Enzyme-Triggered Chromogenic and Fluorogenic Probes for Myrosinase Activity Detection.

Myrosinase, a thioglucosidase, is a key enzyme in the mechanism of defense of plants that hydrolyzes glucosinolates (GSLs) into isothiocyanates. These isothiocyanates are the main bioactive molecules exerting protective effect in Brassicales plants. These plants that contain this specific enzyme-substrate couple belong to our daily human diet and have demonstrated health benefits, such as chemopreventive effects. Thus, the detection of myrosinase activity is a key aspect of the production of isothiocyanates from glucosinolates. Two novel chromogenic and fluorogenic GSLs, GSL p-nitrophenoxy (GSL-pNP) and GSL-4-methylumbelliferone (GSL-4MU), were designed and synthesized to be used as simple and reliable molecular tools to spectrophotometrically detect myrosinase activity in simple and complex mixtures. Notably, the chromogenic GSL enabled the UV-vis detection and quantification of isolated myrosinase activity, while fluorogenic GSL could be used for in vitro activity monitoring of more complex plant materials, such as seeds.

The effect of nitrogen management on seed yield and quality in traditional and canola-quality white mustard.

The article presents the results of a three-year field study that was conducted in Poland to evaluate the yield and quality of seeds and oil from traditional (SAM) and canola-quality white mustard (SAC) in response to different N fertilizer rates (0, 40, 80, 120, and 160 kg ha-1). Seed yields were 25% higher in SAM than SAC. The seeds of SAC contained more crude fat (by 3%) and crude fiber (by 6%) than the seeds of SAM. In turn, the seeds of SAM were a richer source of total protein (by 7%). The content of glucosinolates (GSLs) was 8-10 times lower in the seeds of SAC than SAM. The seeds of both mustard cultivars were most abundant in γ-tocopherol (γ-T) (90-94%). The seeds of SAC were characterized by a higher content of γ-T and a lower α-T/γ-T ratio than SAM seeds. White mustard oil contained mostly MUFAs (69-75%). However, C22:1 accounted for more than 50% of MUFAs in the oil SAM. In the oil SAC, the proportion of C22:1 did not exceed 6%, whereas C18:1 accounted for nearly 85% of total MUFAs. Nitrogen fertilization induced a significant increase in seed yields (by 33%), a decrease in crude fat content (by 3-4%), and an increase in total protein content (by 4%), and crude fiber content (by 7%). Nitrogen decreased GSL levels by 31% in SAM seeds. In SAC, N fertilization induced differences in the qualitative composition of GSLs, but did not affect the total GSL content of seeds. Higher N rates increased the content of α-T and γ-T, the α-T/γ-T ratio, and total T content. Nitrogen fertilization decreased the content of C18:3 in the seeds of the SAM. In SAC, the application of N decreased the content of C18, C18:1, and C18:3, and increased the biosynthesis of C18:2, C20:1, and C22:1.

Decoding comparative taste and nutrition regulation in Chinese cabbage via integrated metabolome and transcriptome analysis.

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is a widely consumed leafy vegetable known for its various health-beneficial nutrients. Caixin (ET and JY) represent distinct cultivars of Chinese cabbage that exhibit differential consumer preference attributed to variations in taste and nutritional content, with ET being characterized as sweeter and more nutritionally superior compared to JY. However, limited research has been conducted to explore regulation of flavor and nutrition-related quality traits in Chinese cabbage. In this pioneer study, comprehensive trans-meta-analysis was used to compare the metabolic and molecular underpinnings behind unique taste and nutritional profiles of ET and JY. 8-Methylsulfonyloctyl glucosinolates and Uridine 5'-diphospho-D-glucose exhibited the highest correlation coefficient in Pearson meta-meta-association, which modulate flavor and nutrition processes. While DAMs primarily featured L-Homomethionine, saccharic acid, 1,6-Di-O-caffeoyl-ß-D-glucose, and Rutin, with notable variations in expression between ET and JY. Conspicuously, DEGs encoding structural enzymes i.e. Glucosinolates (MAM, CYP, UGT), flavonoids (CHS, CHI, F3H) and sucrose (SPS, SPP, SUS) synthases were identified as key players in nutrient and flavor production. Multi-omics conjoint analysis revealed that saccharides, amino acids, ascorbates, flavonoids, organic acids and vitamins were positively correlated with taste and nutrition, and were found to be overexpressed in ET. While aliphatic glucosinolates were abundant in JY compared to ET, they might play a critical role in regulating quality traits. Besides, HPLC and RT-qPCR corroborated multi-omics data reliability. These findings offer novel insights into the mechanisms governing the regulation of taste and nutritional levels in Chinese cabbage.

4-Aldrithiol-based photometric assay for detection of methylthioalkylmalate synthase activity.

In Brassica plants, glucosinolates are a diverse class of natural products, of which aliphatic methionine-derived glucosinolates are the most abundant form. Their structural diversity comes from the elongation of some side-chains by up to 9 carbons, which, after the formation of the core glucosinolate structure, can undergo further chemical modifications. Methylthioalkylmalate synthase (MAMS) catalyzes the iterative elongation process for aliphatic methionine-derived glucosinolates. Most biochemical studies on MAMS have been performed using liquid chromatography/mass spectrometry (LC/MS)-based assays or high-performance liquid chromatography (HPLC)-based assays. The LC/MS- and HPLC-based methods are endpoint assays, which cannot be monitored in real time and require a laborious process for data collection. These analytical methods are inefficient for performing multiple enzymatic assays needed to determine steady-state kinetic parameters or for mechanistic evaluation of pH-dependence and kinetic isotope effect studies. Although the function of MAMS has long been defined, there is a gap in knowledge as it pertains to biochemical characterization of this plant enzyme. Part of this may be due to the lack of efficient methods that can be used for this type of research. This chapter describes a continuous photometric assay to track MAMS activity in real time using the 4-aldrithiol reagent for reaction detection.

Chemical Composition, Antimicrobial and Antioxidant Activities of Broccoli, Kale, and Cauliflower Extracts.

The brassicas have the potential to prevent chronic non-communicable diseases and it is proposed to evaluate the chemical composition, antioxidant and antimicrobial potential of broccoli, cabbage and extracts. The extracts were prepared and characterized and the antioxidant potential was evaluated against three radicals while the antimicrobial potential was analyzed using three techniques against four bacteria. The extracts have glucosinolates and phenolic compounds in their composition, and effectively inhibit the 2,2-diphenyl-1-picrylhydrazyl radical. The extracts of broccoli and cauliflower showed an inhibitory effect against hydroxyl radicals and nitric oxide. Disk diffusion showed that broccoli and cauliflower extract were active against three bacteria, while kale extract showed active halos for Gram-negative bacteria. Kale extract had an inhibitory effect Gram-positive bacteria, cauliflower extract inhibited the growth of Staphylococcus aureus. The cauliflower extract thus had a higher concentration of phenols, a strong antioxidant activity and promising results at a concentration of 100 mg/mL against S. aureus.

Effect of ultrasonic and conventional extraction on bioactive components, glucosinolate content and antidiabetic activity of Crambe tataria.

This study was conducted to determine and compare the phenolic compounds, glucosinolate contents and antidiabetic effects of the extracts obtained by ultrasonic and conventional extraction method of the leaves and flowers of the Crambe tataria. The highest antioxidant activity (12.95 mg/mL IC50 value) and total phenolic content (1313.57 mg GAE/100 g fw) were detected in the ultrasonic flower extract. In total flavonoid results, extracts obtained from the flower part of C. tataria had higher values than that of extracts obtained from the leaf part. The most abundant phenolic component in the flower extract was catechin. The highest catechin content in all samples was detected in the ultrasonic flower extract with a value of 374.37 mg/kg. Rutin was the dominant phenolic component in the leaf extract. Rutin values were 654.38 mg/kg and 757.30 mg/kg for conventional and ultrasonic extraction, respectively. In glucosinolate analysis, the highest glucoraphanin content was obtained in flower samples and by conventional extraction method (3466.84 mg/kg). The highest contents of sinigrin (689.97 mg/kg), glucotropaeolin (420.89 mg/kg), glucoerucin (357.27 mg/kg), glucoraphasatin (181.11 mg/kg) and gluconasturtin (66.07 mg/kg) were detected in ultrasonic flower extracts. The highest α-amylase and α-glucosidase enzyme inhibition effects belonged to the ultrasonic flower extract with values of 3.70 mg/mL and 4.89 mg/mL, respectively. As a result, this study determined for the first time that ultrasonic extraction of C. tataria flowers has much higher bioactive components and antidiabetic effects, revealing the potential use of this plant in the fields of medicine, pharmacology and chemistry.

Cultivated Winter-Type Lunaria annua L. Seed: Deciphering the Glucosinolate Profile Integrating HPLC, LC-MS and GC-MS Analyses, and Determination of Fatty Acid Composition.

Lunaria annua L. (Brassicaceae) is an ornamental plant newly identified in Europe as a promising industrial oilseed crop for its valuable very-long-chain monounsaturated fatty acids (MUFAs), especially erucic acid (EA) and nervonic acid (NA). L. annua seeds were obtained from annual winter-type plants selected and cultivated in Northern France. Using a systematic multiple-method approach, we set out to determine the profile and content of glucosinolates (GSLs), which are the relevant chemical tag of Brassicaceae. Intact GSLs were analyzed through a well-established LC-MS method. Identification and quantification were performed by HPLC-PDA of desulfo-GSLs (dGLs) according to the official EU ISO method. Moreover, GSL structures were confirmed by GC-MS analysis of the related isothiocyanates (ITCs). Seven GSLs were identified, directly or indirectly, as follows: 1-methylethyl GSL, (1S)-1-methylpropyl GSL, (Rs)-5-(methylsulfinyl)pentyl GSL, (Rs)-6-(methylsulfinyl)hexyl GSL, (2S)-2-hydroxy-4-pentenyl GSL, 2-phenylethyl GSL, and 1-methoxyindol-3-ylmethyl GSL. In other respects, the FA composition of the seed oil was determined. Results revealed cultivated L. annua seed to be a source of NA-rich oil, and presscake as a valuable coproduct. This presscake is indeed rich in GSLs (4.3% w/w), precursors of promising bioactive molecules for agricultural and nutraceutical applications.

Optimal Brassicaceae family microgreens from a phytochemical and sensory perspective.

Microgreens, also called superfoods, emerge because of their high levels of nutrients, diverse flavour profiles, and sustainable cultivation methods, which make them culinary delights and valuable to a healthy and flavorful diet. The present study investigated Brassicaceae family microgreens, proposing a novel system (quality indices) that allows scoring among them. Fourteen Brassica microgreen species were morphological, phytochemical, and sensorial investigated. The morphological assessment revealed that radish microgreens exhibited the highest leaf area (p < 0.05), while red mizuna demonstrated superior yield. Cauliflower microgreens contained the highest concentrations of ascorbic acid (HPLC-DAD) and total phenolic content (p < 0.05). Phytochemical analysis using HPLC-MS/MS identified over 18 glucosinolates and phenolic compounds. Red mustard and red cabbage showed the highest glucosinolate content (p < 0.05). Watercress exhibited the highest phenolic compound content (p < 0.05), primarily flavonoids, while broccoli and radish contained the highest isothiocyanate levels. Cauliflower microgreens resulted in the most consumer-accepted variety. Appling quality indices scoring system identified radish, cauliflower, and broccoli microgreens as the most promising species. This study underscores the potential of Brassica microgreens as an excellent source of health-promoting phytochemicals with favorable market acceptance, providing valuable insights for both nutritional research and commercial applications.

Comprehensive Quality Assessment of Brassica napus L. Seeds via HPTLC, LC-QToF, and Anatomical Investigation.

The Brassicaceae family, commonly referred to as cruciferous plants, is globally cultivated and consumed, with the Brassica genus being particularly renowned for its functional components. These vegetables are rich sources of nutrients and health-promoting phytochemicals, garnering increased attention in recent years. This study presents a comprehensive microscopic, chromatographic, and spectroscopic characterization of Brassica napus L. seeds from Kazakhstan aimed at elucidating their morphological features and chemical composition. Microscopic analysis revealed distinct localization of flavonoids, total lipids, and alkaloids. High-performance thin-layer chromatography (HPTLC) analysis of seed extracts demonstrated a complex chemical profile with significant quantities of non-polar compounds in the hexane extracts. Additionally, methanolic extracts revealed the presence of diverse chemical compounds, including alkaloids, flavonoids, and glucosinolates. The chemical composition exhibited varietal differences across different Brassica species, with B. napus L. seeds showing higher concentrations of bioactive compounds. Furthermore, liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QToF-MS) analysis provided insights into the chemical composition, with sinapine isomers, feruloyl, and sinapoyl choline derivatives as major compounds in the seeds. This study contributes to a better understanding of the chemical diversity and quality control methods' approximations of B. napus L. seeds, highlighting their importance in functional food and nutraceutical applications.

Glucosinolate Hydrolytic Products-A Multi-Arm Warrior.

BACKGROUND: Glucosinolates (GSLs) are the most controversial yet ignored class of phytochemicals. These are the middleman phytochemicals that have low bioactivity. But once there is any injury in the plant-manmade, insect caused, or natural-magic happens. The compound is broken down into smaller phytochemicals referred to as glucosinolate hydrolytic products (GHPs; nitriles, isothiocyanates [ITCs], and thiocyanates). These hydrolytic products are like a showstopper of the fashion industry. These compounds have some of the highest bioactivity in nature. They have been associated with a varied range of bioactivities (anticancer, antioxidant, insecticidal, weedicide, etc.) by researchers across the globe. OBJECTIVE: The objective of the current article is to provide a critical review to highlight some of the important bioactivities of these ignored compounds and for promoting researchers to at least give these compounds a chance-to glow in the dark. METHODS: This review has been written from analysis of accessible literature, mostly from the last 5 years (2018-2023), with some critically essential exceptions. RESULTS: The review highlighted a brief background of GSLs and its hydrolysis. Efforts were made to include most of the biological properties of the compound. Special emphasis has been given to the anticancer activities of the compound with details of the involved mechanism. CONCLUSIONS: Considering the wide array of bioactivities of GHPs, it is essential to consider it as a prospective medicinal compound. More GHPs-in a similar manner as sulforaphane-can be proceeded to phase trials. HIGHLIGHTS: The mechanistic pathway for production of GHPs and related biological activities have been discussed in detail. The bioactivities have been further explained using the involved mechanism.

Glucosinolates and Their Hydrolytic Products-A Love Story of Environmental, Biological, and Chemical Conditions.

BACKGROUND: Glucosinolates (GSL) play an important role in providing defense to plants and helping them to cope with various biotic, as well as abiotic, stresses. Many living beings including humans and animals, including some herbivores, have adapted themselves to use this defense mechanism for their own use. More than 120 glucosinolates are distributed within a large number of plants. Many factors are known to influence the GSL composition in a plant. Among these, cofactors, myrosinase isozymes, heavy metals and the environmental conditions such as light, CO2 and temperature are important in regulation. These factors ensure that different glucosinolate compositions can be produced by the plants, thus impacting the defense mechanism. OBJECTIVE: The objective of the current review is to highlight the importance of the factors responsible for affecting glucosinolate composition and concentration. METHODS: The review has been compiled using accessible literature from Pubmed, Scopus, and Google scholar. Efforts have been made to restrict the literature to the last 5 years (2018-2023), with some exceptions. RESULTS: The current critical review acts as a resource for all the researchers working on these essential compounds. It provides information on the factors that may influence glucosinolate production. It also gives them an opportunity to modify the glucosinolate composition of a plant using the given information. CONCLUSIONS: Glucosinolates have long been an ignored class of biomolecule. The plethora of biological activities of the compounds can be useful. Though there are some harmful components such as goitrin and progoitrin, these can be easily removed by modulating some of the factors highlighted in the review. HIGHLIGHTS: The current review has covered most of the factors that have the ability to modify glucosinolate composition and concentration. The mechanistic action of these factors has also been discussed using the current available literature.

Relationship between secondary metabolites and insect loads in cabbage with different leaf shapes and positions.

INTRODUCTION: Secondary metabolites in plants play a crucial role in defense mechanisms against insects, pests, and pathogens. These metabolites exhibit varying distributions within and among plant parts under different biotic and abiotic conditions. Understanding the intricate relationships between secondary metabolites and insect populations can be helpful for elucidating plant defense mechanisms and enhancing agricultural managing efficiencies. OBJECTIVE: To investigate the influence of the glucosinolate profile in the leaves of three cabbage (Brassica oleracea var. capitata L.) varieties on insect loads. METHODS: Glucosinolate profiles across different leaf positions (such as bottom, middle, and center) and leaf shapes (such as curly and non-curly leaf) of three cabbage varieties (Xiagan [XGA], Xiaguang [XGU], and Qiangxia [QIX]) were analyzed by using high-performance liquid chromatography-mass spectrometry (LC-MS). The insect loads were recorded by visually inspecting the upper and lower layers of each target leaf. RESULTS: Increasing concentrations of four glucosinolates, namely, glucoiberin, progoitrin, glucoraphanin, and glucobrassicin, were positively related to insect loads. While increasing concentrations of the other four glucosinolates, such as neoglucobrassicin, 4-methoxyglucobrassicin, sinigrin, and gluconapin, were negatively related to insect loads. Furthermore, both glucosinolate synthesis and insect loads were significantly higher in the curly-shaped and middle-position leaves than in the non-curly-shaped and bottom- and central-position leaves across the cabbage varieties. CONCLUSION: Differences in glucosinolate profiles across leaf positions and shapes strongly influenced the insect loads of the three Brassica varieties. This link may further extend our understanding of the real defense power of a particular variety against herbivore damage.

Variations of Major Glucosinolates in Diverse Chinese Cabbage (Brassica rapa ssp. pekinensis) Germplasm as Analyzed by UPLC-ESI-MS/MS.

In this study, the variability of major glucosinolates in the leaf lamina of 134 Chinese cabbage accessions was investigated using Acquity ultra-performance liquid chromatography (UPLC-ESI-MS/MS). A total of twenty glucosinolates were profiled, of which glucobrassicanapin and gluconapin were identified as the predominant glucosinolates within the germplasm. These two glucosinolates had mean concentration levels above 1000.00 µmol/kg DW. Based on the principal component analysis, accessions IT186728, IT120044, IT221789, IT100417, IT278620, IT221754, and IT344740 were separated from the rest in the score plot. These accessions exhibited a higher content of total glucosinolates. Based on the VIP values, 13 compounds were identified as the most influential and responsible for variation in the germplasm. Sinigrin (r = 0.73), gluconapin (r = 0.78), glucobrassicanapin (r = 0.70), epiprogoitrin (r = 0.73), progoitrin (r = 0.74), and gluconasturtiin (r = 0.67) all exhibited a strong positive correlation with total glucosinolate at p < 0.001. This indicates that each of these compounds had a significant influence on the overall glucosinolate content of the various accessions. This study contributes valuable insights into the metabolic diversity of glucosinolates in Chinese cabbage, providing potential for breeding varieties tailored to consumer preferences and nutritional demands.

The thermal degradation of glucomoringin and changes of phenolic compounds in moringa seed kernels during different degrees of roasting.

The effect of heat treatment on the abundant bioactive compounds in moringa seed kernels (MSKs) during different degrees of roasting remains sparingly explored despite the flour of roasted MSKs has been incorporated into the human diet (e.g., cakes, cookies, and burgers) as a substitute to enrich the nutritional content. Therefore, we investigated the impacts of different roasting conditions (e.g., temperature and duration) on bioactive compounds (e.g., glucosinolates (GSLs), phenolic acids and alkaloids) and antioxidant capacity of MSKs. Our results showed that light and medium roasting increased the glucomoringin (GMG, the main GSL in MSKs) content from 43.7 (unroasted MSKs) to 69.7-127.3 µmol/g MSKs (dry weight), while excessive/dark roasting caused thermally-induced degradation of GMG (trace/undetectable level) in MSKs, resulting in the formation of various breakdown products (e.g., thiourea, nitrile, and amide). In addition, although roasting caused a significant reduction of some phenolic compounds (e.g., gallic, chlorogenic, p-coumaric acids, and trigonelline), other phenolic acids (e.g., caffeic and ferulic acids) and alkaloids (e.g., caffeine, theobromine, and theophylline) remarkably increased after roasting, which may contribute to the enhanced total phenolic content (up to 2.9-fold) and antioxidant capacity (up to 5.8-fold) of the roasted MSKs.

Exploring the bioaccessibility of polyphenols and glucosinolates from Brassicaceae microgreens by combining metabolomics profiling and computational chemometrics.

Microgreens constitute natural-based foods with health-promoting properties mediated by the accumulation of glucosinolates (GLs) and phenolic compounds (PCs), although their bioaccessibility may limit their nutritional potential. This work subjected eight Brassicaceae microgreens to in vitro gastrointestinal digestion and large intestine fermentation before the metabolomics profiling of PCs and GLs. The application of multivariate statistics effectively discriminated among species and their interaction with in vitro digestion phases. The flavonoids associated with arugula and the aliphatic GLs related to red cabbage and cauliflower were identified as discriminant markers among microgreen species. The multi-omics integration along in vitro digestion and fermentation predicted bioaccessible markers, featuring potential candidates that may eventually be responsible for these functional foods' nutritional properties. This combined analytical and computational framework provided a promising platform to predict the nutritional metabolome-wide outcome of functional food consumption, as in the case of microgreens.

Germination Increases the Glucomoringin Content in Moringa Sprouts via Transforming Tyrosine.

Moringa seeds are an excellent dietary source of phytochemicals (i.e., glucosinolates, GSLs; isothiocyanates, ITCs) with health-beneficial effects. Although numerous studies have been conducted on moringa seeds, the effect of germination on the regulation of GSLs remains scarcely explored. The present study investigated the dynamic changes of GSLs in moringa seeds during germination (at 25, 30, and 35 °C for 6 days in the dark) through an untargeted metabolomics approach and compared the antioxidant capacity of ungerminated and germinated moringa seeds. Our results showed that germination significantly increased the total GSL content from 150 (day 0) to 323 µmol/g (35 °C, day 6) on a dry weight (DW) basis, especially glucomoringin (GMG), the unique glucosinolate in moringa seeds, which was significantly upregulated from 61 (day 0) to 149 µmol/g DW (35 °C, day 4). The upregulation of GMG corresponded to the metabolism of tyrosine, which might be the initial precursor for the formation of GMG. In addition, germination enhanced the total ITC content from 85 (day 0) to 239 µmol SE/g DW (35 °C, day 6), indicating that germination may have also increased the activity of myrosinase. Furthermore, germination remarkably increased the total phenolic content (109-507 mg GAE/100 g DW) and antioxidant capacity of moringa seeds. Our findings suggest that moringa sprouts could be promoted as a novel food and/or ingredient rich in GMG.

LC/MS-Based Metabolomics Reveals Chemical Variations of Two Broccoli Varieties in Relation to Their Anticholinesterase Activity: In vitro and In silico Studies.

Broccoli is commonly consumed as food and as medicine. However, comprehensive metabolic profiling of two broccoli varieties, Romanesco broccoli (RB) and purple broccoli (PB), in relation to their anticholinergic activity has not been fully disclosed. A total of 110 compounds were tentatively identified using UPLC-Q-TOF-MS metabolomics. Distinctively different metabolomic profiles of the two varieties were revealed by principal component analysis (PCA). Furthermore, by volcano diagram analysis, it was found that PB had a significantly higher content of phenolic acids, flavonoids, and glucosinolates, indicating the different beneficial health potentials of PB that demonstrated higher antioxidant and anticholinergic activities. Moreover, Pearson's correlation analysis revealed 18 metabolites, mainly phenolic and sulfur compounds, as the main bioactive. The binding affinity of these biomarkers to the active sites of acetyl- and butyryl-cholinesterase enzymes was further validated using molecular docking studies. Results emphasize the broccoli significance as a functional food and nutraceutical source and highlight its beneficial effects against Alzheimer's disease.

Microbial terroir: associations between soil microbiomes and the flavor chemistry of mustard (Brassica juncea).

Here, we characterized the independent role of soil microbiomes (bacterial and fungal communities) in determining the flavor chemistry of harvested mustard seed (Brassica juncea). Given the known impacts of soil microbial communities on various plant characteristics, we hypothesized that differences in rhizosphere microbiomes would result in differences in seed flavor chemistry (glucosinolate content). In a glasshouse study, we introduced distinct soil microbial communities to mustard plants growing in an otherwise consistent environment. At the end of the plant life cycle, we characterized the rhizosphere and root microbiomes and harvested produced mustard seeds for chemical characterization. Specifically, we measured the concentrations of glucosinolates, secondary metabolites known to create spicy and bitter flavors. We examined associations between rhizosphere microbial taxa or genes and seed flavor chemistry. We identified links between the rhizosphere microbial community composition and the concentration of the main glucosinolate, allyl, in seeds. We further identified specific rhizosphere taxa predictive of seed allyl concentration and identified bacterial functional genes, namely genes for sulfur metabolism, which could partly explain the observed associations. Together, this work offers insight into the potential influence of the belowground microbiome on the flavor of harvested crops.

Stability and bioaccessibility of micronutrients and phytochemicals present in processed leek and Brussels sprouts during static in vitro digestion.

Vegetables are frequently processed before consumption. However, vegetable functionalization continues beyond ingestion as the human digestive tract exposes vegetable products to various conditions (e.g. elevated temperature, pH alterations, enzymes, electrolytes, mechanical disintegration) which can affect the stability of micronutrients and phytochemicals. Besides the extent to which these compounds withstand the challenges posed by digestive conditions, it is equally important to consider their accessibility for potential absorption by the body. Therefore, this study investigated the impact of static in vitro digestion on the stability (i.e. concentration) and bioaccessibility of vitamin C, vitamin K1, glucosinolates, S-alk(en)yl-l-cysteine sulfoxides (ACSOs) and carotenoids in Brussels sprouts (Brassica oleracea var. gemmifera) and leek (Allium ampeloprasum var. porrum). Water-soluble compounds, glucosinolates and ACSOs, remained stable during digestion while vitamin C decreased by >48%. However, all water-soluble compounds were completely bioaccessible. Lipid-soluble compounds were also stable during digestion but were only bioaccessible for 26-81%.

Engineering Brassica Crops to Optimize Delivery of Bioactive Products Postcooking.

Glucosinolates are plant-specialized metabolites that can be hydrolyzed by glycosyl hydrolases, called myrosinases, creating a variety of hydrolysis products that benefit human health. While cruciferous vegetables are a rich source of glucosinolates, they are often cooked before consumption, limiting the conversion of glucosinolates to hydrolysis products due to the denaturation of myrosinases. Here we screen a panel of glycosyl hydrolases for high thermostability and engineer the Brassica crop, broccoli (Brassica oleracea L.), for the improved conversion of glucosinolates to chemopreventive hydrolysis products. Our transgenic broccoli lines enabled glucosinolate hydrolysis to occur at higher cooking temperatures, 20 °C higher than in wild-type broccoli. The process of cooking fundamentally transforms the bioavailability of many health-relevant bioactive compounds in our diet. Our findings demonstrate the promise of leveraging genetic engineering to tailor crops with novel traits that cannot be achieved through conventional breeding and improve the nutritional properties of the plants we consume.