Food matrix and processing on allergenic activity

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Food Matrix and Processing on allergenic activity
Presented by Siriruk Kanchanateeraphong, MD.
Jan10, 2014

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Food matrix and processing on allergenic activity

  1. 1. • • • • • Overviews Development of Food Processing Processing induced Modification Impact of Processing on Food Allergens Clinical Implication
  2. 2. Overviews Food processing: • Modulate allergic reaction(sensitization) • Processing affects by – altering their shape, molecular weight and structural – modulating immunoglobulin E-binding capacity (changing IgE reactivity) lead to mediator releases. • Sites on molecule recognized by IgE are called “epitopes”
  3. 3. Epitopes • short regions(8 to 15 amino) residues, • tend to be mobile, • adopt a disordered secondary structure, • be stable in food processing. • various segments of polypeptide chain and brought together by protein folding, • food processing affect in folded and destroy conformational epitopes • found in unprocessed or raw foods or reveal new epitopes previously hidden by protein folding. Middleton’s Allergy: Principles and Practice 8th Edition
  4. 4. Effects of thermal processing on allergenicity is difficult; • the time-temperature combinations used in food processing, • the impact of water activity on the stability of individual allergens to thermal, • the different methods employed to determine allergenic activity. Allergen Cow’s milk Reactivity raw, pasteurized, or UHT Safety extensively heated e.g., baked products such as muffins or cakes * Baking modifies the proteins much more than pasteurization. Hen’s egg Peanut raw, boiling extensively heated e.g., roasted and fried * Cooking usually reduces but does not abolish the allergenic potency of egg. ** Maillard reaction introduced by roasting. Middleton’s Allergy: Principles and Practice 8th Edition
  5. 5. Classification of Allergens Allergen Source Protein molecules Products Cupins plant • Vicilin-like 7S seed storage globulins • Legumin-like 11S seed storage globulins legumes (e.g., soybean, peanut, lupin), tree nuts (e.g., hazelnut, walnut, cashew, pecan, almond), seeds (e.g., sesame, mustard). Prolamin superfamily (three group of proteins) skeleton of cysteine residues. • 2S albumins • Lipid-transfer proteins (LTPs) • Cereal α-amylase inhibitors fresh fruits (e.g., apple, kiwi, peach) seeds (e.g., peanut, tree nut, sesame) wheat (monocotyledonous plants) and cereals (e.g., barley) Bet v 1 superfamily fruit • Bet v 1 homolog • Gly m 4, Api g 1 apple-Birch pollen (oral allergy syndrome) soy bean, celery splice Tropomyosin shellfish species • Met e 1 crustacean and molluscan, greasy back shrimp Parvalbumin muscle fish • apo and holo form white muscle fish Caseins mammalian milk • phosphoserine • phosphothreonine milk Others: -Lipocalins -β-lactoglobulin -ovomucoid and ovalbumin • Bos d 5 • Gal d 1 and Gal d 2 inhalant allergen cow’s milk eggs
  6. 6. Development of Food Processing • The ability of humans to make and control fire, which began about 125,000 years ago • Variety to cook foods including using heated stones for boiling, burying food wrapped in leaves in the hot embers of fires, or baking fish in clay • Advent of urban living need to preserve foods after the harvest • In the twenty-first century, when most of the world’s population live in cities Middleton’s Allergy: Principles and Practice 8th Edition
  7. 7. Development of Food Processing • • • • Post-harvest treatments Primary processing Secondary processing Complex foods
  8. 8. Post-harvest treatments Nature of Processing Modified atmosphere for storage of fruit and vegetables such as cooling, cleaning, sorting and packing Source: Apple Impact of Processing Bet v 1 homologs is upregulated during storage, levels are higher in fruit stored for 4-5 months LTP allergens is downregulated during storage levels are higher in fresh fruit Middleton’s Allergy: Principles and Practice 8th Edition
  9. 9. Primary processing Nature of Processing Removal of outer layers by physical or chemical peeling Source: Peach Impact of Processing Loss of allergens such as LTPs located in the outer layers Middleton’s Allergy: Principles and Practice 8th Edition
  10. 10. Secondary processing Nature of Processing Source Impact of Processing Fruit purees and fresh juices Peach, apple Labile Bet v 1 homologs are modified. Prolamin superfamily fruit LTPs retain a native-like structure. Preparation of pasteurized, UHT fruit juices and milk Peach, apple, Labile Bet v 1 homologs are modified. Prolamin superfamily fruit LTPs retain a native-like structure. Milk allergens retain their native structure. milk Boiling - Maize, lentil, fish, milk, egg Wheat, peanut Prolamin superfamily LTPs and 2S albumin retain a native-like structure after boiling, although seeds are boiled, much of the protein is lost into cooking water. Alters, the structure of cupin allergens (7S and 11S seed storage proteins) and can render them insoluble. Roasting and frying Peanut Thermostable, notably prolamin superfamily 2S albumin retain their native structure and solubility after roasting and frying. Some cupin allergens (7S and 11S seed storage proteins) are altered by roasting and become insoluble. Maillard modification
  11. 11. Secondary processing Nature of Processing Source Impact of Processing Preparation of powdered ingredients Celery spice, milk Maillard modifications Deamidation Gluten Acidic conditions Hydrolyzed food ingredients Milk, egg, Enzymatic (usually microbial proteases) and chemical gluten treatments used to hydrolyze protein ingredients to change their functional properties Oil refining Soybean, peanut Proteins are removed during the refining process, and residual protein levels in highly refined oils are very low. Middleton’s Allergy: Principles and Practice 8th Edition
  12. 12. Complex foods Nature of Processing Source Impact of Processing Fining agents added to alcoholic beverages Beer, wine, spirits Certain beverages contain residual levels of fining agents, usually are highly modified compared with the raw Fermented foods Milk, soybean Lactic acid fermentations, to unfold protein and precipitate or form gelled networks due to reduced pH. Secrete proteases that can hydrolyze proteins. Baked foods Milk, eggs Food ingredients may be included that are raw or have already been processed (e.g., skimmed milk powder, pasteurized egg white). Complex interactions between different food ingredients Middleton’s Allergy: Principles and Practice 8th Edition
  13. 13. Novel processing techniques Pulsed electric field and ohmic heating processes • to preserve more of the natural flavor, texture, and nutritional quality of foods and • to address issues of sustainable food production and energy cost reduction. Middleton’s Allergy: Principles and Practice 8th Edition
  14. 14. Processing-induced Modification Heating processes(thermal processing) Process of structural and chemical changes such as denaturation, aggregation and the Maillard reaction, impacts on allergenicity of protein Glycation reaction Conjugation with reducing sugars through Maillard reaction, effect improving functional properties and masking food protein allergenicity. New epitopes emerged as hydrophobic High pressure Processing structural changes, such as denaturation and aggregates, also influence in allergenic potential. But application of high pressure during enzymatic hydrolysis more effectively reduce antigenicity and serum IgE-binding properties Enzymatic hydrolysis Proteolytic enzyme in animal, plant and organism destroy allergenic epitopes, by hydrolysis broken down into small peptide molecules and amino acids Lactic acid fermentation Proteolytic enzyme during fermentation by lactic acid bacteria(probiotic bacteria) break some epitopes and partial degradation IgE-epitope Guanhao Bu. Dairy Sci. & Technol. (2013) 93:211–223 Middleton’s Allergy: Principles and Practice 8th Edition
  15. 15. Denaturation and Aggregation Food processing conditions; • high temperature • extremes of pH on structure • aggregation Native, secondary structure elements such as • α-helices and β-sheets (blue) • disordered polypeptide segments (pink) • intermediate structures with residual (black) Middleton’s Allergy: Principles and Practice 8th Edition
  16. 16. Maillard modification Chemical reaction of amino acid + reducing sugar • requiring heat Carbonyl group + nucleophilic amino acid Glucosylamine and water formation • BUT unstable Form a complex mixture • NEW flavor + odors Middleton’s Allergy: Principles and Practice 8th Edition
  17. 17. Impact of Processing on Food Allergens A consequence of complexity and diversity of food composition and processing Proteins in raw foods and ingredients, • To transformed into carry new adducts(e.g.sugars) and behave different in digestion • To affected the way in food proteins are presented to immune system(antibody responses, food-specific IgE-binding affected by the conformational state of molecule ) Middleton’s Allergy: Principles and Practice 8th Edition
  18. 18. Food Allergens and Clinical Implications Classification of these allergens into protein families provides a framework for examining various aspects of food, Common structural attributes such as; • CUPINS, • PROLAMIN SUPERFAMILY, • BET V 1 SUPERFAMILY, • TROPOMYOSINS, • PARVALBUMINS, • CASEINS, • and others: Lipocalins, β-lactoglobulin(Bos d 5), Ovomucoid(Gal d 1) and Ovalbumin(Gal d 2) Middleton’s Allergy: Principles and Practice 8th Edition
  19. 19. CUPINS • Share core β-barrel motif in cupin superfamily – vicilin-like 7S seed(e.g. Ara h 1) and legumin-like 11S seed storage globulins • Range of important allergenic foods including; – legumes(e.g. soybean, peanut, lupin), tree nuts(e.g. hazelnut, walnut, cashew, pecan, almond), and other seeds (e.g., sesame, mustard) • Prone to aggregate formation after heating or solutions of extreme pH and low ionic strength. Middleton’s Allergy: Principles and Practice 8th Edition
  20. 20. Aim: To investigated the effect of thermal treatment on allergen structure and IgE-binding capacity, potency to histamine release and ability to induce T-cell proliferation and cytokine production from peanut allergic patients. Patient 35 pts: challenge with Ara h 1 purified from either raw (N-Ara h 1) or roasted (R-Ara h 1) Intervention To observed structure, IgE immunoreactivity, mediator release assay and cytokine production Primary outcome To determined factors affect the allergenic properties of a major peanut allergen, Ara h 1. Fany Blanc. Mol Nutr Food Res. 2011(55):1887–1894
  21. 21. Figure1. Characterization of heat-treated Ara h 1 by SDS-PAGE analysis Boiling(H-Ara h 1) resulted in aggregation and hydrolysis of Ara h 1 • Boiling, alone or with of glucose caused a partial loss of secondary structure • Roasted peanuts (R-Ara h 1) appeared to be highly denatured Fany Blanc. Mol Nutr Food Res. 2011(55):1887–1894
  22. 22. Figure 4. IgE-binding capacity of native and heat-treated Ara h 1. Native-Ara h 1 Heated Ara h 1 Boiled H- and G-Ara h 1 had greatly reduced IgE-binding capacities for all pts •Boiling resulted in either a very slight native-Ara h 1 or more marked heated Ara h 1 reduction in IgE-binding. • Increase in IC50 values for H-Ara h 1 and G-Ara h 1, significantly less IgE reactive. Fany Blanc. Mol Nutr Food Res. 2011(55):1887–1894
  23. 23. Figure5. Effect of thermal treatment on b-hexosaminidase and proliferating cells and cytokine induction capacity b-hexosaminidase IL-5 IL-13 • Boiling Ara h 1(100oc 15min) form complex aggregates resulted in partial loss secondary structure and reduced IgE-binding capacity. • The aggregates also reduced capacity to elicit histamine release and potential reduced allergenic potency. Fany Blanc. Mol Nutr Food Res. 2011(55):1887–1894
  24. 24. Aim: To establish the effect of thermal treatment mimicking the roasting process on the allergenicity of Ara h 1 and a mix of 2S albumins from peanut(Ara h 2/6) Patient 12 peanut-allergic pts: purified Ara h 1 and Ara h 2/6, observed after native and roasting ingestion Intervention To assess the structure, IgE binding fragments and degranulation capacities Primary outcome To observed roasting process(Ara h 1 and Ara h 2/6 peanut) changes to affect their allergenicity Y.M. Vissers. Clinical&Experimental Allergy. 41:1631–1642
  25. 25. Fig. 1. SDS-PAGE and Western blot of the native and thermally processed Ara h 1 and Ara h 2/6 Ara h 1 Ara h 2/6 Both Residual soluble Ara h 1, Ara h 2/6 that heating had significant hydrolysis of protein Y.M. Vissers. Clinical&Experimental Allergy. 41:1631–1642
  26. 26. Fig.4 Analysis of IC50(ng/mL)values obtained using IgE capture inhibition assay • Increase of the IC50 value corresponds to decrease in IgE-binding capacity. • IgE-binding capacity of R+g and R-g Ara h 1,decreased 9000- and 3.6-fold, compared with native Ara h 1 Y.M. Vissers. Clinical&Experimental Allergy. 41:1631–1642
  27. 27. Histamine release (ng/mL) Extensive heating reduced the degranulation capacity of Ara h 2/6 but significantly increased the degranulation capacity of Ara h 1 Percentage of b-hexosaminidase release Y.M. Vissers. Clinical&Experimental Allergy. 41:1631–1642
  28. 28. PROLAMIN SUPERFAMILY • Several groups of proteins, conserved skeleton of cysteine residues by presence of a-helical globular domain • 3 major proteins as: 2S albumins, Lipid-transfer proteins (LTPs) and Cereal α-amylase inhibitors • Others as hydrophobic protein(Gly m 1, soybean), Indolines(wheat) and alpha-globulins(cereal grains) • Theirs stability to heat and gastrointestinal digestion Middleton’s Allergy: Principles and Practice 8th Edition
  29. 29. PROLAMIN SUPERFAMILY • 3 majors group of proteins – 2S albumins, a low-molecular-weight major of seed storage proteins of dicotyledonous plants such as Sin a 1 from yellow mustard, Ara h2 and Ara h 6 from peanut – Cereal α-amylase inhibitors, structurally similar to LTPs and 2S albumins, storage protein in seeds of wheat, barley, rye, corn and rice of inhibitors trypsin and α-amylase Middleton’s Allergy: Principles and Practice 8th Edition
  30. 30. PROLAMIN SUPERFAMILY Lipid-transfer proteins (LTPs), a disulfide bonds to mediate phospholipid between vesicles and membranes – High concentration in epidermal tissue of Rosaceae family in fresh fruits and vegetables – Apple(Mal d 3) is greatest soon after picking, but it tends to decrease during postharvest storage in a modified atmosphere. (Sancho AI, et al. J Agric Food Chem 2006;54:5098-104) – Peach(rPru p 3) is removed of outer layers, such as peeling, significantly reduces the potential for an allergic reaction. (Fernandez-R.M., et al. Clin Exp Allergy 1999;29:1239-47) Middleton’s Allergy: Principles and Practice 8th Edition
  31. 31. Aim: to study the effect of heat-induced structural changes on allergenicity of 2S albumins, N-Ara h 2/6 was then further heated for 15 minutes at 110uC in the presence or absence of glucose. Patient 34 peanut-allergic pts: observed after heating and glycation treatments of 2S albumins(Ara h 2/6) peanut ingestion. Methods To assessed cellular proliferative potency and IgE reactivity and functionality of allergens Primary outcome To evaluated effect of processing on structure and IgE reactivity/functionality of peanut protein. Yvonne M.V. PLoS ONE/journal.pone. 2011:6(8)
  32. 32. Figure1. Effect of heating on secondary structure and oligomeric state of Ara h 2/6. Yvonne M.V. PLoS ONE/journal.pone. 2011:6(8)
  33. 33. Effect of thermal treatment on the IgE binding capacity of Ara h 2/6. Effect of thermal treatment on activation of effector cells induced by Ara h 2/6 No effect on T-cell reactivity via heat induced denaturation, reduced IgE reactivity and subsequent functionality of Ara h 2/6. Conversely, Ara h 2 and 6 purified from roasted peanut retained the structure and IgE reactivity/functionality of the native protein. Yvonne M.V. PLoS ONE/journal.pone. 2011:6(8)
  34. 34. BET V 1 SUPERFAMILY • Major birch pollen allergen, relevant sensitizing protein causing called ‘birch-fruit-vegetable syndrome’ • Belongs to related protein family 10(PR-10)such as – fruits of Rosaceae (Mal d 1 in apple, Pru a 1 in cherry, and Pyr c 1 in pear) – vegetables of Apiaceae (Api g 1 in celery and Dau c 1 in carrot) – Hazelnut(Cor a 1.04), soybean(Gly m 4), mungbean(Vig r 1) and peanut (Ara h 8) • Reactions confined to the oropharynx in termed of ‘oral allergy syndrome(OAS)’ and occasionally systemic reactions. Middleton’s Allergy: Principles and Practice 8th Edition
  35. 35. Aim: To evaluate whether cooked Bet v 1–related food allergens induce IgE- and T cell–mediated reactions in vitro and in vivo Patient Patients birch pollen allergy who experienced OAS and AD on ingestion of fresh apple, celery, or carrot Intervention To determined protein structures, mediator release, Bet v 1–specific T-cell lines with epitope specificity compared native and cooked food allergens. Primary outcome To evaluated T-cell epitopes of Bet v 1 were relevant for cross-reactivity with each food allergen. And conformational changes, resulting in diminished IgE-binding capacity not structure Bohle et al. J Allergy Clin Immunol 2006;118:242-9
  36. 36. Bet v 1 and Api g 1 partly restored structure, but Mal d 1 and Dau c 1 did not Bohle et al. J Allergy Clin Immunol 2006;118:242-9
  37. 37. • Incubation at 40C hardly reduced basophil activation by all allergens • At 60C reduced the mediator-releasing capacity of Api g 1 completely and to a lesser extent the capacity of Bet v 1, Mal d 1, and Dau c 1. • at 80C and 100C abolished their mediator-releasing capacity. In vitro, cooked food allergens lost the capacity to bind IgE and to induce mediator release but had the same potency to activate Bet v 1–specific T cells as native proteins. In vivo, ingestion of cooked birch pollen–related foods did not induce OAS but caused atopic eczema to worsen. Bohle et al. J Allergy Clin Immunol 2006;118:242-9
  38. 38. Aim: To determined information about the allergenicity of processed celery in celery-allergic patients Patient 12 pts with allergic reactions to raw or raw and cooked celery, DBPCFCs with raw celery, cooked celery and celery spice Intervention To performed thermal stability of celery allergen and mediator release assay to assessed allerginicity of processes Primary outcome To assess the allergenicity of processed celery by cooked celery and celery spice B.K. Ballmer-Weber. Allergy 2002:57:228–235
  39. 39. Thermal stability of celery by EAST inhibition • Monosensitized to celery allergen, Api g 1, almost complete inhibition • shortest heating period decrease of inhibition potency of celery RBL cell mediator release assay. • IgE raised against raw celery reacted with Api g 1, the major celery allergen • But, IgE-heated celery did not react with Api g 1 B.K. Ballmer-Weber. Allergy 2002:57:228–235
  40. 40. TROPOMYOSINS • Allergen from crustacean and molluscan shellfish • α-helical structural protein in both muscle and nonmuscle cells, highly conserved across kingdom. • Greasy back shrimp (Met e 1) is the major heatstable allergen in many crustacean species. Middleton’s Allergy: Principles and Practice 8th Edition
  41. 41. Aim: To detected shellfish-derived tropomyosin range of crustacean and mollusc species and to analysed impact of heatprocessing on antibody recognition for improved allergen. Patient Fresh or frozen specimens of 11 different crustacean and 7 mollusc species Intervention To determined protein profile of shellfish in raw and heated extracts and effect of heat treatment Primary outcome S.D.Kamath et al. Food Chemistry 141(2013);4031–4039
  42. 42. • The heated-shellfish displayed a more protein-banding pattern. • The heated-crustacean signified of heat-stable proteins. But the heated-mollusc have different intensities. S.D.Kamath et al. Food Chemistry 141(2013);4031–4039
  43. 43. Fig. 4. Inhibition-ELISA for the quantitative analysis of cross-reactivity of the mAb • Lobster and crab heated were able to inhibit reactivity in a dosedependent • Molluscs heated were not able to achieve any inhibit, even concentration. Cross-reactive tropomyosin was detected in crustacean species, with partial in detect in molluscs but none in oyster, octopus and squid. Heating has a profound effect on major shellfish allergen tropomyosin, targetting N-terminal region of tropomyosin, must be developed to differentiate in crustaceans and molluscs S.D.Kamath et al. Food Chemistry 141(2013);4031–4039
  44. 44. PARVALBUMINS • major allergen found in the white muscle of fish. • apo form reduced IgE-binding capacity, lacks the calcium ions found in the holo form • Thermal processing usually reduces but does not abolish the allergenic activity of fish Middleton’s Allergy: Principles and Practice 8th Edition
  45. 45. Aim: To investigate the effect of glycosylation on the digestibility and IgE-binding of codfish parvalbumin Patient 21 pts: positive history of immediate-type hypersensitivity reactions to fish, with specific IgE >5 kU/L Intervention Native and glycosylated parvalbumins at various conditions were analysed for apparent molecular weight and IgE-binding Primary outcome To investigated result of thermal treatment on the digestibility and IgE-binding of codfish parvalbumin Harmen H.J. BioMed Research International. Volume 2013,10:756-789
  46. 46. Figure 3: Secondary structure content of different forms of parvalbumin • The difference in intensity is slightly difference in protein concentration. • Native parvalbumin is structurally sensitive to low pH conditions, while glycosylation provides some protection against such sensitivity. Harmen H.J. BioMed Research International. Volume 2013,10:756-789
  47. 47. • Glycosylation of parvalbumin, formation of higher structures, are more potent IgE- binders than native Fish allergen can potentially lead to increased allergenicity, even while the protein’s digestibility is not affected by such processing. Harmen H.J. BioMed Research International. Volume 2013,10:756-789
  48. 48. CASEINS • A mammalian milk proteins with a loose tertiary, highly hydrated structure. • To possess clusters of phosphoserine and phosphothreonine residues that bind amorphous calcium phosphate Middleton’s Allergy: Principles and Practice 8th Edition
  49. 49. Aim: To compare the allergenicity of caseins(CSN) and whey proteins(WP) of thermally processed cow and buffalo milk Patient 3-4 wks-old male mice were sensitised by CSN or WP from cow or buffalo milk then obtained raw and different thermal processed milk Intervention To assessed humoral response(IgG, IgE level) and splenocyte stimulation index. Primary outcome To determined boiling and sterilisation of cow and buffalo milk may be affect the allergenicity Umesh K.S. J SciFoodAgric 2013; 93:2287–2292
  50. 50. Umesh K.S. J SciFoodAgric 2013; 93:2287–2292
  51. 51. Umesh K.S. J SciFoodAgric 2013; 93:2287–2292
  52. 52. Relative percentage change in allergenicity of cow’s and buffalo’s milk compared to raw milk with respect to milk protein-specific IgE response. The boiling and sterilisation of milk clearly affect the allergenicity by decreasing humoral and cell-mediated responses. CSN and WP of sterilised milk are less allergenic than raw milk. Umesh K.S. J SciFoodAgric 2013; 93:2287–2292
  53. 53. Others ALLERGEN FAMILIES • Inhalant allergens: Lipocalins • Cow’s milk protein: β-lactoglobulin(Bos d 5) • Egg white proteins: ovomucoid(Gal d 1) and ovalbumin(Gal d 2). Middleton’s Allergy: Principles and Practice 8th Edition
  54. 54. Clinical Implications Post-harvest treatments Individuals with birch pollen–related fruit allergies may tolerate freshly picked but not stored fruit. Individuals may experience reverse symptoms, although severity of LTP allergies may completely preclude consumption of problem fruit Primary processing Peeling fruits can make them safe for consumption by certain individuals with LTP allergies. Secondary processing Complex foods Middleton’s Allergy: Principles and Practice 8th Edition
  55. 55. Clinical Implications Post-harvest treatments Primary processing Secondary processing Fruit purees and fresh juices Individuals Bet v 1–related fruit allergies usually can consume pureed fruit products. These foods can still trigger reactions in individuals with LTP fruit allergies. Preparation of pasteurized, UHT fruit juices and milk Individuals Bet v 1–related fruit allergies usually can consume UHT-processed fruit products. Processing is insufficient to make UHT juices safe for individuals with LTP fruit allergies. The allergenic potential of UHT milk resembles that of pasteurized and raw milk. Boiling Boiling seeds and milk reduces their allergenicity but does not abolish it. For some foods (e.g., polenta), the extent of cooking affects the residual level of allergenic activity Complex foods Middleton’s Allergy: Principles and Practice 8th Edition
  56. 56. Clinical Implications Post-harvest treatments Primary processing Secondary processing Roasting and frying The major peanut 2S albumin allergens retain their allergenic activity, explaining why roasted peanuts possess significant allergenic activity. Allergenic activity of the 7S and 11S globulins is retained to some extent after roasting. Maillard modifications may further contribute to the allergenic activity of roasted peanuts. Preparation of powdered ingredients Powdered food ingredients have allergenic activity similar to unprocessed foods and can promote trigger reactions when included in recipes or through cross-contact in other foods (e.g., residual milk powder in foods otherwise free from milk). Complex foods Middleton’s Allergy: Principles and Practice 8th Edition
  57. 57. Clinical Implications Post-harvest treatments Primary processing Secondary processing Deamidation Induces formation of novel IgE epitopes through glutamine deamidation, which results in individuals reacting to foods prepared with deamidated gluten ingredients who can otherwise safely consume wheat flour–containing foods. Hydrolyzed food ingredients Hydrolysis reduces IgE reactivity but does not abolish it completely Oil refining In the EU, highly refined soybean oils are considered safe for consumption Highly refined peanut oils do not appear to cause adverse reactions, but these do not have EU labeling derogation. Complex foods Middleton’s Allergy: Principles and Practice 8th Edition
  58. 58. Clinical Implications Post-harvest treatments Primary processing Secondary processing Complex foods Fining agents added to alcoholic beverages Individuals with allergies to fish triggered by collagen or egg can react to alcoholic beverages Reactions to fining agents are rare, and many individuals with egg, milk, or fish allergy can safely consume these beverages. Fermented foods Although fermented milk and yogurt may retain some allergenic activity, other highly modified foods, such as soy sauce, may have substantially reduced allergenic activity and may not present a hazard to certain allergic patients. Middleton’s Allergy: Principles and Practice 8th Edition
  59. 59. Aim: To determine traces of egg, milk, and fish-derived processing aids used in wine making might elicit clinical reactions in food-allergic patients. Patient 14 pts: allergy to egg (n=5), milk (n=5), or fish (n=4) Methods Skin prick tests with fining agents, and fined/unfined wines Double-blind placebo-controlled food challenges with fined and unfined wines. Primary outcome The allergenicity of fining agents: ovalbumin, lysozyme, casein and fish protein S Kirschner. J InvestigAllergolClinImmunol 2009; Vol.19(3):210-217
  60. 60. Skin prick test with fined and unfined wines in patients allergic to egg, milk and fish. ovalbumin or lysozyme casein fish protein Although concentrated fining agents containing ovalbumin, lysozyme, and casein were allergenic in the skin prick test, no patient reacted adversely in the provocation test to fined wine S Kirschner. J InvestigAllergolClinImmunol 2009; Vol.19(3):210-217
  61. 61. Clinical Implications Post-harvest treatments Primary processing Secondary processing Complex foods Baked foods Evidence from oral food challenge studies indicates that baking reduces the allergenic activity of milk, and foods with baked milk may be given to children whose infantile cow’s milk allergy is beginning to resolve. Middleton’s Allergy: Principles and Practice 8th Edition
  62. 62. Aim: To evaluate the natural history of tolerance development who incorporated baked-milk products into their diets. Patient 88 egg-allergic children: underwent sequential food challenges to baked-cheese (pizza) followed by unheated-milk. Methods comparison group, Immunologic parameters were measured at challenge visits. Primary outcome To evaluated tolerance to baked-milk underwent sequential food challenges followed by unheated-milk. Jennifer S. Kim. J AllergyClinImmunol. 2011;128(1):125–131
  63. 63. Initially baked-milk-tolerant are 7.6 times more likely to develop unheatedmilk tolerance than subjects who were initially baked-milk-reactive over the follow-up period; HR=7.62 [1.75, 33.14] P=.007 Jennifer S. Kim. J AllergyClinImmunol. 2011;128(1):125–131
  64. 64. Aim: to determine whether SPT wheal size and/or serum sIgE levels to milk proteins could be used to predict successfully passing a baked milk challenge Patient 35 children: history of allergic reactions to milk and food challenges to baked milk Methods retrospective chart review, determined by a positive SPT or elevated serum sIgE Primary outcome To determine serum sIgE and SPT that may be useful in predicting outcomes to baked milk challenges. Lisa M.B. Ann AllergyAsthmaImmunol. 2012;109(5):309–313
  65. 65. Milk SPT wheal size was a better marker for food challenge outcome to baked milk, compared to casein SPT and milk protein sIgE levels. Identified >90% NPVs Lisa M.B. Ann AllergyAsthmaImmunol. 2012;109(5):309–313
  66. 66. Symptoms at first reported Immunologic responses Lisa M.B. Ann AllergyAsthmaImmunol. 2012;109(5):309–313
  67. 67. Aim: to investigate the mechanisms responsible for the reduced allergenicity displayed by heat-treated egg white allergens Patient 39 C3H/HeJ mices: orally sensitized with ovalbumin (OVA) or ovomucoid (OM) and challenged native or heated proteins Methods Evaluate allergenicity by Immunoreactivity and digestibility by mediator release assay and basophil activation assay Primary outcome To investigate factors behind reduced allergenicity of two major egg white allergens, ovalbumin (OVA) and ovomucoid, when to heattreatment. Gustav BS. J Allergy ClinImmunol. 2011;127(4):990–7
  68. 68. Gustav BS. J Allergy ClinImmunol. 2011;127(4):990–7
  69. 69. Gustav BS. J Allergy ClinImmunol. 2011;127(4):990–7
  70. 70. Reduced allergenicity of heated egg white proteins partially resulting from altered digestion and absorption in the gastrointestinal tract may explain the clinical tolerance of extensively heated egg in the majority of egg-allergic children Gustav BS. J Allergy ClinImmunol. 2011;127(4):990–7
  71. 71. Aim: To characterize immunologic changes associated with ingestion of baked egg and evaluate the role that baked egg diets plays in the development of tolerance to regular egg. Patient 79 baked egg-tolerated children: incorporated baked egg into their diet. Methods comparison group, Immunologic parameters were measured at follow-up visits. Primary outcome To evaluate predictors of baked and regular egg tolerance and assess the time to development of regular egg tolerance. Stephanie AL. J AllergyClinImmunol. 2012;130(2):473–480
  72. 72. Stephanie AL. J AllergyClinImmunol. 2012;130(2):473–480
  73. 73. Recommendations to perform baked egg challenge based on clinical status and testing Dietary baked egg is safe, convenient, and well accepted by patients. Introducing baked egg to egg-allergic children presents an important shift in the treatment paradigm for egg allergy Stephanie AL. J AllergyClinImmunol. 2012;130(2):473–480
  74. 74. • Food processing and food matrix can affect the structure change and allergenic activity(IgE-binding capacity and mediator release) • Processing triggers chemical changes including unfolding, aggregation, addition of glucose(Maillard modification) • Heat resistant allergen, retained structure and allergenic activity after severe thermal processing(e.g. canning, roasting) • Thermal treatments such as baking can reduce the allergenicity of certain foods (e.g. milk, eggs) and induced early tolerance.

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