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Brassica juncea mustard seed are used to make mustard paste or condiment. Mustard seed contains glucosinolates which are converted to isothiocyanates following cell disruption by the enzyme, myrosinase. Isothiocyanates are sulphur-containing compounds which give a pungent flavour to the mustard condiment. Three mustard seed cultivars from two seasons were processed into Dijon- and wholegrain-style mustard and glucosinolates and isothiocyanates analysed. Canadian cv. Centennial tended to contain higher glucosinolates compared with the French cv. AZ147 and Ukrainian cv. Chorniava. Conversion of the mustard seed into a wholegrain condiment had a lesser effect on total isothiocyanates and sinigrin content compared with the Dijon-style preparation. The Canadian mustard cultivars produced wholegrain-style mustard with higher total isothyocyantes and sinigrin compared with the French and Ukrainian cultivars. In summary, results herein suggest that Canadian mustard seed cvs. Centennial and Forge, and wholegrain processing may result in a condiment with greater bioactive composition.

The objective of this study is to compare the fatty acid composition of commercially available edible oils derived from certified organic and conventional agricultural methods. A total of 59 certified organic and 53 conventional oils were purchased from retail markets in Sydney, Australia. Organic and conventional products were matched for comparison according to the description of production methods, labelled total fat content, brand name (wherever possible), and country of origin. Total fat was extracted and the fatty acid composition of the oils was determined by gas chromatography. No consistent overall trend of difference in the fatty acid composition was observed between organic and conventional oils. Saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids were all significantly different between types of oil (P < 0.001 in all three), and each had significant interaction between type and production method (P = 0.002, P < 0.001 and P < 0.001, respectively) indicating that organic and conventional oils differed in these components in an inconsistent fashion. Despite this, there were large differences particularly between MUFA and PUFA components in specific pairs of oils, especially in sunflower and mustard seed oils. The absence of an overall difference in the fatty acid composition of organic and conventional oils does not support the tenet that organic foods are of a higher nutritional quality than their conventional counterparts.

Myrosinase, an enzyme found in all glucosinolate containing plants, is responsible for the conversion of glucosinolates into products that can be beneficial to our health. In this study, the temperature and pressure stability of partially purified myrosinase from mustard seeds was studied in a model system. Temperature inactivation started at 60 °C and the inactivation kinetics were studied in detail between 65 and 75 °C. Inactivation could be described by the consecutive step or the biphasic model. Mustard seed myrosinase was quite pressure stable, as its activity was retained after pressure treatments up to 600 MPa combined with temperatures up to 60 °C. At low pressures there was an antagonistic effect between pressure and thermal treatment, since myrosinase activity was retained after treatments at 70 °C up to 300 MPa. This pressure stability indicates that pressure treatment may be a valuable alternative for thermal treatment if one wants to retain myrosinase activity.

This study investigates the effects of temperature and pressure on inactivation of myrosinase extracted from black, brown and yellow mustard seeds. Brown mustard had higher myrosinase activity (2.75 un/mL) than black (1.50 un/mL) and yellow mustard (0.63 un/mL). The extent of enzyme inactivation increased with pressure (600-800 MPa) and temperature (30-70° C) for all the mustard seeds. However, at combinations of lower pressures (200-400 MPa) and high temperatures (60-80 °C), there was less inactivation. For example, application of 300 MPa and 70 °C for 10 min retained 20%, 80% and 65% activity in yellow, black and brown mustard, respectively, whereas the corresponding activity retentions when applying only heat (70° C, 10 min) were 0%, 59% and 35%. Thus, application of moderate pressures (200-400 MPa) can potentially be used to retain myrosinase activity needed for subsequent glucosinolate hydrolysis.

In this study, the essential oil from mustard seed was isolated by simultaneous steam distillation and extraction (SDE) and analyzed by gas chromatography-mass spectrometry (GC-MS). Fourteen components were identified in the mustard seed essential oil with allyl isothiocyanate being the main component (71.06%). The essential oil has a broad-spectrum antimicrobial activity with inhibition zones and MIC values in the range of 9.68-15.57 mm and 128-512 μg/mL respectively. The essential oil was subsequently encapsulated in complex coacervation microcapsules with genipin, a natural water-soluble cross-linker. The optimum parameters for the hardening effectiveness of the genipin-hardened essential oil microcapsules were 8h at 40°C and pH 10.0 with a genipin concentration of 0.075 g/g gelatin. The genipin-hardened microcapsules had a particle size of mainly 5-10 μm and strong chemistry stability which is potential for its application in food preservation.

The mineral fraction of six mustards (whole seed or flour) and 40 mustard sauces has been determined by atomic absorption spectroscopy. Mineral macroelements (Na, K, Ca, Mg) and microelements (Cu, Fe, Mn, Zn) were studied in order to characterize these products in relation to their base seed: mustard. Potassium, calcium and magnesium were the major macroelements in mustard seeds, while higher levels of sodium were found in mustard sauces. By means of correlation and discriminant analysis, the samples have been grouped and classified. It is shown that all components of the mineral fraction are useful parameters for quality control analysis of mustard sauces.

Three different mustard globulin (isoforms), purified and isolated, using three extraction solutions (differing in ionic strength) were studied for structural integrity as a function of pH. Evidence of a molten globule state (a reversible intermediary state between the native and fully denatured forms) was obtained. This phenomenon may ultimately prove to be important in the translocation of these proteins across biological membranes at the time of their biosynthesis. Circular dichroism, hydrophobic probe, fluorescence spectral scans and differential scanning calorimetry were used to study this phenomenon. Secondary and tertiary structures (circular dichroism (CD) data) were found to be similar for globulins from higher ionic strength extractions, but different from the globulin from distilled water extraction; however, for all three isoforms, little change in secondary structure fractions as a function of pH was observed. Changes in tertiary structure (near-UV CD and intrinsic fluorescence data) as a function of pH were observed for all three globulin isoforms with greatest changes in tertiary structure being seen in the acidic pH range, i.e. 3–5. In contrast, all globulins were shown to undergo the least conformational change in the pH range of 6–9.

Phosphatidylethanolamine and glucose were added to the degummed mustard seed oil (20.16μmol/g oil) to prepare blank oil (O), glucose added oil (OG), phosphatidylethanolamine added oil (OP), and both phosphatidylethanolamine and glucose added oil (OPG). These oils were heated at 160°C for 10min. Absorbance and fluorescence measurement confirmed the occurrence of Maillard type reactions. During oil incubation (both at 40 and 104°C), the heated OP and OPG oils showed the highest oxidative stability. Moreover, the degradations of tocols in these oils were 16-17% (72h at 104°C) and 7-20% (53days at 40°C), while that in other oils (O and OG) were 56-65% (24h at 104°C) and 20-57% (19days at 40°C), respectively. Maillard type reaction products of phosphatidylethanolamine showed potent antioxidant activity. Some of the reaction products such as Amadori product, phosphatidylethanolamine-linked pyrrolecarbaldehyde and 2,3-dihydro-1H-imidazo[1,2-α]pyridine-4-ylium derivatives were identified using LC-TOF MS analysis.

Amino acid analyses in seed of local Ethiopian mustard ( Brassica carinata Braun) show high levels of (in g/100 g protein) glutamic acid (20·7), arginine (10·8) and proline (6·5), while histidine (2·9) and tyrosine (2·5) were lowest. Variation between selections existed. ‘Mulio giant’ has consistently high values while ‘CRRS-5’ and ‘Figiri white’ were lower. Mean amino acid contents in local Ethiopian mustard were comparable to that of rape ‘Double-zero’. Crude protein in Ethiopian mustard seed (47·6%) was higher than in ‘Double-zero’ (38·7%). While erucic acid (40·6%) was a major fatty acid in Ethipian mustard and to a lesser extent oleic, linoleic and linolenic acids, ‘Double-zero’ showed the opposite trend (despite similarities in iodine and saponification numbers). Ethiopian mustards had higher glucosinolates (79·7 μmoles/g), mainly sinigrin (77·2 μmoles/g), and lower gluconapin and progoitrin than ‘Double-zero’, whose glucosinolate content was 10 μmoles/g. Although ‘Figiri white’ had no gluconapin, it had the highest sinigrin (99 μmoles/g) compared to 58 μmoles/g in ‘Mulio giant’.