title: Quantification of γ- and α-tocopherol isomers in combination with pattern recognition model as a tool for differentiating dry-cured shoulders of Iberian pigs raised on different feeding systems.
abstract: BACKGROUND
  Quantification of γ- and α-tocopherol in dry-cured shoulders of Iberian pigs was evaluated as a tool for differentiating feeding backgrounds or regimens. Samples (n = 115) were obtained over two different seasons from the four categories of pigs described in the Industry Quality Policy, i.e. pigs fed in free-range conditions (FREE-RANGE), pigs fed in free-range conditions and provided feed supplements (FREE-FEED), pigs fed outdoors with feed and with access to grass (FEED-OUT) and pigs fed in intensive conditions with feed (FEED). Linear discriminant functions were calculated and validated.
  
  
  RESULTS
  The validation results showed that 20% of the muscle samples were not correctly classified into the four feeding categories, giving an 80% success rate. The FEED group had the lowest proportion of errors, with 100% of samples correctly classified. For the FREE-RANGE group, 87% of samples were assigned to the correct feeding system by cross-validation; however, 13% were considered as FREE-FEED. A higher rate of correct classification can be obtained when using three categories or by calculating the weight gain in free-range conditions using regression equations.
  
  
  CONCLUSIONS
  Taking into account the high variability of the samples and the high success in classification, these results are of interest and may be applied in practical situations.
authors.affiliation: Departamento de Producción Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, E-28040, Madrid, Spain.
authors.forename: Ana I
authors.initials: AI
authors.lastname: Rey
authors.forename: Daniel
authors.initials: D
authors.lastname: Amazan
authors.forename: Clemente J
authors.initials: CJ
authors.lastname: López-Bote
authors.forename: Juan M
authors.initials: JM
authors.lastname: García-Casco
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D017849:Animals, Inbred Strains; D000975:Antioxidants / Q000032:analysis / Q000378:metabolism; D004032:Diet / Q000662:veterinary*; D016002:Discriminant Analysis; D005513:Food Inspection / Q000379:methods*; D063427:Food Quality; D057141:Food, Preserved / Q000032:analysis* / Q000592:standards; D065928:Forests; D016014:Linear Models; D008460:Meat / Q000032:analysis* / Q000592:standards; D018482:Muscle, Skeletal / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism; D010363:Pattern Recognition, Automated; D012782:Shoulder; D013030:Spain; D034421:Sus scrofa; D015430:Weight Gain; D024502:alpha-Tocopherol / Q000032:analysis* / Q000378:metabolism; D024504:gamma-Tocopherol / Q000032:analysis* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D024504:gamma-Tocopherol; D024502:alpha-Tocopherol
keywords: Iberian pig; authentication; dry-cured shoulder; α-tocopherol; γ-tocopherol