Quality traits in muscle biceps femoris and back-fat from purebred Iberian and reciprocal Iberian×Duroc crossbred pigs

The present study evaluated the physico-chemical characteristics of muscle biceps femoris and back-fat from purebred Iberian (PBI) pigs and reciprocal crossbred Iberian × Duroc pigs (IB × D pigs: Iberian dams × Duroc sires; D × IB pigs: Duroc dams × Iberian sires). Muscles from PBI pigs contained significantly higher amounts of IMF, heme pigments and iron than those from crossbred pigs. In addition, muscles from PBI pigs were darker (lower L^*-values) and redder (higher a^*-values) and exhibited a more intense colour (higher chroma value) which was closer to the true red axis (lower hue value) than muscles from crossbred pigs. Back-fat from PBI pigs had significantly higher percentages of monounsaturated fatty acids (MUFA) and significantly smaller percentages of polyunsaturated fatty acids (PUFA) than those from crossbred pigs. Regarding the fatty acid profiles of the muscle lipid fractions, the genetic background particularly affected the composition of the polar lipid (PL) fraction. PL in muscles from PBI pigs contained significantly higher proportions of oleic acid and total MUFA and significantly lower amounts of arachidonic acid, certain long-chain PUFA (ω-6 and ω-3 fatty acids) and total amount of PUFA than PL in muscles from crossbred pigs. The results obtained indicate that tissues from PBI pigs would be more suitable for the production of dry-cured meats than those from cross-bred pigs. The position of the dam or the sire in reciprocal Iberian × Duroc crosses had no clear effects on meat quality.     

n-Alkane content of intramuscular lipids of Iberian fresh ham from different feeding systems and crossbreeding

n-Alkane content of intramuscular lipids (Biceps femoris muscle) of the Iberian pig have been determined. Thirty-four pigs, divided into four groups, based in the feeding system (Montanera, fed on acorns and pasture; and Pienso, fed on a concentrate feed) and in the genotype (Iberian pure pigs; and Iberian crossbred with Duroc 50%) were studied. n-Alkane content of intramuscular lipids has not been affected by neither crossbreeding nor feeding, although the analysis of feeds administered to the pigs showed greater n-alkane values in pasture (consumed by animals in montanera), than in acorns and concentrate feed.     

Instrumental colour of Iberian ham subcutaneous fat and lean (biceps femoris): Influence of crossbreeding and rearing system

The influence of crossbreeding (Iberian vs Iberian×Duroc 50% pigs) and rearing system (Montanera vs Pienso) on the instrumental colour of Iberian ham (subcutaneous fat and biceps femoris muscle) and the relationships to sensory appearance and chemical composition were researched by using a factorial design. In subcutaneous fat, a significant effect (p<0.05) of crossbreeding and rearing system was found: b* and chroma were larger in hams from Iberian pigs than from Iberian×Duroc (50%) pigs, and L*, a* and chroma were larger in Pienso hams than in Montanera hams. CIEL*a*b* variables of subcutaneous fat were closely related to subcutaneous fatty acid composition, the largest correlationships involving L* (L* and 18:0, 0.652, p<0.001; L* and 18:1, -0.616, p<0.001). Instrumental colour variables and sensory appearance were also correlated (L* and fat pinkness, -0.539, p<0.001). In lean (biceps femoris), instrumental colour data was not affected by crossbreeding and rearing system. CIEL*a*b* variables were not related to chemical composition (moisture, NaCl, intramuscular fat and pigment content), although they were correlated to sensory appearance (L* and marbling, 0.419, p=0.014).     

Influence of sex and terminal sire line on performance and carcass and meat quality of Iberian pigs reared under intensive production systems

A trial was conducted to study the effects of sex (castrated males; females) and terminal sire line (DD, Danish Duroc; SD, Spanish Duroc; RIB, Retinto Iberian) on performance and carcass and meat quality of pigs slaughtered at 145 kg body weight. The female line was pure Iberian in all cases. Each treatment was replicated five times (six pigs). Females were more efficient, had less carcass and inter- and intramuscular fat and more trimmed primal cuts yield than castrated males. Duroc sired pigs grew faster and had better feed conversion and carcass quality than RIB sired pigs. Crossbreeds from SD had less carcass yield than crossbreeds from DD or RIB. We conclude that productive performance and primal cuts yield were higher for females than for castrated males. Danish Duroc sires are an alternative to Spanish Duroc and Retinto Iberian sires for production of heavy pigs destined for the dry cured industry.     

Differentiation of the raw material of the Iberian pig meat industry based on the use of amplified fragment length polymorphism

The present study is the first step of the development of a new analytical technique to discriminate the genotypes of purebred Iberian and crossbred Iberian×Duroc pigs. A DNA test of breed identity has clear advantages for the protection of the brand name of high-prized products of purebred Iberian pigs. Amplified fragment length polymorphism procedure was used to analyze the genomic DNA samples of 77 Duroc and 80 Iberian pigs from the most representative populations. Thirteen primer combinations produced 588 amplified fragments. A total number of 139 fragments were polymorphic and 14 out of them were detected in Duroc and never in Iberian pigs. A panel of the nine most frequent markers allows the discrimination between purebred and crossbred animals. The values of the probability of exclusion of the pure Iberian origin (P(EC)) were 0.97 and 0.78, for crossbred individuals with 50 or 25% of Duroc genes, respectively.     

Effect of gender and castration of females and slaughter weight on performance and carcass and meat quality of Iberian pigs reared under intensive management systems

A total of 360 Iberian dam × Duroc sire pigs was used to study the influence of gender and castration of females (CM, castrated males; CF, castrated females; IF, intact females) and slaughter weight (SW; 145 and 156 kg body weight, BW) on performance and carcass and meat quality. Each treatment was replicated four times (15 pigs). Intact females ate less, tended to have better feed conversion and had less carcass fat and more primal cuts yield than CM and CF. Pigs slaughtered at 156 kg BW ate more feed and had worse feed conversion than pigs slaughtered at 145 BW. An increase in SW improved carcass yield, but tended to decrease trimmed ham yield. Intact females are an alternative to castrated females for intensive production of Iberian pigs. Also, the reduction in slaughter weight from 156 to 145 kg BW is recommended for this type of production.     

Carcass composition and meat quality of three different Iberian×Duroc genotype pigs

Carcass composition and meat quality of Longissimus dorsi (LD) and Biceps femoris (BF) muscles from three different Iberian×Duroc genotype pigs were studied: GEN1: ♂ Iberian×♀ Duroc1; GEN2: ♂ Duroc1×♀ Iberian; GEN3: ♂ Duroc2×♀ Iberian. Duroc1 (DU1) were selected for the manufacture of dry-cured meat products while Duroc2 (DU2) were pigs selected for meat production, with high percentages of meat cuts and low carcass fat. Genotype had a significant effect on the differences found while sex had not. GEN2 showed the highest weights at days 180 and 238 of weaning and the highest slaughter weights (day 316) followed by GEN3, while the lowest weights were found in GEN1. GEN3 had well conformed carcasses in comparison with GEN1 and GEN2, since GEN3 showed the highest percentages of ham and loin and the highest weight of loin as well as the lowest back and ham fat thickness. However, the use of DU2 pigs in the cross with Iberian had negative effects on meat quality, as GEN3 gave the worst meat quality in both muscles, postmortem pH, cook and drip loss, and colour and the lowest percentages of intramuscular fat (IMF). In subcutaneous fat (SCF), GEN3 had higher percentages of polyunsaturated fatty acids (PUFA) than GEN2, while GEN2 had higher saturated fatty acids (SFA) levels. In LD, IMF from GEN3 showed the highest percentage of MUFA and PUFA; while the fatty acid profile of GEN2 was more saturated. BF muscle showed similar trends, but not significantly so. On the other hand, few differences were found between reciprocal crosses (GEN1 vs. GEN2). GEN2 showed higher IMF in LD than GEN1, agreeing with their carcass weight. As a result, GEN1 had a fatty acid profile of IMF in the LD that was more unsaturated.     

Study of salting and post-salting stages of fresh and thawed Iberian hams

Fresh raw material has been traditionally used to obtain dry-cured Iberian ham, although the use of thawed raw material is increasing. This type of raw material has been previously studied for dry-cured production employing White pigs, where the salting time has been reduced to reach similar NaCl concentrations. The aim of this work was the analysis of salting and post-salting stages of Iberian hams, employing fresh or thawed raw materials. The results showed that fresh Iberian hams had higher salt concentrations than thawed Iberian hams for the salting time ratio used, a ratio established to reduce the freezing/thawing effect that was previously observed working with White ham. This fact shows that the Iberian raw material in dry-cured ham manufacturing is less affected, by the freezing/thawing process than the White raw material.     

Effect of the Iberian×Duroc reciprocal cross on productive parameters, meat quality and lipogenic enzyme activities

The aim of this study was to investigate the effect of the Iberian×Duroc reciprocal cross on: (i) productive parameters, (ii) physico-chemical traits of three muscles with different oxidative patterns (Longissimus dorsi, Biceps femoris and Psoas maior) and (iii) lipogenic enzyme activities (glucose-6-phosphate dehydrogenase and malic enzyme) in subcutaneous adipose and muscle tissues. Fourteen Duroc-sired (Duroc♂×Iberian♀) and 14 Iberian-sired castrate male pigs (Iberian♂×Duroc♀) were selected at weaning and were reared until 235 days of age. Iberian-sired pigs had significantly higher weight at slaughter (147.7kg vs. 138.8kg, p<0.05) as well as a greater ham and foreleg weight than Duroc-sired pigs. The fatty acid composition of subcutaneous adipose tissue of Duroc-sired pigs showed a higher percentage of C18:0 (13.21% vs. 14.34%, p<0.05) and a lower percentage of monounsaturated fatty acids (47.79% vs. 46.73%, p<0.05) compared to that from Iberian-sired pigs. Contrary to productive parameters, there were no noticeable differences between reciprocal cross in parameters defining meat quality, although there was a clear muscle effect on such parameters with this effect being significant for most of the traits. No differences were found between reciprocal crosses for glucose-6-phosphate dehydrogenase and malic enzymes activities in both muscular and subcutaneous adipose tissues. Lipogenic enzyme activities were considerably higher in subcutaneous adipose tissue compared to muscles. Glucose-6-phosphate dehydrogenase activity did not differ (p>0.05) between muscles, whereas malic enzyme activity was higher (p<0.05) in Psoas maior compared to Biceps femoris and those were higher than in Longissimus dorsi, which was consistent with the positive correlations (p<0.05) found between malic enzyme activity and traits defining oxidative metabolic type. On the contrary, negative correlations (p<0.05) were found between malic enzyme activity and intramuscular fat content, which could suggest that there are differences among muscles in the ability of depositing fatty acids from other tissues.     

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

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).     

Linear hydrocarbons content of intramuscular lipids of dry-cured Iberian ham

This study has been carried out to determine the linear hydrocarbons content (n-alkane and n-alkene) in intramuscular lipids (biceps femoris muscle) of dry-cured Iberian ham considering "feeding system" (Montanera: fed on acorns and pasture and concentrate feed) and "genotype" (hams from Iberian pure pigs and hams from Iberian crossbreed with Duroc in a 50%). The linear hydrocarbons from n-C(14) to n-C(32) range were present in the four studied groups. n-Alkenes fraction (60-76 mg/kg of intramuscular fat) was higher than n-alkanes fraction (34-38 mg/kg). The most abundant n-alkane and n-alkene were the shortest chain ones. Feeding and genotype did not influence linear hydrocarbons content (neither n-alkanes nor n-alkenes).     

Effect of feeding system on the growth and carcass characteristics of Iberian pigs, and the use of ultrasound to estimate yields of joints

Forty three-castrated male Iberian pigs of the Torbiscal line with an average initial weight of 102.27kg were used. A group of 22 pigs was fed according to the traditional way in free-range conditions with acorn and grass from November to January. Another group of 21 animals was fed 3.72kg/day of a conventional feed that contained 12.53MJME/kg, 16.21% crude protein, 4.94% fat and 6.64% of crude fiber, during the same period. Measurements of backfat thickness and Longissimus dorsi muscle area at the last rib were taken by means of a real-time ultrasound device (Kretz Technick Inc., 600 V-V2.32, Sonovet, Austria) in all pigs before slaughter. After slaughter, carcass, ham and foreleg weights and backfat and muscle area measurement from the last rib chop were recorded. The average daily gain, carcass yield, fat thickness, loin area, ham weight and proportion of hams were significantly higher (P<0.05) in the pigs fed in confinement than in those fed extensively (653.36g, 77.97%, 56.46mm, 3031mm(2), 22.26kg and 14.32% vs 501.48g, 76.94%, 51.74mm, 2673mm(2), 21.52kg and 13.79%, respectively). This paper shows the prediction equations for hams, forelegs and total hams and forelegs weights and proportions with respect to slaughter weight and live ultrasound measurements in pigs fed either extensively or in confinement. The ultrasound measurements better predicted the carcass cuts absolute amounts (R(2)=0.591-0.875) than the carcass cuts proportions (R(2)=0.23-0.40). The use of real-time ultrasound should be used with caution to predict the absolute quantities of hams and forelegs from Iberian pigs since the ultrasound measurements are only moderately accurate.     

Effect of Iberian × Duroc genotype on composition and sensory properties of dry‐cured ham

BACKGROUND: Dry‐cured ham quality from three different Iberian × Duroc genotypes was studied: GEN1, Iberian × Duroc1; GEN2, Duroc1 × Iberian; GEN3, Duroc2 × Iberian. GEN1 and GEN2 are reciprocal crosses, while the difference between GEN2 and GEN3 is the Duroc sire line. The line Duroc1 (DU1) was selected for the manufacture of dry‐cured meat products, whereas the line Duroc2 (DU2) was selected for meat production with low carcass fat. RESULTS: Dry‐cured hams from all genotypes had similar chemical composition. However, intramuscular fat of dry‐cured hams from GEN3 was more unsaturated than that from GEN2, while GEN1 was intermediate. Lipid oxidation, measured as 2‐thiobarbituric acid‐reactive substances (TBARS) and hexanal content, was similar between genotypes. The colour of hams was affected by genotype; hams from GEN2 showed higher lightness (CIE L*), while those from GEN3 had a less intense colour (lower a* and C*). Texture measured instrumentally did not differ between genotypes; however, in the sensory analysis, panellists considered hams from GEN3 more fibrous, while those from GEN2 were considered juicier. Hams from GEN3 were also perceived as saltier and more acid. CONCLUSION: Genotype affected the quality of Iberian hams, with those from GEN3 being of lower quality, and this genotype was considered less suitable for the manufacture of Iberian dry‐cured ham. Copyright © 2007 Society of Chemical Industry     

Effect of Iberian×Duroc genotype on dry-cured loin quality

Dry-cured loins from three different pig genotypes were studied: GEN1: ♂ Iberian × ♀ Duroc1, GEN2: ♂ Duroc1 × ♀ Iberian; GEN3: ♂ Duroc2 × ♀ Iberian. GEN1 and GEN2 are reciprocal crosses, while the difference between GEN2 and GEN3 is the Duroc sire line. The genotype of pigs Duroc1 was selected for the manufacture of dry-cured meat products, while the genotype Duroc2 was selected for meat production. The chemical composition of the dry-cured loins was significantly different, especially the intramuscular fat (IMF) content which was highest in GEN2. Dry-cured loins from GEN3 showed lower CIE a^∗ and chroma values. IMF from GEN2 was more saturated whereas GEN3 had higher percentages of PUFA and MUFA. Loins from GEN3 had higher TBA-RS values (p > 0.05) and hexanal contents. Loins from GEN3 had higher Warner–Bratzler shear force (p > 0.05) and instrumental hardness than those from GEN2, being intermediate in GEN1. Panellists considered that loins from GEN2 were more marbled, more odorous, juicier, sweeter and less salty than loins from GEN3. Therefore, loins from GEN2 had the best quality, followed by GEN1, while GEN3 had the worst quality.     

Preference and juiciness of Iberian dry-cured loin as affected by intramuscular fat content, crossbreeding and rearing system

Preference ranking tests for juiciness and overall liking of dry cured loins from Iberian pigs with different genetic backgrounds (pure Iberian or crossbred Iberian×Duroc pigs), reared under different productive systems (outdoors on acorns and grass or indoors with mixed diets) and with different intramuscular fat (IMF) content, were conducted. IMF showed a positive influence on preference for juiciness and liking in subjects over 25 years of age, while younger consumers showed a similar trend for juiciness but not for preference. Loins from pure Iberian pigs showed significantly better ranking for juiciness and overall liking than those from crossbred pigs, even when the IMF content was similar. Dry cured loins from pigs reared outdoors and fed on acorns and pasture were ranked significantly better than those from animals fed indoors on concentrates, even though the mixed diets used were enriched in monounsaturated fatty acids and vitamin E in order to obtain meat with similar features to that of pigs reared outdoors, and despite very similar IMF contents. In conclusion, dry cured loins with high IMF content, from pure Iberian pigs and reared outdoors on acorns and grass attain the highest consumer preference.     

Effect of vaccination against gonadotrophin-releasing factor on growth performance, carcass, meat and fat quality of male Duroc pigs for dry-cured ham production

The aim of this study was to compare production, carcass and meat quality parameters, boar taint compounds and fat composition of green and dry-cured hams, between immunocastrated (IM), surgically castrated (CM) and female (FE) Duroc purebred pigs (n=75, 138.7±8.27kg). Liveweight and fat and muscle thicknesses were measured and average daily gain was calculated during growth. Carcass, meat and fat quality parameters were measured. Immunocastrated grew faster than CM or FE after the second dose of vaccine. IM had the lowest dressing percentage but similar % of ham and carcass lean to FE and CM. The effect of the immunocastration on carcass fatness depended on the location, did not affect fat and meat quality and reduced skatole and androstenone levels. Both in green and dry-cured ham, immunocastration slightly altered FA composition. Thus, Duroc pigs vaccinated with Improvac are suitable for the production of high quality dry-cured ham.     

FRESH AND PROCESSED QUALITIES OF COUNTRY-STYLE CURED HAMS FROM PUREBRED DUROC AND GENETICALLY UNDEFINED MARKET HOGS

The objective of this study was to determine country-style processing differences between hams from purebred Duroc market hogs and market hogs of unknown genetic makeup. Genetically undefined hams purchased from commercial suppliers were sampled the same day as hams from Duroc market hogs. Processing and curing followed standard commercial procedures. After curing, hams were weighed and sliced using a band saw. Slices from the approximate center of the ham were utilized to evaluate cured objective color, moisture content, pH, and salt content. There were no significant differences in cured ham yield between Duroc and genetically undefined market hogs. Intramuscular fat content was greater (P< 0.05) in hams from Duroc market hogs when compared to the hams from genetically undefined pigs. Subjective color, marbling and firmness scores were higher (P< 0.05) in hams from Duroc pigs. Objective color evaluation of cured, center-slices favored the hams from Duroc market hogs.     

Consumers’ preferences for Iberian dry-cured ham and the influence of mast feeding: An application of conjoint analysis in Spain

This paper analyzes consumers’ preferences for Iberian dry-cured ham, one of the most typical and highly prized meat products in Spain. The data were obtained by a survey carried out between April and May 2006 with a sample of 417 consumers in Extremadura (SW Spain). Conjoint Analysis was used to estimate the relative importance of the main attributes affecting preferences for Iberian ham and to create consumer segments with similar preference profiles. Results have shown that Price and Type of ham are the most important attributes for the choice of ham. Simulation analyses determined the surcharge that consumers are willing to pay for an Iberian mast-fed ham instead of an Iberian ham, thus identifying an ideal cluster for Iberian mast-fed ham.     

DNA tests based on coat colour genes for authentication of the raw material of meat products from Iberian pigs

Traceability in the meat supply chain depends on systems based on electronic identification, but DNA tests would be suitable to audit the genetic origin of some labelled meat products. Differentiated labelling is required for highly prized meat products from purebred Iberian pigs and from animals crossbred with the Duroc breed. A panel of breed specific markers based on polymorphisms found in two coat colour genes was investigated in the present study. The genotyping of the G/C or A/G polymorphisms at nucleotide positions ?160 and 727 bp of the melanocortin receptor 1 (MC1R) gene can be indistinctly used to discriminate the Duroc specific allele (MC1R*4) from all the alleles (MC1R*3, MC1R*6 and MC1R*7) found in the Iberian breed. It allows one to differentiate unambiguously samples from purebred Iberian and Duroc crossbred genotypes. The additional genotyping of the A/G polymorphism at position 2462 of the pink‐eyed dilution (OCA2) gene, four microsatellites (SW24, SW413, SW874 and SW1057) and nine amplified fragment length polymorphism (AFLP) markers would allow one to detect Duroc crossbred genotypes with a probability of exclusion of the pure Iberian origin greater than 0.968. The validation of batches of marketed products may be achieved with more single tests on pooled DNA samples. Copyright © 2004 Society of Chemical Industry