title: Characterization and improvement of apple extracts for the diagnosis of apple IgE-mediated allergy.
abstract: BACKGROUND
  The production process of reliable fruit extracts is not well established.
  
  
  OBJECTIVE
  To improve the overall quality of apple extracts by reducing protein loss during the manufacturing process and to evaluate the improved extracts using in vivo and in vitro experiments.
  
  
  METHODS
  Two types of extracts were prepared from peels of Golden Delicious apples (Malus domesticus). Extract A was extracted, 1:2 wt/vol, for 30 minutes at 40 degrees C in 0.01 M phosphate-buffered saline, and extract B was extracted, 1:2 wt/vol, in phosphate-buffered saline with 20% polyvinylpolypyrrolidone and 2-mmol/L EDTA. Both extracts were filtered, dialyzed in 3.5-kDa dialysis membranes, and lyophilized. The antigenic and allergenic profiles were analyzed using immunoblot and enzyme-linked immunosorbent assay. Nine patients clinically sensitive to apples and 12 controls underwent skin testing with both extracts.
  
  
  RESULTS
  Extracts A and B had dry weight yields of 0.71% and 1.86% and protein contents of 104.6 and 257 microg/mg of freeze-dried material, respectively. A steady and progressive loss of protein, greater in extract A than in extract B, was detected at different intervals during the manufacturing process of both extracts. Extract B produced larger wheal sizes than extract A (P = .008). Enzyme-linked immunosorbent assay inhibition results confirmed that extract B had a greater inhibition capacity than extract A.
  
  
  CONCLUSIONS
  A progressive loss of protein content occurs during the manufacturing of apple extracts. Wheal sizes induced by extract B were significantly larger than those induced by extract A and prick-by-prick solutions. Extract B was also more potent in vitro than extract A.
authors.affiliation: Allergy Department, Hospital de la Vega Baja, Orihuela, Alicante, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Ferrer
authors.forename: Jerónimo
authors.initials: J
authors.lastname: Carnés
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Gallego
authors.forename: Carmen
authors.initials: C
authors.lastname: Andréu
authors.forename: Enrique
authors.initials: E
authors.lastname: Fernández-Caldas
mesh_terms: D000328:Adult; D000485:Allergens / Q000737:chemistry* / Q000276:immunology; D005260:Female; D005512:Food Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000737:chemistry*; D008297:Male; D027845:Malus / Q000737:chemistry* / Q000276:immunology; D010936:Plant Extracts / Q000737:chemistry / Q000276:immunology; D011506:Proteins / Q000032:analysis; D012882:Skin Tests; D013030:Spain
chemical_list: D000485:Allergens; D010936:Plant Extracts; D011506:Proteins; D007073:Immunoglobulin E