The effect of the change from a herbage- to a concentrate-based diet on the oxidative stability of raw and cooked lamb meat G. Luciano a, ⁎, L. Biondi a , M. Scerra b , A. Serra c , M. Mele c , M. Lanza a , A. Priolo a a Dipartimento di Scienze delle Produzioni Agrarie e Alimentari (DISPA), University of Catania, Via Valdisavoia 5, Catania 95123, Italy b Dipartimento di Scienze e Tecnologie Agro-forestali e Ambientali, University of Reggio Calabria, Località Feo di Vito, Reggio Calabria 89100, Italy c Dipartimento di Scienze Agrarie, Alimentari e Agro-Ambientali, University of Pisa, Via del Borghetto, 80, Pisa 56124, Italy abstract article info Article history: Received 13 December 2012 Received in revised form 22 March 2013 Accepted 10 May 2013 Keywords: Lamb meat Lipid oxidation Colour Finishing diet Pasture Fatty acids Over 89 days, 10 lambs (S) were fed concentrates and hay in stall, while 9 lambs (P) grazed at pasture. Two groups of 9 animals grazed at pasture until switching to a concentrate-based diet for 14 or 37 days before slaughter (P-S14 and P-S37). The fat content of longissimus dorsi muscle (LM) increased with increasing du- ration of concentrate feeding (P= 0.05). As a consequence, the concentration of polyunsaturated fatty acids (PUFA) and of the highly peroxidisable (HP) PUFA in the polar lipids was similar between treatments. Lipid oxidation in fresh LM over 8 days of storage was affected by the diet (P b 0.0005) with the P-S37 and P treat- ments producing, respectively, the highest and the lowest TBARS values. The P treatment reduced TBARS in cooked minced LM over 2 days of storage and no difference was found between the P-S14, P-S37 and S treat- ments. Colour stability of fresh LM was not noticeably affected by the dietary treatment. © 2013 Elsevier Ltd. All rights reserved. 1. Introduction One of the main challenges in marketing meat is the retention of quality during storage and retail display by delaying the oxidative de- terioration of muscle components, such as lipids and myoglobin, which compromises the sensory and nutritional quality (Faustman, Sun, Mancini, & Suman, 2010). The exogenous addition of antioxidants to the meat or the adoption of opportune packaging systems are used to delay the oxidative processes in meat (Balasundram, Sundram, & Samman, 2006; McMillin, 2008). On the other hand, the inherent ox- idative stability of meat may vary depending on the dietary back- ground of the animals because the balance between pro-oxidant and antioxidant components in muscle can be strongly affected by the diet (Descalzo & Sancho, 2008). Polyunsaturated fatty acids (PUFA) in the phospholipid fraction of cell membranes are highly oxidizable substrates and may act as pro-oxidants, while antioxidant molecules of dietary origin may contribute to meat oxidative stability (Morrissey, Sheehy, Galvin, Kerry, & Buckley, 1998). For ruminants, extensive feeding systems based on pasture gener- ally promote the deposition of highly unsaturated PUFA in muscle, but provide higher levels of dietary antioxidants compared to diets based on concentrate feeds (Wood & Enser, 1997). For this reason, pasture-based diets confer on the meat a superior oxidative stability compared to diets based on concentrates only (Luciano et al., 2012). While most of the muscle antioxidant defences can remain active in fresh meat, cooking represents a significant deteriorative stress which impairs meat oxidative stability (Alfaia et al., 2010). Although little information has been provided on the effect of the animal diet on the oxidative stability of cooked meat, it has been demonstrated that diets based exclusively on pasture decrease lipid oxidation in cooked meat and the occurrence of oxidation-derived off-flavours compared to grain-based diets (Luciano et al., 2009; Tansawat, Maughan, Ward, Martini, & Cornforth, 2013). However, in the Medi- terranean environment, the availability of herbage is uneven and lim- ited to rather short seasons (Vasta et al., 2012). Therefore, a number of intermediate solutions between exclusively pasture-based or concentrate-based feeding systems are adopted for ruminants. For ex- ample, animals raised on pasture often receive supplemental concen- trates or, in other instances, animals initially grown at pasture are subsequently finished on concentrates in stall. However, such modifi- cations in the composition of the diet can alter the balance between pro-oxidants and antioxidants in muscle, with a possible impact on meat oxidative stability (Luciano et al., 2011; O’Sullivan et al., 2003). In lambs, it has been clearly demonstrated that a finishing period on concentrates in stall after a growing period on a diet based on herb- age at pasture can modify the fatty acid composition of intramuscular fat. Particularly, long finishing periods on concentrate-based diets are able to mask the effects of the preceding growing phase at pasture, Meat Science 95 (2013) 212–218 ⁎ Corresponding author. Tel.: +39 095234486; fax: +39 095234345. E-mail address: giuseppe.luciano@unict.it (G. Luciano). 0309-1740/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.meatsci.2013.05.015 Contents lists available at SciVerse ScienceDirect Meat Science journal homepage: www.elsevier.com/locate/meatsci