Allergenic and novel food proteins: State of the art and challenges in the allergenicity assessment

Allergenicity of alternative proteins: research hotspots, new findings, evaluation strategies, regulatory status, and future trends: a bibliometric analysis

As the world population rises, the demand for protein increases, leading to a widening gap in protein supply. There is an unprecedented interest in the development of alternative proteins, but their allergenicity has raised consumer concerns. This review aims to highlight and correlate the current research status of allergenicity studies on alternative proteins based on previously published studies. Current research keywords, hotspots and trends in alternative protein sensitization were analyzed using a mixed-method approach that combined bibliometric analysis and literature review. According to the bibliometric analysis, current research is primarily focused on food science, agriculture, and immunology. There are significant variations in the type and amount of allergens found in alternative proteins. A significant amount of research has been focused on studying plant-based proteins and the cross-reactivity of insect proteins. The allergenicity of alternative proteins has not been studied extensively or in depth. The allergenicity of other alternative proteins and the underlying mechanisms warrant further study. In addition, the lack of a standardized allergy assessment strategy calls for additional efforts by international organizations and collaborations among different countries. This review provides new research and regulatory perspectives for the safe utilization of alternative proteins in human food systems.

Molecular characterization and allergenicity assessment of different samples of Mung Bean

Legumes represent a promising nutritional alternative source of proteins to meat and dairy products. Additionally, Novel Foods (Regulation EU 2015/2283) can help meet the rising protein demand. However, despite their benefits, emerging allergenicity risks must be considered. The aim of this work is the molecular characterization of the Novel Food Mung bean protein isolate for allergenicity prediction with High Resolution Mass Spectrometry analysis. The assessment of the allergenicity was evaluated in silico by comparing protein sequences of the Novel Food with other known legume allergens, using bioinformatic databases. The results highlighted similarity higher than 60 % of the protein structure of Mung bean with two known allergens of soybean and pea. Furthermore, enzymatic hydrolysis effects on allergenic potential was evaluated by immunoblotting analysis using sera of patients allergic to legumes. The protein hydrolysates obtained showed a high nutritional quality and a reduced allergenic potential, making them suitable for hypoallergenic food formulations.

Utilizing proteomics to identify and optimize microalgae strains for high-quality dietary protein: a review

Algae-derived protein has immense potential to provide high-quality protein foods for the expanding human population. To meet its potential, a broad range of scientific tools are required to identify optimal algal strains from the hundreds of thousands available and identify ideal growing conditions for strains that produce high-quality protein with functional benefits. A research pipeline that includes proteomics can provide a deeper interpretation of microalgal composition and biochemistry in the pursuit of these goals. To date, proteomic investigations have largely focused on pathways that involve lipid production in selected microalgae species. Herein, we report the current state of microalgal proteome measurement and discuss promising approaches for the development of protein-containing food products derived from algae.

Composition, functional properties, health benefits and applications of oilseed proteins: A systematic review

Common oilseeds, such as soybean, peanut, rapeseed, sunflower seed, sesame seed and chia seed, are key sources of edible vegetable oils. Their defatted meals are excellent natural sources of plant proteins that can meet consumers' demand for health and sustainable substitutes for animal proteins. Oilseed proteins and their derived peptides are also associated with many health benefits, including weight loss and reduced risks of diabetes, hypertension, metabolic syndrome and cardiovascular events. This review summarizes the current status of knowledge on the protein and amino acid composition of common oilseeds as well as the functional properties, nutrition, health benefits and food applications of oilseed protein. Currently, oilseeds are widely applied in the food industry regarding for their health benefits and good functional properties. However, most oilseed proteins are incomplete proteins and their functional properties are not promising compared to animal proteins. They are also limited in the food industry due to their off-flavor, allergenic and antinutritional factors. These properties can be improved by protein modification. Therefore, in order to make better use of oilseed proteins, methods for improving their nutrition value, bioactive activity, functional and sensory characteristics, as well as the strategies for reducing their allergenicity were also discussed in this paper. Finally, examples for the application of oilseed proteins in the food industry are presented. Limitations and future perspectives for developing oilseed proteins as food ingredients are also pointed out. This review aims to foster thinking and generate novel ideas for future research. It will also provide novel ideas and broad prospects for the application of oilseeds in the food industry.

Cultured Meat Safety Research Priorities: Regulatory and Governmental Perspectives

As with every new technology, safety demonstration is a critical component of bringing products to market and gaining public acceptance for cultured meat and seafood. This manuscript develops research priorities from the findings of a series of interviews and workshops with governmental scientists and regulators from food safety agencies in fifteen jurisdictions globally. The interviews and workshops aimed to identify the key safety questions and priority areas of research. Participants raised questions about which aspects of cultured meat and seafood production are novel, and the implications of the paucity of public information on the topic. Novel parameters and targets may require the development of new analytical methods or adaptation and validation of existing ones, including for a diversity of product types and processes. Participants emphasized that data sharing of these efforts would be valuable, similar to those already developed and used in the food and pharmaceutical fields. Contributions to such databases from the private and public sectors would speed general understanding as well as efforts to make evaluations more efficient. In turn, these resources, combined with transparent risk assessment, will be critical elements of building consumer trust in cultured meat and seafood products.

Designing healthier plant-based foods: Fortification, digestion, and bioavailability

Many consumers are incorporating more plant-based foods into their diets as a result of concerns about the environmental, ethical, and health impacts of animal sourced foods like meat, seafood, egg, and dairy products. Foods derived from animals negatively impact the environment by increasing greenhouse gas emissions, land use, water use, pollution, deforestation, and biodiversity loss. The livestock industry confines and slaughters billions of livestock animals each year. There are concerns about the negative impacts of some animal sourced foods, such as red meat and processed meat, on human health. The livestock industry is a major user of antibiotics, which is leading to a rise in the resistance of several pathogenic microorganisms to antibiotics. It is often assumed that a plant-based diet is healthier than one containing more animal sourced foods, but this is not necessarily the case. Eating more fresh fruits, vegetables, nuts, and whole grain cereals has been linked to improved health outcomes but it is unclear whether next-generation plant-based foods, such as meat, seafood, egg, and dairy analogs are healthier than the products they are designed to replace. Many of these new products are highly processed foods that contain high levels of saturated fat, sugar, starch, and salt, and low levels of micronutrients, nutraceuticals, and dietary fibers. Moreover, they are often rapidly digested in the gastrointestinal tract because processing disrupts plant tissues and releases the macronutrients. Consequently, it is important to formulate plant-based foods to reduce the levels of nutrients linked to adverse health effects and increase the levels linked to beneficial health effects. Moreover, it is important to design the food matrix so that the macronutrients are not digested and absorbed too quickly, but the micronutrients are highly bioavailable. In this article, we discuss how next-generation plant-based foods can be made healthier by controlling their nutrient profile, digestibility, and bioavailability.

Edible Insects as a Novel Source of Bioactive Peptides: A Systematic Review

The production of food and feed to meet the needs of the growing world's population will soon become a serious challenge. In search for sustainable solutions, entomophagy is being proposed as an alternative source of proteins, with economic and environmental advantages when compared to meat. Edible insects are not only a valuable source of important nutrients, but their gastrointestinal digestion also originates small peptides with important bioactive properties. The present work intends to provide an exhaustive systematic review on research articles reporting bioactive peptides identified from edible insects, as demonstrated by in silico, in vitro, and/or in vivo assays. A total of 36 studies were identified following the PRISMA methodology, gathering 211 potentially bioactive peptides with antioxidant, antihypertensive, antidiabetic, antiobesity, anti-inflammatory, hypocholesterolemia, antimicrobial, anti-severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), antithrombotic, and immunomodulatory properties, originated from the hydrolysates of 12 different insect species. From these candidates, the bioactive properties of 62 peptides were characterized in vitro and 3 peptides were validated in vivo. Data establishing the scientific basis of the health benefits associated with the consumption of edible insects can be a valuable contribution to overcoming the cultural issues that hinder the introduction of insects in the Western diet.

Advanced Proteomic and Bioinformatic Tools for Predictive Analysis of Allergens in Novel Foods

In recent years, novel food is becoming an emerging trend increasingly more demanding in developed countries. Food proteins from vegetables (pulses, legumes, cereals), fungi, bacteria and insects are being researched to introduce them in meat alternatives, beverages, baked products and others. One of the most complex challenges for introducing novel foods on the market is to ensure food safety. New alimentary scenarios drive the detection of novel allergens that need to be identified and quantified with the aim of appropriate labelling. Allergenic reactions are mostly caused by proteins of great abundance in foods, most frequently of small molecular mass, glycosylated, water-soluble and with high stability to proteolysis. The most relevant plant and animal food allergens, such as lipid transfer proteins, profilins, seed storage proteins, lactoglobulins, caseins, tropomyosins and parvalbumins from fruits, vegetables, nuts, milk, eggs, shellfish and fish, have been investigated. New methods for massive screening in search of potential allergens must be developed, particularly concerning protein databases and other online tools. Moreover, several bioinformatic tools based on sequence alignment, motif identification or 3-D structure predictions should be implemented as well. Finally, targeted proteomics will become a powerful technology for the quantification of these hazardous proteins. The ultimate objective is to build an effective and resilient surveillance network with this cutting-edge technology.

Evaluation of subchronic oral dose toxicity and allergen of freeze-dried powder of Locusta migratoria (Orthoptera: Acrididae) as a novel food source

The migratory locust, Locusta migratoria (Orthoptera: Acrididae), is a well-known edible insect which may serve as new source of human food and animal feed. However, potential toxicity and food safety of L. migratoria had not been investigated extensively until now. Therefore, in this study, we aimed to investigate toxicity of freeze-dried powder of L. migratoria (fdLM) and identify allergic components in ELISA and PCR techniques. In this subchronic study, fdLM was administered once daily by oral gavage at the doses of 750, 1500, and 3000 mg/kg/day. No toxicological changes were observed in both sexes of rats for 13 weeks in accordance with the OECD guidelines and GLP conditions. In addition, fdLM did not induced increases of serum immunoglobulin E and 21 homologous proteins were not detected under our present conditions. In conclusion, the NOAEL (no-observed-adverse-effect level) was 3000 mg/kg/day and no target organ was identified in both sexes. In conclusion, we found that fdLM is safe with no adverse effects and offers the potential of its use as an edible ingredient or other biological uses.

Alternative Protein Sources and Novel Foods: Benefits, Food Applications and Safety Issues

The increasing size of the human population and the shortage of highly valuable proteinaceous ingredients has prompted the international community to scout for new, sustainable, and natural protein resources from invertebrates (e.g., insects) and underutilized legume crops, unexploited terrestrial and aquatic weeds, and fungi. Insect proteins are known for their nutritional value, being rich in proteins with a good balance of essential amino acids and being a valuable source of essential fatty acids and trace elements. Unconventional legume crops were found rich in nutritional, phytochemical, and therapeutic properties, showing excellent abilities to survive extreme environmental conditions. This review evaluates the recent state of underutilized legume crops, aquatic weeds, fungi, and insects intended as alternative protein sources, from ingredient production to their incorporation in food products, including their food formulations and the functional characteristics of alternative plant-based proteins and edible insect proteins as novel foods. Emphasis is also placed on safety issues due to the presence of anti-nutritional factors and allergenic proteins in insects and/or underutilized legumes. The functional and biological activities of protein hydrolysates from different protein sources are reviewed, along with bioactive peptides displaying antihypertensive, antioxidant, antidiabetic, and/or antimicrobial activity. Due to the healthy properties of these foods for the high abundance of bioactive peptides and phytochemicals, more consumers are expected to turn to vegetarianism or veganism in the future, and the increasing demand for such products will be a challenge for the future.

Monitoring Yellow Mealworm (Tenebrio molitor) as a Potential Novel Allergenic Food: Effect of Food Processing and Matrix

The consumption of insects has increased in western countries, raising concerns about their potential to induce food allergic reactions in sensitized/allergic individuals. This work intended to develop a real-time PCR approach for the detection/quantification of yellow mealworm (Tenebrio molitor) as a potential allergenic food in complex matrices. For this purpose, reference mixtures simulating the production of pork sausages and wheat biscuits containing known amounts of mealworm were used. Real-time PCR with TaqMan probe targeting the cytochrome b gene of T. molitor was able to detect up to 2 fg of insect DNA, and 1.0 and 0.1 mg/kg of mealworm flour in autoclaved sausages and baked biscuits, respectively. Generally, the method showed acceptable analytical performance parameters, confirming its suitability/applicability for a wide range of foods. However, real-time PCR data showed significant differences among food matrix and processing, highlighting the importance of using appropriate calibration models for quantitative analysis. Finally, the real-time PCR approach was successfully validated with blind mixtures and applied to commercial samples, demonstrating its efficacy and reliability in the quantification of mealworm in processed foodstuffs.

Gastrointestinal fate of food allergens and its relationship with allergenicity

Food allergens are closely related to their gastrointestinal digestion fate, but the changes in food allergens during digestion and related mechanisms are quite complicated. This review presents in detail digestion models for predicting allergenicity, the fates of food allergens in oral, gastric and duodenal digestion, and the applications of digestomics in mapping IgE-binding epitopes of digestion-resistant peptides. Moreover, this review highlights the structure-activity relationships of food allergens during gastrointestinal digestion. Digestion-labile allergens may share common structural characteristics, such as high flexibility, rendering them easier to be hydrolyzed into small fragments with decreased or eliminated allergenicity. In contrast, the presence of disulfide bonds, tightly wound α-helical structures, or hydrophobic domains in food allergens helps them resist gastrointestinal digestion, stabilizing IgE-binding epitopes, thus maintaining their sensitization. In rare cases, digestion leads to increased allergenicity due to exposure of new epitopes. Finally, the action of the food matrix and processing on the digestion and allergenicity of food allergens as well as the underlying mechanisms was overviewed. The food matrix can directly act on the allergen by forming complexes or new epitopes to affect its gastrointestinal digestibility and thereby alter its allergenicity or indirectly affect the allergenicity by competing for enzymatic cleavage or influencing gastrointestinal pH and microbial flora. Several processing techniques attenuate the allergenicity of food proteins by altering their conformation to improve susceptibility to degradation by digestive enzymes. Given the complexity of food components, the food itself rather than a single allergen should be used to obtain more accurate data for allergenicity assessment. PRACTICAL APPLICATION: The review article will help to understand the relationship between food protein digestion and allergenicity, and may provide fundamental information for evaluating and reducing the allergenicity of food proteins.

Identification of Allergens in White- and Red-Fleshed Pitaya (Selenicereus undatus and Selenicereus costaricensis) Seeds Using Bottom-Up Proteomics Coupled with Immunoinformatics

White-fleshed pitaya (Selenicereus undatus) and red-fleshed pitaya (Selenicereus costaricensis) are becoming increasingly popular because of their nutritional and medicinal benefits. However, in addition to their beneficial properties, allergy to pitaya fruits has occurred in daily life. In this study, we investigated the protein profile of pitaya fruit seeds and focused on the most reactive proteins against immunoglobulin E (IgE) in sera from allergic patients by immunoblotting. A protein band of approximately 20 kDa displayed a clear reaction with the serum IgE. The protein bands of interest were excised, in-gel digested, and analyzed using liquid chromatography–tandem mass spectrometry (LC–MS/MS), followed by data searching against a restricted database (Caryophyllales in UniProtKB) for protein identification. Immunoinformatic tools were used to predict protein allergenicity. The potential allergens included cupin_1 and heat shock protein 70 (HSP70) in white-fleshed pitaya seeds, and cupin_1, heat shock protein 70, and heat shock protein sti1-like in red-fleshed pitaya seeds are potential allergens. The expression of potential allergens was further verified at the transcriptional level in the species of S. undatus and S. costaricensis.

A spotlight on analytical prospects in food allergens: From emerging allergens and novel foods to bioplastics and plant-based sustainable food contact materials

The present review throws a spotlight on new and emerging food safety concerns in view of a well-established food allergen risk arising from global socio-economic changes, international trade, circular economy, environmental sustainability, and upcycling. Food culture globalization needs harmonization of regulations, technical specifications, and reference materials towards mutually recognised results. In parallel, routine laboratories require high-throughput reliable analytical strategies, even in-situ testing devices, to test both food products and food contact surfaces for residual allergens. Finally, the currently neglected safety issues associated to possible allergen exposure due to the newly proposed bio- and plant-based sustainable food contact materials require an in-depth investigation.

A new paradigm to search for allergenic proteins in novel foods by integrating proteomics analysis and in silico sequence homology prediction: Focus on spirulina and chlorella microalgae

Since novel nutrient sources with high protein content, such as yeast, fungi, bacteria, algae, and insects, are increasingly introduced in the consumer market, safety evaluation studies on their potentially allergenic proteins are required. A pipeline for in silico establishing the sequence-based homology between proteins of spirulina (Arthrospira platensis) and chlorella (Chlorella vulgaris) micro-algae and those included in the AllergenOnline (AO) database (AllergenOnline.org) is described. The extracted proteins were first identified through tryptic peptides analysis by reversed-phase liquid chromatography and high resolution/accuracy Fourier-transform tandem mass spectrometry (RPLC-ESI-FTMS/MS), followed by a quest on the UniProt database. The AO database was subsequently interrogated to assess sequence similarity between identified microalgal proteins and known allergens, based on criteria established by the World Health Organization (WHO) and Food and Agriculture Organization (FAO). A direct search for microalgal proteins already included in allergen databases was also performed using the Allergome database. Six proteins exhibiting a significant homology with food allergens were identified in spirulina extracts. Five of them, i.e., two thioredoxins (D4ZSU6, K1VP15), a superoxide dismutase (C3V3P3), a glyceraldehyde-3-phosphate dehydrogenase (K1W168), and a triosephosphate isomerase (D5A635), resulted from the search on AO. The sixth protein, C-phycocyanin beta subunit (P72508), was directly obtained after examining the Allergome database. Two proteins exhibiting significant sequence homology with food allergens were retrieved in chlorella extracts, viz. calmodulin (A0A2P6TFR8), which is related to troponin c (D7F1Q2), and fructose-bisphosphate aldolase (A0A2P6TDD0). Specific serum screenings based on immunochemical tests should be undertaken to confirm or rule out the allergenicity of the identified proteins.

Oilseed meals into foods: an approach for the valorization of oilseed by-products

The excellent health benefits of oil extracted from seeds have increased its application in foods, pharmaceutical and cosmetic industries. This trend leads to a growing research area on their by-products, oilseed meals, to minimize environmental and economic issues. Examples of these by-products are soybean, peanut, kenaf seed, hemp, sesame, and chia seed meals. It is well known that soybean meals have wide applications in food and non-food industries, while other seed meals are not well established. Most oilseed meals are rich in health beneficial compounds and are potential sources of plant protein, dietary fiber, and antioxidants. Many studies have reported on the valorization of these by-products into value-added food products such as bakery and meat products to increase their nutritional and functional properties. These efforts contribute to the sustainability, development of novel functional food and support the zero-waste concept for the environment. This review aims to provide information on the composition of selected oilseed meals from soybean, peanut, hemp, kenaf, sesame and chia seeds, their potential applications in the bakery, meat, beverage, pasta, and other food products, and to highlight the issues and challenges associated with the utilization of oilseed meals into various food products.

Detection of Lectin Protein Allergen of Kidney Beans (Phaseolus vulgaris L.) and Desensitization Food Processing Technology

With the increase of food allergy events related to not properly cooked kidney beans (Phaseolus vulgaris L.), more and more researchers are paying attention to the sensitization potential of lectin, one of the major storage and defensive proteins with the specific carbohydrate-binding activity. The immunoglobulin E (IgE), non-IgE, and mixed allergic reactions induced by the lectins were inducted in the current paper, and the detection methods of kidney bean lectin, including the purification strategies, hemagglutination activity, specific polysaccharide or glycoprotein interactions, antibody combinations, mass spectrometry methods, and allergomics strategies, were summarized, while various food processing aspects, such as the physical thermal processing, physical non-thermal processing, chemical modifications, and biological treatments, were reviewed in the potential of sensitization reduction. It might be the first comprehensive review on lectin allergen detection from kidney bean and the desensitization strategy in food processing and will provide a basis for food safety control.

Nutritional, functional, and allergenic properties of silkworm pupae

Edible insects are a food source that has high nutritional value. Domestic silkworm pupae are an important by-product of sericulture and have a long history as food and feed ingredients in East Asia. Silkworm pupae are a good source of protein, lipids, minerals, and vitamins and are considered a good source of nutrients for humans. Silkworm pupae are a valuable insect source of substances used in healthcare products, medicines, food additives, and animal feed. Because silkworm pupae are being increasingly used in the human diet, potential allergic reactions to the substances they contain must be elucidated. Here, we present an overview of the benefits of silkworm pupae. First, we describe their nutritional value. Second, we report their functional properties and applications, focusing on their potential use in the food and pharmaceutical industries. Finally, we consider the current state of research regarding silkworm pupae-induced allergies.

Safety of frozen and dried formulations from whole house crickets (Acheta domesticus) as a Novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Food and Food Allergens (NDA) was asked to deliver an opinion on the safety of frozen and dried formulations from house crickets (Acheta domesticus) as a novel food pursuant to Regulation (EU) 2015/2283. The NF is proposed in three formulations: (i) frozen, (ii) dried, (iii) ground. The main components of the NF are protein, fat and fibre (chitin) in the dried form of the NF, and water, protein, fat and fibre (chitin) in the frozen form of the NF. The Panel notes that the concentrations of contaminants in the NF depend on the occurrence levels of these substances in the insect feed. The Panel further notes that there are no safety concerns regarding the stability of the NF if the NF complies with the proposed specification limits during its entire shelf-life. The NF has a high-protein content, although the true protein levels in the NF are overestimated when using the nitrogen-to-protein conversion factor of 6.25, due to the presence of non-protein nitrogen from chitin. The applicant proposed to use the NF in the form of a snack, and as a food ingredient in a number of food products. The target population proposed by the applicant is the general population. The Panel notes that, considering the composition of the NF and the proposed conditions of use, the consumption of the NF is not nutritionally disadvantageous. The Panel notes that no genotoxicity and no subchronic toxicity studies with the NF were provided by the applicant. Considering that no safety concerns arise from the history of use of A. domesticus or from the compositional data of the NF, the Panel identified no other safety concerns than allergenicity. The Panel considers that the consumption of the NF might trigger primary sensitisation to A. domesticus proteins and may cause allergic reactions in subjects allergic to crustaceans, mites and molluscs. Additionally, allergens from the feed may end up in the NF. The Panel concludes that the NF is safe under the proposed uses and use levels.

Safety of frozen and dried formulations from migratory locust (Locusta migratoria) as a Novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Food and Food Allergens (NDA) was asked to deliver an opinion on the safety of frozen and dried formulations from migratory locust (Locusta migratoria) as a novel food pursuant to Regulation (EU) 2015/2283. The term migratory locust refers to the adult of the insect species Locusta migratoria. The NF is proposed in three formulations i) frozen without legs and wings; ii) dried without legs and wings; iii) ground with legs and wings. The main components of the NF are protein, fat and fibre (chitin) in the dried form of the NF, and water, protein, fat and fibre (chitin) in the frozen form of the NF. The Panel notes that the concentration of contaminants in the NF depends on the occurrence levels of these substances in the insect feed. The Panel notes that there are no safety concerns regarding the stability of the NF if the NF complies with the proposed specification limits during its entire shelf-life. The NF has a high protein content, although the true protein levels in the NF are overestimated when using the nitrogen-to-protein conversion factor of 6.25, due to the presence of non-protein nitrogen from chitin. The applicant proposed to use the NF as frozen, dried and ground in the form of snack, and as a food ingredient in a number of food products. The target population proposed by the applicant is the general population. The Panel notes that considering the composition of the NF and the proposed conditions of use, the consumption of the NF is not nutritionally disadvantageous. The submitted history of use and toxicity studies from literature did not raise safety concerns. The Panel considers that the consumption of the NF might trigger primary sensitisation to L. migratoria proteins and may cause allergic reactions in subjects with allergy to crustaceans, mites and molluscs. Additionally, allergens from the feed may end up in the NF. The Panel concludes that the NF is safe under the proposed uses and use levels.

Insect Protein-Based Diet as Potential Risk of Allergy in Dogs

Before insects can be used widely as an alternative source of dietary protein, their allerginicity should be investigated. Therefore, the aim of our study was to assess the potential adverse reactions of the immune system of dogs against Tenebrio molitor proteins. Dogs sensitised to storage mites T. putrescentiae and A. siro were included. Clinically healthy and clinically allergic dogs were compared. Proteins were extracted from mealworm larvae and their digestibility determined by in vitro incubation with digestive proteases. Mealworm protein extracts and digests were analysed by SDS-PAGE. Canine sera tested for the presence of mite-specific IgEs were used for subsequent Western blotting. LC-MS/MS analysis was used to identify mealworm proteins and their allergenic potential was predicted with the AllermatchTM tool. The binding of canine sera IgEs to mealworm proteins was confirmed; however, the differences between the two groups of dogs were not significant. Moreover, no clear correlation was found between sensitisation to storage mites and clinical status of the dogs. Altogether, 17 different proteins were identified, including tropomyosin, α-amylase, and Tm-E1a cuticular protein that are known cross-reacting IgE-binding allergens. Our results suggest that dogs allergic to mites may clinically express also the cross-reactivity with mealworm proteins.

Allergens from Edible Insects: Cross-reactivity and Effects of Processing

PURPOSE OF REVIEW

The recent introduction of edible insects in Western countries has raised concerns about their safety in terms of allergenic reactions. The characterization of insect allergens, the sensitization and cross-reactivity mechanisms, and the effects of food processing represent crucial information for risk assessment.

RECENT FINDINGS

Allergic reactions to different insects and cross-reactivity with crustacean and inhalant allergens have been described, with the identification of new IgE-binding proteins besides well-known pan-allergens. Depending on the route of sensitization, different potential allergens seem to be involved. Food processing may affect the solubility and the immunoreactivity of insect allergens, with results depending on species and type of proteins. Chemical/enzymatic hydrolysis, in some cases, abolishes immunoreactivity. More studies based on subjects with a confirmed insect allergy are necessary to identify major and minor allergens and the role of the route of sensitization. The effects of processing need to be further investigated to assess the risk associated with the ingestion of insect-containing food products.

Non-animal proteins as cutting-edge ingredients to reformulate animal-free foodstuffs: Present status and future perspectives

Consumer interest in protein rich diets is increasing, with more attention being paid to the protein source. Despite the occurrence of animal proteins in the human diet, non-animal proteins are gaining popularity around the world due to their health benefits, environmental sustainability, and ethical merit. These sources of protein qualify for vegan, vegetarian, and flexitarian diets. Non-animal proteins are versatile, derived mainly from cereals, vegetables, pulses, algae (seaweed and microalgae), fungi, and bacteria. This review's intent is to analyze the current and future direction of research and innovation in non-animal proteins, and to elucidate the extent (limitations and opportunities) of their applications in food and beverage industries. Prior knowledge provided relevant information on protein features (processing, structure, and techno-functionality) with particular focus on those derived from soy and wheat. In the current food landscape, beyond conventionally used plant sources, other plant proteins are gaining traction as alternative ingredients to formulate animal-free foodstuffs (e.g., meat alternatives, beverages, baked products, snack foods, and others). Microbial proteins derived from fungi and algae are also food ingredients of interest due to their high protein quantity and quality, however there is no commercial food application for bacterial protein yet. In the future, key points to consider are the importance of strain/variety selection, advances in extraction technologies, toxicity assessment, and how this source can be used to create food products for personalized nutrition.

Development of a sample preparation approach for the analysis of fining agents in wines by liquid chromatography with tandem mass spectrometry

During winemaking a wide variety of processing aids such as albumin, caseinates and lysozyme are often used. These proteins are considered allergenic and could become a human health risk in susceptible individuals. In our knowledge, there are no methods published for the analysis of these three proteins simultaneously by liquid chromatography with tandem mass spectrometry, with electrospray ionization. Therefore, in this work, a sample preparation approach for the analysis of α-casein, β-casein, albumin and lysozyme, in a single run, was performed and compared with published data. Through a pH adjustment, combining the use of cellulose ester membranes, a precipitation with organic solvents and a final concentration/clean-up, we achieved recovery values from 90.7 to 108.6%. The method was validated, showing determination coefficients R² ≥ 0.99. This method was able to quantify proteins even at lower levels (limits of quantification from 0.01 to 0.25 mg/L) than the current legal limits.

Safety of dried yellow mealworm (Tenebrio molitor larva) as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on dried yellow mealworm (Tenebrio molitor larva) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The term yellow mealworm refers to the larval form of the insect species Tenebrio molitor. The NF is the thermally dried yellow mealworm, either as whole dried insect or in the form of powder. The main components of the NF are protein, fat and fibre (chitin). The Panel notes that the levels of contaminants in the NF depend on the occurrence levels of these substances in the insect feed. The Panel notes that there are no safety concerns regarding the stability of the NF if the NF complies with the proposed specification limits during its entire shelf life. The NF has a high protein content, although the true protein levels in the NF are overestimated when using the nitrogen-to-protein conversion factor of 6.25, due to the presence of non-protein nitrogen from chitin. The applicant proposed to use the NF as whole, dried insect in the form of snacks, and as a food ingredient in a number of food products. The target population proposed by the applicant is the general population. The Panel notes that considering the composition of the NF and the proposed conditions of use, the consumption of the NF is not nutritionally disadvantageous. The submitted toxicity studies from the literature did not raise safety concerns. The Panel considers that the consumption of the NF may induce primary sensitisation and allergic reactions to yellow mealworm proteins and may cause allergic reactions in subjects with allergy to crustaceans and dust mites. Additionally, allergens from the feed may end up in the NF. The Panel concludes that the NF is safe under the proposed uses and use levels.

Comparison of digestibility and potential allergenicity of raw shrimp (Litopenaeus vannamei) extracts in static and dynamic digestion systems

In this work, a simplified dynamic digestion system was developed, and used for comparing the digestibility and potential allergenicity of raw shrimp extracts (RSE) in static and dynamic digestion systems. Protein hydrolysis was analyzed by electrophoresis, and the potential allergenicity was reflected in IgG/IgE binding ability and activation of basophils. In comparison with static digestion, protein hydrolysis indicated different kinetic behaviors, especially tropomyosin (TM) showed better digestion stability during dynamic digestion. The potential allergenicity of RSE exhibited different changing trends with digestion in the two systems. However, the apparent molecular weight (Mw) of immune fragments (>11 kDa) showed good approximation, and the IgE-binding fragment near 70 kDa revealed outstanding digestion stability than primordial protein in both systems. In conclusion, the dynamic conditions had a significant impact on the assessment of the persistence and potential allergenicity of digestion-resistant allergens, while the apparent Mw of IgG/IgE binding hydrolysate was not affected.

Current Trends in Proteomic Advances for Food Allergen Analysis

Food allergies are a global food challenge. For correct food labelling, the detection and quantification of allergens are necessary. However, novel product formulations and industrial processes produce new scenarios, which require much more technological developments. For this purpose, OMICS technologies, especially proteomics, seemed to be relevant in this context. This review summarises the current knowledge and studies that used proteomics to study food allergens. In the case of the allergenic proteins, a wide variety of isoforms, post-translational modifications and other structural changes during food processing can increase or decrease the allergenicity. Most of the plant-based food allergens are proteins with biological functions involved in storage, structure, and plant defence. The allergenicity of these proteins could be increased by the presence of heavy metals, air pollution, and pesticides. Targeted proteomics like selected/multiple reaction monitoring (SRM/MRM) have been very useful, especially in the case of gluten from wheat, rye and barley, and allergens from lentil, soy, and fruit. Conventional 1D and 2-DE immunoblotting have been further widely used. For animal-based food allergens, the widely used technologies are 1D and 2-DE immunoblotting followed by MALDI-TOF/TOF, and more recently LC-MS/MS, which is becoming useful to assess egg, fish, or milk allergens. The detection and quantification of allergenic proteins using mass spectrometry-based proteomics are promising and would contribute to greater accuracy, therefore improving consumer information.

Protein digestion of different protein sources using the INFOGEST static digestion model

In vitro digestion systems are valuable tools for understanding and monitoring the complex behavior of food degradation during digestion, thus proving to be good candidates for replacing in vivo assays. The aim of the present work was to study protein hydrolysis in a selection of different protein sources using the harmonized INFOGEST static protocol: three isolated proteins (collagen, zein, and whey protein) and five foods (sorghum flour, wheat bran cereals, peanuts, black beans, and pigeon peas). The proteins of all the substrates were analyzed by SDS-PAGE and HPLC-MS/MS. Individual amino acid composition was analyzed by high-performance liquid chromatography (HPLC). EAA/NEAA (essential amino acids/ nonessential amino acids) ratios in the substrates from low to high were as follows: wheat bran cereals, peanuts, collagen, zein, whey protein, sorghum, pigeon peas, and black beans. The results revealed sorghum, whey protein, and zein as good sources of BCAA. In all substrates, no intact protein from the substrates was visually detected by SDS-PAGE after the intestinal phase of in vitro digestion with the INFOGEST protocol. However, digestion-resistant peptides were detected in all substrates after the intestinal digestion phase. Protein hydrolysis was high in whey protein isolate and pigeon pea and low for wheat bran cereals and bovine collagen.

The hidden 'plant side' of insect novel foods: A DNA-based assessment

In the context of novel foods, a category for which the market demand is increasing worldwide, the consumption of edible insects and related insect-based products is expected to grow in the next years. Insects represent an important source of energy for the human diet but there is a lack of scientific knowledge about their processing to ensure safe food items to the consumer. In this study we adopted a combined DNA-based approach to verify the identity of the declared species in five categories of commercial insect-based products (mt COI DNA barcoding) and to characterize plant declared ingredients or contaminants (nu ITS2 DNA metabarcoding) with particular attention to putative elements of allergenic concern belonging, for example to the insect rearing substrate. Moreover, the same approach has been used to assess its sensitivity to cases of contamination and counterfeits to insect flour with low cost (and potentially allergenic) vegetable flours like wheat and soybean. Results show the success of insect DNA barcoding authentication even for highly processed products. Furthermore, the DNA metabarcoding analysis revealed a high efficacy as a screening method to identify both plant ingredients and vegetal traces belonging to insect farming or possible adulteration events, also acting as an early warning strategy for the occurrence of allergens of human concern. This approach could support the development of new risk assessment procedures for novel foods by regulatory authorities to ensure their quality, safety, and acceptance which will become more required in order to face the challenge of feeding the world population in the next decades.

Review: Seafood Allergy and Potential Application of High Hydrostatic Pressure to Reduce Seafood Allergenicity

High hydrostatic pressure (HHP), a novel non-thermal processing technology, can inactivate microorganisms in food with ultra-high pressure over 100 MPa. In recent years, it has shown unique potential in alleviating seafood allergenicity. Seafood, as a primary high-quality protein source, is one of popular food products in many human populations, while seafood allergy remains an obstacle to the consumption of seafood and calls for processing raw materials to reduce their allergenicity. Heating and fermentation as conventional methods, along with HHP as a rising novel technology, have been applied in seafood processing, such as shrimp and squid. This review provides a brief introduction of current key publications and limitations of researches on seafood allergy. In addition, characteristics and principles, processing parameters and effects of HHP treatment on seafood of current researches were detailed. Our main goal was to support readers to keep abreast with knowledge on seafood allergy and provide new insights of using HHP for seafood processing to achieve lower allergenicity.

The role of incurred materials in method development and validation to account for food processing effects in food allergen analysis

The issue of undeclared allergens represents a matter of great concern, being the subject of many alert notifications by the Rapid Alert System for Food and Feed portal of the European Commission, often leading to food recalls. The availability of reliable analytical approaches able to detect and quantify hidden allergens in processed foods is increasingly requested by the food industry, food safety authorities and regulatory bodies to protect sensitive consumers' health. The present review discusses the fundamental role of incurred materials for method development and analytical performance assessment in a metrology perspective on testing for undeclared allergens in processed foodstuffs. Due to the nature of the analytes and their susceptibility to various processing effects, reliability and comparability of results have posed a great challenge. In this context, the use of incurred samples as reference materials permits simulation of the effects of food processing on target analyte structure affecting analyte extractability and detectability. Graphical abstract ᅟ.