Acid Composition Of Subcutaneous Fat Research Articles

The effects of age of castration on carcass characteristics, meat quality and fatty acid profile of finishing South African Mutton Merino lambs

This study compared the effect of either keeping South African Mutton Merino (SAMM) ram lambs intact, or castrated with age applicable methods on their carcass characteristics, meat quality and fatty acid composition of subcutaneous fat (SCF) and intramuscular fat (IMF). Ten lambs per treatment were castrated early at one week of age (EAR) with an elastrator band (4.4 kg ± 0.78 kg: mean ± SD), another 10 lambs at eight weeks of age (late castration - LAT) with a burdizzo (23.6 kg ± 2.26 kg: mean ± SD), whereas another ten lambs were left intact (CON). The two castration methods used were based on cost, ethical prescriptions and to mimic commercial operations. The lambs were housed individually in 30 pens (1.404 m2) for the duration of the study. Animals were housed on an elevated slatted wooden floor in the same metabolic building with an extractor fan to promote ventilation. At the start of the feeding trial, the age of the lambs was on average two and a half months with a live weight of 24.3 kg ± 4.10 kg (mean ± SD). The lambs were fed a standard commercial finishing diet for 67 days and slaughtered when they reached approximately 44.2 kg ± 6.35 kg (mean ± SD) live weight. After slaughter, carcass characteristics (cold carcass) and meat quality were evaluated. The left 3-rib cut was dissected (9th through 11th rib) and the muscle percentage for CON lambs was higher compared to both EAR and LAT lambs. Therefore, CON lambs produced leaner carcasses compared to EAR and LAT lambs. Castration status had no effect on meat Warner-Bratzler shear force (WBSF), consumer sensory analysis nor colour. For proximate composition, CON lambs had higher moisture compared to LAT lambs while LAT had higher dry matter compared to CON lambs. Both, EAR and LAT lamb’s meat had higher organic matter compared to CON lamb’s meat, but these differences were negligible. For IMF in the longissimus thoracic et lumborum muscle, CON lambs’ meat had higher total PUFA, α-linolenic acid, total PUFA n-6, linoleic acid, PUFA:SFA ratio and PUFA:MUFA ratio than meat from both EAR and LAT lambs. Eicosapentaenoic acid (EPA) and total PUFA n-3 were both higher for meat from CON lambs than LAT lamb’s meat, while palmitic acid and conjugated linoleic acid (CLA) were higher for EAR lamb’s meat than CON lamb’s meat and EAR lambs than LAT lamb’s meat, respectively. For SCF, CON lambs had higher heptadecenoic acid and linolelaidic acid than LAT lambs. The calculated atherogenicity index (AI) of SCF was higher for LAT lambs compared to CON lambs. Limited effects of castration age on the possible health benefits of SAMM lamb meat were proven in the current study. It is however suggested that for a higher production response and carcass muscle content, to either keep SAMM rams intact or at least postpone castration for as long as possible.

Variation in fatty acid composition of subcutaneous fat from beef carcases commercially produced in Australia

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The effect of dietary Echium oil supplementation on the fatty acid profile, omega-3 fatty acid content and subcutaneous fat quality of pork

This study evaluated the effect of five dietary oils - palm (Control), soya, linseed, fish and Echium oil at a 1% inclusion level- on growth performance, feed efficiency, subcutaneous fat quality and fatty acid composition of subcutaneous fat. The trial consisted of 60 gilts, randomly allocated to ten groups with six animals per pen. Dietary treatment had no significant effect on growth performance, feed efficiency or lean meat content of pigs. All colour parameters, extractable fat content, fat free dry matter, and moisture content of subcutaneous fat were unaffected by dietary treatment. The only significant difference for fat firmness was between the control treatment containing palm oil (Bergafat HPL 106) and the linseed oil treatment (P = 0.049), with the control producing the hardest fat. The iodine value was significantly lower in the control treatment (P < 0.001). Both the Echium and linseed oil treatments increased the ratio of polyunsaturated fatty acid:saturated fatty acid (PUFA:SFA) and decreased the omega-6:omega-3 (n-6:n-3) ratio of subcutaneous fat. Stearidonic acid concentration of subcutaneous fat was the highest (P < 0.001) for the Echium oil treatment (0.21%). The fish oil treatment had significantly higher levels (P < 0.001) of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) and total EPA+DPA+DHA than all other treatments. The Echium oil treatment resulted in significantly (P < 0.001) higher EPA, DPA and EPA+DPA+DHA levels in subcutaneous fat than the linseed oil, soya oil and control treatments. The result suggests that Echium oil can be used in pig diets to improve the long chain n-3 fatty acid content of subcutaneous fat.

Replacing soybean meal with Narbon vetch (Vicia narbonensis L.) in pig diets: composition of subcutaneous fat and fresh loin, and sensory attributes of dry-cured product

Aim of the study: To evaluate the consequences for pork quality traits of replacing soybean meal with Narbon vetch in pig diets.Area of study: Castilla-Leon, Spain.Material and methods: 48 Duroc × Iberian barrows were fed diets with 0% (V0), 5% (V5), 10% (V10) and 20% (V20) inclusion of Narbon vetch. Pork quality traits investigated were 1) intramuscular fat, protein and moisture content of fresh loin, 2) fatty acid composition of subcutaneous fat, and 3) sensory attributes (Triangle test and a Simple Difference Test with a non-trained taste panel) of cured loin.Main results: Inclusion of Narbon vetch in the diet showed no significant effect on intramuscular fat, protein and moisture in fresh loin samples. Stearic acid was higher in subcutaneous fat of V5 than in V0 and V10 (p &lt; 0.05), and oleic acid was higher in V10 than in V0, V5 and V20 (p &lt; 0.05); no other differences in fatty acid composition were observed. Taste panelists tended to be able to distinguish V10 from V0 cured loins (p &lt; 0.10), and were able to distinguish V20 from V0 loins (p &lt; 0.05), in particular due to a perceived difference in taste, texture and marbling. No differences in intensity of the texture, marbling, aroma and color of cured loins were found between V0 and V5.Research highlights: Inclusion of Narbon vetch in pig diets did not significantly affect fresh loin composition or fatty acid composition of subcutaneous fat. Consumers perceived a difference in sensory characteristics of cured loin with replacement of soybean meal with Narbon Vetch, but they did not characterize this as more favorable.

On-site visible–near IR prediction of iodine number and fatty acid composition of subcutaneous fat of raw hams as phenotypes for a heavy pig breeding program

The quality of subcutaneous fat of raw hams is a trait of interest in selective breeding programs for pig lines used in dry-cured ham production, and rapid, non-invasive methods for its assessment are available. However, the efficacy of such methods to provide indicator traits for breeding programs needs to be proven. The study investigated the accuracy of on-site visible–near IR spectroscopy predictions of iodine number and fatty acid (FA) composition of raw ham subcutaneous fat, and it evaluated their effectiveness as indicator traits of ham fat quality in a pig breeding program. Prediction equations were developed using visible–near IR spectra acquired at the slaughterhouse from five sites in subcutaneous fat of raw hams of 1025 crossbred pigs. Pigs were raised, under standardized rearing and feeding conditions, in the sib-testing program of the Goland C21 boar line and slaughtered at nine months of age and average body weight of 166 ± 15 kg. Accuracy was generally relatively poor, but R2 in external validation was >0.7 for iodine number and concentration of C18:2n-6, polyunsaturated FAs and omega-6 FAs. To assess the effectiveness of the on-site predictions as indicator traits in a breeding program, (co)variance components of the measured traits (OBS) and of their predictions using in-lab (in-lab-PR) or on-site (on-site-PR) spectrometers were estimated. Available records for OBS were 6814 and 2048, for iodine number and FA composition, respectively. Predictions using in-lab were available for pigs slaughtered between 2006 and 2014, for a total of 10 153 records. Predictions using on-site were obtained from spectra collected since 2011, for a total of 10 296 records. The estimated heritabilities for the investigated traits ranged from 0.34 to 0.50 and were greater for on-site-PR than for OBS. Genetic correlations between OBS and in-lab-PR were very close to 1.00 for all the investigated traits, whereas those between OBS and on-site-PRED ranged from 0.86 to 0.94. On-site visible-IR predictions are accurate enough to support the use of this technique for large-scale phenotyping of raw ham fat quality, even when dealing with animals of a single genetic line raised in standardized conditions, and may be implemented as indicator traits in breeding programs.

Authenticating common Australian beef production systems using Raman spectroscopy

Australian grain-fed and grass-fed beef products garner premium market prices and many beef processors market branded beef supported by production system claims. Given beef cattle nutrition alters the fatty acid composition of subcutaneous fat and grass and grain-fed cattle can be differentiated using Raman spectra of the fat, this study aimed to evaluate if Raman spectroscopy and chemometric modelling can differentiate grass fed cattle from a variety of production systems. To this end, subcutaneous fat from a total of 520 beef carcases with 130 from long term grain-fed, short term grain-fed, grass-fed and supplemented grass-fed beef cattle were measured. Classification of carcases using Partial Least Squares Discriminant Analysis (PLS-DA) demonstrated spectra were able to correctly classify long term grain-fed (96%), short term grain-fed (85%), grass-fed (83%) and supplemented grass-fed (83%) carcases based on the test dataset. Spectral patterns including peaks that characterise fatty acids have been shown to underpin this classification. Overall, this study demonstrates Raman spectroscopy is a useful tool for the authentication and discrimination of beef carcases from different production systems.

Short Communication: The potential of portable near infrared spectroscopy for assuring quality and authenticity in the food chain, using Iberian hams as an example

This communication assesses the use of a portable near infrared (NIR) instrument to measure quantitative (fatty acid profile) properties and qualitative (‘Premium’ and ‘Non-premium’) categories of individual Iberian pork carcasses at the slaughterhouse. Acorn-fed Iberian pigs have more unsaturated fats than pigs fed conventional compound feed. Recent advances in miniaturisation have led to a number of handheld NIR devices being developed, allowing processing decisions to be made earlier, significantly reducing time and costs. The most common methods used for assessing quality and authenticity of Iberian hams are analysis of the fatty acid composition of subcutaneous fat using gas chromatography and DNA analysis. In this study, NIR calibrations for fatty acids and classification as premium or non-premium ham, based on carcass fat measured in situ, were developed using a portable NIR spectrometer. The accuracy of the quantitative equations was evaluated through the standard error of cross validation or standard error of prediction of 0.84 for palmitic acid (C16:0), 0.94 for stearic acid (C18:0), 1.47 for oleic acid (C18:1) and 0.58 for linoleic acid (C18:2). Qualitative calibrations provided acceptable results, with up to 98% of samples (n = 234) correctly classified with probabilities ⩾0.9. Results indicated a portable NIR instrument has the potential to be used to measure quality and authenticity of Iberian pork carcasses.

Distinct correlations between lipogenic gene expression and fatty acid composition of subcutaneous fat among cattle breeds

BackgroundThe fatty acid (FA) composition of adipose tissue influences the nutritional quality of meat products. The unsaturation level of FAs is determined by fatty acid desaturases such as stearoyl-CoA desaturases (SCDs), which are under control of the transcription factor sterol regulatory element-binding protein (SREBP). Differences in SCD genotype may thus confer variations in lipid metabolism and FA content among cattle breeds. This study investigated correlations between FA composition and lipogenic gene expression levels in the subcutaneous adipose tissue of beef cattle breeds of different gender from the Basque region of northern Spain. Pirenaica is the most important beef cattle breed in northern Spain, while Salers cattle and Holstein-Friesian cull cows are also an integral part of the regional beef supply.ResultsPirenaica heifers showed higher monounsaturated FA (MUFA) and conjugated linoleic acid (CLA) contents in subcutaneous adipose tissue than other breeds (P < 0.001). Alternatively, Salers bulls produced the highest oleic acid content, followed by Pirenaica heifers (P < 0.001). There was substantial variability in SCD gene expression among breeds, consistent with these differences in MUFA and CLA content. Correlations between SCD1 expression and most FA desaturation indexes (DIs) were positive in Salers (P < 0.05) and Pirenaica bulls, while, in general, SCD5 expression showed few significant correlations with DIs. There was a significant linear correlation between SCD1 and SRBEP1 in all breeds, suggesting strong regulation of SCD1 expression by SRBEP1. Pirenaica heifers showed a stronger correlation between SCD1 and SREBP1 than Pirenaica bulls. We also observed a opposite relationship between SCD1 and SCD5 expression levels and opposite associations of isoform expression levels with the ∆9 desaturation indexes.ConclusionsThese results suggest that the relationships between FA composition and lipogenic gene expression are influenced by breed and sex. The opposite relationship between SCD isoforms suggests a compensatory regulation of total SCD activity, while opposite relationships between SCD isoforms and desaturation indexes, specially 9c-14:1 DI, previously reported as an indicator of SCD activity, may reflect distinct activities of SCD1 and SCD5 in regulation of FA content. These findings may be useful for beef/dairy breeding and feeding programs to supply nutritionally favorable products.

Caracterización comercial y nutricional de la grasa subcutánea de terneros y vacas de desvieje sacrificados en la Comunidad Autónoma del País Vasco

Este trabajo se ha llevado a cabo con el objetivo de comparar la calidad comercial de la canal y la composición de ácidos grasos de la grasa subcutánea de vacas de desvieje de raza Frisona de más de 30 meses de edad, y de terneros de 12 meses de edad de las razas Pirenaica y Salers sacrificados en un matadero comercial de la Comunidad Autónoma del País Vasco. Las vacas de raza Frisona presentaron canales de menor peso (p&lt;0,05), aunque similar al grupo de los terneros de raza Pirenaica y menor conformación (p&lt;0,001) y estado de engrasamiento (p&lt;0,01) en comparación con los grupos de terneros. La grasa subcutánea de las vacas de desvieje presentó un mayor contenido de ácidos grasos saturados (p&lt;0,001) y ramificados (p&lt;0,05), y un menor contenido de ácidos grasos monoinsaturados (p&lt;0,01) y poliinsaturados (p&lt;0,001) en comparación con la de los terneros de las razas Pirenaica y Salers. El porcentaje de ácidos grasos monoinsaturados de tipo trans fue significativamente superior en la grasa subcutánea de los terneros de raza Pirenaica (p&lt;0,001), mientras que el contenido de 10t-18:1 fue significativamente mayor en la grasa de terneros de raza Pirenaica, intermedio en la grasa de terneros de raza Salers, y menor en la grasa de las vacas de desvieje (p&lt;0,001). Esto dio lugar a una relación 10t/11t &lt;1 y un perfil isomérico relativo de trans-18:1 y ácidos linoleico conjugados más saludable en la grasa de las vacas de desvieje de raza Frisona en comparación con los grupos de terneros. Esta idea podría contribuir a la valorización de las canales procedentes de vacas de desvieje desde el punto de vista de su comercialización y de la rentabilidad de las explotaciones ganaderas de vacuno en la Comunidad Autónoma del País Vasco.

Effect of growth rate on live performance, carcass and green thigh traits of finishing Italian heavy pigs

This study aimed at investigating the effects of growth rate (GR) on live performance, carcass and dressed green ham (DRHAM) traits of finishing heavy pigs managed in accordance with the regulations governing the production of Protected Denomination of Origin (PDO) dry-cured hams. Data were obtained from 233 crossbred pigs restrictively fed from 90 to 165 kg BW. Individual BW, daily feed intake, and weights of carcass and main cuts were recorded. Thighs were measured for subcutaneous fat thickness, analysed for fatty acid composition of subcutaneous fat, and dry-cured hams were weighed. Records were classified according to GR quartile, calculated using the residuals of a statistical model that included the effects of pen, sex and diet. Data were analysed using the same model with the addition of the effect of GR quartile. Average GR ranged from 578 in the first quartile to 748 g/d in the fourth. Final BW and weights of carcass, DRHAM and dry-cured ham increased as the GR quartile increased (p < .01). An increase in GR improved feed efficiency linearly (p < .001) and tended to increase the thickness of subcutaneous fat of DRHAM, whereas seasoning losses decreased linearly with increasing average GR. In conclusion, targeting the GR of finishing pigs at a minimum of 750 g/d and consequently increasing final BW to around 175–180 kg may be a way to improve feed efficiency and some quality traits of DRHAM.

Effect of progressive reduction in crude protein and lysine of heavy pigs diets on some technological properties of green hams destined for PDO dry-cured ham production

In order to investigate the effects of dietary crude protein (CP) and lysine (Lys) content on some technological properties of green hams destined for Protected Designation of Origin (PDO) dry-cured ham, green hams visual appraisal scores, thickness, iodine number and fatty acid composition of subcutaneous fat, and ham weight losses during seasoning (SL) were assessed. The green hams were obtained from 233 pigs fed four diets containing 140 to 110g/kg CP and 6.5 to 5.3g/kg total Lys from 90 to 165kg body weight. A reduction in dietary CP and Lys of up to 20% compared with conventional feeds led to a 15% increase in the thickness of the subcutaneous fat, a 5% decrease in linoleic and polyunsaturated fatty acids in subcutaneous fat and a 7% decrease in SL. A 20% reduction of CP and Lys in diets for finishing pigs has positive effects on the technological properties of green hams destined for PDO dry-cured ham production.

日本短角種の枝肉皮下脂肪中の脂肪酸組成にSCD, FASN, SREBP-1 およびGHの各遺伝子多型が及ぼす影響

日本短角種の枝肉皮下脂肪中の脂肪酸組成に<I>SCD, FASN, SREBP-1</I> および<I>GH</I>の各遺伝子多型が及ぼす影響

Water requirements of liquid-fed heavy pigs: Effect of water restriction on growth traits, animal welfare and meat and ham quality

Reducing water waste, and therefore the total volume of manure produced, is one of the ways to lower the environmental impact of intensive pig farming. The aim of this trial was to verify whether the absence of additional fresh drinking water could compromise the production traits or behaviour of liquid-fed heavy pigs. Sixty animals (initial BW 78kg) were divided into two experimental groups, both fed a liquid diet (water-to-feed ratio 3:1 w/w). All pens were equipped with nipple drinkers; one of the groups had permanent access to fresh water (working drinkers—WD), whereas the other group had no water supply except that delivered with food (dry drinkers—DD). The pigs were housed in temperature- and humidity-controlled rooms. They were brought to a weight of 160kg and then slaughtered. Hams were dry-cured according to the directives for Parma ham production. No significant differences (P>0.05) were observed between the experimental groups with respect to growth parameters (ADG and FCR), behavioural traits, blood parameters or the qualitative traits of carcasses (dressing out, lean meat yield, backfat thickness), meat (pH, colour, WHC, fatty acid composition of subcutaneous fat and tenderness) and cured hams (weight losses, sensory properties, chemical composition and oxidative status). With respect to drinking behaviour, a low number of visits to the drinker were recorded for both groups and data seem to indicate a high amount of water wasted by pigs provided with additional water delivery by nipple drinkers. Liquid feeding did not suppress drinkers use or drinker manipulation in both groups.

Genetic variation in fatty acid composition of subcutaneous fat in cattle

Genetic parameters were estimated for fatty acid composition of subcutaneous beef fat of 1573 animals which were the progeny of 157 sires across seven breeds grown out on pasture and then finished on either grain or grass in northern New South Wales or in central Queensland. There was genetic variation in individual fatty acids with estimates of heritability for the proportions of C14 : 0, C14 : 1c9, C16 : 0, C16 : 1c9, C18 : 0 and C18 : 1c9 fatty acids in subcutaneous beef fat of the order of 0.4 or above. Also substantial correlations between some fatty acids were observed. Genetic correlations between fatty acids and fat depth at the P8 site suggested that much of the genetic variation in fatty acid composition was related to changes in fatness. Selection for decreased fatness resulted in decreased proportions of C18 : 1c9 with concomitant increases in C18 : 0, C14 : 0 and C16 : 0. This suggested that selection for decreased fatness at a given weight will result in a decrease in the proportions of monounsaturated fatty acids in the subcutaneous fat in the carcass with a corresponding increase in the proportions of saturated fatty acids.

Effect of protein level in commercial diets on pork meat quality

This study assessed the effect of protein level on meat quality, intramuscular and subcutaneous fat, instrumental texture and sensory attributes on Longissimus dorsi in pork. Animals were fed two experimental diets that produced two animal groups with different percentages of intramuscular fat (IMF) (1.76 vs. 2.63). There were no significant differences in meat quality or texture profile analysis parameters between IMF groups. The percentage of saturated fatty acids was also similar, but the percentage of monounsaturated was significantly higher in the group with higher IMF and the percentage of polyunsaturated fatty acids was higher in the group with lower IMF. IMF groups had little effect on the fatty acid composition of subcutaneous fat. Warner-Bratzler shear force (WBSF) values were significantly higher in the group with lower IMF, whereas tenderness was higher in the group with higher IMF. Finally, WBSF appeared to be a good predictor of the tenderness for grill-cooked pork.

Effects of the fattening period on the fatty acid composition of fat deposits and free amino acid and inosinic acid contents of the longissimus muscle in carcasses of Japanese Black steers

The effects of the fattening period on carcass characteristics, fatty acid composition of fat deposits, and muscle free amino acid (FAA) and inosinic acid (IMP) contents were evaluated in Japanese Black steers. Ten castrated, 10-month-old calves derived from the same sire were divided into five to be slaughtered at the age of 30 months after a 20-month fattening period (20-month group) and five to be slaughtered at the age of 34 months after a 24-month fattening period (24-month group). Concerning the fatty acid composition of subcutaneous fat, the percentage of palmitoleic acid was higher (P < 0.05) in the 24- than in the 20-month group, but no difference was noted in any other fatty acids. For intermuscular fat, no difference was observed in any fatty acids. The percentages of oleic acid and total monounsaturated fatty acid of intramuscular and perinephric fat were higher (P < 0.05) in the 24- than in the 20-month group. Of the FAAs in the longissimus thoracis muscle, the threonine and tyrosine contents were lower (P < 0.05) in the 24- than in the 20-month group. The IMP content was higher (P < 0.05) in the 24- than in the 20-month group, suggesting an effect of prolongation of the fattening period.

Interactive effects of dietary fat source and slaughter weight in growing-finishing swine: II. Fatty acid composition of subcutaneous fat1

Crossbred pigs (n=288) were used to test the interactive effects of dietary fat source and slaughter weight on the fatty acid composition of subcutaneous fat. Pigs were blocked by initial BW (28.1 kg), and, within blocks, pens (8 pigs/pen) were randomly assigned to either grower and finisher diets devoid of added fat (Ctrl) or diets formulated with 5% beef tallow (BT), poultry fat (PF), or soybean oil (SBO). Immediately after treatment allotment, as well as at mean block BW of 45.5, 68.1, 90.9, and 113.6 kg, 1 pig was randomly selected from each pen, slaughtered, and, within 1 h postmortem, samples of backfat were removed from each carcass between the 4th and 8th thoracic vertebra and separated into the inner, middle, and outer layers for fatty acid composition analysis. During the first 17.4 kg of BW gain, percentages of all SFA increased by more than 4% in subcutaneous fat of pigs fed the Ctrl and BT diets, but decreased by 4.4 and 7.7% in pigs fed the PF and SBO diets, respectively (fat source x slaughter weight, P<0.001). Proportions of all MUFA in subcutaneous fat from BT-fed pigs increased by 6.1% during the first 17.4 kg of BW gain, but MUFA percentages in SBO-fed pigs decreased by 9.1% between 28.1 and 45.5 kg (fat source x slaughter weight, P<0.001). Conversely, percentages of all PUFA from SBO-fed pigs increased by 39.9%, whereas PUFA concentrations in BT-fed pigs decreased by 12.6% as slaughter weight increased from 28.1 to 45.5 kg (fat source x slaughter weight, P<0.001). Resultant iodine values (IV) of subcutaneous fat from SBO-fed pigs increased (P<0.05) from 73.5 to 85.2 within the first 17.4 kg of BW gain, and remained elevated above those of their contemporaries fed the Ctrl, BT, or PF diets at each subsequent slaughter weight (fat source x slaughter weight, P<0.001). The inner backfat layer had the greatest (P<0.05) proportions of all SFA and the least (P<0.05) proportions of all PUFA, whereas the outer layer had the least (P<0.05) percentages of all SFA but the greatest (P<0.05) percentages of all MUFA. Even though the middle and outer subcutaneous fat layers had similar (P>0.05) PUFA percentages, the greatest (P<0.05) and least (P<0.05) IV were in the outer and middle layers, respectively. As expected, the fat source included in swine diets was responsible for the fatty acid compositional changes in subcutaneous fat, yet the results of this study indicate that feeding 5% SBO dramatically increased the polyunsaturation of subcutaneous fat within the first 17.4 kg of BW gain, with backfat IV exceeding 80 thereafter.

Changes in the Concentrations of Free Fatty Acid, Monoacylglycerol, and Diacylglycerol in the Subcutaneous Fat of Iberian Ham during the Dry-Curing Process

Changes in diacylglycerols, monoacylglycerols, and free fatty acid composition of subcutaneous fat of six Iberian hams during the dry-cured process were investigated. In addition, an analytical method for simultaneous quantification of diacylglycerols, monoacylglycerols, and free fatty acid by solid-phase extraction-gas chromatography was developed. The different molecular species of free fatty acids, monoacylglycerols, and diacylglycerols and 1,2- and 1,3-isomers of diacylglycerols have been described for the first time in this type of sample. A logarithmic increase of the 1,3-diacylglycerol profile throughout the processing time has been found, reaching a balance value of 62% around 500 days. The formation of diacylglycerol isomers takes place, although the 1,3-/1,2-diacylglycerol ratio increases during the process to 1.65 due to isomerization of the 1,2-form toward the 1,3-form. The profiles of monoacyl- and diacylglycerols and free fatty acids follow the same trend. The experimental values of free fatty acid are greater than theoretical prediction, probably due to phospholipid and monoacylglycerol hydrolysis.

Comparison Between Two Different Levels of Replacement of Free-range Rearing by an Oleic Acid and-tocopherol Enriched Diet on the Quality of Fresh Meat from Iberian Duroc (50%) Pigs

The aim of this work was to study the effect of two types of pig feeding systems (known as recebo) on fatty acid composition, tocopherols contents and susceptibility to lipid oxidation in muscle. A total of 26 Iberian Duroc (50%) barrows were divided into two groups (named as short replacement (SR) and long replacement (LR) groups) according to length of replacement of free-range rearing (based on acorn and pasture) by an oleic acid and B-tocopherol (200 mg/kg) enriched concentrate feed (SR group: 67 days in free-range rearing and finished during 20 days with concentrate diet; LR: 55 days in free-range rearing, finished 50 days with concentrate). No differences were found in chemical composition and colour of Gluteo biceps muscle between the two management systems, except for B-tocopherol content, which showed higher content (p 0.001) in LR pigs than in SR pigs. The fatty acid composition of subcutaneous fat was slightly affected by feeding system. Total intramuscular and neutral lipids from Gluteo biceps muscle presented a higher proportion of C18: 1 n 9 (p 0.05) in SR than in LR pigs; however, no differences were found in total saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA). Composition of polar lipids revealed a higher proportion of MUFA and lower of total n 3 fatty acids in LR than in SR pigs. Feeding regime significantly affected susceptibility of muscle to iron-ascorbate-induced peroxidation. Muscles from pigs reared on SR system showing higher levels (p 0.05) of MDA after 50 and 100 min of incubation. These results indicate that the content of oleic acid and tocopherol in muscle depends on the levels of both provided by dietary means, more than the practised handling.

Effects of barley variety fed to steers on carcass characteristics and color of meat.

This study evaluated the effect of barley varieties in the diets of finishing steers on carcass composition, fat, and lean color and the fatty acid profile of subcutaneous fat. Crossbred steers (391 kg initial BW) were assigned randomly to one of five finishing diets composed primarily of corn (n = 9), Morex barley (n = 9), Steptoe barley, (n = 9), or two experimental barley varieties SM3 (n = 9) and SM5 (n = 9). Grains were cracked prior to feeding. Diets were formulated (DM basis) to be isonitrogenous (2.24% N) and isocaloric (2.01 Mcal/kg NEm and 1.35 Mcal/kg NEg). Steers were slaughtered according to industry-accepted procedures when it was visually estimated that 70% of carcasses would grade USDA Choice. After a 24-h chill at 4 degrees C, carcass quality and yield grade data were collected by trained, experienced university personnel. Objective color (L*, a*, and b*) of both the LM and subcutaneous fat were measured, and samples of subcutaneous fat were removed from the 10th- to 12th-rib region for fatty acid analysis. Diet did not affect hot carcass weight (P = 0.15), fat thickness (P = 0.58), LM area (P = 0.57), percentage of internal fat (P = 0.52), yield grade (P = 0.96), marbling (P = 0.73), or quality grade (P = 0.10). However, the LM from steers fed diets formulated with Morex and SM5 barley varieties tended to be lighter (higher L* values, P = 0.08) than the LM from steers fed the corn-based diet. Additionally, fat from steers fed corn tended to be more yellow (higher Hunter b* values, P = 0.09) than fat from steers fed barley-based diets. Although grain source had only minimal effects on the fatty acid composition of subcutaneous fat samples, pentadecanoic acid (15:0) was greater (P < 0.05) in fat from steers fed SM3 and Steptoe barley varieties than in fat from steers fed corn. Stearic acid (18:0) concentrations were higher (P < 0.05) in fat samples from steers fed corn than in those fed the experimental barley lines (SM3 and SM5). Conversely, fat samples from steers fed Steptoe and SM5 barley had greater (P < 0.05) gadoleic acid (20:1) concentrations than fat from steers fed corn or Morex variety. Although the variety/line of barley included in the finishing diet may affect LM and fat color, grain-source (barley vs. corn) had little effect on beef carcass quality and yield grades and did not greatly alter the fatty acid composition of subcutaneous fat.