillary gas chromatography analysis of Ethiopian mustard to determine variability of fatty acid composition

Ethiopian mustard (Brassica carinata A. Braun) is an oil crop grown in Ethiopia. However, the oil is considered low quality, as it contains long chain monounsaturated fatty acids, mainly erucic acid. High erucic acid content is beneficial for the polymer industry, whereas low erucic acid is recommended for food purposes. Both linoleic and linolenic acids are essential fatty acids; however, less than 3% linolenic acid is preferred for oil stability. The objectives of this study were to determine fatty acid composition of Ethiopian mustard to determine the range of genetic diversity for these traits. The genotypes were analysed by capillary gas chromatography (CGC). Twenty‐six fatty acids were identified. In all accessions, the predominant fatty acids were erucic, linoleic, α‐linolenic and oleic, followed by gadoleic and palmitic. To a lesser extent stearic, vaccinic, nervonic and behenic acids were found in all accessions. Significant correlations were found between palmitic acid and stearic acid (positive), between erucic acid and palmitic, stearic, vaccinic, oleic, linoleic and α‐linolenic acids (negative) and eicosenoic acid (positive). Selection and hybridization techniques can be applied to modify the oil content of Ethiopian mustard, considering the variability observed. Copyright © 2004 Society of Chemical Industry     

Glucosinolate profiles of international rapeseed lines (Brassica napus and Brassica campestris)

Seed samples from a range of international rapeseed lines (Brassica napus L and B campestris L) were analysed for glucosinolate content using high performance liquid chromatography (HPLC). This analytical method provided a total profile consisting of eight different glucosinolates, including those used to define the Canola standard. The data indicated that broad categories of distinct glucosinolate profiles existed among the seed lines analysed. Indole glucosinolate content, expressed as a percentage of total glucosinolate content, was higher in the low glucosinolate lines of B napus. The actual contents of all eight glucosinolates in the seed were variable, particularly gluconapin, glucobrassicanapin and progoitrin. The importance of this HPLC procedure in facilitating selection for high or low contents of individual glucosinolates is discussed.     

Improved analysis of sinigrin in Ethiopian mustard

An ion‐pair reversed‐phase high‐performance liquid chromatography (HPLC) method was developed for the analysis of sinigrin in Ethiopian mustard (Brassica carinata A. Braun) seed and seed fractions. Separation was compared on several RP‐HPLC columns (Inertsil^® ODS‐4 C₁₈ and ZORBAX^® Eclipse XDB‐C₁₈) with an isocratic eluent containing 100% aqueous (aq.) tetramethylammonium bromide (10 mm , pH 5.0). Sinigrin retention was affected by HPLC variables including the type of ion‐pair reagent, buffer strength and pH, acetonitrile concentration, column temperature and eluent flow rate. Partial validation demonstrated this optimised chromatographic condition to be linear, accurate and precise. Multistage extraction using 70% (v/v) aq. methanol was more efficient than 50% (v/v) aq. acetonitrile. In addition, the matrix effect and recovery rate as well as processing efficiency of the analytical protocol were determined. This method is suitable for high throughput analysis of sinigrin in Ethiopian mustard seed and seed fractions.     

Sea buckthorn berries: A potential source of valuable nutrients for nutraceuticals and cosmoceuticals

Sea buckthorn (Hippopha? rhamnoides L.), an ancient crop with modern virtues has recently gained worldwide attention, mainly for its nutritional and medicinal value as the berries contain different kinds of nutrients and bioactive compounds including vitamins, fatty acids, free amino acids and elemental components. This review briefly summarises the current literature and discusses its potential as a crop and its post harvest processing. The available compositional data regarding sea buckthorn berries is tabulated to produce a comprehensive source of recent information on chemical and medicinally important constituents of different origin and varieties. The presence of valuable chemicals and nutritionally important constituents in sea buckthorn berries, and from the scientific knowledge of their importance, it is clear that sea buckthorn berry is one of the most important sources of these constituents, and should be used as alternative nutritional sources in the commercial market. Similarly in depth investigation on the effect of processing on the total nutrient content of sea buckthorn berries species growing in different agro-ecological regions needs to be carried out. Thus, several important knowledge gaps identified in this paper would give impetus to new academic and R&D activities, in turn generating innovative job profile in food and cosmoceutical industries.     

Changes in volatile compounds of pickled mustard tuber (Brassica juncea var. tsatsai) during the pickling process

This study was carried out to determine the changes of volatile compounds composition during pickled mustard tuber production. The samples were collected at different pickling stages from the traditional industry production way in Chongqing, China. Gas chromatography–mass spectrometry were performed after simultaneous distillation and extraction. The results showed that ITC (isothiocyanates) possessed the highest relative percentage area (RPA) 78.87%, followed by sulphide compounds with RPA of 14.48%. Main volatile compounds that determined were allyl ITC, dimethyl trisulphide, (2-isothiocyanatoethyl)-benzene, n-Hexadecanoic acid and linolenic acid ethyl ester, which were responsible for the hot and pungent flavour of pickled mustard tuber. The sulphides, acids, aldehydes, alcohols, phenols, esters, nitriles and heterocyclic compounds increase with pickling time but ITC increase at the first and second pickling stage, then start to decrease in the last pickling stage. It was also demonstrated that more than 60-day pickling time was necessary for the formation of the typical aroma notes.     

Amino acid composition,foaming, emulsifying properties and surface hydrophobicity of mustard protein isolate as affected by pH and NaCl

Amino acid composition, protein hydrophobicity, foaming and emulsifying properties of mustard protein isolate at pH 3, 5, 7 and in 0.05 and 0.1 m NaCl were studied. Glutamic (19.18 ± 0.30%) and aspartic (7.49 ± 0.11%) acids were the dominants. Foaming ability was enhanced by NaCl. Time to reach 75 mL foam was 23% higher in water than in NaCl. Drained volume after 10 min was concentration dependent and was the lowest in 0.05 and 0.1 m NaCl at protein concentration of 2.5% and 5%. The emulsifying properties were pH and concentration dependent, and the best results were obtained at pH 3, corresponding to the highest positive charge density of the protein surface. The highest emulsion stability (90.22 ± 3.52%) was obtained in 0.05 m NaCl and 5% protein concentration, whereas the lowest (63.00 ± 1.06%) was in water at all protein concentrations. Protein hydrophobicity was low and depended of pH but not of NaCl.     

Sandwich enzyme-linked immunosorbent assay (ELISA) for detection of mustard in foods

ABSTRACT:  Undeclared mustard residues in food products could trigger allergic reactions in mustard-allergic consumers. Our objective was to develop and validate a sandwich-type ELISA for the detection of mustard residues in foods. A mixture of yellow, brown, and oriental mustard seeds was used to immunize 3 rabbits and 1 sheep. Two mustard ELISAs were developed by utilizing the reciprocal combination of rabbit and sheep polyclonal antimustard sera as the capture and detector reagents. Binding was visualized by addition of rabbit antisheep or goat antirabbit IgG antibody labeled with alkaline phosphatase and subsequent addition of substrate. The optimized ELISAs have limits of quantification (LOQ) of 1 and 3 ppm (μg of ground, whole mustard seeds/mL) for the sheep capture and rabbit capture formats, respectively. Only rapeseed cross-reacted in the rabbit and sheep capture mustard ELISAs at a level equivalent to 12300 and 16900 ppm of mustard. The mean percent recovery for cooked frankfurters spiked with 0 to 1000 ppm mustard flour was 95.3%± 10.7%. A limited retail survey of 29 foods revealed that, of 15 samples having mustard declared on the ingredient list, 2 baked bean products contained no detectable mustard, possibly owing to a decrease in extractability and detectability of mustard proteins after subjecting to thermal processing. For the remaining 14 samples without mustard declared on the label, 3 samples contained detectable mustard, presumably due to the labeling of mustard as "spice" or inadvertent cross-contamination. This sandwich-type ELISA can serve as a powerful tool for food manufacturers and regulatory agencies to detect and quantify mustard residues in processed foods.     

固相萃取-超高效液相色谱法检测榨菜中氯吡苯脲的研究

建立了固相萃取-超高效液相色谱法定榨菜中氯吡苯脲的方法。样品匀浆后经乙腈提取,固相萃取柱净化后,在流动相为乙腈-纯水（体积比65∶35）、紫外检测波长为260 nm的色谱条件下进行分离检测。结果表明:丙基乙二胺PSA分散固相萃取柱对样品净化效果好,氯吡苯脲在0.1¹0.0μg/m L范围内线性关系良好,相关系数r=0.9993,方法检出限为0.03 mg/kg,试样在0.1¹.0 mg/kg添加水平下的平均回收率在96.3%¹03.2%之间,RSD值在0.4%².2%之间。结论:方法准确度较好,操作简单快捷,样品净化效果好,测定低限能满足限量要求。      

纤维素酶改性榨菜皮膳食纤维的理化性质的研究

采用纤维素酶对榨菜皮粗纤维进行改性,分析了在不同温度和p H条件下改性榨菜皮膳食纤维理化性质的变化。结果表明,改性纤维中水溶性膳食纤维含量增加了80.02%,不溶性膳食纤维含量下降9.76%;改性榨菜皮膳食纤维的持水力、吸水膨胀力及NO2-吸附能力均显著提高（p<0.01）;改性纤维阳离子交换能力与粗纤维差异显著（p<0.01）,并在60℃达到最大值0.657mmol/g;p H7时改性纤维胆固醇吸附能力比p H2时吸附能力强。形貌结构分析显示改性纤维粒径更小,更加疏松,有较大的空腔和裂缝,但主要成分及化学结构没有受到明显的影响。      

Purification and Biochemical Characterization of Peroxidase Isolated from White Cabbage (Brassica Oleracea var. capitata f. alba)

Peroxidase enzyme was purified for the first time from white cabbage (Brassica oleracea var. capitata f. alba) in a single step using affinity chromatography and some biochemical characteristics of the purified enzyme were determined. The peroxidase was purified 24.7-fold with an overall recovery of 4.3% and a specific activity of 964.5. The molecular weight of the purified peroxidase was approximately 73.2 kDa as calculated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and it showed maximum activity at pH 6.5 and 30°C. For the guaiacol substrate, the K_M and V_max values were found as 3.19 mM and 0.2 EU/mL, respectively. Additionally, the IC₅₀ and K_i values were determined as 0.517 and 0.994 ± 0.453 mM, respectively, for 4-aminobenzohydrazide. 4-amino benzohydrazide showed non-competitive inhibition.     

Effects of yellow mustard mucilage on functional and rheological properties of buckwheat and pea starches

The effects of yellow mustard mucilage (YMM) on the functional and rheological properties of buckwheat and pea starch were studied. Addition of YMM resulted in a marked increase of peak viscosity for both buckwheat and pea starches. Dynamic oscillation measurements showed that the storage modulus (G′), loss modulus (G″) and dynamic viscosity (η*) of buckwheat and pea starches were increased but tangent δ was decreased by addition of YMM. The gel textures of both starches were markedly changed by the presence of YMM, which resulted in an increase of hardness, adhesiveness and chewiness but a decrease of resilience. Differential scanning calorimetry showed that the presence of YMM slightly increased melting enthalpy (ΔH) and the phase transition temperature range (T_c–T_o) of buckwheat starch but these did not change much for pea starch. Addition of YMM–locust bean gum mixture (9:1) similarly increased the viscosity of buckwheat and pea starches but decreased gel hardness. The swelling powers of both starches and solubility of buckwheat starch were slightly decreased in the presence of YMM. Addition of YMM slowed the syneresis of buckwheat and pea starch gels.     

The use of glucosinolates for cultivar identification in swede,Brassica napus L var napobmssica (L) peterm

A quantitative study of the glucosinolates in the seed, cortex and medulla (peeled root) from nine cultivars (cvs) of swede, Brassica napus L var napobrassica (L) Peterm using high performance liquid chromatography was undertaken to see whether such characteristics could be used as a biochemical index of cultivar identity. All nine cultivars could be distinguished following an analysis of medulla glucosinolates, but the analysis of seed and cortex glucosinolates yielded no such useful information.     

Decomposition of sinigrin by methanol/ammonia/water treatment in model systems and mustard (Brassica nigra L.) seed meal

 Sinigrin (allylglucosinolate) was stored at 20  °C, 40  °C, and 60  °C in solutions containing 10% ammonia in 95% methanol (CH₃OH/NH₃/H₂O). The individual samples were analyzed for their contents of sinigrin, its decomposition product allyl isothiocyanate (AITC) and other reaction products. The major reaction products were allyl thiourea, methyl ester of N-allyl thiocarbamoyl acid and allyl cyanide. A newly identified decomposition product of sinigrin was ethylcyanide. Defatted Brassica nigra seed meal was treated by the CH₃OH/NH₃/H₂O mixture to simulate the procedure used for rape and mustard seed meal detoxification. suspensions of the meal in the above mixture of solvents were heated at 20  °C, 40  °C and 60  °C, respectively. The major reaction products were the same as those arising from sinigrin. Minor products identified were 4-hydroxybenzyl isothiocyanate formed from sinalbin and 2-hydroxy-butenyl cyanide which arises from progoitrin. In all cases, AITC was very rapidly decomposed. Mechanisms explaining sinigrin decomposition are presented and discussed. Received: 3 May 1999     

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.