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Research article2003Peer reviewed

The influence of RN genotype, including the new V199I allele, on the eating quality of pork loin

Josell A, Enfalt AC, von Seth G, Lindahl G, Hedebro-Velander I, Andersson L, Lundstrom K


The eating quality of M. longissimus dorsi (LD) from RN- homozygotes, RN- heterozygotes and RN- non-carriers was investigated in a Swedish Hampshire x Finnish Landrace pig population. The recently identified new allele (V1991, here denoted rn*) at the RN locus was also detected among the pigs selected and included in the sensory evaluation. The number of animals varied from 10 to 15 in the five genotype groups; RN-/RN-, RN-/rn+, RN-/rn*, rn+/rn+ and rn+/rn* (in total 59 pigs). In addition, one pig was determined to be rn*/rn* but was excluded from the analysis. The three genotypes in which the RN allele was represented (RN-/RN-, RN-/rn+ and RN-/rn*) had higher glycogen and lower protein contents as well as lower ultimate pH (measured 48 h post-mortem) in LD than the non-carriers (rn+/rn+ and rn + rn*). Of the sensory parameters evaluated (tenderness, chewing time, chewing residual, juiciness, meat flavour and acidity), the five RN genotypes only affected acidity significantly; the RN- allele contributing to a more acid taste in LD. The influence of the rn* allele resembled that of rn + on the sensory parameters. When the material was divided into three groups (homo-Zygous, heterozygous and non-carriers of the RN- allele) the juiciness was found to be significantly influenced by RN genotype, and LD from animals that were homozygous and heterozygous with respect to the RN- allele exhibited a higher juiciness than LD from non-carriers. The RN- allele also tended to contribute to greater tenderness, which was significantly higher in LD from heterozygous carriers than from non-carriers of the RN- allele. A more rapid decline in pH (measured as pH at 45 min and 3 It postmortem) contributed to a greater tenderness in LD (according to a trained panel and Warner-Bratzler shear force). In addition to the RN genotype, the decline in pH was influenced by carcass weight, which varied between 71 and 97 kg, and by stunning procedure, which changed during the course of the study from individual to group stunning with CO, The individual stunning procedure contributed to a lower pH in the initial post-mortem phase (pH(45)), whereas a higher carcass weight and the RN- allele lowered the pH in the mid-post-mortem region (pH(3h) and pH(24h)), significantly (P less than or equal to 0.05). The pH continued to decline after 24 h post-mortem and the ultimate pH was not reached until 48 h post-mortem. The cooking loss, juiciness and acidity were related to the specific characteristics of the RN- carriers, such as higher glycogen content, lower protein content and lower ultimate pH (pH(48h)) (C) 2003 Elsevier Ltd. All rights reserved


pork; crossbreed; RN gene; PRKAG3 gene; V199I; eating quality

Published in

Meat Science
2003, Volume: 65, number: 4, pages: 1341-1351

      SLU Authors

      • UKÄ Subject classification

        Animal and Dairy Science
        Food Science
        Veterinary Science

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