Comprehensive quantification of sesame allergens in processed food using liquid chromatography-tandem mass spectrometry

Quantification of salmon nasal cartilage extracts using liquid chromatography-tandem mass spectrometry

Proteoglycans are high molecular weight glycoproteins with potential benefits in preventing osteoarthritis, reducing inflammation, enhancing immune function, and promoting skin health. Aggrecan, a key proteoglycan with glycosaminoglycan (GAG) chains, poses challenges in accurate quantification due to its complex structure. We hypothesize that by selecting target peptides from core proteins that exclude post-translational modifications such as GAG attachment, proteoglycans can be analyzed with high sensitivity and accuracy. In this study, we identified aggrecan from salmon nasal cartilage (Oncorhynchus keta) using liquid chromatography-mass spectrometry (LC-MS). We developed a quantitative multiple reaction monitoring (MRM)-MS assay with stable-isotope-labeled peptides. This method demonstrated high precision and sensitivity, achieving a limit of detection (LOD) of 0.0008 μg/mL and a lower limit of quantification (LLOQ) of 0.0025 μg/mL. These findings validate that targeting core proteins enables accurate proteoglycan quantification and support its application in quality assessment and development of salmon nasal cartilage-based foods.

Mass Spectrometry-Based Method for Multiple Allergens Control: Application to Bakery Goods

In recent years, mass spectrometry has played a key role as a confirmatory method to unequivocally identify multiple allergens, increasing the level of protection of allergic consumers. Despite advances made in methods of development, food processing still represents a critical issue in terms of the detection and accurate quantification of allergens due to chemical/structural modifications that can occur on the protein moiety or interferences of matrix compounds that might impair their final detection. Based on the multi-allergen MS/MS method devised within the ThrAll project, in this paper, we investigated the applicability of the developed method for the detection of traces of allergenic ingredients including egg, milk, soy, almond, hazelnut, peanuts, and sesame in two different kind of food matrices, namely cookies and rusks. The products were produced at laboratory scale in a food pilot plant that underwent different technological and thermal treatments. The challenge was to validate, in these extensively processed foods, the selected proteotypic peptide-markers capable of tracing the culprit ingredients in baked goods despite the processing the foods had undergone for their production. To accomplish this goal, the multi-target method developed on a low-resolution MS platform was transferred to a high-resolution MS system, and the pre-identified markers were also checked and validated on the new platform in order to be considered robust markers able to be indistinctly used on both types of platforms. Finally, the sensitivity of the method in terms of the Limit of Detection (LOD) and Limit of Quantification (LOQ) was calculated and the effect of the processing conditions on allergens detection in both baked goods was also investigated.

Selection of signature peptide biomarkers for the sesame allergens in commercial food based on LC-MS/MS

Sesame is a commonly used food ingredient, yet it is one of the eight major allergens. As sesame is often consumed in various processed forms, it is important to establish methods for detecting sesame allergens in processed foods. Liquid chromatography-tandem mass spectrometry (LC-MS/MS), using characteristic peptides as biomarkers, detects multiple allergenic proteins simultaneously with high sensitivity and accuracy. Choosing robust biomarkers is beneficial for developing a specific, universal, and sensitive method. To obtain excellent peptides of sesame allergens, sixteen commercial products were used as test materials. Proteins from these materials were extracted, digested, and analyzed. Peptides were screened based on several criteria, including specificity and amino acid composition. Only peptides showing process robustness were retained. Ultimately, nine peptides were selected as the best biomarkers. Based on the above peptides, it is possible to achieve precise and high-sensitivity detection of sesame allergens in processed products.

Development of a Novel Electrochemical Immunosensor for Rapid and Sensitive Detection of Sesame Allergens Ses i 4 and Ses i 5

Due to their lipophilicity and low content, the major sesame oleosin allergens, Ses i 4 and Ses i 5, are challenging to identify using conventional techniques. Then, a novel unlabeled electrochemical immunosensor was developed to detect the potential allergic activity of sesame oleosins. The voltammetric immunosensor was constructed using a composite of gold nanoparticles (AuNPs), polyethyleneimine (PEI), and multi-walled carbon nanotubes (MWCNTs), which was synthesized in a one-pot process and modified onto a glass carbon electrode to enhance the catalytic current of the oxygen reduction reaction. The oleosin antibody was then directed and immobilized onto the surface of the electrode, which had been modified with streptavidin (SPA), through the fragment crystallizable (Fc) region of the antibody. Under optimized conditions, the immunosensor exhibited a linear response within a detection range of 50 to 800 ng/L, with detection limits of 0.616 ng/L for Ses i 4 and 0.307 ng/L for Ses i 5, respectively. The immunosensor demonstrated excellent selectivity and stability, making it suitable for the quantification of sesame oleosins. The comparative analysis of various detection methods for sesame allergens was conducted, revealing that the immunosensor achieved a wide detection range and low limit of detection (LOD). Compared to traditional enzyme-linked immunosorbent assay (ELISA), the immunosensor successfully quantified the allergenicity potential of Ses i 4 and Ses i 5 in roasted sesame seeds at temperatures of 120 °C, 150 °C, and 180 °C. This innovative method offers a new perspective for the rapid quantification of sesame oleosins in foods and real-time monitoring of allergic potential, providing significant advancements in the field of food allergy detection.

Quantifying allergenic proteins using antibody-based methods or liquid chromatography-mass spectrometry/mass spectrometry: A review about the influence of food matrix, extraction, and sample preparation

Accurate quantification of allergens in food is crucial for ensuring consumer safety. Pretreatment steps directly affect accuracy and efficiency of allergen quantification. We systematically reviewed the latest advances in pretreatment steps for antibody-based methods and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) protein quantification methods in food. For antibody-based methods, the effects induced by food matrix like decreased allergen solubility, epitope masking, and nonspecific binding are of the upmost importance. To mitigate interference from the matrix, effective and proper extraction can be used to obtain the target allergens with a high protein concentration and necessary epitope exposure. Removal of interfering substances, extraction systems (buffers and additives), assistive technologies, and commercial kits were discussed. About LC-MS/MS quantification, the preparation of the target peptides is the crucial step that significantly affects the efficiency and results obtained from the MS detector. The advantages and limitations of each method for pre-purification, enzymatic digestion, and peptide desalting were compared. Additionally, the application characteristics of microfluidic-based pretreatment devices were illustrated to improve the convenience and efficiency of quantification. A promising research direction is the targeted development of pretreatment methods for complex food matrices, such as lipid-based and carbohydrate-based matrices.

Development of a rapid and reliable method to simultaneously detect seven food allergens in processed foods using LC-MS/MS

Rapid analysis of multiple food allergens is required to confirm the appropriateness of food allergen labelling in processed foods. This study aimed to develop a rapid and reliable method to simultaneously detect trace amounts of seven food allergenic proteins (wheat, buckwheat, milk, egg, crustacean, peanut, and walnut) in processed foods using LC-MS/MS. Suspension-trapping (S-Trap) columns and on-line automated solid-phase extraction were used to improve the complex and time-consuming pretreatment process previously required for allergen analysis using LC-MS/MS. The developed method enabled the simultaneous detection of selected marker peptides for specific proteins derived from seven food ingredients in five types of incurred samples amended with trace amounts of allergenic proteins. The limit of detection values of the method for each protein were estimated to be <1 mg/kg. The developed analytical approach is considered an effective screening method for confirming food allergen labelling on a wide range of processed foods.

Lipid matrix-specific pretreatment method for enhancing the extractability and allergenicity maintenance of bovine milk allergens in ELISA detection

The presence of various components in the food matrix makes allergen detection difficult and inaccurate, and pretreatment is an innovative breakthrough point. Food matrices were categorised based on their composition. Subsequently, a pretreatment method was established using a combination of ultrasound-assisted n-hexane degreasing and weakly alkaline extraction systems to enhance the detection accuracy of bovine milk allergens. Results showed that more allergens were obtained with less structural destruction, as demonstrated using immunological quantification and spectral analysis. Concurrently, allergenicity preservation was confirmed through liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, a KU812 cell degranulation model, and western blotting. The method exhibited good accuracy (bias, 8.47%), repeatability (RSDr, 1.52%), and stability (RSDR, 5.65%). In foods with high lipid content, such as chocolate, the allergen content was 2.29-fold higher than that of commercial kits. Laser confocal scanning microscopy (LCSM) and scanning electron microscopy (SEM) analyses revealed a significant decrease in fat content after post-pretreatment using our method. In addition, colloidal stability surpassed that achieved using commercial kits, as indicated through the PSA and zeta potential results. The results demonstrated the superiority of the extractability and allergenicity maintenance of lipid matrix-specific pretreatment methods for improving the accuracy of ELISA based allergen detection in real food.

Sesame Detection in Food Using DNA-Functionalized Gold Nanoparticles: A Sensitive, Rapid, and Cost-Effective Colorimetric Approach

Food safety control is a key issue in the food and agriculture industries. For such purposes, developing miniaturized analytical methods is critical for enabling the rapid and sensitive detection of food supplements, allergens, and pollutants. Here, a novel bioanalytical methodology based on DNA-functionalized gold nanoparticles (AuNPs) and colorimetric detection was developed to detect the presence of sesame (a major allergen) through sesame seed DNA as a target, in food samples. The presence of sesame DNA induces controlled nanoparticle aggregation/desegregation, resulting in a color change (from blue to red) proportional to sesame DNA concentration. The incorporation of multicomponent nucleic acid enzymes (MNAzymes) in this strategy has been carried out to perform an isothermal signal amplification strategy to improve the sensitivity of detection. Also, open-source software for color analysis was used to ensure an unbiased visual color-change detection, enhancing detection accuracy and sensitivity and opening the possibility of performing a simple and decentralized analyte detection. The method successfully detected the presence of sesame DNA in sesame seed, sesame oil, olive oil, and sunflower oil. In brief, the developed approach constitutes a simple and affordable alternative to perform a highly sensitive detection of DNA in food without complex methodologies or the requirement of expensive instrumentation.

Recent advance in sesame allergens: Influence of food processing and their detection methods

Sesame (Sesamum indicum L.) is a valuable oilseed crop with numerous nutritional benefits containing a diverse range of bioactive compounds. However, sesame is also considered an allergenic food that triggers various mild to severe adverse reactions (e.g., anaphylaxis). Strict dietary avoidance of sesame components is the best option to protect the sensitized consumers. Sesame or sesame-derived foods are always consumed after certain food processing operations, which would cause a considerable impact on the structure of sesame proteins, changing their sensitization capacity and detectability. In the review, the molecular structure properties, and immunological characteristics of the sesame allergens were described. Meanwhile, the influence of food processing techniques on sesame proteins and the relevant detection techniques used for the sesame allergens quantification are also emphasized critically. Hopefully, this review could provide valuable insight into the development and management for the new "Big Eight" sesame allergen in food industry.

Development of a fluorescent multiplexed lateral flow immunoassay for the simultaneous detection of crustacean allergen tropomyosin, sarcoplasmic calcium binding protein and egg allergen ovalbumin in different matrices and commercial foods

A quantum dot (QD) based multiplexed lateral flow immunoassay (xLFIA) for the simultaneous detection of egg allergen ovalbumin, crustacean allergen tropomyosin (TM) and sarcoplasmic calcium binding protein (SCP) was developed in this study. QD-labeled rabbit anti-ovalbumin, SCP and TM antibodies were applied as fluorescent detection probes. The chromatography system was optimized to reduce the mutual interference of different test lines. Visual and instrumental detection limits of the xLFIA were 0.1 and 0.05 μg/mL for SCP, both 0.05 μg/mL for ovalbumin and both 0.5 μg/mL for TM. As low as 0.10 % crab powder, 0.01 % egg white powder and 0.05 % shrimp powder could be detected in all three model foods using xLFIA. Besides, the xLFIA detection results of 23 of 28 commercial foods were consistent with ingredient labels. These findings indicate that the developed xLFIA is a practical tool for point-of-care detection of egg and crustacean allergens in processed and commercial foods.

Establishment of a targeted proteomics method for the quantification of collagen chain: Revealing the chain stoichiometry of heterotypic collagen fibrils in sea cucumber

Collagen is the most abundant and important structural biomacromolecule in sea cucumbers. The sea cucumber collagen fibrils were previously confirmed to be heterotypic, nevertheless, the stoichiometry of collagen α-chains governing the complexity of collagen fibrils is still poorly understood. Herein, four representative collagen α-chains in sea cucumber including two clade A fibrillar collagens, one clade B fibrillar collagen, and one fibril-associated collagen with interrupted triple helices were selected. After the screening of signature peptides and optimization of multiple reaction monitoring (MRM) acquisition parameters including fragmentation, collision energy, and ion transition, a feasible MRM-based method was established. Consequently, the stoichiometry of the four collagen chains was determined to be approximately 100:54:3:4 based on the method. The assembly forms of sea cucumber collagen fibrils were further hypothesized according to the chain stoichiometry. This study facilitated the quantification of collagen and understanding of the collagen constituents in sea cucumber.

Fluorescence immunoassay based on magnetic separation and ZnCdSe/ZnS quantum dots as a signal marker for intelligent detection of sesame allergen in foods

To detect sesame allergens, a novel fluorescent immunoassay incorporating a magnetic separation step has been developed via two measurement devices: a fluorescence spectrophotometer and a smartphone equipped with a color reader. Sesame allergen monoclonal antibody (Ab) was covalently bonded with quantum dots (QDs) to act as a signal probe. The capture probes were synthesized as sesame allergen (SA) modified carboxyl-functional magnetic polystyrene microspheres (MPMs). Analytical variables such as the amount of modified SA, the reaction volume of the QDs-Ab, the ionic strength, the pH, and the incubation time of the reaction were optimized. The analytical range and the limit of detection (LOD) of the spectrophotometer-based assay were 80-640 μg/L and 12.75 μg/L, respectively. The analytical range and the LOD with smartphone read-out were 80-640 μg/L and 10.15 μg/L, respectively. Furthermore, the developed assay using the fluorescence spectrophotometer and the smartphone read-out was successfully applied to field testing of SA in solution extracts of biscuits, bread, almond beverage, and energy bars with acceptable results. The recovery rates were in the range 89-108%. It was concluded that the new assay may be used for rapid sesame allergen testing in the laboratory and in the field.

Development of a simple and reliable LC-MS/MS method to simultaneously detect walnut and almond as specified in food allergen labelling regulations in processed foods

We developed a simple and reliable analytical method using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) to simultaneously detect walnut and almond as specified in regulations for food allergen labelling in processed foods. Five specific target peptides derived from walnut 2S albumin and 7S globulin and three target peptides from almond 11S globulin were selected by analysing several varieties of walnut and almond, eight kinds of other nuts, and ten kinds of major allergen ingredients or cereals. The limit of detection for the walnut 2S albumin peptide GEEMEEMVQSAR (m/z 698.3 [precursor] > 316.1 [product]) was 0.22 ± 0.02 μg/g, and that for almond 11S globulin peptide GNLDFVQPPR (m/z 571.8 [precursor] > 369.2 [product]) was 0.08 ± 0.02 μg/g when extracted walnut and almond protein were spiked into butter cookie chocolate ice cream. These peptides had good linearity (R2 > 0.999) for each calibration curve with a range of 0.1-50 μg/mL protein concentration in the sample solutions, and sufficient recovery rates (90.4-101.5%) from the spiked samples. The developed analytical approach is applicable to a wide variety of processed foods for food allergen labelling.

Immunocolorimetric assay based on amplified gold nanoparticles and magnetic separation beads for detection of sesame allergens in food

We have developed a magnetic separation-based immunocolorimetric assay to detect sesame allergens. Sesame monoclonal antibody (Ab) was modified onto gold nanoparticles (AuNPs) to create signal probes (AuNPs-Ab), and sesame allergens (SA) were attached to carboxyl-functionalized magnetic polystyrene microspheres (MPMs) to act as capture probes (MPMs-SA). Based on the competition format, the capture probes competed with the sesame allergens in the sample to bind the corresponding signal probes. When sesame allergens were present, two immune complexes (AuNPs-Ab@MPMs-SA and AuNPs-Ab@SA) were formed. The immune complex AuNPs-Ab@SA was used to quantify the sesame allergens in the sample. This immunoassay had a detection linear range from 50 to 800 μg L^-1 with a limit of detection (LOD) of 45.53 μg L^-1. Based on the optimized conditions, the recovery of sesame allergens in bread, biscuit, almond beverage, and energy bar samples was between 82.50% and 116.67%. The LODs for the bread, biscuit, almond beverage, and energy bar samples were 0.36, 0.36, 0.27, and 0.55 mg kg^-1, respectively.

Sesame as a source of food allergens: clinical relevance, molecular characterization, cross-reactivity, stability toward processing and detection strategies

Sesame is an allergenic food with an increasing allergy prevalence among the European/USA population. Sesame allergy is generally life-persisting, being the cause of severe/systemic adverse immune responses in sesame-allergic individuals. Herein, clinical data about sesame allergy, including prevalence, diagnosis, relevance, and treatments are described, with focus on the molecular characterization of sesame allergens, their cross-reactivity and co-sensitization phenomena. The influence of food processing and digestibility on the stability/immunoreactivity of sesame allergens is critically discussed and the analytical approaches available for their detection in foodstuffs. Cross-reactivity between sesame and tree nuts or peanuts is frequent because of the high similarities among proteins of the same family. However, cross-reactivity phenomena are not always correlated with true clinical allergy in sensitized patients. Data suggest that sesame allergens are resistant to heat treatments and digestibility, with little effect on their immunoreactivity. Nevertheless, data are scarce, evidencing the need for more research to understand the effect of food processing on sesame allergenicity modulation. The demands for identifying trace amounts of sesame in foods have prompted the development of analytical methods, which have targeted both protein and DNA markers, providing reliable, specific, and sensitive tools, crucial for the effective management of sesame as an allergenic food.

Smartphone-integrated fluorescent quenching immunochromatographic test strips designed for the determination of sesame allergens in food samples

A highly sensitive smartphone-integrated fluorescence quenching immunochromatographic assay (FQICA) for the detection of sesame allergen was proposed. Sesame antibodies were adsorbed on the surface of the gold nanoparticles to form fluorescent acceptors (AuNPs-Ab). Ovalbumin (OVA) protein was labeled with quantum dots (QDs) to form signal probes (QDs-OVA), which were coated on the C-line of the assay strips. A mixture of QDs-OVA and sesame protein was coated on the T-line of the strip. For FQICA, the concentration of the analyte was positively correlated with the fluorescence signal. The developed FQICA had high sensitivity for the detection of sesame protein, and its visual LOD was 80 μg/L and the quantitative LOD was 40 μg/L. In addition, the method had high specificity, except for a small cross-reaction between sesame and walnut. The visual LODs in bread, ham, and biscuits were 640 μg/L. The quantitative LODs were 320 μg/L for biscuits and 640 μg/L for bread and ham. Comparing the developed FQICA with a commercial ELISA kit, the recoveries of sesame protein in both methods were between 80% and 120%.

Sesame allergy: mechanisms, prevalence, allergens, residue detection, effects of processing and cross-reactivity

Sesame allergy is a serious public health problem and is mainly induced by IgE-mediated reactions, whose prevalence is distributed all over the world. Sesame has been included on the priority allergic food list in many countries. This review summarizes the mechanism and prevalence of sesame allergy. The characteristics, structures and epitopes of sesame allergens (Ses i 1 to Ses i 7) are included. Moreover, the detection methods for sesame allergens are evaluated, including nucleic-acid, immunoassays, mass spectrometry, and biosensors. Various processing techniques for reducing sesame allergenicity are discussed. Additionally, the potential cross-reactivity of sesame with other plant foods is assessed. It is found that the allergenicity of sesame is related to the structures and epitopes of sesame allergens. Immunoassays and mass spectrometry are the major analytical tools for detecting and quantifying sesame allergens in food. Limited technologies have been successfully used to reduce the antigenicity of sesame, involving microwave heating, high hydrostatic pressure, salt and pH treatment. More technologies for reducing the allergenicity of sesame should be widely investigated in future studies. The reduction of allergenicity in processed sesames should be ultimately confirmed by clinical studies. What's more, sesame may exhibit cross-reactivity with peanut and tree nuts.

Effect of Roasting on the Conformational Structure and IgE Binding of Sesame Allergens

Sesame can trigger a systemic allergic reaction. In the present study, we investigated the responses of the structure and IgE binding of sesame allergens to different roasting treatments (120, 150, and 180 °C for 5 to 30 min). We analyzed the tryptic digestion peptides using a label-free mass spectrometry method. The total amount of soluble proteins in sesame was significantly reduced by roasting at 180 °C, followed by 150 °C. Ses i 1 was the most stable protein during processing as it still possessed a higher protein abundance compared to other allergens after roasting under 180 °C. The most unstable allergens were Ses i 4 and Ses i 7, which suffered severe protein degradation at 180 °C. Roasting at 180 °C remarkably increased the secondary structure content of α-helices but decreased that of β-sheets, whereas roasting at 120 and 150 °C had a limited effect on the secondary structure of sesame proteins. Moreover, serum pool Western blot analysis showed that the main allergens were oleosin of Ses i 4 and Ses i 5. The IgE-binding ability of sesame allergens was significantly decreased under 180 °C roasting, as well as the solubility of sesame proteins, which showed remarkable congruence in changes. Relative quantification results indicate that individual sesame allergens respond differently to the roasting process. In general, sesame allergens are unstable under roasting treatment. Therefore, the allergenic potential of sesame allergens may be minimized by selecting appropriate parameters during processing.

Application of peptide biomarkers in life analysis based on liquid chromatography-mass spectrometry technology

Biomedicine is developing rapidly in the 21st century. Among them, the qualitative and quantitative analysis of peptide biomarkers is of considerable importance for the diagnosis and therapy of diseases and the quality evaluation of drugs and food. The identification and quantitative analysis of peptides have been going on for decades. Traditionally, immunoassays or biological assays are generally used to quantify peptides in biological matrices. However, the selectivity and sensitivity of these methods cannot meet the requirements of the application. The separation and analysis technique of liquid chromatography-mass spectrometry (LC-MS) supplies a reliable alternative. In contrast to immunoassays, LC-MS methods are capable of providing the analytical prowess necessary to satisfy the demands of peptide biomarker research in the life sciences arena. This review article provides a historical account of the in-roads made by LC-MS technology for the detection of peptide biomarkers in the past 10 years, with the focus on the qualification/quantification developments and their applications.

Proteomic Advances in Cereal and Vegetable Crops

The importance of vegetables in human nutrition, such as cereals, which in many cases represent the main source of daily energy for humans, added to the impact that the incessant increase in demographic pressure has on the demand for these plant foods, entails the search for new technologies that can alleviate this pressure on markets while reducing the carbon footprint of related activities. Plant proteomics arises as a response to these problems, and through research and the application of new technologies, it attempts to enhance areas of food science that are fundamental for the optimization of processes. This review aims to present the different approaches and tools of proteomics in the investigation of new methods for the development of vegetable crops. In the last two decades, different studies in the control of the quality of crops have reported very interesting results that can help us to verify parameters as important as food safety, the authenticity of the products, or the increase in the yield by early detection of diseases. A strategic plan that encourages the incorporation of these new methods into the industry will be essential to promote the use of proteomics and all the advantages it offers in the optimization of processes and the solution of problems.

Sesame as an allergen in Lebanese food products: Occurrence, consumption and quantitative risk assessment

Despite the intensive use of sesame in the Middle Eastern diet, studies on this allergen in this region are lacking. A survey on the occurrence of sesame in Lebanese food products that did not contain this allergen as an ingredient, a food consumption survey conducted in Beirut schools, and the most recent sesame eliciting dose estimates were used to build a probabilistic risk assessment model providing estimates of sesame-induced allergic reactions per eating occasion and per week in Lebanese children and adolescents. Of 1270 food samples analysed, 34% contained sesame proteins (0.44-3392 mg kg^-1). Sesame was detected in 47% of unlabeled bulk samples, 43% of samples with PAL, and 27% of samples without PAL. "Sfouf" had the highest concentration of sesame proteins (mean 549 mg kg^-1), highest mean exposure per eating occasion (78 mg sesame proteins for children and 103 mg sesame proteins for adolescents), and posed the highest predicted risk per eating occasion (>20%) and per week (>13% individuals predicted in simulation experience at least 1 reaction). Bakery products (notably "sfouf") may pose a serious risk to sesame-allergic children and adolescents in Lebanon. Enhanced guidance on the use of PAL is needed to better protect allergic consumers.

Advances on the rapid and multiplex detection methods of food allergens

With the gradually increasing prevalence of food allergy in recent years, food allergy has become a major public health problem worldwide. The clinical symptoms caused by food allergy seriously affect people's quality of life; there are unknown allergen components in novel food and hidden allergens caused by cross contamination in food processing, which pose a serious risk to allergy sufferers. Thus, rapid and multiplex detection methods are required to achieve on-site detection or examination of allergic components, so as to identify the risk of allergy in time. This paper reviews the progress of high-efficiency detection of food allergens, including enhanced traditional detection techniques and emerging detection techniques with the ability high-throughput detection or screening potential food allergen, such as xMAP, biosensors, biochips, etc. focusing on their sensitivity, applicability of each method in food, along with their pretreatment, advantages, limitation in the application of food analysis. This paper also introduces the challenges faced by these high-efficiency detection technologies, as well as the potential of customized allergen screening methods and rapid on-site detection technology as future research directions.

Multispecies Identification of Oilseed- and Meat-Specific Proteins and Heat-Stable Peptide Markers in Food Products

Consumer demand for both plant products and meat products enriched with plant raw materials is constantly increasing. Therefore, new versatile and reliable methods are needed to find and combat fraudulent practices in processed foods. The objective of this study was to identify oilseed species-specific peptide markers and meat-specific markers that were resistant to processing, for multispecies authentication of different meat and vegan food products using the proteomic LC-MS/MS method. To assess the limit of detection (LOD) for hemp proteins, cooked meatballs consisting of three meat species and hemp cake at a final concentration of up to 7.4% were examined. Hemp addition at a low concentration of below 1% was detected. The LOD for edestin subunits and albumin was 0.9% (w/w), whereas for 7S vicilin-like protein it was 4.2% (w/w). Specific heat-stable peptides unique to hemp seeds, flaxseed, nigella, pumpkin, sesame, and sunflower seeds, as well as guinea fowl, rabbit, pork, and chicken meat, were detected in different meat and vegan foods. Most of the oilseed-specific peptides were identified as processing-resistant markers belonging to 11S globulin subunits, namely conlinin, edestin, helianthinin, pumpkin vicilin-like or late embryogenesis proteins, and sesame legumin-like as well as 2S albumins and oleosin isoforms or selected enzymic proteins.

Magnetic Ti3C2 MXene functionalized with β-cyclodextrin as magnetic solid-phase extraction and in situ derivatization for determining 12 phytohormones in oilseeds by ultra-performance liquid chromatography-tandem mass spectrometry

Magnetic solid phase extraction integrated with in situ derivations for the profiling of 12 phytohormones in a single rapeseed seed was developed by using ultra-high performance liquid chromatography-tandem mass spectrometry. The Fe₃O₄@Ti₃C₂@β-cyclodextrin nanoparticles were firstly synthesized and used as an adsorbent for the solid-phase extraction of phytohormones. The magnetic dispersive solid-phase extraction and in situ derivation by the addition of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide were ingeniously combined. This efficient pre-treatment method integrated the extraction, purification, and derivatization processes into one single step. Satisfactory methodological performance was achieved by optimization of the parameters. Linearities (R² > 0.9928) and recoveries (80.4 %-115.1%) at three spiked levels, as well as the low matrix effect (from -16.63% to 17.06%) and limits of detection (0.89-13.62 pg/mL) were obtained. The spatio-temporal profiling of target phytohormones in different tissues of rapeseed germination was investigated. This method was successfully employed for analyzing target phytohormones in different oilseeds samples.

Proteomic analysis of oilseed cake: a comparative study of species-specific proteins and peptides extracted from ten seed species

BACKGROUND

In recent years there has been a visible trend among consumers to move away from consuming meat in favor of plant products. Meat producers have therefore been trying to meet the expectations of consumers by introducing new products to the food market with a greater proportion of plant ingredients. Meat products are enriched not only by the addition of vegetable oils but also by ground or whole oilseeds or their preparation. In this study, we present in-solution tryptic digestion and an ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS)-based proteomics approach to investigate specific proteins and peptides of ten oilseed cakes, by-products of cold pressing oil from coconut, evening primrose, hemp, flax, milk thistle, nigella, pumpkin, rapeseed, sesame, and sunflower seeds, for authentication purposes.

RESULTS

We identified a total of 229 unique oilseed proteins. The number of specific proteins varied depending on the sample, from 4 to 48 in evening primrose and sesame. Moreover, we identified approximately 440 oilseed unique peptides in the cakes of all the analyzed oilseeds; the largest amounts were found in sesame (107 peptides), sunflower (100), pumpkin, hemp (42), rapeseed (36), and flax cake (35 peptides).

CONCLUSIONS

We provide novel information on unique / species-specific peptide markers that will extend the scope of testing the authenticity of a wide range of foods. The results of this peptide discovery experiment may further contribute to the development of targeted methods for the detection and quantification of oilseed proteins in processed foods, and thus to the improvement of food quality. © 2020 Society of Chemical Industry.

Peptide markers for distinguishing guinea fowl meat from that of other species using liquid chromatography-mass spectrometry

The inability to easily identify the animal species in highly processed meat products makes them highly susceptible to adulterations. Reliable methods for detecting the species origin of meat used in processed food are required to ensure adequate labelling and minimize food fraud and allergenic potential. Liquid chromatography high resolution mass spectrometry was employed to identify new heat-stable guinea-fowl-specific peptide markers that can differentiate guinea fowl meat from other commonly consumed animal species, including closely related poultry species, in highly processed food products. We identified 26 unique guinea-fowl-specific markers. The high stability of guinea-fowl-specific peptides was confirmed by analysing food products with guinea fowl meat content ranging from 4% to 100%. The findings indicate that sensitive and reliable LC-MS/MS methods can be developed for the targeted detection and quantification of guinea fowl meat in highly processed meat products.

Identification of species-specific peptide markers in cold-pressed oils

In recent years, cold-pressed vegetable oils have become very popular on the global market. Therefore, new versatile methods with high sensitivity and specificity are needed to find and combat fraudulent practices. The objective of this study was to identify oilseed species-specific peptide markers, using proteomic techniques, for authentication of 10 cold-pressed oils. In total, over 380 proteins and 1050 peptides were detected in the samples. Among those peptides, 92 were found to be species-specific and unique to coconut, evening primrose, flax, hemp, milk thistle, nigella, pumpkin, rapeseed, sesame, and sunflower oilseed species. Most of the specific peptides were released from major seed storage proteins (11 globulins, 2S albumins), and oleosins. Additionally, the presence of allergenic proteins in the cold-pressed oils, including pumpkin Cuc ma 5, sunflower Hel a 3, and six sesame allergens (Ses i 1, Ses i 2, Ses i 3, Ses i 4, Ses i 6, and Ses i 7) was confirmed in this study. This study provides novel information on specific peptides that will help to monitor and verify the declared composition of cold-pressed oil as well as the presence of food allergens. This study can be useful in the era of widely used unlawful practices.

Food authentication in real life: How to link nontargeted approaches with routine analytics?

In times of increasing globalization and the resulting complexity of trade flows, securing food quality is an increasing challenge. The development of analytical methods for checking the integrity and, thus, the safety of food is one of the central questions for actors from science, politics, and industry. Targeted methods, for the detection of a few selected analytes, still play the most important role in routine analysis. In the past 5 years, nontargeted methods that do not aim at individual analytes but on analyte profiles that are as comprehensive as possible have increasingly come into focus. Instead of investigating individual chemical structures, data patterns are collected, evaluated and, depending on the problem, fed into databases that can be used for further nontargeted approaches. Alternatively, individual markers can be extracted and transferred to targeted methods. Such an approach requires (i) the availability of authentic reference material, (ii) the corresponding high-resolution laboratory infrastructure, and (iii) extensive expertise in processing and storing very large amounts of data. Probably due to the requirements mentioned above, only a few methods have really established themselves in routine analysis. This review article focuses on the establishment of nontargeted methods in routine laboratories. Challenges are summarized and possible solutions are presented.