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    Harry Wichers

    ABSTRACT
    Soy protein is the main protein source for plant-based infant formula, whereas pea protein is considered as a potential alternative plant protein source. This study assessed the structural changes of soy and pea proteins after heating... more
    Soy protein is the main protein source for plant-based infant formula, whereas pea protein is considered as a potential alternative plant protein source. This study assessed the structural changes of soy and pea proteins after heating between 65 °C and 100 °C, and its effects on the in vitro digestibility in the context of infant digestion. We found that with increased heating intensity, both soy and pea proteins unfolded, manifested as the increased surface hydrophobicity, thereby potentially improving the accessibility to digestive enzymes. Their final in vitro digestibility increased from ∼ 30% of non-treated samples to ∼ 60% of 100 °C-heated samples for soy protein, and from ∼ 52% to ∼ 65% for pea protein. Surface hydrophobicity was strongly positively correlated to the overall digestibility. Therefore, the heating temperatures that enabled protein unfolding promoted the digestibility of soy and pea proteins under infant digestion conditions.
    ScopeChitin, the most abundant polysaccharide found in nature after cellulose, is known for its ability to support wound healing and to lower plasma‐oxidized low‐density lipoprotein (LDL) levels. Studies have also revealed... more
    ScopeChitin, the most abundant polysaccharide found in nature after cellulose, is known for its ability to support wound healing and to lower plasma‐oxidized low‐density lipoprotein (LDL) levels. Studies have also revealed immunomodulatory potential but contradicting results are often impossible to coalesce through usage of chitin of different or unknown physicochemical consistency. In addition, only a limited set of cellular models have been used to test the bioactivity of chitin.Methods and ResultsChitin is investigated with well‐defined physicochemical consistency for its immunomodulatory potency using THP‐1 macrophages, impact on intestinal epithelial barrier using Caco‐2 cells, and fermentation by fecal‐derived microbiota. Results show that chitin with a degree of acetylation (DA) of ≈83%, regardless of size, does not affect the intestinal epithelial barrier integrity. Large‐sized chitin significantly increases acetic acid production by gut microbiota without altering the compo...
    Heat treatment is a commonly applied unit operation in the processing of β-lactoglobulin containing products. This does, however, influence its structure and thereby impacts its activity and digestibility. We describe how various... more
    Heat treatment is a commonly applied unit operation in the processing of β-lactoglobulin containing products. This does, however, influence its structure and thereby impacts its activity and digestibility. We describe how various heat-treatments of β-lactoglobulin change the digestibility using a modified version of the current consensus INFOGEST protocol. Additionally, protein was investigated for its translocation over the intestinal epithelial barrier, which would bring them in contact with immune cells. The extent of gastric digestibility was higher when the protein structure was more modified, while the influence of glycation with lactose was limited. Translocation studies of protein across Caco-2 cell monolayers showed a lower translocation rate of protein heated in solution compared to the others. Our study indicates that structural modifications after different heat-treatments of β-lactoglobulin increase in particular gastric digestibility and the translocation efficiency across intestinal epithelial cells.
    Tyrosinase‐related protein 1 (TYRP1) is one of three tyrosinase‐like glycoenzymes in human melanocytes that are key to the production of melanin, the compound responsible for the pigmentation of skin, eye, and hair. Difficulties with... more
    Tyrosinase‐related protein 1 (TYRP1) is one of three tyrosinase‐like glycoenzymes in human melanocytes that are key to the production of melanin, the compound responsible for the pigmentation of skin, eye, and hair. Difficulties with producing these enzymes in pure form have hampered the understanding of their activity and the effect of mutations that cause albinism and pigmentation disorders. Herein we show that the typical tyrosinase‐like subdomain of TYRP1 contains two zinc ions in the active site instead of copper ions as found in tyrosinases, which explains why TYRP1 does not exhibit tyrosinase redox activity. In addition, the structures reveal for the first time that the Cys‐rich subdomain, which is unique to vertebrate melanogenic proteins, has an epidermal growth factor‐like fold and is tightly associated with the tyrosinase subdomain. Our structures suggest that most albinism‐related mutations of TYRP1 affect its stability or activity.
    Antivrieseiwitten hebben de eigenschap om het vriespunt te verlagen en rekristallisatie van ijs tegen te gaan. Deze eiwitten komen voor in poolvissen, insekten, planten en micro-organismen. Bovendien geven ze de ijskristallen een andere... more
    Antivrieseiwitten hebben de eigenschap om het vriespunt te verlagen en rekristallisatie van ijs tegen te gaan. Deze eiwitten komen voor in poolvissen, insekten, planten en micro-organismen. Bovendien geven ze de ijskristallen een andere morfologie
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    Protein-enriched insect fractions mitigated Clostridium difficile toxin A-mediated Caco-2 barrier damage by increasing gene transcription of cell junctional and proliferation proteins.
    The ever-growing world population puts pressure on food security. To tackle this, waste stream proteins and novel protein sources need to be evaluated for nutritional value, which requires information on digesta peptide composition in... more
    The ever-growing world population puts pressure on food security. To tackle this, waste stream proteins and novel protein sources need to be evaluated for nutritional value, which requires information on digesta peptide composition in comparison to established protein sources and coupling to biological parameters. Here, we present a novel combined experimental and computational approach comparing seventeen protein sources with cow’s whey protein (WPC) as benchmark. In vitro digestion was followed by proteomics analysis and statistical model clustering based on Bayesian Information Criterion. Next, we incorporated functional protein data after evaluating the effects of eighteen protein digests on intestinal barrier integrity, viability, brush border enzyme activity and immune parameters using a bioengineered intestine. Our data show that a holistic approach allows evaluating a dietary protein’s potential for delivery of bioactive peptides, where protein source (animal, plant or novel...
    Background: Allergic sensitisation towards cashew nut often happens without a clear history of eating cashew nut. IgE cross-reactivity between cashew and pistachio nut is well described; however, the ability of cashew nut-specific IgE to... more
    Background: Allergic sensitisation towards cashew nut often happens without a clear history of eating cashew nut. IgE cross-reactivity between cashew and pistachio nut is well described; however, the ability of cashew nut-specific IgE to cross-react to common tree nut species and other Anacardiaceae, like mango, pink peppercorn, or sumac is largely unknown. Objectives: Cashew nut allergic individuals may cross-react to foods that are phylogenetically related to cashew. We aimed to determine IgE cross-sensitisation and cross-reactivity profiles in cashew nut-sensitised subjects, towards botanically related proteins of other Anacardiaceae family members and related tree nut species. Method: Sera from children with a suspected cashew nut allergy (n = 56) were assessed for IgE sensitisation to common tree nuts, mango, pink peppercorn, and sumac using dot blot technique. Allergen cross-reactivity patterns between Anacardiaceae species were subsequently examined by SDS-PAGE and immunoblot...
    Controlling allergens in food is a matter of increasing importance for the food industry, especially in light of recent legislation. Effective handling of allergens depends on identifying allergenic ingredients, creating separate... more
    Controlling allergens in food is a matter of increasing importance for the food industry, especially in light of recent legislation. Effective handling of allergens depends on identifying allergenic ingredients, creating separate production lines for allergen-free products, and effective labelling to inform consumers about which products are safe to eat. Recent attention has also focused on novel methods to manage allergens in food, for example by reducing allergenicity through the prudent selection of raw food materials and improved processing techniques. Part 1 discusses the diagnosis of offending foods and how allergens can affect the quality of life. Expanding on these fundamentals, Part 2 reviews the effect of different methods of food processing on allergens and novel technologies which can reduce the potency of allergens or remove them altogether from foods. The final part of the book covers the key area of risk assessment and allergen management to achieve more uniform standards within the industry. Practical strategies to improve consumer acceptance of GM foods are also discussed.
    Anti-cancer T-cell responses are often halted due to the immune-suppressive micro-environment, in part related to tumor-associated macrophages. In the current study, we assessed indigestible β-glucans (oatβG, curdlan, grifolan,... more
    Anti-cancer T-cell responses are often halted due to the immune-suppressive micro-environment, in part related to tumor-associated macrophages. In the current study, we assessed indigestible β-glucans (oatβG, curdlan, grifolan, schizophyllan, lentinan, yeast whole glucan particles (yWGP), zymosan and two additional yeast-derived β-glucans a and b) for their physicochemical properties as well as their effects on the plasticity of human monocyte-derived macrophages that were polarized with IL-4 to immune-suppressive macrophages. Beta-glucans were LPS/LTA free, and tested for solubility, molecular masses, protein and monosaccharide contents. Curdlan, yeast-b and zymosan re-polarized M(IL-4) macrophages towards an M1-like phenotype, in particular showing enhanced gene expression of CCR7, ICAM1 and CD80, and secretion of TNF-α and IL-6. Notably, differential gene expression, pathway analysis as well as protein expressions demonstrated that M(IL-4) macrophages treated with curdlan, yeast-...
    Abstract We studied several sustainable alternative protein concentrates and a whey protein concentrate as reference, to determine their protein composition, digestibility and quality using the harmonized INFOGEST static protocol. The... more
    Abstract We studied several sustainable alternative protein concentrates and a whey protein concentrate as reference, to determine their protein composition, digestibility and quality using the harmonized INFOGEST static protocol. The proteins concentrates were analyzed to determine their conversion factor, degree of hydrolysis, true ileal digestibility, in vitro digestible indispensable amino acid score (IVDIAAS) and total absorbable amino acids and total essential amino acids. The results revealed that whey, blood plasma concentrate and yeast protein concentrate have a high mean true ileal indispensable amino acid in vitro digestibility (91.1–85.8%), closely followed by corn, pea, potato and proteins derived from lesser meal worms (ranging between 82.5 and 77.9%). Mycoprotein gave a much lower score in the mass balance, so that its other results could not be interpreted as being reliable. Whey, potato, blood plasma and yeast protein concentrates ranked highest in IVDIAAS (between 119 and 97.2), followed by lesser meal worm and pea (between 73.8 and 57.8) with corn protein concentrate having the lowest IVDIAAS due to underrepresentation of lysine. The method and data presented in this paper can form a start for further applying the INFOGEST in vitro digestion protocol to evaluate protein quality.
    Advanced glycation end products (AGEs) can be present in food or be endogenously produced in biological systems. Their formation has been associated with chronic neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease,... more
    Advanced glycation end products (AGEs) can be present in food or be endogenously produced in biological systems. Their formation has been associated with chronic neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and amyotrophic lateral sclerosis. The implication of AGEs in neurodegeneration is related to their ability to bind to AGE-specific receptors and the ability of their precursors to induce the so-called “dicarbonyl stress”, resulting in cross-linking and protein damage. However, the mode of action underlying their role in neurodegeneration remains unclear. While some research has been carried out in observational clinical studies, further in vitro studies may help elucidate these underlying modes of action. This review presents and discusses in vitro methodologies used in research on the potential role of AGEs in neuroinflammation and neurodegeneration. The overview reveals the main concepts linking AGEs to neurodegeneration, the...
    The introduction of baked milk products in cow’s milk (CM) allergic children has previously been shown to accelerate induction tolerance in a selected group of children. However, there is no standardized baked milk product on the market.... more
    The introduction of baked milk products in cow’s milk (CM) allergic children has previously been shown to accelerate induction tolerance in a selected group of children. However, there is no standardized baked milk product on the market. Recently, a new standardized, heated and glycated cow’s milk protein (HP) product was developed. The aim of this study was to measure safety and tolerability of a new, well characterized heated CM protein (HP) product in cow’s milk allergic (CMA) children between the age of 3 and 36 months. The children were recruited from seven clinics throughout the Netherlands. The HP product was introduced in six incremental doses under clinical supervision. Symptoms were registered after introduction of the HP product. Several questionnaires were filled out by parents of the children. Skin prick tests were performed with CM and HP product, sIgE to CM and α-lactalbumin (Bos d4), β-lactoglobulin (Bos d5), serum albumin (Bos d 6), lactoferrin (Bos d7) and casein (...
    2015 (WHO), obesity and consequently diabetes type II are among the biggest global health problems. Even though dietary and lifestyle changes may eventually reduce obesity for some individuals, new safe and more efficacious drugs are... more
    2015 (WHO), obesity and consequently diabetes type II are among the biggest global health problems. Even though dietary and lifestyle changes may eventually reduce obesity for some individuals, new safe and more efficacious drugs are required for successful weight reduction and treatment of type 2 diabetes in a large proportion of obese individuals. It has been shown that various G-protein coupled receptors (GPCRs) expressed in various tissues such as liver, muscle, pancreatic islets, immune cells and the central nervous system are involved. GPCRs are important targets for food components. The members of this large family of membrane proteins are involved in virtually every physiological process. This study will focus on the interaction between food ligands and GPCRs. Reduction of obesity and related diseases by targeted nutritional treatment
    De rol van voeding voor een goed werkend immuunsysteem wordt steeds duidelijker. Een goed gebalanceerde voeding kan bijdragen aan het voorkomen van ziekte in het vroege leven (allergie, infecties) en het late leven (ontsteking,... more
    De rol van voeding voor een goed werkend immuunsysteem wordt steeds duidelijker. Een goed gebalanceerde voeding kan bijdragen aan het voorkomen van ziekte in het vroege leven (allergie, infecties) en het late leven (ontsteking, infecties). Het belang van macro- en micronutrienten voor het normaal functioneren van het immuunsysteem is reeds lang bekend. We leren ook steeds meer over nieuwe voedingsmiddelen en -componenten die specifieke effecten op het immuunsysteem kunnen hebben. Dit zijn onder andere probiotica, prebiotica en voedingsvezels, componenten van (moeder) melk, vetzuren (PUFA en SCFA), en antioxidantia. Deze kunnen het immuunsysteem zowel rechtstreeks beinvloeden als indirect via effecten op darmbacterien en darmepitheel. Dit artikel probeert een overzicht te geven van de huidige kennis op dit gebied, met een focus op de mogelijke rol van voeding in het voorkomen van allergie, infectie, en ontsteking.
    Chitin and chitosan have been recognised for their beneficial health effects since the 1980s. Over the past few decades, numerous studies and several clinical trials have been performed which demonstrated that these compounds can reduce... more
    Chitin and chitosan have been recognised for their beneficial health effects since the 1980s. Over the past few decades, numerous studies and several clinical trials have been performed which demonstrated that these compounds can reduce body weight and cardiovascular disease (CVD), improve wound healing, but can also modulate the immune system and demonstrate antifungal and antibacterial activity. In particular, weight reduction and improvement of cardiovascular status are interesting targets as the prevalence of obesity and CVD are increasing. Both diseases are associated with various pathological disorders, including diabetes and hypertension and put a strain on healthcare costs and capacity. In general, lifestyle‐based interventions such as the oral intake of chitin and/or chitosan are becoming increasingly popular as these are easily integrated into current treatments and improve the self‐assertiveness of patients. Of interest, but beyond the scope of this chapter, is the use of chitin‐glucans as supplements in cosmetics. Several studies have demonstrated that chitin‐glucan reduced wrinkling and skin‐ageing, suggesting an interaction between the chitin‐glucan and cells of the epidermis. Although these effects may not be attributed to chitin alone, this does demonstrate the strong biological potential of chitin on cells of the human body. In this chapter, scientific literature has been reviewed that demonstrated the beneficial health effects of chitin and chitosan from an immunomodulatory point‐of‐view. First, we provide an overview of in vitro studies that offer in‐depth mechanistic insights, followed by describing preclinical animal studies. Finally, we list various human intervention trials that most clearly demonstrate the beneficial health effects of chitin and chitosan. Furthermore, we purposely discriminate between data on chitin and chitosan as they are chemically distinct and therefore possibly demonstrate unique effects on health
    Chitin and chitosan have been recognised for their beneficial health effects since the 1980s. Over the past few decades, numerous studies and several clinical trials have been performed which demonstrated that these compounds can reduce... more
    Chitin and chitosan have been recognised for their beneficial health effects since the 1980s. Over the past few decades, numerous studies and several clinical trials have been performed which demonstrated that these compounds can reduce body weight and cardiovascular disease (CVD), improve wound healing, but can also modulate the immune system and demonstrate antifungal and antibacterial activity. In particular, weight reduction and improvement of cardiovascular status are interesting targets as the prevalence of obesity and CVD are increasing. Both diseases are associated with various pathological disorders, including diabetes and hypertension and put a strain on healthcare costs and capacity. In general, lifestyle‐based interventions such as the oral intake of chitin and/or chitosan are becoming increasingly popular as these are easily integrated into current treatments and improve the self‐assertiveness of patients. Of interest, but beyond the scope of this chapter, is the use of chitin‐glucans as supplements in cosmetics. Several studies have demonstrated that chitin‐glucan reduced wrinkling and skin‐ageing, suggesting an interaction between the chitin‐glucan and cells of the epidermis. Although these effects may not be attributed to chitin alone, this does demonstrate the strong biological potential of chitin on cells of the human body. In this chapter, scientific literature has been reviewed that demonstrated the beneficial health effects of chitin and chitosan from an immunomodulatory point‐of‐view. First, we provide an overview of in vitro studies that offer in‐depth mechanistic insights, followed by describing preclinical animal studies. Finally, we list various human intervention trials that most clearly demonstrate the beneficial health effects of chitin and chitosan. Furthermore, we purposely discriminate between data on chitin and chitosan as they are chemically distinct and therefore possibly demonstrate unique effects on health
    Background Tree nut-allergic individuals are often sensitised towards multiple nuts and seeds. The underlying cause behind a multi-sensitisation for cashew nut, hazelnut, peanut and birch pollen is not always clear. We investigated... more
    Background Tree nut-allergic individuals are often sensitised towards multiple nuts and seeds. The underlying cause behind a multi-sensitisation for cashew nut, hazelnut, peanut and birch pollen is not always clear. We investigated whether immunoglobulin E antibody (IgE) cross-reactivity between cashew nut, hazelnut and peanut proteins exists in children who are multi-allergic to these foods using a novel IMMULITE®-based inhibition methodology, and investigated which allergens might be responsible. In addition, we explored if an allergy to birch pollen might play a role in this co-sensitisation for cashew nut, hazelnut and peanut. Methods Serum of five children with a confirmed cashew nut allergy and suffering from allergic symptoms after eating peanut and hazelnut were subjected to inhibition immunoassays using the IMMULITE® 2000 XPi. Serum-specific IgE (sIgE) to seed storage allergens and pathogenesis-related protein 10 (PR10) allergens were determined and used for molecular multi...
    Specific nutrients including n-3 long chain polyunsaturated fatty acids (LCPUFAs), flavonoids, vitamin A, D and E are considered to possess protective properties on human health by impacting on immunological reactions. An... more
    Specific nutrients including n-3 long chain polyunsaturated fatty acids (LCPUFAs), flavonoids, vitamin A, D and E are considered to possess protective properties on human health by impacting on immunological reactions. An ‘inflammation-suppressive’ effect appears to be the common denominator of the beneficial effects of most of these dietary components which may protect against the development of chronic immune disorders such as allergy. However, the majority of these promising data are from preclinical studies such as animal disease models, as the majority of clinical studies only indicate associations. PUFAs, especially n-3 LCPUFAs, have been shown to interact with both the sensitization as well as the effector phase in food allergy. However, it should be noted and realised that PUFAs are highly susceptible to lipid oxidation. Flavonoids and fat-soluble vitamins both contain anti-inflammatory properties and are able to act as anti-oxidants as well. Here, we explore the...
    The double-blind, placebo-controlled food challenge test (DBPCFC) is the gold standard in cashew nut allergy. This test is costly, time-consuming and not without side effects. Analysis of IgE-reactivity to cashew nut components may reduce... more
    The double-blind, placebo-controlled food challenge test (DBPCFC) is the gold standard in cashew nut allergy. This test is costly, time-consuming and not without side effects. Analysis of IgE-reactivity to cashew nut components may reduce the need for food challenge tests. In a prospective and multicentre study, children with suspected cashew nut allergy underwent a DBPCFC with cashew nut. Specific IgE to cashew nut and to the components Ana o 1, 2 and 3 were determined. A skin prick test (SPT) with cashew nut extract was performed. The association between the outcome of the food challenge test and specific IgE to Ana o 1, 2 and 3 was assessed with logistic regression analyses, unadjusted and adjusted for other diagnostic variables. Discriminative ability was quantified with a concordance index (c). 173 children (103 boys, 60%) with a median age of 9 years were included. 79% had a positive challenge test outcome. A steep rise in the risk of a positive challenge was observed for spec...

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