Effect of Sex and Fat Depot Location on Fat Composition of Rasa Aragonesa Lambs

The quality of lamb fat is important in sheep carcass markets because it affects the degree of acceptance by consumers. In Spain, consumption of beef and lamb is important and young lambs are highly valued. In addition, the precocity of the female determines slaughter at younger ages than males, to avoid excessive fat. Therefore, the effect of sex and fat depot location (omental, mesenteric, kidney knob, subcutaneous, intermuscular and intramuscular) on the fatty acid composition in 30 Rasa Aragonesa lambs (15 males and 15 females) of 24 kg live weight and three months of age, were studied. Oleic, palmitic and stearic fatty acids were the main fatty acids making up the fat in all the fat depots from lambs. There were no significant differences (p0.05) in the fat composition between male and female lambs, even though females had significantly more fat than males in all the fat depots considered (p0.05). Criteria associated with sex did not affect the composition of fat. Ratio of fatty acids n-6/n-3 values were in the range of recommended average values (4), except for intramuscular fat, where values marginally higher were observed (5.5). The internal (omental, mesenteric and kidney knob) fat depots contained more saturated fatty acids than the edibles depots (subcutaneous, intermuscular and intramuscular) (p0.05). Consequently, the internal fat depot was firmer than fat from the surface of the carcass. Fatty acid of intramuscular fat depot had the highest content of PUFA of all fat deposits studied.La calidad de la grasa de cordero es importante en los mercados de canales ovinas porque afecta al grado de aceptación de los consumidores. En España, el consumo de carne de res y cordero es importante, y los corderos jóvenes son muy valorados. Además, la precocidad de las hembras determina su sacrificio a edades más tempranas que los machos para evitar su excesivo engrasamiento. Por tanto, se estudiaron el efecto del sexo y del depósito de grasa (omental, mesentérica, pelvicorrenal, subcutánea, intermuscular e intramuscular) sobre la composición de ácidos grasos en 30 corderos de raza Rasa Aragonesa (15 machos y 15 hembras) de 24 kg de peso vivo y tres meses de edad. Los principales ácidos grasos que componen la grasa en todos los depósitos de grasa de los corderos fueron los ácidos oleico, palmítico y esteárico. No hubo diferencias significativas (p0.05) en la composición de la grasa entre los corderos machos y hembras, a pesar de que las hembras presentaron significativamente más grasa que los machos en todos los depósitos considerados (p0.05). Los criterios asociados con el sexo no afectaron a la composición de la grasa. La relación de ácidos grasos n-6/n-3 se encontró en el rango de los valores promedio recomendados (4), excepto la grasa intramuscular, donde se observaron valores más altos (5.5). Los depósitos de grasa interna (omental, mesentérica y pelvicorrenal) mostraron más ácidos grasos saturados que los depósitos comestibles (subcutáneo, intermuscular e intramuscular) (p0.05). En consecuencia, el depósito de grasa interna presentó grasa más firme que el de la superficie de la canal. Los ácidos grasos del depósito intramuscular presentó el contenido más alto de ácidos grasos poliinsaturados de todos los depósitos de grasa estudiados

Raw-cured Spanish traditional meat product 'Chistorra de Navarra': sensory and composition quality standards

The aim of this work was to set the quality standards of the chistorra de Navarra, a raw-cured Spanish traditional meat product, through the study of its sensory and physicochemical features. The quality of chistorra samples, coming from 50 different artisan producers, were assessed during three sessions by expert assessors (n = 15). In the first session, instrumental colour (L*a*and b*) and appearance and odour parameters were evaluated in the raw products. In the second session, texture and flavour attributes were determined in cooked products. Finally, in the third session, the best 10 classified chistorras from the first and second sessions were sensorially evaluated and sampled for further analysis: texture (Warner Bratzler and texture profile analysis (TPA)), chemical composition, and fatty acid profile. The chistorras with the highest sensory scores had high shear force values, flavour intensity, and fat/hydroxyproline ratio. The average fatty acid profile obtained for chistorra de Navarra was: 42% saturated fatty acids (SFA), 45% monounsaturated fatty acids (MUFA), and 13% polyunsaturated fatty acids (PUFA), which was similar to the one found in other raw-cured sausages. Considering the sensory evaluation, chistorra was defined as a product with an intense orange colour, and with high resistance value in the initial bite. It was also characterised by a high juiciness and tenderness, aroma, and meat flavour. In mouth, the pork fat, one of the ingredients of chistorra, was balanced without any of the ingredients dominating. Chemically, the chistorra was characterised by a fat content close to 67% (dry matter), low hydroxyproline occurrence (≤0.6), and protein amount ranging 18 38%

Adipose tissue modification through feeding strategies and their implication on adipogenesis and adipose tissue metabolism in ruminants

Dietary recommendations by health authorities have been advising of the importance of diminishing saturated fatty acids (SFA) consumption and replacing them by polyunsaturated fatty acids (PUFA), particularly omega-3. Therefore, there have been efforts to enhance food fatty acid profiles, helping them to meet human nutritional recommendations. Ruminant meat is the major dietary conjugated linoleic acid (CLA) source, but it also contains SFA at relatively high proportions, deriving from ruminal biohydrogenation of PUFA. Additionally, lipid metabolism in ruminants may differ from other species. Recent research has aimed to modify the fatty acid profile of meat, and other animal products. This review summarizes dietary strategies based on the n-3 PUFA supplementation of ruminant diets and their effects on meat fatty acid composition. Additionally, the role of n-3 PUFA in adipose tissue (AT) development and in the expression of key genes involved in adipogenesis and lipid metabolism is discussed. It has been demonstrated that linseed supplementation leads to an increase in alpha-linolenic acid (ALA) and eicosapentaenoic acid (EPA), but not in docosahexaenoic acid (DHA), whilst fish oil and algae increase DHA content. Dietary PUFA can alter AT adiposity and modulate lipid metabolism genes expression, although further research is required to clarify the underlying mechanism.This research was funded by IS-FOOD Institute (Universidad Pública de Navarra)

Predicting beef carcass fatness using an image analysis system

The amount and distribution of subcutaneous fat is an important factor affecting beef carcass quality. The degree of fatness is determined by visual assessments scored on a scale of five fatness levels (the SEUROP system). New technologies such as the image analysis method have been developed and applied in an effort to enhance the accuracy and objectivity of this classification system. In this study, 50 young bulls were slaughtered (570 ± 52.5 kg) and after slaughter the carcasses were weighed (360 ± 33.1 kg) and a SEUROP system fatness score assigned. A digital picture of the outer surface of the left side of the carcass was taken and the area of fat cover (fat area) was measured using an image analysis system. Commercial cutting of the carcasses was performed 24 h post-mortem. The fat trimmed away on cutting (cutting fat) was weighed. A regression analysis was carried out for the carcass cutting fat (y-axis) on the carcass fat area (x-axis) to establish the accuracy of the image analysis system. A greater accuracy was obtained by the image analysis (R2 = 0.72; p 0.001). These results show the image analysis to be more accurate than the visual assessment system for predicting beef carcass fatness

Comparative description of growth, fat deposition, carcass and meat quality characteristics of Basque and Large White pigs

Characteristics of growth, fat deposition, carcass and meat quality of pigs from the Basque Black Pied breed were described and compared with those of Large White pigs. Four pens, two per breed, of eleven pigs born during the same two week period, were simultaneously fattened and slaughtered, under the same conditions. The experiment was carried out over a fixed duration (124 days) and slaughter was carried out at a fixed average age (202 days). Basque pigs showed lower growth and feed efficiency and higher backfat depth (2.6 vs. 1.7 cm, P < 0.001) than Large White pigs. The difference was especially noticeable in the middle subcutaneous fat layer (0.5 cm, P < 0.001). The meat of Basque pigs was darker, redder, more marbled, and with higher pH values than in Large White pigs. Differences in fatty acid composition were observed between breeds but they were not statistically significant (P > 0.05) because of high variability observed between animals. The Basque breed exhibited an early and higher adipose development and a higher activity of enzymes responsible for lipid synthesis than the Large White. The diameter of intramuscular adipose cells was larger in Basque (40.2 vs. 33.0 μm, P < 0.001) than in Large White pigs. The results show the particular characteristics of the Basque breed as compared to pig lines highly selected for lean growth efficiency.This work was funded by the Departamento de Educación y Cultura del Gobierno de Navarra