Proteolytic pattern of myofibrillar protein and meat tenderness as affected by breed and aging time R. Marino a , M. Albenzio a, ⁎, A. della Malva a , A. Santillo a , P. Loizzo b , A. Sevi a a Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, University of Foggia, Via Napoli 25, 71112, Foggia, Italy b Dipartimento di Scienze del Suolo, delle Piante e degli Alimenti, University of Bari, Via Amendola 165/a, 70121, Bari, Italy abstract article info Article history: Received 21 June 2012 Received in revised form 4 December 2012 Accepted 3 April 2013 Keywords: Podolian Friesian Romagnola Meat tenderness Myofibrillar proteins Proteolysis The effects of breed and aging time (1, 7, 14, 21 days) were evaluated on meat tenderness and on proteolysis in 24 young bulls from Romagnola × Podolian crossbreed, Podolian and Friesian breed. Shear force decreased with aging in all breeds and showed the highest values at 1 and 7 days in Podolian meat. Myofibrillar frag- mentation index significantly increased in Podolian meat throughout aging whereas in Friesian and in Cross- breed meat it increased only in the first week. Proteolysis was investigated by SDS-PAGE and 2-dimensional electrophoresis showing a different quantity and expression profile of myofibrillar proteins among breeds. In all breeds a decrease of troponin-T and an increase of troponin-T derived polypeptides during aging were ob- served. The highest decrease of troponin-T together with the presence of fragments of MHC in Podolian meat during aging was an outcome of a more extensive proteolysis in this breed. Data suggest that tenderness and proteolytic changes during aging are related to animal's breed. © 2013 Elsevier Ltd. All rights reserved. 1. Introduction Breed is an important factor that can influence the characteristics of the raw muscle tissue (Cuvelier et al., 2006) and hence of the fin- ished product. A large number of genetically distinct cattle breed are reared in Italy and this genetic diversity produces meat with many different qualities. Chianina, Marchigiana, Romagnola, Maremmana, and Podolian cattle, which descended from the same original stock, are indigenous Italian breeds widespread throughout Italy. The farms which follow the cow-calf line are small or middle sized and most of them are lo- cated in hilly or mountainous areas. These autochthonous breeds cur- rently number a total of 150,000 head of cattle involved in selection activities (A.N.A.B.I.C., 2011). Podolian breed is a rustic and frugal breed exploiting grazing areas covered with shrubs, stubbles and thickets. It is a typical breed well adapted to the difficult climatic conditions of the rural areas of Southern Italy (d'Angelo et al., 2006). Physical activity along with the leanness of Podolian breed can account for the low tenderness which often characterizes its meat and may give rise to reduced con- sumer acceptability (Napolitano, Caporale, Carlucci, & Monteleone, 2007). Podolian breed has been crossbred with other beef breeds to improve sensorial properties (Braghieri, Cifuni, Girolami, Riviezzi, & Napolitano, 2005). Romagnola breed derives from the Podolian breed, maintaining the morphological features of a grazing animal. However, in the last decades, this breed has been subjected to a selec- tion work gaining the characteristics of a modern beef-cattle type (Sbarra, Mantovani, & Bittante, 2009). Indeed meat production char- acteristics of Romagnola breed are comparable to Limousine breed as investigated by Keane and Allen (2002). Friesian is a worldwide spread dairy breed with a high potential for milk production, male progeny of this breed is sometimes raised in intensive system for beef production. Tenderness is considered one of the most important components of meat quality, inadequate meat tenderness has been identified as the major cause of consumer dissatisfaction (Grunert, 1997; Miller, Carr, Ramsey, Crockett, & Hoover, 2001) so any improvement in ten- derness would increase the commercial value of the final product (Brooks et al., 2000). Meat tenderness is the result of different factors such as the amount and solubility of connective tissue, sarcomere shortening during rigor development and post mortem proteolysis of myofibrillar proteins (Koohmaraie & Geesink, 2006). Aging is one of the most influential factors affecting meat tenderness involving complex changes in muscle metabolism in the post slaughter period and is dependent on animal breed, metabolic status and environmen- tal factors such as rearing system and stress (Cifuni, Napolitano, Riviezzi, Braghieri, & Girolami, 2004. Many studies focused the effect of breed type and aging on senso- rial and texturial meat quality parameters of bovine meat (Monson, Sanudo, & Sierra, 2005; Vieira, Cerdeño, Seffano, Lavín, & Mantecón, 2007). Analysis of muscle proteins during aging time is necessary to understand the biological basis of changes in meat tenderness and their differences among breeds. In the last years, several studies on Meat Science 95 (2013) 281–287 ⁎ Corresponding author. Tel.: +39 0881 589327; fax: +39 0881589502. E-mail address: m.albenzio@unifg.it (M. Albenzio). 0309-1740/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.meatsci.2013.04.009 Contents lists available at SciVerse ScienceDirect Meat Science journal homepage: www.elsevier.com/locate/meatsci