Effect of origin, breeding and processing conditions on the isotope ratios of bioelements in dry-cured ham Matteo Perini a,b , Federica Camin b , José Sánchez del Pulgar c , Edi Piasentier a,⇑ a Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Udine, via Sondrio 2, 33100 Udine, Italy b IASMA – Research & Innovation Centre, Fondazione Edmund Mach, Food Quality & Nutrition Area, via E. Mach 1, 38010 San Michele all’Adige, Trento, Italy c Food Technology, Facultad de Veterinaria, UEx, Campus Universitario s/n, 10003 Cáceres, Spain article info Article history: Available online 1 July 2012 Keywords: IRMS Dry-cured ham Origin Husbandry system Pork processing abstract The stable isotope ratios (SIR) of the bioelements ( 2 H/ 1 H, 13 C/ 12 C, 15 N/ 14 N, 18 O/ 16 O, 34 S/ 32 S) of the defatted dry matter and marbling and subcutaneous fat fractions, were assessed on 86 ham samples belonging to six different types, with the aim of ascertaining the effect of origin and production system on 11 isotopic ratios. The ham types were obtained from pigs reared in three regions, examining in every location one different production factor at two levels of expression: pig genotype (local breed vs. industrial hybrid) in Friuli (Italy), pig feeding regime (Bellota vs. Campo) in Extremadura (Spain) and ham seasoning time (mid vs. end) in Emilia (Italy). The isotopic composition of meteoric water and the dietary abundance of C 4 plants allowed to distinguish Italian PDO from Spanish hams. The contrasting treatments within the regional batches generated promising differences in SIR, potentially useful for tracing the whole ham pro- duction system, including the processing procedure. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction The stable isotopes ratios (SIR) of bioelements, which depend on botanical, geographical, agronomic and climatic factors, trans- mitted from water and plants to animal products, have been widely proposed for meat authenticity and origin assessment. As recently reviewed by Schmidt, Rossmann, Rummel, and Tanz (2009), studies on pork are few in comparison with those on rumi- nant meat species. The pioneering experiments of DeNiro and Ep- stein (1978) presented the 13 C/ 12 C (expressed as d 13 C values) of the major biochemical fractions of pork, analyzed as an experimental food of flies. Mitchell, Steele, and Hare (1993) then changed the 13 C/ 12 C levels in pig tissues by switching the animals from two opposite C 3 or C 4 plant diets. Eventually the isotope ratio mass spectrometry (IRMS) was used around year 2000 to trace Iberian swine production system. González-Martin and colleagues from Salamanca University first differentiated the fresh pork from fat- tening Iberian pigs according to their feeding regime on the basis of 13 C/ 12 C in adipose tissue samples (González-Martin, González- Pérez, Hernández Méndez, Marqués-Marcia, & Sanz Poveda, 1999) and then, by joint analysis of 13 C/ 12 C and 34 S/ 32 S of liver tis- sue, they discriminated both fattening diet and pig breed (Gon- zález-Martin, González-Pérez, Hernández Méndez, & Sánchez González, 2001). Other studies on stable isotopic ratios were car- ried out on pigs to evaluate the mechanisms influencing the frac- tionation of body tissues (Nardoto, De Godoy, Ferraz, Ometto, & Martinelli, 2006; Tuross, Warinner, Kirsanow, & Kester, 2008; War- inner & Tuross, 2009, 2010) or individual molecular compounds (Hare, Fogel, Stafford, Mitchell, & Hoering, 1991; Howland et al., 2003; Stott, Davies, Evershed, & Tuross, 1997) and their implication for ecology and archeology. These researches make an important contribution to understanding the production factors (genetic type, age, growth rate, feeding composition, nutritive level, etc.) affect- ing the isotopic signatures of swine tissues and their relationship with geographical origin and breeding system. However, isotopic fractionation might occur even during pig meat processing and storage (Thiem, Lüpke, & Seifert, 2004). As claimed by Schmidt et al. (2009), who concluded their review stating that IRMS method ‘‘has so far not been applied to meat products’’, further experi- ments would be necessary in order to fully understand the influ- ence of biochemical pathways on isotopic shifts during the manufacturing processes of meat. Among meat products, dry-cured ham is a valuable traditional one which originated in southern European countries, where it is often guaranteed by a protected designation of origin (PDO) and represents an important part of the agro-food economy. As an example, PDO dry-cured ham (prosciutto) is the main product of the Italian pig industry and more than 80% of pig production is des- tined for the PDO traditional Italian ham market (Renaville et al., 2010). To obtain unique quality traits, the production of PDO dry-cured hams is subjected to rules established by several 0308-8146/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.foodchem.2012.06.084 ⇑ Corresponding author. Tel.: +39 0432 558190; fax: +39 0432 558199. E-mail address: edi.piasentier@uniud.it (E. Piasentier). Food Chemistry 136 (2013) 1543–1550 Contents lists available at SciVerse ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem