Fatty acids and triacylglycerols profiles from different types of Iberian dry-cured hams

Abstract

Thirty hams were allotted into four groups according to fattening diet (“Montanera” – acorns and pasture; and “Pienso” – concentrated diet) and genotype of pigs (Iberian and Iberian × Duroc pigs). Total lipids, triacylglycerol composition and fatty acids from neutral lipids fraction were measured in biceps femoris muscle. Fattening diet largely affected lipid composition of hams. Total intramuscular lipids and triacylglycerols content were higher in Montanera hams than in Pienso hams. In Montanera hams, triacylglycerols contained more oleic acid (C18:1) and less stearic (C18:0) and palmitic (C16:0) acids (p<0.001) and accordingly less PSO, PPL, PPO, PPS, SSO (p<0.001) and more OLL, OOL, OOO triacylglycerols compared to Pienso hams (p<0.001). Genotype of pigs has an important effect in triacylglycerols composition but only a limited effect on their fatty acids composition. So, Iberian hams contained more of PLLn, PLL, POLn and POL + SLL compared to Iberian × Duroc hams (p<0.001) and POO and SOO were present in a higher quantity in Iberian × Duroc hams (p<0.01).

Introduction

Iberian ham is a high value dry-cured product from the southwest of Spain, characterized by a high intramuscular fat content and a particular and intense flavour (Garcı́a et al., 1996; López-Bote, 1998; Ruiz, Ventanas, Cava, Timón, & Garcı́a, 1998a). Features of the pigs fattening phase, finished extensively with acorns and pasture (Montanera), or in confinement with concentrate feed (Pienso), are the main factors affecting sensory quality of hams. Crossbreed pigs, mainly Iberian × Duroc pigs, are used to improve the growth rate and the carcass lean content. It is traditionally accepted that hams from free-range pure Iberian pigs attain the highest sensory quality and they reach the highest prices in the market. The effect of feeding and breeding on the Iberian ham characteristics has been previously studied in several papers (Antequera et al., 1992; Cava et al., 1997; Garcı́a et al., 1996; Ruiz et al., 1998b; Tejeda, Gandemer, Antequera, Viau, & Garcı́a, 2002). Several approaches have been applied in order to determine the feeding received by Iberian pigs. All the procedures are based on fat properties: melting and slip point, iodine value and fatty acid profiles from different fat depots. These methods are based on the fact that Montanera produces pigs containing higher percentages of oleic acid than Pienso (Cava et al., 1997; Ruiz et al., 1998b). More recently, the attention was focused on triacylglicerols (TGs) composition of lipids because TGs represent the chemical forms in which the fatty acids are in adipose tissues. So, most of the physical and chemical properties of adipose tissues are related to TGs composition. According to their unsaturation, TGs are in liquid or solid state at room temperature. The physical state of the intramuscular fat affects many quality traits of dry-cured hams such as appearance and colour, dry-cured process, rancidity development or cohesiveness of the cut (Bailey, Cutting, Enser, & Rhodes, 1973). TGs composition has been used for distinguishing adipose tissues according to the rearing conditions (Davenel, Riaublanc, Marchal, & Gandemer, 1999; Riaublanc, Gandemer, Gambotti, Davenel, & Monin, 1999). In a recent study of intramuscular lipids in fresh Iberian ham, Tejeda et al. (2002) showed a marked effect of diet on both, the fatty acid composition of the TGs and the proportions of the main TGs, but the effect of genotype on the TGs composition and fatty acids of TGs was very limited.

TGs determination has become a feasible system to characterize oils and fats. The objective of this study was to identify the profiles of TGs of Iberian dry-cured hams and to elucidate the effect of the feeding system (Montanera and Pienso) and the genetic factors (crossbreeding of Iberian pig with Duroc pig) on the TGs composition.