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%.

Innovative analytical methodologies for characterizing chemical exposure with a view to next-generation risk assessment

The chemical burden on the environment and human population is increasing. Consequently, regulatory risk assessment must keep pace to manage, reduce, and prevent adverse impacts on human and environmental health associated with hazardous chemicals. Surveillance of chemicals of known, emerging, or potential future concern, entering the environment-food-human continuum is needed to document the reality of risks posed by chemicals on ecosystem and human health from a one health perspective, feed into early warning systems and support public policies for exposure mitigation provisions and safe and sustainable by design strategies. The use of less-conventional sampling strategies and integration of full-scan, high-resolution mass spectrometry and effect-directed analysis in environmental and human monitoring programmes have the potential to enhance the screening and identification of a wider range of chemicals of known, emerging or potential future concern. Here, we outline the key needs and recommendations identified within the European Partnership for Assessment of Risks from Chemicals (PARC) project for leveraging these innovative methodologies to support the development of next-generation chemical risk assessment.

Chestnut Wood Tannins in Broiler Diets: Pharmacokinetics, Serum Levels during Rearing, and Intestinal Absorption Pattern of Gallic Acid

Studies on the bioavailability, serum levels, and absorption of hydrolyzable tannin compounds are lacking. In this study, we performed a pharmacokinetic trial, measured the serum levels of compounds in broilers that were reared with different feed added or not with tannins, and tested the digestibility of tannins throughout the intestinal tract. Only gallic acid and 4-O-methyl gallic acid were found in the serum. Moreover, gallic acid showed a 41.8% absolute oral bioavailability and a 72.3% relative bioavailability of gallic acid from chestnut extract compared to the standard. The rapid metabolization caused alternating serum levels during the day and night. These patterns were not affected by the feed type or the previous addition of tannins in the feed. The absorption and metabolization in the intestines occurred gradually throughout the intestinal tract. The latter was true for gallic acid as well as ellagic acid, which was not found in the serum. We can conclude that components from chestnut tannins are absorbed throughout all components of the intestinal tract and are eliminated quickly with little interaction from the feed and previous addition of tannins. Moreover, ellagic acid seems to be absorbed but would remain accumulated in the intestinal tissue or be metabolized by the microbiome.

Impact of refrigerated storage on (bio)chemical conversions of health-related compounds in pretreated, pasteurized Brussels sprouts and leek

Vegetable processing often consists of multiple processing steps. Research mostly focused on the impact of individual processing steps on individual health-related compounds. However, there is a need for more holistic approaches to understand the overall impact of the processing chain on the health potential of vegetables. Therefore, this work studied the impact of pretreatment (relatively intact versus pureed vegetable systems), pasteurization and subsequent refrigerated storage (kinetic evaluation) on multiple health-related compounds (vitamin C, vitamin K1, carotenoids, glucosinolates and S-alk(en)yl-L-cysteine sulfoxides (ACSOs)) in Brussels sprouts and leek. It could be shown that differences introduced by different types of pretreatment were not nullified during pasteurization and refrigerated storage. Clearly, enzymatic conversions controlled during pretreatment resulted in different health-related compound profiles still observable after pasteurization. Moreover, about -42% and -100% relative concentration differences of ACSOs and dehydroascorbic acid, respectively, were detected immediately after pasteurization, while glucosinolates concentrations decreased by about 47% during refrigerated storage. All other compounds were stable during pasteurization and refrigerated storage.

Emerging pharmaceutical therapies of Ascidian-derived natural products and derivatives

In a growing multidrug-resistant environment, the identification of potential new drug candidates with an acceptable safety profile is a substantial crux in pharmaceutical discovery. This review discusses several aspects and properties of approved marine natural products derived from ascidian sources (phylum Chordata, subphylum Tunicata) and/or their deduced analogues including their biosynthetic origin, (bio)chemical preclinical assessments and known efficacy-safety profiles, clinical status in trials, but also translational developments, opportunities and final conclusions. The review also describes the preclinical assessments of a large number of other ascidian compounds that have not been involved in clinical trials yet. Finally, the emerging research on the connectivity of the ascidian hosts and their independent or obligate symbiotic guests is discussed. The review covers the latest information on the topic of ascidian-derived marine natural products over the last two decades including 2022, with the majority of publications published in the last decade.

Identification and characterization of CYP71 subclade cytochrome P450 enzymes involved in the biosynthesis of bitterness compounds in Cichorium intybus

Industrial chicory (Cichorium intybus var. sativum) and witloof (C. intybus var. foliosum) are crops with an important economic value, mainly cultivated for inulin production and as a leafy vegetable, respectively. Both crops are rich in nutritionally relevant specialized metabolites with beneficial effects for human health. However, their bitter taste, caused by the sesquiterpene lactones (SLs) produced in leaves and taproot, limits wider applications in the food industry. Changing the bitterness would thus create new opportunities with a great economic impact. Known genes encoding enzymes involved in the SL biosynthetic pathway are GERMACRENE A SYNTHASE (GAS), GERMACRENE A OXIDASE (GAO), COSTUNOLIDE SYNTHASE (COS) and KAUNIOLIDE SYNTHASE (KLS). In this study, we integrated genome and transcriptome mining to further unravel SL biosynthesis. We found that C. intybus SL biosynthesis is controlled by the phytohormone methyl jasmonate (MeJA). Gene family annotation and MeJA inducibility enabled the pinpointing of candidate genes related with the SL biosynthetic pathway. We specifically focused on members of subclade CYP71 of the cytochrome P450 family. We verified the biochemical activity of 14 C. intybus CYP71 enzymes transiently produced in Nicotiana benthamiana and identified several functional paralogs for each of the GAO, COS and KLS genes, pointing to redundancy in and robustness of the SL biosynthetic pathway. Gene functionality was further analyzed using CRISPR/Cas9 genome editing in C. intybus. Metabolite profiling of mutant C. intybus lines demonstrated a successful reduction in SL metabolite production. Together, this study increases our insights into the C. intybus SL biosynthetic pathway and paves the way for the engineering of C. intybus bitterness.

Nicotine in the button mushroom Agaricus bisporus, endogenous biosynthesis?

In early 2009 nicotine was unexpectedly detected in dried mushroom samples. As its origin has not yet been elucidated, this study addressed possible endogenous synthesis of nicotine. Therefore, Agaricus bisporus fruiting bodies were grown in a representative and controlled (nicotine-free) setup. Fruiting bodies (fresh versus stored, intact versus processed (sliced/cooked)) from different harvest days and flushes were analysed with a validated, sensitive dilute-and-shoot UHPLC-MS/MS methodology for nicotine and its precursors putrescine and nicotinic acid. Neither storage nor processing initiated any endogenous nicotine biosynthesis (detection limit 1.6 ng g^-1 fresh weight). In contrast, putrescine and nicotinic acid were detected in all samples, with increasing amounts in the different treatments. In silico analysis of the fully sequenced genome of A. bisporus confirmed its inability to produce nicotine. The data obtained do not provide evidence for natural, endogenous presence of nicotine in mushrooms, indicating an exogenous contamination source (e.g. contamination during hand-picking, sample preparation/analysis).

Multi-Allergen Quantification in Food Using Concatemer-Based Isotope Dilution Mass Spectrometry: A Collaborative Study

BACKGROUND

Food allergen analysis is essential for the development of a risk-based approach for allergen management and labeling. Mass spectrometry has become a method of choice for allergen analysis, even if quantification remains challenging. Moreover, harmonization is still lacking between laboratories, while interlaboratory validation of analytical methods is necessary for such harmonization.

OBJECTIVE

This collaborative study aimed to evaluate the potential of mass spectrometry for food allergen detection and quantification using a standard addition quantification strategy and a stable isotope-labeled concatemer as an internal standard.

METHODS

In-house-produced test material (cookies), blank and incurred with four allergens (egg, milk, peanut and hazelnut), allergen standards, an internal standard and the complete methodology (including sample preparation and UHPLC-MS/MS method) were provided to nine laboratories involved in the study. Method sensitivity and selectivity were evaluated with incurred test material and accuracy with spiked test material. Quantification was based on the standard addition strategy using certified reference materials as allergen protein standards and a stable isotope-labeled concatemer as an internal standard.

RESULTS

All laboratories were able to detect milk, hazelnut and peanut in the incurred cookies with sufficient sensitivity to reach the AOAC INTERNATIONAL Standard Method Performance Requirements (SMPR® 2016.002). Egg detection was more complicated due to food processing effects, yet five laboratories reached the sensitivity requirements. Recovery results were laboratory dependent. Some milk and hazelnut peptides were quantified in agreement with SMPR by all participants. Furthermore, over 90% of the received quantification results agreed with SMPR for method precision.

CONCLUSION

The encouraging results of this pioneering collaborative study represent an additional step towards harmonization among laboratories testing for allergens.

HIGHLIGHTS

In this pioneer collaborative study, food allergens were analyzed by mass spectrometry with characterized incurred and spiked test materials, calibration with certified reference material and a single stable isotope-labeled concatemer as an internal standard.

Assessment of transcriptional reprogramming of lettuce roots in response to chitin soil amendment

Chitin soil amendment is known to improve soil quality, plant growth and stress resilience, but the underlying mechanisms are not well understood. In this study, we monitored chitin's effect on lettuce physiology every two weeks through an eight-week growth period, analyzed the early transcriptional reprogramming and related metabolomic changes of lettuce, in response to crab chitin treatment in peat-based potting soil. In commercial growth conditions, chitin amendment still promoted lettuce growth, increased chlorophyll content, the number of leaves and crop head weight from week six. The flavonoid content in lettuce leaves was altered as well, showing an increase at week two but a decrease from week six. Transcriptomic analysis showed that over 300 genes in lettuce root were significantly differentially expressed after chitin soil treatment. Gene Ontology-term (GO) enrichment analysis revealed statistical overrepresentation of GO terms linked to photosynthesis, pigment metabolic process and phenylpropanoid metabolic process. Further analysis of the differentially expressed genes (DEGs) showed that the flavonoid pathway was mostly upregulated whereas the bifurcation of upstream phenylpropanoid pathway towards lignin biosynthesis was mostly downregulated. Metabolomic analysis revealed the upregulation of salicylic acid, chlorogenic acid, ferulic acid, and p-coumaric acid in chitin-treated lettuce seedlings. These phenolic compounds (PCs) mainly influence the phenylpropanoid biosynthesis pathway and may play important roles in plant defense reactions. Our results suggest that chitin soil amendments might activate induced resistance by priming lettuce plants and promote lettuce growth via transcriptional changes.

Sunflower Bark Extract as a Biostimulant Suppresses Reactive Oxygen Species in Salt-Stressed Arabidopsis

A survey of plant-based wastes identified sunflower (Helianthus annuus) bark extract (SBE), produced via twin-screw extrusion, as a potential biostimulant. The addition of SBE to Arabidopsis (Arabidopsis thaliana) seedlings cultured in vitro showed a dose-dependent response, with high concentrations causing severe growth inhibition. However, when priming seeds with SBE, a small but significant increase in leaf area was observed at a dose of 0.5 g of lyophilized powder per liter. This optimal concentration of SBE in the culturing medium alleviated the growth inhibition caused by 100 mM NaCl. The recovery in shoot growth was accompanied by a pronounced increase in photosynthetic pigment levels and a stabilization of osmotic homeostasis. SBE-primed leaf discs also showed a similar protective effect. SBE mitigated salt stress by reducing the production of reactive oxygen species (ROS) (e.g., hydrogen peroxide) by about 30% and developing more expanded true leaves. This reduction in ROS levels was due to the presence of antioxidative agents in SBE and by activating ROS-eliminating enzymes. Polyphenols, carbohydrates, proteins, and other bioactive compounds detected in SBE may have contributed to the cellular redox homeostasis in salt-stressed plants, thus promoting early leaf development by relieving shoot apical meristem arrest. Sunflower stalks from which SBE is prepared can therefore potentially be valorized as a source to produce biostimulants for improving salt stress tolerance in crops.

Development of incurred chocolate bars and broth powder with six fully characterised food allergens as test materials for food allergen analysis

The design and production of incurred test materials are critical for the development and validation of methods for food allergen analysis. This is because production and processing conditions, together with the food matrix, can modify allergens affecting their structure, extractability and detectability. For the ThRAll project, which aims to develop a mass spectrometry-based reference method for the simultaneous accurate quantification of six allergenic ingredients in two hard to analyse matrices. Two highly processed matrices, chocolate bars and broth powder, were selected to incur with six allergenic ingredients (egg, milk, peanut, soy, hazelnut and almond) at 2, 4, 10 and 40 mg total allergenic protein/kg food matrix using a pilot-scale food manufacturing plant. The allergenic activity of the ingredients incurred was verified using food-allergic patient serum/plasma IgE, the homogeneity of the incurred matrices verified and their stability at 4 °C assessed over at least 30-month storage using appropriate enzyme-linked immunosorbent assays (ELISA). Allergens were found at all levels from the chocolate bar and were homogenously distributed, apart from peanut and soy which could only be determined above 4 mg total allergenic ingredient protein/kg. The homogeneity assessment was restricted to analysis of soy, milk and peanut for the broth powder but nevertheless demonstrated that the allergens were homogeneously distributed. All the allergens tested were found to be stable in the incurred matrices for at least 30 months demonstrating they are suitable for method development.

Selecting processing robust markers using high resolution mass spectrometry for the detection of milk in food products

BACKGROUND

Cow's milk allergy is one of the most reported food allergies in Europe. To help patients suffering from food allergies it is important to be able to detect milk in different foods. An analytical method that is gaining interest in the field of allergen detection is Ultra-High Performance Liquid Chromatography-tandem Mass Spectrometry, where the analyte is a target peptide. When these peptide biomarkers are selected the effect of food processing should be taken into account to allow a robust detection method.

OBJECTIVE

This works aims at identifying such processing stable peptide markers for milk for the Ultra-High Performance Liquid Chromatography-tandem Mass Spectrometry based detection of food allergens in different food products.

METHODS

Milk-incurred food materials that underwent several processing techniques were produced. This was followed by establishing tryptic peptide profiles from each matrix using Ultra-High Performance Liquid Chromatography-High Resolution Mass Spectrometry .

RESULT

A careful comparison of peptide profiles/intensities and the use of specific exclusion criteria resulted in the selection of 8 peptide biomarkers suitable for application in Ultra-High Performance Liquid Chromatography-tandem Mass Spectrometry based milk detection methods. One of these markers is a α-lactalbumin specific peptide, which has been determined to be stable in different incurred materials for the first time.

CONCLUSION

To our knowledge, this is the first systematic and experimentally based approach for the selection of suitable milk peptide biomarkers robust towards multiple, often applied food processing techniques for milk. Ensuring the exact knowledge of the food processing circumstances by starting from well-defined raw material and using fully controlled settings to produce incurred test material allowed the construction of a peptide database with robust markers. These robust markers can be used for the development of a robust detection method for milk in different food matrices.

Multi-Class UHPLC-MS/MS Method for Plant Toxins and Cyanotoxins in Food Supplements and Application for Belgian Market Samples

The presence of plant toxins and/or cyanotoxins in food supplements implies consumer health risks. Therefore, a targeted ultra-high performance liquid chromatographic-tandem mass spectrometric method to detect/quantify 25 toxins simultaneously in food supplement formulations was developed and validated. Full validation for tablets/powders and secondary validation for a liquid and soft gel capsule indicated that most compounds were efficiently extracted (≥ 75%), while others were only partly extracted (18 - 61%). Trueness was fulfilled (70 - 120%), with some exceptions (mostly at the lowest validation level). Intralaboratory repeatability, intra- and interlaboratory reproducibility values of ≤ 20%, ≤ 25%, and ≤ 25% were obtained for most, respectively. Matrix effects were found to be significant for most compounds. Good sensitivity (µg/kg level) was observed for galegin(e), lycopsamine, lycorine, rubiadin, skimmiamine, and vascin(e), in contrast to helveticoside, lucidin, lucidin-3-primveroside, plumbagin(e), and thujone, which were detected at the mg/kg level. The other compounds were characterized by a sensitivity between 10 to 1000 µg/kg. The validated methodology was applied for 52 food supplements (tablets, capsules, liquids/syrup, etc.) purchased from the Belgian market. In more than 25% of the samples, one or more toxins were detected (concentrations determined using standard addition). Lycopsamine, microcystin LR, solamargine, thujone, and vasicin(e) were the most frequently detected toxins. A clear link between the toxins detected and the plant species on the food supplement ingredient list could not always be established. This generic "dilute-and-shoot" procedure can be used for further research on toxins in food supplements and by extension other plant/algae-based food/feed commodities (herbs, edible flowers, etc.).

Parkinson's disease patients' short chain fatty acids production capacity after in vitro fecal fiber fermentation

Animal models indicate that butyrate might reduce motor symptoms in Parkinson's disease. Some dietary fibers are butyrogenic, but in Parkinson's disease patients their butyrate stimulating capacity is unknown. Therefore, we investigated different fiber supplements' effects on short-chain fatty acid production, along with potential underlying mechanisms, in Parkinson's patients and age-matched healthy controls. Finally, it was investigated if this butyrate production could be confirmed by using fiber-rich vegetables. Different fibers (n = 40) were evaluated by in vitro fermentation experiments with fecal samples of Parkinson's patients (n = 24) and age-matched healthy volunteers (n = 39). Short-chain fatty acid production was analyzed by headspace solid-phase micro-extraction gas chromatography-mass spectrometry. Clostridium coccoides and C. leptum were quantified through 16S-rRNA gene-targeted group-specific qPCR. Factors influencing short-chain fatty acid production were investigated using linear mixed models. After fiber fermentation, butyrate concentration varied between 25.6 ± 16.5 µmol/g and 203.8 ± 91.9 µmol/g for Parkinson's patients and between 52.7 ± 13.0 µmol/g and 229.5 ± 42.8 µmol/g for controls. Inulin had the largest effect, while xanthan gum had the lowest production. Similar to fiber supplements, inulin-rich vegetables, but also fungal β-glucans, stimulated butyrate production most of all vegetable fibers. Parkinson's disease diagnosis limited short-chain fatty acid production and was negatively associated with butyrate producers. Butyrate kinetics during 48 h fermentation demonstrated a time lag effect in Parkinson's patients, especially in fructo-oligosaccharide fermentation. Butyrate production can be stimulated in Parkinson's patients, however, remains reduced compared to healthy controls. This is a first step in investigating dietary fiber's potential to increase short-chain fatty acids in Parkinson's disease.

Upcycling of Belgian endive (Cichorium intybus var. foliosum) by-products. Chemical composition and functional properties of dietary fibre root powders

By-products of Belgian endive represent an interesting yet underutilised source of dietary fibre (DF). Dietary fibre concentrates (DFC) that are low in sugar and neutral in taste are sought by the food industry to increase DF content and improve texture in food products. The aim was to set up a biorefinery process to produce DFC from forced roots of Belgian endive (DFC-BE) and characterise the resulting product. As a control, non-treated forced roots powder (FRP-BE) was tested. Water extraction significantly (p < 0.05) decreased the content of sugars, phenolic acids (PA) and sesquiterpene lactones (SL) in DFC-BE. In contrast, total dietary fibre concentration (TDF) was higher in DFC-BE (81.82 g/100 g DW) in comparison to FRP-BE (49.04 g/100 g DW). DFC-BE offers an excellent water holding capacity (WHC) of 14.71 g water/g DW and a swelling capacity (SWC) of 23.46 mL water/g DW, suggesting possible use as a functional food ingredient.

Discovery based high resolution MS/MS analysis for selection of allergen markers in chocolate and broth powder matrices

Peptide marker identification is an important step in development of a mass spectrometry method for multiple allergen detection, since specificity, robustness and sensitivity of the overall analytical method will depend on the reliability of the proteotypic peptides. As part of the development of a multi-analyte reference method, discovery analysis of two incurred food matrices has been undertaken to select the most reliable peptide markers. Six allergenic ingredients (milk, egg, peanut, soybean, hazelnut, and almond) were incurred into either chocolate or broth powder matrix. Different conditions of protein extraction and purification were tested and the tryptic peptide pools were analysed by untargeted high resolution tandem mass spectrometry and the resulting fragmentation spectra were processed via a commercial software for sequence identification. The analysis performed on incurred foods provides both a prototype effective and straightforward sample preparation protocol and delivers reliable peptides to be included in a standardized selected reaction monitoring method.

Kinetics of drosopterin release as indicator pigment for heat-induced color changes of brown shrimp (Crangon crangon)

Heat-induced color changes of crustaceans are commonly described as the release of astaxanthin. In this study on Crangon crangon, it was found that astaxanthin plays a minor role in the (dis)coloration. By LC-HRMS, two polar, process dependent pigments were found. One pigment was identified as riboflavin and one as drosopterin (level-2 certainty). Thermal treatments had highest effect on drosopterin concentration changes and were chosen as indicator for a kinetic study of heat-induced color changes. The kinetic data fitted a consecutive step model (r² = 0.971), including a first step in which drosopterin was released (k_d,85°C = 0.95 ± 0.09 min^-1; Ea_d = 105 ± 4 kJ/mol) and a second step where drosopterin is degraded (k_b,85°C = 0.02 ± 0.002 min^-1; Ea_b = 190 ± 15 kJ/mol). The kinetic model shows that shrimp should be heated at lower temperatures (<80 °C) than the heating temperatures used by fishermen (86-101 °C), creating opportunities for quality optimization. Therefore, this study delivers essential information needed in a comprehensive quality optimization study of the cooked brown shrimp.

Ultra-High-Performance Supercritical Fluid Chromatography as a Separation Tool for Fusarium Mycotoxins and Their Modified Forms

A simple, reliable method for the detection of free and modified Fusarium mycotoxins in beer using state-of-the-art ultra-high-performance supercritical fluid chromatography (UHPSFC) with low-resolution tandem MS (MS/MS) is presented in this paper. The UHPSFC-MS/MS method was developed for nivalenol, deoxynivalenol, 15-acetyl-deoxynivalenol, 3-acetyl-deoxynivalenol, deoxynivalenol-3-glucoside, HT-2 toxin, T-2 toxin, T-2 toxin-3-glucoside, neosolaniol, diacetoxyscirpenol, zearalenone, α-zearalenol, and β-zearalenol and their internal standards deepoxy-deoxynivalenol and zearalanone. Due to the broad range of the physicochemical properties of the aforementioned, the sample preparation step was minimized to avoid analyte losses. Extraction with acetonitrile-water-acetic acid (79 + 20 + 1, v/v/v) and hexane in combination with solid-phase extraction (C18) was followed by a filtration step. After filtration, the extract was evaporated, and the remaining residue was redissolved in a mobile phase for injection (methanol-water; 90 + 10, v/v). A mobile phase consisting of supercritical CO2 and a small portion of methanol was used. The developed multimycotoxin method permits the simultaneous determination of multiple fusariotoxins in an one-step chromatographic run using UHPSFC-MS/MS. SFC is a promising strategy; however, the retention mechanism is complex, leading to the unpredictable nature of elution and to some mycotoxins not being retained on the column. This restricts the applicability of UHPSFC in multimycotoxin analyses. The present study is the first report on the use of UHPSFC for the analysis of free and modified Fusarium mycotoxins.

Comparative chemical screening and genetic analysis reveal tentoxin as a new virulence factor in Cochliobolus miyabeanus, the causal agent of brown spot disease on rice

Brown spot disease, caused by Cochliobolus miyabeanus, is currently considered to be one of the most important yield reducers of rice (Oryza sativa L.). Despite its agricultural importance, little is known about the virulence mechanisms deployed by the fungus. Therefore, we set out to identify novel virulence factors with a role in disease development. This article reports, for the first time, the production of tentoxin by C. miyabeanus as a virulence factor during brown spot disease and the identification of the non-ribosomal protein synthetase (NRPS) CmNps3, responsible for tentoxin biosynthesis. We compared the chemical compounds produced by C. miyabeanus strains differing in virulence ability using ultra-high-performance liquid chromatography (UHPLC) coupled to high-resolution Orbitrap mass spectrometry (HRMS). The production of tentoxin by a highly virulent strain was revealed by principal component analysis of the detected ions and confirmed by UHPLC coupled to tandem-quadrupole mass spectrometry (MS/MS). The corresponding NRPS was identified by in silico genome analysis and confirmed by gene deletion. Infection tests with wild-type and Cmnps3 mutants showed that tentoxin acts as a virulence factor and is correlated with chlorosis development during the second phase of infection. Although rice has previously been classified as a tentoxin-insensitive plant species, our data demonstrate that tentoxin production by C. miyabeanus affects symptom development.

Development, validation and application of an ultra high performance liquid chromatographic-tandem mass spectrometric method for the simultaneous detection and quantification of five different classes of veterinary antibiotics in swine manure

In this study, a fast, simple and selective ultra high performance liquid chromatographic-tandem mass spectrometric (UHPLC-MS/MS) method for the simultaneous detection and quantification of colistin, sulfadiazine, trimethoprim, doxycycline, oxytetracycline and ceftiofur and for the detection of tylosin A in swine manure was developed and validated. First, a simple extraction procedure with acetonitrile and 6% trichloroacetic acid was carried out. Second, the supernatant was evaporated and the pellet was reconstituted in 1 ml of water/acetonitrile (80/20) and 0.1% formic acid. Extracts were filtered and analyzed by UHPLC-MS/MS on a Kinetex C18 column using gradient elution. The method developed was validated according to the criteria of Commission Decision 2002/657/EC. Recovery percentages varied between 94% and 106%, repeatability percentages were within the range of 1.7-9.2% and the intralaboratory reproducibility varied between 2.8% and 9.3% for all compounds, except for tylosin A for which more variation was observed resulting in a higher measurement uncertainty. The limit of detection and limit of quantification varied between 1.1 and 20.2 and between 3.5 and 67.3 μg/kg, respectively. This method was used to determine the presence and concentration of the seven antibiotic residues in swine manure sampled from ten different manure pits on farms where the selected antibiotics were used. A link was found between the antibiotics used and detected, except for ceftiofur which is injected at low doses and degraded readily in swine manure and was therefore not recovered in any of the samples. To the best of our knowledge, this is the first method available for the simultaneous extraction and quantification of colistin with other antibiotic classes. Additionally, colistin was never extracted from swine manure before. Another innovative aspect of this method is the simultaneous detection and quantification of five different classes of antibiotic residues in swine manure.

Virulence, Host-Selective Toxin Production, and Development of Three Cochliobolus Phytopathogens Lacking the Sfp-Type 4'-Phosphopantetheinyl Transferase Ppt1

The Sfp-type 4'-phosphopantetheinyl transferase Ppt1 is required for activation of nonribosomal peptide synthetases, including α-aminoadipate reductase (AAR) for lysine biosynthesis and polyketide synthases, enzymes that biosynthesize peptide and polyketide secondary metabolites, respectively. Deletion of the PPT1 gene, from the maize pathogen Cochliobolus heterostrophus and the rice pathogen Cochliobolus miyabeanus, yielded strains that were significantly reduced in virulence to their hosts. In addition, ppt1 mutants of C. heterostrophus race T and Cochliobolus victoriae were unable to biosynthesize the host-selective toxins (HST) T-toxin and victorin, respectively, as judged by bioassays. Interestingly, ppt1 mutants of C. miyabeanus were shown to produce tenfold higher levels of the sesterterpene-type non-HST ophiobolin A, as compared with the wild-type strain. The ppt1 strains of all species were also reduced in tolerance to oxidative stress and iron depletion; both phenotypes are associated with inability to produce extracellular siderophores biosynthesized by the nonribosomal peptide synthetase Nps6. Colony surfaces were hydrophilic, a trait previously associated with absence of C. heterostrophus Nps4. Mutants were decreased in asexual sporulation and C. heterostrophus strains were female-sterile in sexual crosses; the latter phenotype was observed previously with mutants lacking Nps2, which produces an intracellular siderophore. As expected, mutants were albino, since they cannot produce the polyketide melanin and were auxotrophic for lysine because they lack an AAR.

Uncommon occurrence ratios of aflatoxin B1, B 2, G 1, and G 2 in maize and groundnuts from Malawi

We report an unusual aflatoxin profile in maize and groundnuts from Malawi, with aflatoxin G1 found routinely at equal or even higher levels than aflatoxin B1. Aflatoxin B1 (AFB1) ratio in a contaminated sample is generally greater than 50% of total aflatoxin (sum of aflatoxin B1, B2, G1, and G2). In Malawi, the aflatoxin occurrence ratios were determined by examining LC-MS/MS and HPLC fluorescence detection (FLD) data of 156 naturally contaminated raw maize and 80 groundnut samples collected in 2011 and 2012. Results showed that natural aflatoxin occurrence ratio differed. In 47% of the samples, the concentration of AFG1 was higher than that of AFB1. The mean concentration percentages of AFB1/AFB2/AFG1/AFG2 in reference to total aflatoxins were found to be 47:5:43:5%, respectively. The AFG1 and AFB1 50/50 trend was observed in maize and groundnuts and was consistent for samples collected in both years. If the AFB1 measurement was used to check compliance of total aflatoxin regulatory limit set at 10, 20, 100, and 200 μg/kg with an assumption that AFB1≥50% of the total aflatoxin content, 8, 13, 24, and 26% false negative rates would have occurred respectively. It is therefore important for legislation to consider total aflatoxins rather than AFB1 alone.

Sampling of wheat dust and subsequent analysis of deoxynivalenol by LC-MS/MS

An LC-MS/MS method was developed and validated for the determination of deoxynivalenol in wheat dust. Extraction was carried out with acetonitrile/water/acetic acid (79/20/1, v/v/v) followed by a hexane defatting step. Analysis was performed using a Waters Acquity UPLC system coupled to a Quattro Premier XE mass spectrometer. The method was validated according to the criteria mentioned in Commission Decision 2002/657/EC. Due to a high contamination level of wheat dust compared to wheat, limit of detection and limit of quantitation levels of 358 ng/g and 717 ng/g, respectively, were obtained. A small survey was executed on raw wheat materials and their corresponding dust samples (n = 12). The samples were analyzed according to the developed procedure. A linear correlation (R² = 0.941) was found for the deoxynivalenol concentration in dust versus the deoxynivalenol concentration in wheat. Therefore, it would be possible to estimate the cereal contamination through dust contamination.

Development and validation of a QuEChERS based liquid chromatography tandem mass spectrometry method for the determination of multiple mycotoxins in spices

A reliable and rapid method for the determination of multiple mycotoxins was developed using a QuEChERS (quick, easy, cheap, effective, rugged and safe) based extraction procedure in highly pigmented and complex spice matrices, namely red chilli (Capsicum annum ssp.), black and white pepper (Piper nigrum ssp.). High-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used for the quantification and confirmation of 17 chemically diversified mycotoxins. Different extraction procedures were studied and optimized in order to obtain better recoveries. Mycotoxins were extracted from the hydrated spices using acidified acetonitrile (1% formic acid), followed by partitioning with NaCl and anhydrous MgSO4; excluding the use of dispersive-solid phase extraction. Significant matrix effect was compensated using the matrix matched calibration curves. Electrospray ionization at positive mode was applied to simultaneously detect all the mycotoxins in a single run time of 20min. Multiple reaction monitoring mode, choosing at least two abundant fragment ions per analyte was applied. Coefficients of determination obtained were in the range of 0.9844-0.9997. Recoveries (ranging from 75% to 117%) were in accordance with the performance criteria required by the European Commission. Intra-day reproducibility ranged from 4% to 22% for most of the mycotoxins. The limit of quantification ranged from 2.3 to 146μgkg(-1). The validated method was finally applied to screen mycotoxins in ten of each spice matrix. Aflatoxins, ochratoxin, fumonisins, sterigmatocystin and citrinin were among the detected analytes. Positive findings were further confirmed using relative ion intensities. The potentiality of the method to be used for confirmatory purposes according to Commission Decision 2002/657/EC was assessed.

A two-year investigation towards an effective quality control of incoming potatoes as an acrylamide mitigation strategy in french fries

The current entrance quality control used in the french fries industry is done based on colour evaluation with a United States Department of Agriculture/Munsell colour chart (after a short frying test, typically 180°C for 3 min). On the basis of a study carried out during two consecutive potato storage seasons, the possibility of a more effective entrance control of the raw potato tubers in order to identify batches of potatoes prone to acrylamide formation was evaluated. The current entrance control was compared to two other colour evaluation methods (CIE L*a*b* colour parameters and a process-specific Agtron analyser) and to reducing sugar content determination. Seasonal variability did not affect the slopes of the linear correlation models, for most of the parameters studied. The determination of colour formation measured by the Agtron methodology and reducing sugar content allowed a better identification of batches of potatoes prone to acrylamide formation compared with the current entrance control. Different scenarios represented by decision trees for quality control measures for incoming potatoes were evaluated while considering the investigation value of 600 µg kg⁻¹ for french fries recently prescribed by the European Commission. Samples were categorised based on predictions of threshold values and acrylamide levels in the final product.

Investigation into the possible natural occurence of semicarbazide in Macrobrachium rosenbergii prawns

In the past year there has been an increased incidence in Belgium of cases of positive semicarbazide (SEM) tests in imported freshwater Macrobrachium rosenbergii prawns, seemingly indicating the possible abuse of nitrofurazone, a banned antimicrobial agent. This was in contrast to all other European countries where no significant increase in SEM-positive samples was detected. A possible explanation for this discrepancy between Belgium and the other European Union member states could be the fact that only in Belgium were whole prawns (meat + shell) analyzed for the presence of tissue-bound metabolites of nitrofurans, whereas in the other countries only the edible part (meat) of these prawns was analyzed. To investigate the possible natural occurrence of SEM in freshwater prawns, an animal trial was set up. In this experiment two groups of 10 juvenile M. rosenbergii, previously raised under standardized laboratory conditions, were stocked into two separate aquaria, a control group under reference conditions (no addition of nitrofurazone) and a group exposed to a daily dose of 50 mg of nitrofurazone L(-1) of culture water. Results of this animal trial proved that SEM naturally occurs in M. rosenbergii prawns but that at the current minimum required performance limit (MRPL) no tissue-bound SEM can be found in the meat of nontreated animals. In addition to this animal trial, commercial samples of other crustacean species, the shell and meat of which were analyzed separately, were also analyzed for the presence of SEM.

An LC-MS screening method with library identification for the detection of steroids in dietary supplements

For many years anabolic-androgenic steroids (AAS) are by far the most frequently detected pharmacological substances in doping control. In order to improve their performances, professional sportsmen are often tempted to take dietary supplements. However, due to the frequent and widespread occurrence of contaminated supplements, the use of such products is not without risk for the athletes involved. In order to minimize the chances of an unattended positive doping test or serious health problems, fast and reliable screening methods for the detection of anabolic steroids in dietary supplements are needed. A general screening procedure requires the fast and unambiguous detection of a large range of steroids. Gas chromatography-mass spectrometry (GC-MS) has been used intensively in the detection of doping substances for the past 40 years. Over time, many laboratories have delivered spectra to be included in standard reference databases, one of which is maintained by the National Institute of Standards and Technology (NIST) (Gaithersburg, MD, USA). In recent years, however, liquid chromatography coupled to mass spectrometry (LC-MS) has gained popularity. Unfortunately, existing GC-MS libraries are not applicable to LC-MS analysis. In the present study, a new mass spectral library of 88 steroids was developed, along with a fast UPLC-MS method. For the construction of this mass spectral library, three different mass spectra were measured for each steroid, with a sample cone voltage of 30, 60 and 100 V, respectively. This method was then successfully tested on contaminated dietary supplements which had previously been tested by means of a targeted LC-MS/MS method. Overall, the library search was shown to identify the same compounds as the MRM method.

Implementation of acrylamide mitigation strategies on industrial production of French fries: challenges and pitfalls

This study evaluated various additives or process aids on the industrial production of French fries, based on their acrylamide mitigation potential and other quality parameters. The application of acetic and citric acid, calcium lactate and asparaginase was investigated on the production of frozen par-fried French fries at the beginning and end of the 2008 and 2009 potato storage season. Despite the fact that some of these treatments significantly reduced acrylamide content of the final product in preliminary laboratory experiments, their application on the industrial production of French fries did not result in additional acrylamide reductions compared to the standard product. Asparaginase was additionally tested in a production line of chilled French fries (not par-fried). Since for this product a longer enzyme-substrate contact time is allowed, a total asparagine depletion was observed for the enzyme treated fries after four days of cold storage. French fries upon final frying presented acrylamide contents below the limit of detection (12.5 μg kg⁻¹) with no effects on the sensorial properties of the final product.

Occurrence of mycotoxins in feed as analyzed by a multi-mycotoxin LC-MS/MS method

Crops used for animal feed can be easily contaminated by fungi during growth, harvest, or storage, resulting in the occurrence of mycotoxins. Because animal feed plays an important role in the food safety chain, the European Commission has set maximum levels for aflatoxin B1 and recommended maximum levels for deoxynivalenol, zearalenone, ochratoxin A, and the sum of fumonisin B1 and B2. A multimycotoxin LC-MS/MS method was developed, validated according to Commission Decision 2002/657/EC and EN ISO 17025 accredited for the simultaneous detection of 23 mycotoxins (aflatoxin-B1, aflatoxin-B2, aflatoxin-G1, aflatoxin-G2, ochratoxin A, deoxynivalenol, zearalenone, fumonisin B1, fumonisin B2, fumonisin B3, T2-toxin, HT2-toxin, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, diacetoxyscirpenol, fusarenon-X, neosolaniol, altenuene, alternariol, alternariol methyl ether, roquefortine-C, and sterigmatocystin) in feed. The decision limits of the multimycotoxin method varied from 0.7 to 60.6 microg/kg. The apparent recovery and the results of the precision study fulfilled the performance criteria as set in Commission Decision 2002/657/EC. The analysis of three different feed matrices (sow feed, wheat, and maize) provided a good basis for the evaluation of the toxin exposure in animal production. In total, 67 samples out of 82 (82%) were contaminated; type B-trichothecenes and fumonisins occurred most often. The majority of the infected feed samples (75%) were contaminated with more than one type of mycotoxin.

Development of a multi-mycotoxin liquid chromatography/tandem mass spectrometry method for sweet pepper analysis

A multi-mycotoxin method was developed for the simultaneous determination of trichothecenes (nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, neosolaniol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin, T-2 toxin), aflatoxins (aflatoxin-B(1), aflatoxin-B(2), aflatoxin-G(1) and aflatoxin-G(2)), Alternaria toxins (alternariol, alternariol methyl ether and altenuene), fumonisins (fumonisin-B(1), fumonisin-B(2) and fumonisin-B(3)), ochratoxin A, zearalenone, beauvericin and sterigmatocystin in sweet pepper. Sweet pepper was extracted with ethyl acetate/formic acid (99:1, v/v). After splitting up the extract, two-thirds of the extract was cleaned up using an aminopropyl column followed by an octadecyl column. The remaining part was cleaned up using a strong anion-exchange column. After recombination of both cleaned parts of the sample extract, the combined solvents were evaporated and the residue was dissolved in mobile phase; 20 microL was injected into the chromatographic system, so only one run was used to separate and detect the mycotoxins in positive electrospray ionization using selected reaction monitoring. The samples were analyzed with a Micromass Quattro Micro triple quadrupole mass spectrometer (Waters, Milford, MA, USA). The mobile phase consisted of variable mixtures of water and methanol, 1% acetic acid and 5 mM ammonium acetate. The limits of detection of the multi-mycotoxin method varied from 0.32 microg kg(-1) to 42.48 microg kg(-1). The multi-mycotoxin liquid chromatography/tandem mass spectrometry (LC/MS/MS) method fulfilled the method performance criteria required by the Commission Regulation (EC) No 401/2006. Sweet peppers inoculated by Fusarium species were analyzed using the developed method. Beauvericin (9-484 microg kg(-1)) and fumonisins (fumonisin-B(1) up to 4330 microg kg(-1), fumonisin-B(2) up to 4900 microg kg(-1), and fumonisin-B(3) up to 299 microg kg(-1)) were detected.

Fractionation of free and conjugated steroids for the detection of boldenone metabolites in calf urine with ultra-performance liquid chromatography/tandem mass spectrometry

For over a decade there has been an intensive debate on the possible natural origin of boldenone (androst-1,4-diene-17beta-ol-3-one, 17beta-boldenone) in calf urine and several alternative markers to discriminate between endogenously formed boldenone and exogenously administered boldenone have been suggested. The currently approved method for proving illegal administration of beta-boldenone(ester) is the detection of beta-boldenone conjugates. In the presented method the sulphate, glucuronide and free fractions are separated from each other during cleanup on a SAX column to be able to determine the conjugated status of the boldenone metabolites. The sulphate and glucuronide fractions are submitted to hydrolysis and all three fractions are further cleaned up on a combination of C18/NH2 solid-phase extraction (SPE) columns. Chromatographic separation of the boldenone metabolites was achieved with a Waters Acquity UPLC instrument using a Sapphire C18 (1.7 microm; 2x50 mm) column within 5 min. Detection of the analytes was achieved by electrospray ionisation tandem mass spectrometry. The decision limits of this method, validated according to Commission Decision 2002/657/EC, were 0.08 ng mL(-1) for androsta-1,4-diene-3,17-dione, 0.13 ng mL(-1) for androst-4-ene-3,17-dione, 0.11 ng mL(-1) for 17alpha-boldenone, 0.07 ng mL(-1) for 17beta-boldenone, 0.24 ng mL(-1) for 5beta-androst-1-en-17beta-ol-3-one and 0.58 ng mL(-1) for 6beta-hydroxy-17beta-boldenone. Because of the fractionation approach used in this method there is no need for conjugated reference standards which often are not available. The disadvantage of needing three analytical runs to determine the conjugated status of each of the metabolites was overcome by using fast chromatography.

Monitoring the benzene contents in soft drinks using headspace gas chromatography-mass spectrometry: a survey of the situation on the belgian market

Whenever benzoic acid is combined with ascorbic acid in acidic beverages such as soft drinks, benzene can be formed. To determine the current situation on the Belgian market, a headspace gas chromatographic-mass spectrometric method was developed, which needs little to no sample preparation. This method was then used to analyze 134 soft drinks sampled on the Belgian market by the Federal Agency for the Safety of the Food Chain. Thirty-three percent of the samples contained no detectable benzene, whereas the majority of the samples (47%) contained trace amounts below the limit of quantification of the method (0.3 microg L (-1)). Ten samples were above the European limit for benzene in drinking water of 1 microg L (-1), and one sample had a concentration of 10.98 microg L (-1), thereby exceeding the action limit for benzene in soft drinks of 10 microg L (-1) discussed at the Standing Committee on the Food Chain and Animal Health of the European Commission. Statistical analyses revealed that besides benzoic acid, ascorbic acid, and acidity regulators, the packing may also play an important role in benzene formation.

Characterization of two unknown compounds in methanol extracts of rosemary oil

In this study, two unknown compounds in rosemary oil, containing 3% carnosic acid and 0.3% carnosol, were identified and characterized. After methanol extraction, purification, and analysis by reversed-phase HPLC and LC-MS, a recovery of 92% (+/-8%) of carnosic acid was obtained, but no carnosol was found. However, two unknown compounds with a molecular weight of 330.2 and 302.2 were consistently detected. From additional LC-MS-MS, (1)H NMR, and elemental analyses, it became clear that the first compound (M(w) = 330.2) could not be carnosol. It was hypothesized that it originated from the breakdown of the intramolecular bond of carnosol, followed by the addition of a water molecule. Possibly, an unsaturated double bond was formed after dehydration. Assuming that this compound was an intermediate in the conversion to rosmanol, the second unknown compound (M(w) = 302.2) may have resulted from the breakdown of the intramolecular bond of rosmanol. Similarly, an unsaturated double bond may have been formed. After splitting off carbon oxide, a detectable molecule with a molecular weight of 302.2 was observed.

Analysis of meat samples for anabolic steroids residues by liquid chromatography/tandem mass spectrometry

A rapid, specific and highly sensitive multi-residue method for the determination of anabolic steroid residues in bovine, pork and poultry muscle tissues was developed. The sample preparation involves enzymatic digestion followed by extraction with methanol. The crude extract was cleaned up by solid-phase extraction (SPE) combining C18 and NH2 columns. The detection was carried out by a highly sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method using both positive and negative ionization modes. Natural and synthetic steroids covering different polarities could be extracted, concentrated and purified using one single method. Mobile phase composition and additives were optimized to achieve the highest sensitivity. The linearity was not good enough for quantitative analysis but the method was well-suited for qualitative confirmation. The method was validated according to the European Commission Decision 2002/657/EC. Decision limits (CCalpha) and detection capabilities (CCbeta) were below 0.5 ng g(-1) for all the compounds in the three types of meat studied. The developed method is suitable for routine analysis in our laboratories.

Influence of oil type on the amounts of acrylamide generated in a model system and in French fries

Acrylamide formation was studied by use of a new heating methodology, based on a closed stainless steel tubular reactor. Different artificial potato powder mixtures were homogenized and subsequently heated in the reactor. This procedure was first tested for its repeatability. By use of this experimental setup, it was possible to study the acrylamide formation mechanism in the different mixtures, eliminating some variable physical and chemical factors during the frying process, such as heat flux and water evaporation from and oil ingress into the food. As a first application of this optimized heating concept, the influence on acrylamide formation of the type of deep-frying oil was investigated. The results obtained from the experiments with the tubular reactor were compared with standardized French fry preparation tests. In both cases, no significant difference in acrylamide formation could be found between the various heating oils applied. Consequently, the origin of the deep-frying vegetable oils did not seem to affect the acrylamide formation in potatoes during frying. Surprisingly however, when artificial mixtures did not contain vegetable oil, significantly lower concentrations of acrylamide were detected, compared to oil-containing mixtures.

Combination of liquid chromatography/tandem mass spectrometry and gas chromatography/mass spectrometry for the detection of 21 anabolic steroid residues in bovine urine

For the detection of anabolic steroid residues in bovine urine, a highly sensitive liquid chromatographic/electrospray ionization tandem mass spectrometric (LC/ESI-MS/MS) method was developed using both positive and negative ionization. For four compounds the ESI mode was not sensitive enough and gas chromatographic/mass spectrometric GC/MS detection was therefore still necessary as a complementary method. The sample clean-up consisted of solid-phase extraction (SPE) on a C(18) column followed by enzymatic hydrolysis and a second solid-phase extraction on a combination of a C(18) and a NH(2) column. After this last SPE clean-up, the eluate was split into two equal aliquots. One aliquot was further purified and after derivatization used for GC/MS analysis. The other aliquot was analyzed with LC/MS/MS in both ESI+ and ESI- modes. The method was validated according to the European Commission Decision 2002/657/EC. Decision limits (CCalpha) were between 0.16 and 1 ng ml(-1) for the compounds detected with the LC/MS/MS method. The developed method is used in routine analysis in our laboratory.

Tylosin detection in animal feed by liquid chromatography-tandem mass spectrometry with enzymatic hydrolysis of the tylosin urea adduct

When the use of tylosin as a feed additive was forbidden by Council Regulation 2821/98, the necessity of a chemical confirmation method for the monitoring of the ban was created. Recently a method was developed for the detection of tylosin in animal feed by means of LC-MS/MS. During the validation high deviating values for the decision limit, detection capability, and repeatability for tylosin in cattle feed were observed, and the presence of urea and the formation of a tylosin urea adduct (TUA) were suggested as possible explanations. In this study two hydrolysis approaches for the TUA adduct were compared, namely, a chemical hydrolysis and an enzymatic hydrolysis with urease. The latter yielded a more complete hydrolysis of urea and was used for further validation. The recovery increased by approximately 15-25% depending on the amount of urea present in the feed (0.5-2%). The decision limit and detection capability were hardly influenced by the enzymatic hydrolysis.