Taste and Flavor Perceptions of Glucosinolates, Isothiocyanates, and Related Compounds

Non-enzymatic degradation of aliphatic Brassicaceae isothiocyanates during aqueous heat treatment

Glucosinolate-derived isothiocyanates are valuable for human health as they exert health promoting effects. As thermal food processing could affect their levels in a structure dependent way, the stability and reactivity of 12 Brassicaceae isothiocyanates during aqueous heating at 100 °C and pH 5-8 were investigated. The formation of their corresponding amines and N,N'-dialk(en)yl thioureas was quantified. Further, the potential to form odor active compounds was investigated by HRGC-MS-olfactometry. A strong structure-reactivity relationship was found and shorter side chains and electron withdrawing groups increase the reactivity of isothiocyanates. 3-(Methylsulfonyl)-propyl isothiocyanate was least stable. The main products are the corresponding amines (up to 69% recovery) and formation of N,N'-dialk(en)yl thioureas is only relevant at neutral to basic pH values. Apart from allyl isothiocyanate also 3-(methylthio)propyl isothiocyanate is precursor to many sulfur-containing odor active compounds. Thus, the isothiocyanate-structure affects their levels but also contributes to the flavor of boiled Brassicaceae vegetables.

Metabolomic and Transcriptomic Profiles in Diverse Brassica oleracea Crops Provide Insights into the Genetic Regulation of Glucosinolate Profiles

Glucosinolates (GSLs) are plant secondary metabolites commonly found in the cruciferous vegetables of the Brassicaceae family, offering health benefits to humans and defense against pathogens and pests to plants. In this study, we investigated 23 GSL compounds' relative abundance in four tissues of five different Brassica oleracea morphotypes. Using the five corresponding high-quality B. oleracea genome assemblies, we identified 183 GSL-related genes and analyzed their expression with mRNA-Seq data. GSL abundance and composition varied strongly, among both tissues and morphotypes, accompanied by different gene expression patterns. Interestingly, broccoli exhibited a nonfunctional AOP2 gene due to a conserved 2OG-FeII_Oxy domain loss, explaining the unique accumulation of two health-promoting GSLs. Additionally, transposable element (TE) insertions were found to affect the gene structure of MAM3 genes. Our findings deepen the understanding of GSL variation and genetic regulation in B. oleracea morphotypes, providing valuable insights for breeding with tailored GSL profiles in these crops.

Turning glucosinolate into allelopathic fate: investigating allyl isothiocyanate variability and nitrile formation in eco-friendly Brassica juncea from South Korea

Leaf mustard (Brassica juncea L.) is explored for its biofumigant properties, derived from its secondary metabolites, particularly allyl isothiocyanate (AITC), produced during the enzymatic breakdown of glucosinolates like sinigrin. The research examines eight leaf mustard cultivars developed in Yeosu city, South Korea, focusing on their genetic characteristics, AITC concentration and nitriles formation rates from glucosinolates. Results indicate that the allelopathic effects, largely dependent on AITC concentration and enzymatic activity, vary across cultivar. Sinigrin and AITC constitute 79% and 36%, respectively, of glucosinolate and its hydrolysis products. The cultivar 'Nuttongii' demonstrates significant potential for inhibiting weeds, exhibiting the highest AITC concentration at 27.47 ± 6.46 µmole g-1 These outcomes highlight the importance of selecting mustard cultivars for biofumigation based on their glucosinolate profiles and hydrolysis product yields. The study also identifies a significant genetic influence on AITC and nitrile formation, suggesting that epithiospecifier protein modulation could enhance both allelopathic and other beneficial effects. Collectively, the research underscores the promise of mustard as a sustainable, environmentally friendly alternative to traditional herbicides.

Characterization of flavor and taste profile of different radish (Raphanus Sativus L.) varieties by headspace-gas chromatography-ion mobility spectrometry (GC/IMS) and E-nose/tongue

A comprehensive study of the overall flavor and taste profile of different radishes is lacking. This study systematically compared the volatile profile of six radish varieties using HS-GC-IMS and their correlation with the E-nose analysis. Organic acids and amino acids were quantified, and their association with the E-tongues analysis was explored. A total of 73 volatile compounds were identified, with diallyl sulfide and dimethyl disulfide being the primary sulfides responsible for the unpleasant flavor in radish. Compared to other varieties, cherry radishes boast a significantly higher concentration of allyl isothiocyanate, which likely contributes to their characteristic radish flavor. Moreover, oxalic acid was identified as the most abundant organic acid in radish, accounting for over 97% of its content, followed by malic acid and succinic acid. In conclusion, the distinct flavor and taste characteristics of different radish varieties partially explain their suitability for diverse culinary preferences.

Comprehensive Characterization of Tuber maculatum, New in Uruguay: Morphological, Molecular, and Aromatic Analyses

Although only a few species of Tuber account for the major truffle sales volume, many species that are not considered delicacies are finding their way to the market, especially in regions where the traditionally appreciated ones do not occur. This is the case for whitish truffles. Specimens of whitish truffles were collected in pecan (Carya illinoinensis) orchards in Uruguay in October 2021. Morphological and molecular methods were used to characterize and assess their identity as Tuber maculatum Vittad. An SPME extraction of volatile compounds and GC-MS analyses were performed to characterize the aromatic profile of these specimens and evaluate their potential applications. Among the 60 VOCs detected, 3-octenone (mushroom odor), 3-octanol (moss, nut, mushroom odor), and 2H-pyran-2-one (no odor), followed by octen-1-ol-acetate (no odor) and 2-undecanone (orange, fresh, green odor) were the major compounds in T. maculatum fruiting bodies. The attributes of exotic edible mushrooms of commercial value in the region are highlighted. In particular, this work emphasizes the characteristics of truffles as a byproduct of pecan cultivation.

Sensory Attributes Driving Preference for Wild Rocket (Diplotaxis tenuifolia) Leaves Tasted as a Single Ingredient and as a Part of a Recipe

Two cultivars of wild rocket (Diplotaxis tenuifolia), cv. Denver and Marte, were subjected to chemical determination of flavour-related constituents, sensory descriptive analysis, and measurement of liking by consumer test. Consumers evaluated rocket leaves both as a single ingredient and in a recipe formed by a roll of bresaola with also Grana Padano cheese. Sensory analyses showed that Marte was characterized by a more intense bitterness, hotness, and pungency, which corresponded to a higher total GSL content, mainly due to a higher level of dimeric 4-mercaptobutyl GSL. Five clusters of consumers were identified based on their liking scores. When tasting rocket leaves as a single ingredient, three clusters showed a higher liking for the milder cultivar, one cluster showed an opposite preference, while flavour attributes, such as bitterness and hotness, appeared as the main drivers of liking. Differences in liking were no longer found between the two cultivars when rocket leaves were evaluated in the recipe. Therefore, as rocket leaves are generally consumed as a part of a recipe with other ingredients instead of as a single ingredient, in the assessment of consumer preferences, it should not be neglected the influence of the way in which the product is consumed.

Domestication and the evolution of crops: variable syndromes, complex genetic architectures, and ecological entanglements

Domestication can be considered a specialized mutualism in which a domesticator exerts control over the reproduction or propagation (fitness) of a domesticated species to gain resources or services. The evolution of crops by human-associated selection provides a powerful set of models to study recent evolutionary adaptations and their genetic bases. Moreover, the domestication and dispersal of crops such as rice, maize, and wheat during the Holocene transformed human social and political organization by serving as the key mechanism by which human societies fed themselves. Here we review major themes and identify emerging questions in three fundamental areas of crop domestication research: domestication phenotypes and syndromes, genetic architecture underlying crop evolution, and the ecology of domestication. Current insights on the domestication syndrome in crops largely come from research on cereal crops such as rice and maize, and recent work indicates distinct domestication phenotypes can arise from different domestication histories. While early studies on the genetics of domestication often identified single large-effect loci underlying major domestication traits, emerging evidence supports polygenic bases for many canonical traits such as shattering and plant architecture. Adaptation in human-constructed environments also influenced ecological traits in domesticates such as resource acquisition rates and interactions with other organisms such as root mycorrhizal fungi and pollinators. Understanding the ecological context of domestication will be key to developing resource-efficient crops and implementing more sustainable land management and cultivation practices.

Does fungal infection increase the palatability of oilseed rape to insects?

BACKGROUND

Multiple and simultaneous attacks by pathogens and insect pests frequently occur in nature. Plants respond to biotic stresses by activating distinct defense mechanisms, but little is known about how plants cope with multiple stresses. The focus of this study was the combined interaction of fungal infection caused by Leptosphaeria maculans (synonym Plenodomus lingam) and arthropod infestation by the diamondback moth (Plutella xylostella) in oilseed rape (Brassica napus). We hypothesized that infection by the fungal pathogen L. maculans could alter oilseed rape palatability to P. xylostella-chewing caterpillars. Feeding preference tests were complemented with analyses of defense gene transcription, and levels of glucosinolates (GLSs) and volatile organic compounds (VOCs) in L. maculans-inoculated and non-inoculated (control) leaves to determine possible causes of larval choice.

RESULTS

Caterpillars preferred true leaves to cotyledons, hence true leaves were used for further experiments. True leaves inoculated with L. maculans were more palatable to caterpillars over control leaves during the early stage of infection at 3 days post inoculation (dpi), but this preference disappeared in the later stages of infection at 7 dpi. In parallel, genes involved in the salicylic acid and ethylene pathways were up-regulated in L. maculans-inoculated leaves at 3 and 7 dpi; L. maculans increased the level of total aliphatic GLSs, specifically glucobrassicanapin, and decreased the level of glucoiberin at 3 dpi and altered the content of specific VOCs. A group of 55 VOCs with the highest variability between treatments was identified.

CONCLUSION

We suggest that the P. xylostella preference for L. maculans-inoculated leaves in the early stage of disease development could be caused by the underlying mechanisms leading to changes in metabolic composition. Further research should pinpoint the compounds responsible for driving larval preference and evaluate whether the behavior of the adult moths, i.e. the stage that makes the first choice regarding host plant selection in field conditions, correlates with our results on larval host acceptance. © 2024 Society of Chemical Industry.

Myrosinase isogenes in wasabi (Wasabia japonica Matsum) and their putative roles in glucosinolate metabolism

BACKGROUND

Wasabi, a Brassicaceae member, is well-known for its unique pungent and hot flavor which is produced from glucosinolate (GSL) degradation. Myrosinase (MYR) is a principle enzyme catalyzing the primary conversion of GSLs to GSL hydrolysis products (GHPs) which is responsible for plant defense system and food quality. Due to the limited information in relation to MYRs present in wasabi (Wasabia japonica M.), this study aimed to identify the MYR isogenes in W. japonica and analyze their roles in relation to GSL metabolism.

RESULTS

In results, WjMYRI-1 was abundantly expressed in all organs, whereas WjMYRI-2 showed only trace expression levels. WjMYRII was highly expressed in the aboveground tissues. Interestingly, WjMYRII expression was significantly upregulated by certain abiotic factors, such as methyl jasmonate (more than 40-fold in petioles and 15-fold in leaves) and salt (tenfold in leaves). Young leaves and roots contained 97.89 and 91.17 µmol‧g-1 of GSL, whereas less GSL was produced in mature leaves and petioles (38.36 and 44.79 µmol‧g-1, respectively). Similar pattern was observed in the accumulation of GHPs in various plant organs. Notably, despite the non-significant changes in GSL production, abiotic factors treated samples enhanced significantly GHP content. Pearson's correlation analysis revealed that WjMYRI-1 expression significantly correlated with GSL accumulation and GHP formation, suggesting the primary role of WjMYRI-1-encoding putative protein in GSL degradation. In contrast, WjMYRII expression level showed no correlation with GSL or GHP content, suggesting another physiological role of WjMYRII in stress-induced response.

CONCLUSIONS

In conclusions, three potential isogenes (WjMYRI-1, WjMYRI-2, and WjMYRII) encoding for different MYR isoforms in W. japonica were identified. Our results provided new insights related to MYR and GSL metabolism which are important for the implications of wasabi in agriculture, food and pharmaceutical industry. Particularly, WjMYRI-1 may be primarily responsible for GSL degradation, whereas WjMYRII (clade II) may be involved in other regulatory pathways induced by abiotic factors.

Association of the bitter taste genes TAS2R38 and CA6 and breast cancer risk; a case-control study of Polish women in Poland and Polish immigrants in USA

It is known that the perception of bitterness is mediated by type 2 bitter taste receptors (TAS2Rs). However, recent reports have suggested that the carbonic anhydrase 6 (CA6) gene may also influence bitterness sensing. Genetic variants in these genes could influence dietary intake of brassica vegetables, whose increased consumption has been observed in the literature, though inconsistently, to decrease breast cancer (BC) risk. We hypothesized that the estimated odds ratios (ORs) for the association between BC and taster diplotype (PAV/PAV) and/or genotype A/A, will be in the direction of increased BC risk, potentially due to reduced consumption of brassica vegetables. Using a case-control study of BC in Polish women in Poland (210 cases and 262 controls) and Polish immigrant women to USA (78 cases and 170 controls) we evaluated the association of the taster diplotypes in TAS2R38 gene and genotypes in the CA6 gene and BC risk in these two populations individually and jointly. No significant increase in risk was observed for the TAS2R38 PAV/PAV diplotype (tasters) in each population individually or in the joint population. For the CA6 gene, in the joint population, we observed an increased BC risk for the combined G/A and G/G genotypes (non-tasters) vs A/A (tasters), OR = 1.41 (95% CI 1.04-1.90, p = 0.026) which after adjustment for False Discovery Rate (FDR), was not significant at p≤0.05 level. However, for the joint population and for the combined genotype of the two genes AVI/AVI+G* (non-tasters) vs. PAV/*+A/A (tasters), we observed a significant increase in BC risk, OR = 1.77 (95%CI 1.47-2.74, p = 0.01), for the non-tasters, which remained significant after FDR adjustment. In conclusion for the joint population and the joint effect for the two bitter sensing genes, we observed an increase in BC risk for the bitterness non-tasters, association which is in the opposite direction to our original hypothesis.

Recent advances in the contribution of glucosinolates degradation products to cruciferous foods odor: factors that influence degradation pathways and odor attributes

As one of the most important vegetables and oils consumed globally, cruciferous foods are appreciated for their high nutritional value. However, there is no comprehensive knowledge to sufficiently unravel the "flavor mystery" of cruciferous foods. The present review provides a comprehensive literature on the recent advances regarding the contribution of glucosinolates (GSL) degradation products to cruciferous foods odor, which focuses on key GSL degradation products contributing to distinct odor of cruciferous foods (Brassica oleracea, Brassica rapa, Brassica napus, Brassica juncea, Raphanus sativus), and key factors affecting GSL degradation pathways (i.e., enzyme-induced degradation, thermal-induced degradation, chemical-induced degradation, microwave-induced degradation) during different processing and cooking. A total of 93 volatile GSL degradation products (i.e., 36 nitriles, 33 isothiocyanates, 3 thiocyanates, 5 epithionitriles, and 16 sulfides) and 29 GSL (i.e., 20 aliphatic, 5 aromatic, and 4 indolic) were found in generalized cruciferous foods. Remarkably, cruciferous foods have a distinctive pungent, spicy, pickled, sulfur, and vegetable odor. In general, isothiocyanates are mostly present in enzyme-induced degradation of GSL and are therefore often enriched in fresh-cut or low-temperature, short-time cooked cruciferous foods. In contrast, nitriles are mainly derived from thermal-induced degradation of GSL, and are thus often enriched in high-temperature, long-time cooked cruciferous foods.

Studying Salt-Induced Shifts in Gene Expression Patterns of Glucosinolate Transporters and Glucosinolate Accumulation in Two Contrasting Brassica Species

Brassica crops are well known for the accumulation of glucosinolates-secondary metabolites crucial for plants' adaptation to various stresses. Glucosinolates also functioning as defence compounds pose challenges to food quality due to their goitrogenic properties. Their disruption leaves plants susceptible to insect pests and diseases. Hence, a targeted reduction in seed glucosinolate content is of paramount importance to increase food acceptance. GLUCOSINOLATE TRANSPORTERS (GTRs) present a promising avenue for selectively reducing glucosinolate concentrations in seeds while preserving biosynthesis elsewhere. In this study, 54 putative GTR protein sequences found in Brassica were retrieved, employing Arabidopsis GTR1 and GTR2 templates. Comprehensive bioinformatics analyses, encompassing gene structure organization, domain analysis, motif assessments, promoter analysis, and cis-regulatory elements, affirmed the existence of transporter domains and stress-related regulatory elements. Phylogenetic analysis revealed patterns of conservation and divergence across species. Glucosinolates have been shown to increase under stress conditions, indicating a potential role in stress response. To elucidate the role of GTRs in glucosinolate transportation under NaCl stress in two distinct Brassica species, B. juncea and B. napus, plants were subjected to 0, 100, or 200 mM NaCl. Based on the literature, key GTR genes were chosen and their expression across various plant parts was assessed. Both species displayed divergent trends in their biochemical profiles as well as glucosinolate contents under elevated salt stress conditions. Statistical modelling identified significant contributors to glucosinolate variations, guiding the development of targeted breeding strategies for low-glucosinolate varieties. Notably, GTR2A2 exhibited pronounced expressions in stems, contributing approximately 52% to glucosinolate content variance, while GTR2B1/C2 displayed significant expression in flowers. Additionally, GTR2A1 and GTR1A2/B1 demonstrated noteworthy expression in roots. This study enhances our understanding of glucosinolate regulation under stress conditions, offering avenues to improve Brassica crop quality and resilience.

Effect of peptide formation during rapeseed fermentation on meat analogue structure and sensory properties at different pH conditions

This study aimed to modify the sensory properties of rapeseed protein concentrate using a combination of fermentation and high-moisture extrusion processing for producing meat analogues. The fermentation was carried out with Lactiplantibacillus plantarum and Weissella confusa strains, known for their flavour and structure-enhancing properties. Contrary to expectations, the sensory evaluation revealed that the fermentation induced bitterness and disrupted the fibrous structure formation ability due to the generation of short peptides. On the other hand, fermentation removed the intensive off-odour and flavour notes present in the native raw material. Several control treatments were produced to understand the reasons behind the hindered fibrous structure formation and induced bitterness. The results obtained from peptidomics, free amino ends, and solubility analyses strongly indicated that the proteins were hydrolysed by endoproteases activated during the fermentation process. Furthermore, it was suspected that the proteins and/or peptides formed complexes with other components, such as hydrolysis products of glucosinolates and polysaccharides.

Acidification and tissue disruption affect glucosinolate and S-methyl-l-cysteine sulfoxide hydrolysis and formation of amines, isothiocyanates and other organosulfur compounds in red cabbage (Brassica oleracea var. capitata f. rubra)

Cabbages are rich in sulfur-containing metabolites like glucosinolates (GLSs) and S-methyl-l-cysteine sulfoxide (SMCSO). Tissue disruption initiates hydrolysis of these compounds and bioactive volatile hydrolysis products such as isothiocyanates (ITCs), sulfides, and thiosulfinates are formed. However, nitriles, epithionitriles, or amines can also result from GLSs. Here, the influence of hydrolysis time, extent of tissue disruption (chopping vs. homogenization), and addition of lemon juice or vinegar on the outcome of enzymatic hydrolysis of GLSs and SMCSO was investigated in red cabbage. Chopping led to partial hydrolysis of GLSs, whereas homogenization completely degraded GLSs but only had a small effect on SMCSO. Homogenization increased amine formation from alkenyl and methylthioalkyl ITCs, but not from methylsulfinylalkyl ITCs. Acidification inhibited formation of products from SMCSO. Further, it reduced nitrile and epithionitrile formation and stopped amine formation, thereby increasing ITC levels. Therefore, acidification is a valuable mean to enhance ITC levels in fresh Brassica foods.

Dual functional roles of nutritional additives in nutritional fortification and safety of thermally processed food: Potential, limitations, and perspectives

The Maillard reaction (MR) has been established to be a paramount contributor to the characteristic sensory property of thermally processed food products. Meanwhile, MR also gives rise to myriads of harmful byproducts (HMPs) (e.g., advanced glycation end products (AGEs) and acrylamide). Nutritional additives have attracted increasing attention in recent years owing to their potential to simultaneously improve nutritional quality and attenuate HMP formation. In this manuscript, a brief overview of various nutritional additives (vitamins, minerals, fatty acids, amino acids, dietary fibers, and miscellaneous micronutrients) in heat-processed food is provided, followed by a summary of the formation mechanisms of AGEs and acrylamide highlighting the potential crosstalk between them. The main body of the manuscript is on the capability of nutritional additives to modulate AGE and acrylamide formation besides their traditional roles as nutritional enhancers. Finally, limitations/concerns associated with their use to attenuate dietary exposure to HMPs and future perspectives are discussed. Literature data support that through careful control of the addition levels, certain nutritional additives possess promising potential for simultaneous improvement of nutritional value and reduction of AGE and acrylamide content via multiple action mechanisms. Nonetheless, there are some major concerns that may limit their wide applications for achieving such dual functions, including influence on sensory properties of food products, potential overestimation of nutrition enhancement, and introduction of hazardous alternative reaction products or derivatives. These could be overcome through comprehensive assay of dose-response relationships and systematic evaluation of the diverse combinations from the same and/or different categories of nutritional additives to establish synergistic mixtures.

Characterizing the impact of species/strain-specific Lactiplantibacillus plantarum with community assembly and metabolic regulation in pickled Suancai

To investigate the colonization and impact of the specific Lactiplantibacillus plantarum strains, four isolated strains were applied in pickled Suancai which is a traditional pickled mustard (Brassica juncea). Results showed that strain-8 with the highest lactic acid bacteria (LAB) counts and acetic acid (p < 0.05). There were 11.42 % ∼ 32.35 % differential volatile compounds detected, although nitriles, esters, and acids were predominant. L. plantarum disturbed the microbial community, in which the microbial composition of strain-11 was most similar to the naturally fermented sample. Amino acids, carbohydrate metabolism, and metabolism of cofactors and vitamins were the main functional classes because of the similar dominant microbes (Lactiplantibacillus and Levilactobacillus). The functional units were separated based on NMDS analysis, in which bacterial chemotaxis, amino acid-related units, biotin metabolism, fatty acid biosynthesis, and citrate cycle were significantly different calculated by metagenomeSeq and Benjamin-Hochberg methods (p < 0.05). The contents of most flavor compounds were consistent with their corresponding enzymes. In particular, glucosinolates metabolites were different and significantly related to the myrosinase and metabolic preference of LAB. Therefore, this study revealed the impact mechanism of the specific L. plantarum strains and provided a perspective for developing microbial resources to improve the flavor diversity of fermented vegetables.

Targeted editing of multiple homologues of GTR1 and GTR2 genes provides the ideal low-seed, high-leaf glucosinolate oilseed mustard with uncompromised defence and yield

Glucosinolate content in the two major oilseed Brassica crops-rapeseed and mustard has been reduced to the globally accepted Canola quality level (<30 μmoles/g of seed dry weight, DW), making the protein-rich seed meal useful as animal feed. However, the overall lower glucosinolate content in seeds as well as in the other parts of such plants renders them vulnerable to biotic challenges. We report CRISPR/Cas9-based editing of glucosinolate transporter (GTR) family genes in mustard (Brassica juncea) to develop ideal lines with the desired low seed glucosinolate content (SGC) while maintaining high glucosinolate levels in the other plant parts for uncompromised plant defence. Use of three gRNAs provided highly efficient and precise editing of four BjuGTR1 and six BjuGTR2 homologues leading to a reduction of SGC from 146.09 μmoles/g DW to as low as 6.21 μmoles/g DW. Detailed analysis of the GTR-edited lines showed higher accumulation and distributional changes of glucosinolates in the foliar parts. However, the changes did not affect the plant defence and yield parameters. When tested against the pathogen Sclerotinia sclerotiorum and generalist pest Spodoptera litura, the GTR-edited lines displayed a defence response at par or better than that of the wild-type line. The GTR-edited lines were equivalent to the wild-type line for various seed yield and seed quality traits. Our results demonstrate that simultaneous editing of multiple GTR1 and GTR2 homologues in mustard can provide the desired low-seed, high-leaf glucosinolate lines with an uncompromised defence and yield.

Screening for Fungicide Efficacy in Controlling Blackleg Disease in Wasabi (Eutrema japonicum)

Blackleg disease is devastating for wasabi (Eutrema japonicum) production, occurring at any time and everywhere within the main production area of the Sichuan Province, China. There have been very few studies on the chemical control of this disease. In this study, we isolated and identified a local popular strain of the pathogen Plenodomus wasabiae. The isolated fungus strain caused typical disease spots on the leaves and rhizomes upon inoculation back to wasabi seedlings. The symptoms of blackleg disease developed very quickly, becaming visible on the second day after exposure to P. wasabiae and leading to death within one week. We then evaluated the efficacy of ten widely used fungicides to screen out effective fungicides. The efficacy of the tested fungicides was determined through mycelial growth inhibition on medium plates. As a result, tebuconazole and pyraclostrobin were able to inhibit the mycelial growth of P. wasabiae, and the most widely used dimethomorph in local production areas produced the lowest inhibition activity (13.8%). Nevertheless, the highest control efficacy of tebuconazole and pyraclostrobin on wasabi seedlings was only 47.48% and 39.03%, respectively. Generally, the control efficacy of spraying the fungicide before inoculation was better than that after inoculation. An increase in the application concentration of the two fungicides did not proportionately result in improved performance. We cloned the full-length sequence of sterol 14-demethylase (CYP51) and cytochrome B (CYTB) of which the mutations may contribute to the possible antifungalresistance. These two genes of the isolated fungus do not possess any reported mutations that lead to fungicide resistance. Previous studies indicate that there is a significant difference between fungicides in terms of the effectiveness of controlling blackleg disease; however, the control efficacy of fungicides is limited in blackleg control. Therefore, field management to prevent wound infection and unfavorable environmental conditions are more important than pesticide management.

Consumer Liking of Turnip Cooked by Different Methods: The Influence of Sensory Profile and Consumer Bitter Taste Genotype

Brassica vegetables are bitter, predominantly because they contain bitter-tasting glucosinolates. Individuals with high bitter taste sensitivity are reported to have lower consumption of bitter vegetables. Studies reported that cooking methods can alter the sensory characteristics of vegetables, increasing acceptability. This study investigated consumer liking of turnip cooked by four methods (boiled-pureed, roasted, steamed-pureed and stir-fried) and related this to sensory characteristics. Additionally, this study examined the effect of the bitter taste genotype on taste perception and liking of the cooked turnip samples. Participants (n = 74) were recruited and the TAS2R38 genotype was measured. Liking, consumption intent, perception of bitterness and sweetness of turnip were evaluated. A sensory profile of the cooked turnip variants was also determined by a trained sensory panel. There were significant differences in the overall (p = 0.001) and taste (p = 0.002) liking between cooking methods. Turnip liking was increased when preparation led to sweeter taste profiles. The TAS2R38 genotype had a significant effect on bitter perception (p = 0.02) but did not significantly affect taste liking. In conclusion, the cooking method affected turnip liking, and the bitter perception in turnip was influenced by the TAS2R38 genotype. However, taste sensitivity did not predict turnip liking in this UK adult cohort.

Profiling of Health-Promoting and Taste-Relevant Compounds in Sixteen Radish (Raphanus sativus L.) Genotypes Grown under Controlled Conditions

It is becoming increasingly challenging to maintain crop yields and quality as the global climate changes. The aim of this study was to determine whether and how the profile of health-promoting and taste-related compounds of radishes changes within a growing season. A total of 16 radish (Raphanus sativus L.) genotypes that are commercially available on the Czech market were assessed by means of chemical analysis. Radishes were cultivated in three independent growing cycles under controlled conditions, and the effects of the genotype and growing cycle, as well as their interactions, on the chemical traits were evaluated. Most of the variability in chemical composition was associated with the growing cycle, which accounted for 51.53% of total variance, followed by the genotype (26% of total variance). The interaction between the growing cycle and genotype explained 22.47% of total variance. The growing cycle had the strongest effect on amino acid profiles. More specifically, the amino acids that are known to contribute to overall taste (glycine, along with glutamic and aspartic acids) showed the highest degree of variation, while the amino acids related to glucosinolate biosynthesis (methionine, isoleucine, tryptophan, and phenylalanine) showed relatively low variability. On the other hand, indole glucosinolates were found to differ the most between genotypes.

Bitter Is Better: Wild Greens Used in the Blue Zone of Ikaria, Greece

The current study reports an ethnobotanical field investigation of traditionally gathered and consumed wild greens (Chorta) in one of the five so-called Blue Zones in the world: Ikaria Isle, Greece. Through 31 semi-structured interviews, a total of 56 wild green plants were documented along with their culinary uses, linguistic labels, and locally perceived tastes. Most of the gathered greens were described as bitter and associated with members of Asteraceae and Brassicaceae botanical families (31%), while among the top-quoted wild greens, species belonging to these two plant families accounted for 50% of the wild vegetables, which were consumed mostly cooked. Cross-cultural comparison with foraging in other areas of the central-eastern Mediterranean and the Near East demonstrated a remarkable overlapping of Ikarian greens with Cretan and Sicilian, as well as in the prevalence of bitter-tasting botanical genera. Important differences with other wild greens-related food heritage were found, most notably with the Armenian and Kurdish ones, which do not commonly feature many bitter greens. The proven role of extra-oral bitter taste receptors in the modulation of gastric emptying, glucose absorption and crosstalk with microbiota opens new ways of looking at these differences, in particular with regard to possible health implications. The present study is also an important attempt to preserve and document the bio-cultural gastronomic heritage of Chorta as a quintessential part of the Mediterranean diet. The study recommends that nutritionists, food scientists, and historians, as well as policymakers and practitioners, pay the required attention to traditional rural dietary systems as models of sustainable health.

(R)-8-Methylsulfinyloctyl isothiocyanate from Nasturtium officinale inhibits LPS-induced immunoinflammatory responses in mouse peritoneal macrophages: chemical synthesis and molecular signaling pathways involved

The aim of this study was to develop an optimal synthetic route to obtain natural (R)-8-methylsulfinyloctyl isothiocyanate ((R)-8-OITC), present in watercress, based on the "DAG methodology" as well as to evaluate its potential antioxidant and immunomodulatory effects, exploring possible signaling pathways that could be involved in an ex vivo model of murine peritoneal macrophages stimulated with LPS. Treatment with (R)-8-OITC inhibited the levels of pro-inflammatory cytokines (IL-1β, TNF-α, IL-6, IL-17 and IL-18), intracellular ROS production and expression of pro-inflammatory enzymes (COX-2, iNOS and mPGES-1) through modulation of the expression of Nrf2, MAPKs (p38, JNK and ERK) and JAK/STAT, and the canonical and non-canonical pathways of the inflammasome. Taking all these together, our results provide a rapid and cost-effective synthetic route to obtain natural (R)-8-OITC and demonstrate that it could be a potential nutraceutical candidate for managing immuno-inflammatory pathologies. Therefore, further in vivo trials are warranted.

The effect of high-polyphenol sumac (Rhus coriaria) on food intake using sensory and appetite analysis in younger and older adults: A randomized controlled trial

Aging is accompanied by a decline in appetite and food intake with associated deficiencies in both macronutrients and micronutrients. The aim of this study was to investigate the impact of adding Iranian brown sumac (Rhus coriaria) (CIBS) into butternut squash soup on sensory evaluation and food intake among older adults (n = 20; >65 years old) and younger adults (n = 20; 18-35 years old). To evaluate the polyphenol content and antioxidant activity of the sumac samples, a Folin-Ciocalteu assay (FCR) and ferric ion reducing antioxidant power (FRAP) assay were used, respectively. L-glutamic acid was assessed using a Megazyme L-glutamic acid assay. Compusense software was used to assess the sensory evaluation attributes of free-living older adults and younger adults receiving different doses of sumac in butternut squash soup. Nutritics software was used to assess food intake following the addition of 0.37 g of sumac to soup. CIBS was selected based on a preliminary assessment in vitro for L-glutamic acid, antioxidant, and polyphenol content of six varieties of sumac. Sensory evaluation results revealed that the difference in perceived intensity of brown color between the soup samples with different doses of CIBS was greater in the younger adults' group (p = .001) than in older adults (p = .037). In addition, the food intake study found that during the ad libitum lunch, older adults consumed more energy (kcal; p = .014), protein (g; p = .025), carbohydrate (g; p = .013), and fat (g; p = .002) after soup with sumac compared to control soup. The overall findings of this study suggest that the addition of sumac to food may have a potential benefit in enhancing ad libitum lunch intake in older adults leading to effective management of malnutrition. This may promote healthy aging and minimize the burden and the consequences of anorexia of aging as main public health concerns.

Glucosinolates, a natural chemical arsenal: More to tell than the myrosinase story

Glucosinolates are a group of thioglucosides that belong to the class of plant nitrogen-containing natural products. So far, very little biological activity has been associated with intact glucosinolates. The hydrolysis of glucosinolates has, for long, attracted attention because of the potent biological activity of the hydrolysis products. From allelopathic to antiparasitic, antimicrobial and antineoplastic effects, the activity spectrum of the degradation products of typical glucosinolates has been the subject of much research. The present review seeks to address the various means of glucosinolate degradation (thermal, enzymatic, or chemical degradation) and the ensuing products. It also aims to draw a comparative profile of the various antimicrobial effects of these degradation products to provide a further understanding of the biological function of these important compounds.

Effect of dense phase carbon dioxide treatment on the flavor, texture, and quality changes in new-paocai

This study investigated the effect of dense phase carbon dioxide (DPCD) treatment on the organoleptic properties of new-paocai. Optimal DPCD treatment (25 MPa/40 °C/40 min) was determined by conducting single-factor and orthogonal experiments with the sensory, bactericidal, and electronic eye evaluations. DPCD treatment (25 MPa/40 °C/40 min) did not significantly affect the nitrite, pH, total acid, and organic acid of the new-paocai brine, and the texture of the radish slices did not display substantial changes. Gas chromatography-mass spectrometry (GC-MS) was employed to characterize the new-paocai brine flavor, revealing 63 and 60 respective flavor compounds with and without DPCD treatment. In addition, DPCD treatment significantly reduced the total organic volatile compound content in the paocai from 48.182 μg/mL to 35.952 μg/mL, DPCD has a great influence on volatile flavor substances. The electronic nose (E-nose) effectively distinguished the flavor differences in the new-paocai brine with and without DPCD treatment. This study combined new food processing technology with traditional food production, could provide a new idea for pickle production technology.

Developing multifunctional crops by engineering Brassicaceae glucosinolate pathways

Glucosinolates (GSLs), found mainly in species of the Brassicaceae family, are one of the most well-studied classes of secondary metabolites. Produced by the action of myrosinase on GSLs, GSL-derived hydrolysis products (GHPs) primarily defend against biotic stress in planta. They also significantly affect the quality of crop products, with a subset of GHPs contributing unique food flavors and multiple therapeutic benefits or causing disagreeable food odors and health risks. Here, we explore the potential of these bioactive functions, which could be exploited for future sustainable agriculture. We first summarize our accumulated understanding of GSL diversity and distribution across representative Brassicaceae species. We then systematically discuss and evaluate the potential of exploited and unutilized genes involved in GSL biosynthesis, transport, and hydrolysis as candidate GSL engineering targets. Benefiting from available information on GSL and GHP functions, we explore options for multifunctional Brassicaceae crop ideotypes to meet future demand for food diversification and sustainable crop production. An integrated roadmap is subsequently proposed to guide ideotype development, in which maximization of beneficial effects and minimization of detrimental effects of GHPs could be combined and associated with various end uses. Based on several use-case examples, we discuss advantages and limitations of available biotechnological approaches that may contribute to effective deployment and could provide novel insights for optimization of future GSL engineering.

Effects of Low-Temperature and Low-Salt Fermentation on the Physicochemical Properties and Volatile Flavor Substances of Chinese Kohlrabi Using Gas Chromatography–Ion Mobility Spectrometry

To explore the effect of low-temperature and low-salt fermentation on the volatile flavor substances of Chinese kohlrabi, low-temperature and low-salt fermented Chinese kohlrabi (LSCK) and traditional high-salt fermented Chinese kohlrabi (HSCK) were produced. The physicochemical and texture properties of the two kinds of Chinese kohlrabies were evaluated. Headspace gas chromatography-ion mobility spectrometry (GC-IMS) and electronic nose (E-nose) were used to analyze the volatile flavor substances of the kohlrabi. The results showed that the total acid content significantly decreased (p < 0.05), while protein and reducing sugar contents significantly increased (p < 0.05) by low-temperature and low-salt fermentation. A total of 114 volatile flavor substances were identified. The alcohol, ketone, pyrazine, ether, and nitrile contents in LSCK were significantly higher than those in HSCK (p < 0.05). Moreover, the unpleasant flavor from the 3-methylbutyric acid formation was effectively depressed in LSCK. The principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA) models established by multivariate statistical analysis significantly distinguished the two types of kohlrabies. Multivariate statistical analysis suggested that 16 volatile flavor substances with VIP >1, including tetrahydrothiophene, ethyl 3-(methylthio)propanoate, 3-methylbutyric acid, hexanenitrile, and 3-methyl-3-buten-1-ol, could be used as potential biomarkers for identifying LSCK and HSCK. The E-nose analysis further demonstrated that there was a significant difference in overall flavor between the LSCK and HSCK. The present study provides support for the development of green processing technology and new low-salt Chinese kohlrabi products.

Genome-Wide Association Study of Glucosinolate Metabolites (mGWAS) in Brassica napus L

Glucosinolates (GSLs) are secondary plant metabolites that are enriched in rapeseed and related Brassica species, and they play important roles in defense due to their anti-nutritive and toxic properties. Here, we conducted a genome-wide association study of six glucosinolate metabolites (mGWAS) in rapeseed, including three aliphatic glucosinolates (m145 gluconapin, m150 glucobrassicanapin and m151 progoitrin), one aromatic glucosinolate (m157 gluconasturtiin) and two indole glucosinolates (m165 indolylmethyl glucosinolate and m172 4-hydroxyglucobrassicin), respectively. We identified 113 candidate intervals significantly associated with these six glucosinolate metabolites. In the genomic regions linked to the mGWAS peaks, 187 candidate genes involved in glucosinolate biosynthesis (e.g., BnaMAM1, BnaGGP1, BnaSUR1 and BnaMYB51) and novel genes (e.g., BnaMYB44, BnaERF025, BnaE2FC, BnaNAC102 and BnaDREB1D) were predicted based on the mGWAS, combined with analysis of differentially expressed genes. Our results provide insight into the genetic basis of glucosinolate biosynthesis in rapeseed and should facilitate marker-based breeding for improved seed quality in Brassica species.

Differences in pseudogene evolution contributed to the contrasting flavors of turnip and Chiifu, two Brassica rapa subspecies

Pseudogenes are important resources for investigation of genome evolution and genomic diversity because they are nonfunctional but have regulatory effects that influence plant adaptation and diversification. However, few systematic comparative analyses of pseudogenes in closely related species have been conducted. Here, we present a turnip (Brassica rapa ssp. rapa) genome sequence and characterize pseudogenes among diploid Brassica species/subspecies. The results revealed that the number of pseudogenes was greatest in Brassica oleracea (CC genome), followed by B. rapa (AA genome) and then Brassica nigra (BB genome), implying that pseudogene differences emerged after species differentiation. In Brassica AA genomes, pseudogenes were distributed asymmetrically on chromosomes because of numerous chromosomal insertions/rearrangements, which contributed to the diversity among subspecies. Pseudogene differences among subspecies were reflected in the flavor-related glucosinolate (GSL) pathway. Specifically, turnip had the highest content of pungent substances, probably because of expansion of the methylthioalkylmalate synthase-encoding gene family in turnips; these genes were converted into pseudogenes in B. rapa ssp. pekinensis (Chiifu). RNA interference-based silencing of the gene encoding 2-oxoglutarate-dependent dioxygenase 2, which is also associated with flavor and anticancer substances in the GSL pathway, resulted in increased abundance of anticancer compounds and decreased pungency of turnip and Chiifu. These findings revealed that pseudogene differences between turnip and Chiifu influenced the evolution of flavor-associated GSL metabolism-related genes, ultimately resulting in the different flavors of turnip and Chiifu.

An overview of bitter compounds in foodstuffs: Classifications, evaluation methods for sensory contribution, separation and identification techniques, and mechanism of bitter taste transduction

The bitter taste is generally considered an undesirable sensory attribute. However, bitter-tasting compounds can significantly affect the overall flavor of many foods and beverages and endow them with various beneficial effects on human health. To better understand the relationship between chemical structure and bitterness, this paper has summarized the bitter compounds in foodstuffs and classified them based on the basic skeletons. Only those bitter compounds that are confirmed by human sensory evaluation have been included in this paper. To develop food products that satisfy consumer preferences, correctly ranking the key bitter compounds in foodstuffs according to their contributions to the overall bitterness intensity is the precondition. Generally, three methods were applied to screen out the key bitter compounds in foods and beverages and evaluate their sensory contributions, including dose-over-threshold factors, taste dilution analysis, and spectrum descriptive analysis method. This paper has discussed in detail the mechanisms and applications of these three methods. Typical procedures for separating and identifying the main bitter compounds in foodstuffs have also been summarized. Additionally, the activation of human bitter taste receptors (TAS2Rs) and the mechanisms of bitter taste transduction are outlined. Ultimately, a conclusion has been drawn to highlight the current problems and propose potential directions for further research.

Biscuits Enriched with Monofloral Bee Pollens: Nutritional Properties, Techno-Functional Parameters, Sensory Profile, and Consumer Preference

Bee pollens are potential functional food ingredients as they contain essential nutrients and a wide range of bioactive compounds. The aim of this study was to investigate the effects of enrichment with monofloral bee pollens on the nutritional properties, techno-functional parameters, sensory profile, and consumer preference of biscuits. Biscuits were prepared according to the AACC-approved method by substituting wheat flour with pollens of rapeseed (Brassica napus L.), phacelia (Phacelia tanacetifolia Benth.) and sunflower (Helianthus annuus L.) at 2%, 5% and 10% levels. The macronutrient composition of the biscuits was determined: crude protein content (Kjeldahl method), crude fat content (Soxhlet extraction), ash content (carbonization), moisture content (drying), carbohydrate content (formula). Their total phenolic content (TPC) and in vitro antioxidant capacity (FRAP, TEAC, DPPH) were determined spectrophotometrically. The colour of the biscuits was measured using a tristimulus-based instrument, and their texture was characterized by using a texture analyser. Sensory profile of biscuits was determined by qualitative descriptive analysis (QDA). The consumer acceptance and purchase intention of the biscuits were also evaluated, based on the responses of 100 consumers. Additionally, an external preference map was created to illustrate the relationship between consumer preference and the sensory profile of the biscuits, and penalty analysis was conducted to identify directions for product development. Phacelia pollen appeared to be the most effective for improving the nutritional quality of biscuits. The addition of phacelia pollen at the 10% substitution level increased the protein content and TPC of the control biscuit by 21% and 145%, respectively. Significant changes (p < 0.05) were also observed regarding the colour and texture of biscuits. The results of the QDA revealed that biscuits containing pollens of different botanical sources have heterogeneous sensory attributes. The biscuit containing sunflower pollen at the 2% substitution level was preferred the most (overall liking = 6.9 ± 1.6), and purchase intentions were also the highest for this product. Based on the results of the present study, it is recommended to use sunflower pollen for developing pollen-enriched foods in the future.

Effects of Pre-Harvest Supplemental UV-A Light on Growth and Quality of Chinese Kale

The effects of supplemental UV-A (385 nm) period and UV-A intensity for 5 days before harvest (DBH) on growth, antioxidants, antioxidant capacity, and glucosinolates contents in Chinese kale (Brassica oleracea var. alboglabra Bailey) were studied in plant factory. In the experiment of the UV-A period, three treatments were designed with 10 W·m^-2 UV-A supplement, T1(5 DBH), T2 (10 DBH), and no supplemental UV-A as control. In the experiment of UV-A intensity, four treatments were designed with 5 DBH, control (0 W·m^-2), 5 w (5 W·m^-2), 10 w (10 W·m^-2), and 15 w (15 W·m^-2). The growth light is as follows: 250 μmol·m^-2·s^-1; red light: white light = 2:3; photoperiod: 12/12. The growth and quality of Chinese kale were improved by supplemental UV-A LED. The plant height, stem diameter, and biomass of Chinese kale were the highest in the 5 W·m^-2 treatment for 5 DBH. The contents of chlorophyll a, chlorophyll b, and total chlorophyll were only highly increased by 5 W·m^-2 UV-A for 5 DBH, while there was no significant difference in the content of carotenoid among all treatments. The contents of soluble sugar and free amino acid were higher only under 10 DBH treatments than in control. The contents of total phenolic and total antioxidant capacity were the highest in 5 W·m^-2 treatment for 5 DBH. There was a significant positive correlation between total phenolic content and DPPH and FRAP value. After 5 DBH treatments, the percentages and contents of total aliphatic glucosinolates, sinigrin (SIN), gluconapin (GNA), and glucobrassicanapin (GBN) were highly increased, while the percentages and contents of glucobrassicin (GBS), 4-methoxyglucobrassicin (4-MGBS), and Progoitrin (PRO) were significantly decreased, especially under 10 W·m^-2 treatment. Our results show that UV-A LED supplements could improve the growth and quality of Chinese kale, and 5 W·m^-2 UV-A LED with 5 DBH might be feasible for Chinese kale growth, and 10 W·m^-2 UV-A LED with 5 DBH was better for aliphatic glucosinolates accumulation in Chinese kale.

Chemoinformatics-driven classification of Angiosperms using sulfur-containing compounds and machine learning algorithm

BACKGROUND

Phytochemicals or secondary metabolites are low molecular weight organic compounds with little function in plant growth and development. Nevertheless, the metabolite diversity govern not only the phenetics of an organism but may also inform the evolutionary pattern and adaptation of green plants to the changing environment. Plant chemoinformatics analyzes the chemical system of natural products using computational tools and robust mathematical algorithms. It has been a powerful approach for species-level differentiation and is widely employed for species classifications and reinforcement of previous classifications.

RESULTS

This study attempts to classify Angiosperms using plant sulfur-containing compound (SCC) or sulphated compound information. The SCC dataset of 692 plant species were collected from the comprehensive species-metabolite relationship family (KNApSAck) database. The structural similarity score of metabolite pairs under all possible combinations (plant species-metabolite) were determined and metabolite pairs with a Tanimoto coefficient value > 0.85 were selected for clustering using machine learning algorithm. Metabolite clustering showed association between the similar structural metabolite clusters and metabolite content among the plant species. Phylogenetic tree construction of Angiosperms displayed three major clades, of which, clade 1 and clade 2 represented the eudicots only, and clade 3, a mixture of both eudicots and monocots. The SCC-based construction of Angiosperm phylogeny is a subset of the existing monocot-dicot classification. The majority of eudicots present in clade 1 and 2 were represented by glucosinolate compounds. These clades with SCC may have been a mixture of ancestral species whilst the combinatorial presence of monocot-dicot in clade 3 suggests sulphated-chemical structure diversification in the event of adaptation during evolutionary change.

CONCLUSIONS

Sulphated chemoinformatics informs classification of Angiosperms via machine learning technique.

The Combination of Monochromatic LEDs and Elicitation with Stressors Enhances the Accumulation of Glucosinolates in Mustard Sprouts with Species-Dependency

This work studies the enhancement of glucosinolates (GSLs) in mustard sprouts as health promoters. Sprouts of Sinapis alba, Brassica nigra, and B. carinata were grown under broad-spectrum, monochromatic blue or red light-emitting diode (LED) lamps, irrigated with 0-100 mM sodium chloride (NaCl), and sprayed with 0-250 µM methyl jasmonate (MeJA) as elicitor. The use of LEDs did not result in increased sprout biomass in any case. The effect of the applied treatments on the GSLs depended on the species and were restricted to Brassica spp. The red LEDs produced an overall increase in GSLs over 500% in B. carinata (from 12 to 81 mg 100 g^-1 F.W.), compared to the white broad-spectrum lights, although the highest increase in content was obtained in treated sprouts with 250 µM MeJA (104 an 105 mg 101 g^-1 F.W., under the red and blue LEDs, respectively). The combination of blue LEDs, 100 mM NaCl, and 250 µM MeJA enhanced the levels of GLSs in B. nigra to the maximum (81 mg 100 g^-1 F.W.). Overall, these results indicate that by modifying the growing conditions for a given sprout, enhancement in the accumulation of GSLs as health promoters is possible. The use of these treatments is a sustainable alternative to genetic modification when looking for bioactive-enriched foods, delivering natural plant foods rich in bioactive ingredients (e.g., glucosinolates). Nevertheless, the response to the treatments varies among species, indicating that treatments will require adjustment across sprouts. Further research continues with producing cruciferous sprouts to obtain GSL-enriched formulas for further studying the effects of their bioavailability and bioactivity on health-promotion.

Effect of fermentation stages on glucosinolate profiles in kimchi: Quantification of 14 intact glucosinolates using ultra-performance liquid chromatography-tandem mass spectrometry

•

An analytical method for estimating glucosinolate profiles of kimchi is reported.

•

The method employs ultra-performance liquid chromatography-tandem mass spectrometry.

•

The method is efficient in terms of linearity, sensitivity, accuracy, and precision.

•

The glucosinolate contents and compositions vary with fermentation stage.

•

Total glucosinolates were degraded by 91%–100% in over-fermentation stage.

We developed and validated an ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry-based analytical method to determine intact glucosinolates in kimchi and evaluate the effects of fermentation stages on glucosinolate profiles. The developed method yielded reliable data in the kimchi matrix in terms of selectivity, matrix effect (88 %–105 %), linearity (coefficients of determination ≥0.9991), sensitivity (limits of quantification ≤35 nmol/L), accuracy (82 %–101 %), and precision (≤8%). The kimchi samples contained progoitrin, sinigrin, glucoraphanin, glucoraphenin, glucoalyssin, gluconapin, glucobrassicanapin, glucobrassicin, glucoberteroin, gluconasturtiin, 4-methoxyglucobrassicin, and neoglucobrassicin, of which 4-methoxyglucobrassicin, glucobrassicanapin, and gluconapin were the major compounds. Total glucosinolate content was decreased by 31 %–97 % and 91–100 % in the moderate-fermented and over-fermented samples, respectively, compared with that in the non-fermented samples, revealing sudden glucosinolate degradation between the moderate- and over-fermentation stages. In summary, we report an efficient analytical method to estimate kimchi glucosinolate profiles, which could be a foundation for future studies.

Targeted Mutagenesis of the Multicopy Myrosinase Gene Family in Allotetraploid Brassica juncea Reduces Pungency in Fresh Leaves across Environments

Recent breeding efforts in Brassica have focused on the development of new oilseed feedstock crop for biofuels (e.g., ethanol, biodiesel, bio-jet fuel), bio-industrial uses (e.g., bio-plastics, lubricants), specialty fatty acids (e.g., erucic acid), and producing low glucosinolates levels for oilseed and feed meal production for animal consumption. We identified a novel opportunity to enhance the availability of nutritious, fresh leafy greens for human consumption. Here, we demonstrated the efficacy of disarming the ‘mustard bomb’ reaction in reducing pungency upon the mastication of fresh tissue—a major source of unpleasant flavor and/or odor in leafy Brassica. Using gene-specific mutagenesis via CRISPR-Cas12a, we created knockouts of all functional copies of the type-I myrosinase multigene family in tetraploid Brassica juncea. Our greenhouse and field trials demonstrate, via sensory and biochemical analyses, a stable reduction in pungency in edited plants across multiple environments. Collectively, these efforts provide a compelling path toward boosting the human consumption of nutrient-dense, fresh, leafy green vegetables.

Role of Sulfur Compounds in Vegetable and Mushroom Aroma

At the base of the food pyramid is vegetables, which should be consumed most often of all food products, especially in raw and unprocessed form. Vegetables and mushrooms are rich sources of bioactive compounds that can fulfill various functions in plants, starting from protection against herbivores and being natural insecticides to pro-health functions in human nutrition. Many of these compounds contain sulfur in their structure. From the point of view of food producers, it is extremely important to know that some of them have flavor properties. Volatile sulfur compounds are often potent odorants, and in many vegetables, belonging mainly to Brassicaeae and Allium (Amaryllidaceae), sulfur compounds determine their specific flavor. Interestingly, some of the pathways that form volatile sulfur compounds in vegetables are also found in selected edible mushrooms. The most important odor-active organosulfur compounds can be divided into isothiocyanates, nitriles, epithionitriles, thiols, sulfides, and polysulfides, as well as others, such as sulfur containing carbonyl compounds and esters, R-L-cysteine sulfoxides, and finally heterocyclic sulfur compounds found in shiitake mushrooms or truffles. This review paper summarizes their precursors and biosynthesis, as well as their sensory properties and changes in selected technological processes.

The Volatile Profile of Brussels Sprouts (Brassica oleracea Var. gemmifera) as Affected by Pulsed Electric Fields in Comparison to Other Pretreatments, Selected to Steer (Bio)Chemical Reactions

Pulsed electric fields (PEF) at low field strength is considered a non-thermal technique allowing membrane permeabilization in plant-based tissue, hence possibly impacting biochemical conversions and the concomitant volatile profile. Detailed studies on the impact of PEF at low field strength on biochemical conversions in plant-based matrices are scarce but urgently needed to provide the necessary scientific basis allowing to open a potential promising field of applications. As a first objective, the effect of PEF and other treatments that aim to steer biochemical conversions on the volatile profile of Brussels sprouts was compared in this study. As a second objective, the effect of varying PEF conditions on the volatile profile of Brussels sprouts was elucidated. Volatile fingerprinting was used to deduce whether and which (bio)chemical reactions had occurred. Surprisingly, PEF at 1.01 kV/cm and 2.7 kJ/kg prior to heating was assumed not to have caused significant membrane permeabilization since similar volatiles were observed in the case of only heating, as opposed to mixing. A PEF treatment with an electrical field strength of 3.00 kV/cm led to a significantly higher formation of certain enzymatic reaction products, being more pronounced when combined with an energy input of 27.7 kJ/kg, implying that these PEF conditions could induce substantial membrane permeabilization. The results of this study can be utilized to steer enzymatic conversions towards an intended volatile profile of Brussels sprouts by applying PEF.

Genome-wide analysis of sulfur-encoding biosynthetic genes in rice (Oryza sativa L.) with Arabidopsis as the sulfur-dependent model plant

Sulfur is an essential element required for plant growth and development, physiological processes and stress responses. Sulfur-encoding biosynthetic genes are involved in the primary sulfur assimilation pathway, regulating various mechanisms at the gene, cellular and system levels, and in the biosynthesis of sulfur-containing compounds (SCCs). In this study, the SCC-encoding biosynthetic genes in rice were identified using a sulfur-dependent model plant, the Arabidopsis. A total of 139 AtSCC from Arabidopsis were used as reference sequences in search of putative rice SCCs. At similarity index > 30%, the similarity search against Arabidopsis SCC query sequences identified 665 putative OsSCC genes in rice. The gene synteny analysis showed a total of 477 syntenic gene pairs comprised of 89 AtSCC and 265 OsSCC biosynthetic genes in Arabidopsis and rice, respectively. Phylogenetic tree of the collated (AtSCCs and OsSCCs) SCC-encoding biosynthetic genes were divided into 11 different clades of various sizes comprised of branches of subclades. In clade 1, nearing equal representation of OsSCC and AtSCC biosynthetic genes imply the most ancestral lineage. A total of 25 candidate Arabidopsis SCC homologs were identified in rice. The gene ontology enrichment analysis showed that the rice-Arabidopsis SCC homologs were significantly enriched in the following terms at false discovery rate (FDR) < 0.05: (i) biological process; sulfur compound metabolic process and organic acid metabolic processes, (ii) molecular function; oxidoreductase activity, acting on paired donors with incorporation or reduction of molecular oxygen and (iii) KEGG pathway; metabolic pathways and biosynthesis of secondary metabolites. At less than five duplicated blocks of separation, no tandem duplications were observed among the SCC biosynthetic genes distributed in rice chromosomes. The comprehensive rice SCC gene description entailing syntenic events with Arabidopsis, motif distribution and chromosomal mapping of the present findings offer a foundation for rice SCC gene functional studies and advanced strategic rice breeding.

Isothiocyanates (ITCs) 1-(Isothiocyanatomethyl)-4-phenylbenzene and 1-Isothiocyanato-3,5-bis(trifluoromethyl)benzene—Aldehyde Dehydrogenase (ALDH) Inhibitors, Decreases Cisplatin Tolerance and Migratory Ability of NSCLC

One of the main treatment modalities for non-small-cell lung cancer (NSCLC) is cisplatin-based chemotherapy. However, the acquisition of cisplatin resistance remains a major problem. Existing chemotherapy regimens are often ineffective against cancer cells expressing aldehyde dehydrogenase (ALDH). As such, there is an urgent need for therapies targeting ALDH-positive cancer cells. The present study compares the anticancer properties of 36 structurally diverse isothiocyanates (ITCs) against NSCLC cells with the ALDH inhibitor disulfiram (DSF). Their potential affinity to ALDH isoforms and ABC proteins was assessed using AutoDockTools, allowing for selection of three compounds presenting the strongest affinity to all tested proteins. The selected ITCs had no impact on NSCLC cell viability (at tested concentrations), but significantly decreased the cisplatin tolerance of cisplatin-resistant variant of A549 (A549CisR) and advanced (stage 4) NSCLC cell line H1581. Furthermore, long-term supplementation with ITC 1-(isothiocyanatomethyl)-4-phenylbenzene reverses the EMT phenotype and migratory potential of A549CisR to the level presented by parental A549 cells, increasing E-Cadherin expression, followed by decreased expression of ABCC1 and ALDH3A1. Our data indicates that the ALDH inhibitors DSF and ITCs are potential adjuvants of cisplatin chemotherapy.

Assessment of the Volatile Profiles and Identification of Differentiating Aromas of Wild Undervalued Plants

Wild edible plants have played an important role in traditional diets, including the Mediterranean diet. Many of these plants have acquired an undervalued status, since they are under-appreciated in terms of their nutritional, organoleptic qualities, or their seasonality. However, some of these species are still used in local gastronomy for their aromatic and taste characteristics. This study has investigated the quantitative and qualitative aromatic characteristics of seven undervalued wild plants that determine their organoleptic characteristics. Volatiles of the fresh leaves of each species have been determined by head-space solid-phase microextraction, a sensitive and solvent-free technique, coupled with gas chromatography and mass spectrometry. A total of 37 compounds with remarkable quantitative and qualitative differences were identified. In general, benzenoids and monoterpenoids were the most abundant groups, while branched unsaturated hydrocarbons, fatty alcohols, and sesquiterpenoids were the minor groups. Benzyl nitrile, benzyl isothiocyanate, p-cymene, and 2-hexenal were the main individual volatiles, while benzyl alcohol, eugenol, and α-copaene were the differentiating aromas. The results display that the undervalued species studied could be a suitable choice to include as new environmentally friendly crops, providing a double benefit to producers, because they are a possible way to achieve sustainable production systems, and they are an alternative for consumers, because these plants provide flavors that have high organoleptic qualities.

Flavour Generation during Lactic Acid Fermentation of Brassica Vegetables—Literature Review

Fermentation is a method of food preservation that has been used for centuries. Lactic acid fermentation, apart from extending the shelf-life of vegetables, affects significantly the flavour of food products. In this review, the formation of flavour, including both taste and aroma, in fermented Brassica vegetables is summarized. The flavour-active compounds are generated in various metabolic pathways from many precursors present in raw materials used for fermentation. In Brassica vegetables, a unique group of chemicals, namely glucosinolates, is present, which significantly influence the flavour of fermented products. In this summary, we took a closer look at the flavour of two of the most commonly eaten worldwide fermented Brassica products, which are sauerkraut and kimchi. Finally, the needs and directions for future studies were addressed.

Metabolic Profiling of White and Green Radish Cultivars (Raphanus sativus)

Radish (Raphanus sativus) is a Brassica vegetable important for human nutrition and health because it is rich in diverse metabolites. Although previous studies have evaluated various metabolites, few studies have comprehensively profiled the primary and secondary metabolites in the roots of white- and green-colored radishes. Thus, this study aimed to provide information about the contents of metabolites beneficial for human health in both cultivars and to investigate the relationships between the various metabolites detected. In particular, among the 55 metabolites detected in radish roots, the levels of most amino acids and phenolic acids, vital to nutrition and health, were higher in green radish roots, while slightly higher levels of glucosinolates were observed in white radish roots—information which can be used to develop an effective strategy to promote vegetable consumption. Furthermore, glutamic acid, as a metabolic precursor of amino acids and chlorophylls, was positively correlated with other amino acids (cysteine, tryptophan, asparagine, alanine, serine, phenylalanine, valine, isoleucine, proline, leucine, beta-alanine, lysine, and GABA), and chlorophylls (chlorophyll a and chlorophyll b) detected in radish roots and phenylalanine, a metabolic precursor of phenolic compounds, were positively correlated with kaempferol, 4-hydroxybenzoate, and catechin. In addition, strong positive correlations between carbohydrates (sucrose and glucose) and phenolics were observed in this study, indicating that sucrose and glucose function as energy sources for phenolic compounds.

Sulfur compounds: From plants to humans and their role in chronic disease prevention

Sulfur is essential for the health of plants and is an indispensable dietary component for human health and disease prevention. Its incorporation into our food supply is heavily reliant upon the uptake of sulfur into plant tissue and our subsequent intake. Dietary requirements for sulfur are largely calculated based upon requirements for the sulfur-containing amino acids (SAA), cysteine and methionine, to meet the demands for synthesis of proteins, enzymes, co-enzymes, vitamins, and hormones. SAA are found in abundance in animal sources and are relatively low in plants. However, some plants, particularly cruciferous and allium vegetables, produce many protective sulfur-containing secondary metabolites, such as glucosinolates and cysteine sulfoxides. The variety and quantity of these sulfur-containing metabolites are extensive and their effects on human health are wide-reaching. Many benefits appear to be related to sulfur's role in redox biochemistry, protecting against uncontrolled oxidative stress and inflammation; features consistent within cardiometabolic dysfunction and many chronic metabolic diseases of aging. This narrative explores the origins and importance of sulfur, its incorporation into our food supply and dietary sources. It also explores the overarching potential of sulfur for human health, particularly around the amelioration of oxidative stress and chronic inflammation, and subsequent chronic disease prevention.

Sulforaphane and Its Bifunctional Analogs: Synthesis and Biological Activity

For decades, various plants have been studied as sources of biologically active compounds. Compounds with anticancer and antimicrobial properties are the most frequently desired. Cruciferous plants, including Brussels sprouts, broccoli, and wasabi, have a special role in the research studies. Studies have shown that consumption of these plants reduce the risk of lung, breast, and prostate cancers. The high chemopreventive and anticancer potential of cruciferous plants results from the presence of a large amount of glucosinolates, which, under the influence of myrosinase, undergo an enzymatic transformation to biologically active isothiocyanates (ITCs). Natural isothiocyanates, such as benzyl isothiocyanate, phenethyl isothiocyanate, or the best-tested sulforaphane, possess anticancer activity at all stages of the carcinogenesis process, show antibacterial activity, and are used in organic synthesis. Methods of synthesis of sulforaphane, as well as its natural or synthetic bifunctional analogues with sulfinyl, sulfanyl, sulfonyl, phosphonate, phosphinate, phosphine oxide, carbonyl, ester, carboxamide, ether, or additional isothiocyanate functional groups, and with the unbranched alkyl chain containing 2-6 carbon atoms, are discussed in this review. The biological activity of these compounds are also reported. In the first section, glucosinolates, isothiocyanates, and mercapturic acids (their metabolites) are briefly characterized. Additionally, the most studied anticancer and antibacterial mechanisms of ITC actions are discussed.

Metabolite Characteristics Analysis of Siliques and Effects of Lights on the Accumulation of Glucosinolates in Siliques of Rapeseed

Glucosinolates (GSLs) are naturally occurring secondary metabolites found in the Brassicaceae family, which mainly synthesize in the siliques with a wide range of functions. In this study, we investigated the effects of lights on metabolites in siliques of rapeseed through ultra high-performance liquid chromatography (UPLC)-heated electrospray ionization (HESI)-tandem mass spectrometry (MS/MS). A total of 249 metabolites, including 29 phenolic acids, 38 flavonoids, 22 GSLs, 93 uncalculated and 67 unknown compounds, were identified in siliques of rapeseed. Meanwhile, 62 metabolites showed significant differences after shading treatment, which were mainly GSLs and unknown compounds. Interestingly, the amounts of 10 GSLs had high accumulation levels in siliques, while the expression levels of their corresponding biosynthetic genes (AOP, GSL-OH, IGMT, and ST5a) were obviously reduced after shading treatment. Further evidence showed that the amounts of GSLs were significantly reduced in seeds, in accordance with the expression profiles of transporter genes (BnaGTRs). Our findings indicated that lights could affect the accumulation and transportation of GSLs from siliques to seeds in rapeseed. Therefore, this study facilitates a better understanding of metabolic characteristics of siliques and provides insight into the importance of light for GSLs accumulation and transportation in siliques and seeds of rapeseed.