Evaluation of the QuEChERS method for the determination of phenolic compounds in yellow (Brassica alba), brown (Brassica juncea), and black (Brassica nigra) mustard seeds.

Studies about the phenolic composition of yellow (Brassica alba), brown (Brassica juncea), and black (Brassica nigra) mustard seeds are still scarce in the literature. Hence, this study describes, for the first time, the use of the QuEChERS extraction method followed by UHPLC-MS/MS analysis for phenolic compound determination in the seeds of these mustard species. Under the optimized extraction and analysis conditions, twenty-one phenolic compounds were evaluated. Six, eleven, and seven were found in B. alba, B. juncea, and B. nigra seeds, respectively. The most abundant phenolic compound was sinapic acid, which was found in amounts ranging from 44 to 82 times higher than the other major compounds found in the mustard seeds, ferulic, 4-hydroxybenzoic and protocatechuic acids. Overall, these results are an important contribution to the characterization of the phenolic composition of the three in natura mustard seeds species, and support future reliable phenolic compounds determination with the QuEChERS method.

Antimicrobial efficacy of white mustard essential oil and carvacrol against Salmonella in refrigerated ground chicken.

Essential oils in combination with other antimicrobials can be added to food products to reduce the levels of target microbes lower than the infectious dose required to cause human illness. The purpose of this study was to investigate the antimicrobial efficacy of white mustard essential oil (WMEO) and carvacrol against Salmonella in ground chicken stored at 4 and 10°C. At 4°C, 0.75% WMEO +0.1% carvacrol treatment had significantly lower (P < 0.05) Salmonella at the end of 12-day storage than the control, which contained no antimicrobials. A combination of 0.75% WMEO and 0.01% carvacrol had a bacteriostatic effect against Salmonella in ground chicken samples stored at 10°C for 7 D. The application of the antimicrobials controlled the growth of Salmonella by delaying the exponential phase at temperature abuse and reducing levels of Salmonella to less than the positive control at 4°C. The use of WMEO and carvacrol shows potential in reducing levels of Salmonella under refrigerated conditions and controlling its growth under temperature abuse conditions in raw poultry products. Further research is needed to investigate the toxicity of the compounds and the most efficient way to apply it to a food product to maximize antimicrobial activity.

Inactivation of Thioglucosidase from Sinapis alba (White Mustard) Seed by Metal Salts.

The glucosinolates which are specialized plant metabolites of Brassica vegetables are prone to hydrolysis catalyzed by an endogenous enzyme myrosinase (thioglycoside hydrolase, thioglucosidase) that exists in Brassica plant tissue causing volatile isothiocyanates release. Currently existing literature data on the inactivation of myrosinase is insufficient in particular for use in the analysis of volatile and odor compounds in vegetables rich in glucosinolates. In this study, the impact of different metal salts in effective inactivation of enzyme activity was investigated by solid-phase microextraction (SPME) and GC/MS system in aqueous samples and kohlrabi matrix. A saturated solution of calcium chloride which is commonly used to stop enzyme activity in plant tissue inactivates the myrosinase-glucosinolate system. However, even without the participation of myrosinase, it changes the reaction pathway towards nitrile formation. The model experiment shows that optimum efficiency in inhibition of the enzyme system shows iron(III) ions, silver ions, and anhydride sodium sulfate resulting in no volatile products derived from glucosinolates. However, in the kohlrabi matrix, the strongest enzyme inhibition effect was observed for silver salt resulting in no volatile products, also both anhydrous Na2SO4 and saturated CaCl2 solution seem to be useful inhibitors in flavor studies.

Semen Brassicae reduces thoracic aortic remodeling, inflammation, and oxidative damage in spontaneously hypertensive rats.

BACKGROUND: This study aimed to evaluate the role of Semen Brassicae, a common Traditional Chinese Medicine, in the treatment of hypertension. METHODS: Spontaneously hypertensive rats (SHRs) were divided into five groups and were gavaged with either distilled water, water-decocted solution from Semen Brassicae (0.5, 1 or 2 g/kg), or nifedipine (2.7 mg/kg). Normal rats gavaged with distilled water were used as a control. Systolic (SBP) and diastolic blood pressure (DBP) were measured using a non-invasive method. After 8 weeks of administration, all animals were anesthetized. Abdominal aortic serum was collected to measure serum factors; the thoracic aorta was collected for hematoxylin and eosin staining and western blot analysis. RESULTS: Both SBP and DBP were significantly decreased after Semen Brassicae treatment. Endothelin-1 and angiotensin II levels in abdominal aortic serum, as well as the levels of inflammatory factors interleukin (IL)-1ß, IL-6, and tumor necrosis factor-alpha, were significantly decreased after Semen Brassicae treatment. The wall thickness of the thoracic aorta was significantly reduced after Semen Brassicae treatment. Nitric oxide level and the activity of superoxide dismutase and glutathione peroxidase were significantly increased, and malondialdehyde level was significantly decreased in the abdominal aortic serum after Semen Brassicae treatment. Semen Brassicae treatment increased the levels of peroxisome proliferator-activated receptor gamma and IκB-α and decreased the levels of intercellular adhesion molecule 1, monocyte chemoattractant protein-1, von Willebrand factor, p-IκB-α and p-p65 NF-κB. CONCLUSIONS: In conclusion, water-decocted solution from Semen Brassicae can decrease blood pressure, improve vascular remodeling, and attenuate oxidative stress and inflammation in SHRs.

Simultaneous Analysis of Glucosinolates and Isothiocyanates by Reversed-Phase Ultra-High-Performance Liquid Chromatography-Electron Spray Ionization-Tandem Mass Spectrometry.

A new method to simultaneously analyze various glucosinolates (GSLs) and isothiocyanates (ITCs) by reversed-phase ultra-high-performance liquid chromatography-electron spray ionization-tandem mass spectrometry has been developed and validated for 14 GSLs and 15 ITCs. It involved derivatization of ITCs with N-acetyl-l-cysteine (NAC). The limits of detection were 0.4-1.6 µM for GSLs and 0.9-2.6 µM for NAC-ITCs. The analysis of Sinapis alba, Brassica napus, and Brassica juncea extracts spiked with 14 GSLs and 15 ITCs indicated that the method generally had good intraday (≤10% RSD) and interday precisions (≤16% RSD). Recovery of the method was unaffected by the extracts and within 71-110% for GSLs and 66-122% for NAC-ITCs. The method was able to monitor the enzymatic hydrolysis of standard GSLs to ITCs in mixtures. Furthermore, GSLs and ITCs were simultaneously determined in Brassicaceae plant extracts before and after myrosinase treatment. This method can be applied to further investigate the enzymatic conversion of GSLs to ITCs in complex mixtures.

Glutamine as an Ammonia Donor in Catabolism of the Glucosinolate, Sinalbin, in Biosynthesis of 4-Hydroxybenzylamine.

Amines synthesized by plants may be considered a dietary source of bioactive compounds, which are of interest due to possible health promoting effects. Developing Sinapis alba sprouts are known to produce 4-hydroxybenzylamine, but the reaction mechanism has not yet been established. We propose here a suggested metabolic pathway for the formation of 4-hydroxybenzylamine in S. alba plants. The catabolic sequence starts with a reaction between l-glutamine (Gln) as ammonia donor and 4-hydroxybenzyl carbocation, the enzymatic catalyzed hydrolysis product from sinalbin (4-hydroxybenzylglucosinolate). The suggested reactions are compared with alternative plant metabolic reactions used in the biosynthesis of biogenic amines.

The effect of drying on the native tocopherol and phytosterol content of Sinapis alba L. seeds.

BACKGROUND: Postharvest processing, including drying, has a significant effect on the processability of oil crop seeds. High drying air temperature may significantly affect the levels of bioactive compounds in plant raw materials. We decided to investigate the subject given the lack of data on the drying of mustard seeds. The aim was to determine the effect of drying temperature on free fatty acid, phytosterol and tocopherol levels in the oil obtained from white mustard seeds. Seeds were dried in a thin layer at 40, 60, 80, 100, 120 and 140 °C. Changes in phytosterol levels were assessed using gas chromatography-mass spectrometry and changes in tocopherol levels by high-performance liquid chromatography. RESULTS: The analysis showed that, upon completion of air drying at 40-100 °C, losses of sterols did not exceed 5%, while upon completion of drying at 120 °C and 140 °C these losses amounted to 17-50%. Our investigation also showed that during drying of white mustard seed the total tocopherol levels increased, and the higher the drying temperature, the greater the increment. In seeds air-dried at 120 °C and 140 °C, the increase in tocopherol amounted to 7-9%. CONCLUSION: We also showed that the temperature of the drying agent significantly affects the tocopherol and phytosterol levels. It was found that a maximum temperature of 100 °C provides optimal drying conditions for mustard seeds. Principal component analysis identified two subgroups of oils obtained from seeds dried at 120 °C and 140 °C, which differed considerably from the other samples in terms of their bioactive component contents. © 2019 Society of Chemical Industry.

Evaluating the Antimicrobial Efficacy of White Mustard Essential Oil Alone and in Combination with Thymol and Carvacrol against Salmonella.

It is estimated that nontyphoidal Salmonella causes approximately 1 million illnesses and 378 deaths per year in the United States. Reduction of Salmonella-related foodborne infections can be achieved through application of food antimicrobials. Essential oils in combination with other antimicrobials can be added to food products to reduce the levels of the organism below the infectious dose for healthy individuals. The purpose of this study was to investigate the antimicrobial efficacy of white mustard essential oil (WMEO) against serovars of Salmonella and its potential to be used with carvacrol or thymol to control Salmonella. Results showed that WMEO at the highest concentration of 0.84% (v/v) compared with the positive control had approximately a 6- to 7-log reduction for all serovars. It was found that no difference in susceptibility existed among the serovars tested (P > 0.05). In addition, the MICs were determined to be 0.5, 0.02, and 0.02% for WMEO, carvacrol, and thymol, respectively, against Salmonella Typhimurium. The fractional inhibitory concentration index was calculated. A score of 1 indicated an additive effect occurred when WMEO was combined with thymol or carvacrol. Combining WMEO with carvacrol or thymol indicated that the concentration of individual essential oils needed to inhibit Salmonella can be reduced using these combinations and warrants further study to determine potential use in controlling Salmonella in commercial food products.

Mechanisms of white mustard seed (Sinapis alba L.) volatile oils as transdermal penetration enhancers.

We investigated the transdermal drug permeation enhancement properties and associated mechanisms of white mustard (Sinapis alba L.) seed volatile oil (SVO). Using gas chromatography-mass spectrometry, we showed that SVO was composed primarily of allylisothiocyanate and isothiocyanatocyclopropane. Compared with azone, SVO had better penetration-enhancing effects on three model drugs (5-Fluorouracil, Osthole, and Paeonol), with each having different oil-water partition coefficients. Histopathology showed that SVO did not induce skin irritation when the concentration was lower than 2% (v/v), and it induced less irritation than azone. According to attenuated total reflection-Fourier transform infrared spectroscopy and transmission electron microscopy, SVO induced skin lipid structural disorder and increased the distance between the stratum corneum, which is beneficial to the penetration of drugs. Cellular experiments showed that SVO inhibited Ca2+-ATPase activity, increased intracellular Ca2+ concentration, and changed the membrane potential in HaCaT cells, which promoted drug transfer into the skin. Our findings reveal that SVO is a safe and efficient natural product that has great potential as skin penetration enhancer.

Recovery of phenolic compounds from the by-products of yellow mustard protein isolation.

Nanofiltration (NF) (MWCO 150-300 Da) was evaluated for the recovery of phenolic compounds from the wastewater from the production of yellow mustard protein isolates. Rejection coefficients of 0.70 and 0.87 and transmembrane fluxes of 51.3 L/hm2 and 28.8 L/hm2 were observed under alkaline and acidic conditions, respectively. At low pH, 77% of the phenolic compounds fed to the process were recovered in the retentate. Combination of diafiltration (DF) with NF was beneficial only when processing at low pH. The permeate from the NF process a contained <100 ppm total phenolics, which suggests the possibility of recycling these effluents in the production of yellow mustard protein isolates. p-Hydroxybenzoic acid was the major phenolic compound found both in the waste effluent and in the products of NF processing. Sinapic acid constituted a secondary fraction, and derivatives of quercetin and kaempferol were also detected.

Mineral content in mustard leaves according to the cooking method.

This work evaluated the influence of the cooking methods (cooked in a water bath, in a stove, and in a microwave oven) on the mineral composition of mustard leaves (Sinapis alba). So, raw and cooked samples were digested and afterward the elements calcium, magnesium, potassium, sodium, iron, zinc, phosphor, barium and sulfur were determined using inductively coupled plasma optical emission spectrometry (ICP OES). The experimental work involved a set of five samples from different locations, processed in triplicates. The results were evaluated employing Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA) and Linear Discriminate Analysis (LDA). All techniques showed that the mineral content of the raw and cooked samples in a water bath is different from the samples cooked in stove and microwave oven. Especially for potassium, whose content is strictly controlled for chronic renal patients, this study showed that cooking using microwave oven has the greatest efficiency for reduction.

Comparison of the anti-inflammatory effects of Sinapis alba and Brassica juncea in mouse models of inflammation.

BACKGROUND: Sinapis Semen is derived from the dried mature seeds of Sinapis alba L. or Brassica juncea (L.) Czern. et Coss. Traditionally, the seeds from S. alba are called "White Sinapis Semen" while those from B. juncea are called "Yellow Sinapis Semen". PURPOSE: The present study aimed to compare the chemical composition and the anti-inflammatory effects of 50% aqueous ethanol extracts of the White Sinapis Semen (EWSS) and Yellow Sinapis Semen (EYSS) using both acute (12-O-tetradecanoylphorbol-acetate (TPA)- and arachidonic acid (AA)-induced mouse ear edema) and chronic (multiple applications of croton oil (CO)) inflammatory models. METHODS: The anti-inflammatory effects of EWSS and EYSS were determined by measuring the ear thickness and myeloperoxidase (MPO) activity. The anti-inflammatory mechanism was explored by measuring the protein and mRNA levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß and IL-6 in the ear of the TPA-treated mice. RESULTS: The results showed that both EWSS and EYSS significantly decreased the ear thickness in both the TPA- and AA-induced acute models, as well as in the CO-induced chronic model. In addition, EWSS and EYSS could markedly inhibit the MPO activity in the ears of TPA-, AA- or CO-treated mice. Moreover, EWSS and EYSS also remarkably inhibited the protein and mRNA levels of TNF-α and IL-6 in the ears of TPA-treated mice. Comparatively, EWSS exerted more potent anti-inflammatory effect than that of EYSS. CONCLUSION: Our results revealed that both EWSS and EYSS are effective anti-inflammatory agents against acute and chronic inflammatory processes, and EWSS possess more potent anti-inflammatory effect than EYSS. The anti-inflammatory effect of the two herbs may be mediated, at least in part, by suppressing the mRNA expression of a panel of inflammatory mediators including TNF-α, IL-6 and IL-1ß.

Antiproliferative, Proapoptotic, Antioxidant and Antimicrobial Effects of Sinapis nigra L. and Sinapis alba L. Extracts.

High Brassicaceae consumption reduces the risk of developing several cancer types, probably due to high levels of glucosinolates. Extracts from Sinapis nigra L. (S. nigra) and Sinapis alba L. (S. alba) have been obtained from leaves and seeds under different conditions using ethanol/water mixtures because their glucosinolates are well accepted by the food industry. The EtOH/H2O 8:2 mixture gives better yields in glucosinolate amounts from ground seeds, mainly, sinalbin in S. alba and sinigrin in S. nigra. The highest antiproliferative activity in both non-tumor and tumor cell lines was induced by S. alba seeds extract. To evaluate whether the effect of Sinapis species (spp) was only due to glucosinolate content or whether it was influenced by the extracts' complexity, cells were treated with extracts or glucosinolates, in the presence of myrosinase. Pure sinigrin did not modify cell proliferation, while pure sinalbin was less effective than the extract. The addition of myrosinase increased the antiproliferative effects of the S. nigra extract and sinigrin. Antiproliferative activity was correlated to Mitogen-Activated Protein Kinases modulation, which was cell and extract-dependent. Cell-cycle analysis evidenced a proapoptotic effect of S. alba on both tumor cell lines and of S. nigra only on HCT 116. Both extracts showed good antimicrobial activity in disc diffusion tests and on ready-to-eat fresh salad. These results underline the potential effects of Sinapis spp in chemoprevention and food preservation.

Constant Isothiocyanate-Release Potentials across Biofumigant Seeding Rates.

Biofumigation is an integrated pest-management method involving the mulching of a glucosinolate-containing cover crop into a field in order to generate toxic isothiocyanates (ITCs), which are effective soil-borne-pest-control compounds. Variation in biofumigation efficacy demonstrates a need to better understand the factors affecting pest-control outcomes and develop best practices for choosing biofumigants, growth conditions, and mulching methods that allow the greatest potential isothiocyanate release. We measured the glucosinolate concentrations of six different commercial varieties of three biofumigant plant species: Brassica juncea (ISCI99, Vitasso, and Scala) Raphanus sativus (Diablo and Bento), and Sinapis alba (Ida Gold). The plants were grown in the range of commercially appropriate seeding rates and sampled at three growth stages (early development, mature, and 50% flowering). Within biofumigant species, the highest ITC-release potentials were achieved with B. juncea cv. ISCI99 and R. sativus cv. Bento. The highest ITC-release potential occurred at the 50% flowering growth stage across the species. The seeding rate had a minor impact on the ITC-release potential of R. sativus but had no significant effects on the ITC-release potentials of the B. juncea or S. alba cultivars.

Transcriptional responses to short-term and long-term host plant experience and parasite load in an oligophagous beetle.

Oligophagous herbivores must adjust their enzymatic machinery to the different host plant species they consume. If different hosts are used from one generation to the next, adaptation may be highly plastic, while if a single host is used over several generations, there may be a longer-term response due to natural selection. Using an experimental evolutionary approach, we investigated effects of long-term experience vs. short-term responses to different host plants in the oligophagous mustard leaf beetle Phaedon cochleariae. After 26 generations of continuous feeding on either Brassica rapa, Nasturtium officinale or Sinapis alba, freshly hatched larvae were kept on these plants or moved to one of the other host plants for ten days. Global transcriptional patterns as shown by microarrays revealed that between 1% and 16.1% of all 25,227 putative genes were differentially expressed in these treatments in comparison with the control line constantly feeding on B. rapa. A shift back from S. alba to B. rapa caused the largest changes in gene transcription and may thus represent the harshest conditions. Infection rates with a gregarine parasite were intermediate in all lines that were constantly kept on one host, but much lower or higher when short-term shifts to other host plants occurred. In conclusion, transcriptional plasticity in genes related to metabolism, digestion and general cellular processes plays a key role in long- and short-term responses of the beetle to changing host plant conditions, whereby the specific conditions also affect the interactions between the beetle host and its gregarine parasite.

Susceptibility of herpes simplex virus type 1 to monoterpenes thymol, carvacrol, p-cymene and essential oils of Sinapis arvensis L., Lallemantia royleana Benth. and Pulicaria vulgaris Gaertn.

In recent years, with increased the prevalence of viral infections and having no specific for  their treatment  and also the continuous appearance of resistant viral strains, the finding of novel antiviral agents is necessary. In this study, monoterpenes of thymol, carvacrol, p-cymene and essential oils from Sinapis arvensis L., Lallemantia royleana Benth. and Pulicaria vulgaris Gaertn. were screened for their inhibitory effect against herpes simplex virus type 1 (HSV-1) in vitro on Vero cell line CCL-81-ATCC using a plaque reduction assay. The antiviral activity of three monoterpenes (thymol, carvacrol and p-cymene) and three essential oils were evaluated by cytotoxicity assay, direct plaque test. In addition, the modes of antiviral action of these compounds were investigated during the viral infection cycle. Results showed that the inhibitory concentrations (IC50) were determined at 0.002%, 0.037%, >0.1%, 0.035%, 0.018% and 0.001% for thymol, carvacrol, p-cymene, S. arvensis oil, L. royleana oil and P. vulgaris oil, respectively. A manifestly dose-dependent virucidal activity against HSV-1 could be exhibited for compounds tested. In order to determine the mode of the inhibitory effect, compounds were added at different stages during the viral infection cycle. At maximum noncytotoxic concentrations of the compounds, plaque formation was significantly reduced by more than 80% when HSV-1 was preincubated with p-cymene. However, no inhibitory effect could be observed when the compounds were added to the cells prior to infection with HSV-1 or after the adsorption period. CONCLUSION: These results indicate that compounds affected HSV-1 mostly before adsorption and might interact with the viral envelope. Thymol exhibited a high selectivity index and seems to be a promising candidate for topical therapeutic application as antiviral agent for treatment of herpetic infections.

Oviposition Preference for Young Plants by the Large Cabbage Butterfly (Pieris brassicae ) Does not Strongly Correlate with Caterpillar Performance.

The effects of temporal variation in the quality of short-lived annual plants on oviposition preference and larval performance of insect herbivores has thus far received little attention. This study examines the effects of plant age on female oviposition preference and offspring performance in the large cabbage white butterfly Pieris brassicae. Adult female butterflies lay variable clusters of eggs on the underside of short-lived annual species in the family Brassicaceae, including the short-lived annuals Brassica nigra and Sinapis arvensis, which are important food plants for P. brassicae in The Netherlands. Here, we compared oviposition preference and larval performance of P. brassicae on three age classes (young, mature, and pre-senescing) of B. nigra and S. arvensis plants. Oviposition preference of P. brassicae declined with plant age in both plant species. Whereas larvae performed similarly on all three age classes in B. nigra, preference and performance were weakly correlated in S. arvensis. Analysis of primary (sugars and amino acids) and secondary (glucosinolates) chemistry in the plant shoots revealed that differences in their quality and quantity were more pronounced with respect to tissue type (leaves vs. flowers) than among different developmental stages of both plant species. Butterflies of P. brassicae may prefer younger and smaller plants for oviposition anticipating that future plant growth and size is optimally synchronized with the final larval instar, which contributes >80% of larval growth before pupation.

HPLC-based kinetics assay facilitates analysis of systems with multiple reaction products and thermal enzyme denaturation.

Glucosinolates are plant secondary metabolites abundant in Brassica vegetables that are substrates for the enzyme myrosinase, a thioglucoside hydrolase. Enzyme-mediated hydrolysis of glucosinolates forms several organic products, including isothiocyanates (ITCs) that have been explored for their beneficial effects in humans. Myrosinase has been shown to be tolerant of non-natural glucosinolates, such as 2,2-diphenylethyl glucosinolate, and can facilitate their conversion to non-natural ITCs, some of which are leads for drug development. An HPLC-based method capable of analyzing this transformation for non-natural systems has been described. This current study describes (1) the Michaelis-Menten characterization of 2,2-diphenyethyl glucosinolate and (2) a parallel evaluation of this analogue and the natural analogue glucotropaeolin to evaluate effects of pH and temperature on rates of hydrolysis and product(s) formed. Methods described in this study provide the ability to simultaneously and independently analyze the kinetics of multiple reaction components. An unintended outcome of this work was the development of a modified Lambert W(x) which includes a parameter to account for the thermal denaturation of enzyme. The results of this study demonstrate that the action of Sinapis alba myrosinase on natural and non-natural glucosinolates is consistent under the explored range of experimental conditions and in relation to previous accounts.

Cylindrospermopsin induces biochemical changes leading to programmed cell death in plants.

In the present study we provide cytological and biochemical evidence that the cyanotoxin cylindrospermopsin (CYN) induces programmed cell death (PCD) symptoms in two model vascular plants: the dicot white mustard (Sinapis alba) and the monocot common reed (Phragmites australis). Cytological data include chromatin fragmentation and the increase of the ratio of TUNEL-positive cells in roots, the latter being detected in both model systems studied. The strongest biochemical evidence is the elevation of the activity of several single-stranded DNA preferring nucleases-among them enzymes active at both acidic and alkaline conditions and are probably directly related to DNA breaks occurring at the initial stages of plant PCD: 80 kDa nucleases and a 26 kDa nuclease, both having dual (single- and double-stranded nucleic acid) specificity. Moreover, the total protease activity and in particular, a 53-56 kDa alkaline protease activity increases. This protease could be inhibited by PMSF, thus regarded as serine protease. Serine proteases are detected in all organs of Brassicaceae (Arabidopsis) having importance in differentiation of specialized plant tissue through PCD, in protein degradation/processing during early germination and defense mechanisms induced by a variety of biotic and abiotic stresses. However, knowledge of the physiological roles of these proteases and nucleases in PCD still needs further research. It is concluded that CYN treatment induces chromatin fragmentation and PCD in plant cells by activating specific nucleases and proteases. CYN is proposed to be a suitable molecule to study the mechanism of plant apoptosis.

Elucidation of Thermally Induced Changes in Key Odorants of White Mustard Seeds (Sinapis alba L.) and Rapeseeds (Brassica napus L.) Using Molecular Sensory Science.

Heat-processing of Brassica seeds led to the formation of a characteristic pleasant popcorn-like and coffee-like aroma impression compared to the mainly pea-like aroma of the corresponding raw seeds. To analyze this phenomenon on a molecular basis, raw and roasted white mustard seeds and rapeseeds were analyzed using the sensomics approach. Application of comparative aroma extract dilution analysis (cAEDA) and identification experiments to raw and roasted (140 °C, 30 min) mustard seeds revealed 36 odorants (all identified for the first time) and 47 odorants (41 newly identified), respectively. Twenty-seven odorants in raw and 43 odorants in roasted (140 °C, 60 min) rapeseeds were found, which were all described for the first time. Among the set of volatiles, 2-isopropyl-3-methoxypyrazine (earthy, pea-like) and 4-ethenyl-2-methoxyphenol (clove-like, smoky) showed high FD factors in both raw seeds. 4-Hydroxy-2,5-dimethylfuran-3(2H)-one (caramel-like), 2,3-diethyl-5-methylpyrazine (earthy), dimethyl trisulfide (cabbage-like), and 2-acetyl-1-pyrroline (popcorn-like) were present at high flavor dilution (FD) factors in both roasted Brassica seeds. Odorants, differing in cAEDA or showing high FD factors in at least one of the seeds, were quantitated by stable isotope dilution analysis (SIDA), followed by the calculation of odor activity values (OAVs) using odor thresholds determined in refined sunflower oil. Eighteen aroma compounds in raw and 28 in roasted mustard seeds as well as 14 in raw and 25 in roasted rapeseeds revealed OAVs ≥1. All four aroma recombinates, prepared by mixing the odorants showing OAVs ≥1 in their naturally occurring concentrations, showed a very good similarity with the original seeds and, thus, proved the successful characterization of the respective key odorants.