RESUMEN
Thirty-six Merino Branco lambs were assigned to six dietary treatments: control diet (C) consisting of 90% dehydrated lucerne and 10% wheat bran; C with 6% of oil blend (CO); C with 2.5% of grape seed extract (GS); GS with 6% of oil blend (GSO); C with 25% of Cistus ladanifer (CL), and CL with 6% of oil blend (CLO). Meat lipid and colour stability was then evaluated during 7 days of storage. The effect of inclusion of grape seed extract and C. ladanifer in diets on meat sensory properties was also evaluated. Meat antioxidant potential, determined after oxidation induction by a ferrous/hydrogen peroxide system, decreased with oil supplementation (P<0.001), but inclusion of grape seed extract and C. ladanifer in diets protected the meat against lipid oxidation (P=0.036). Meat colour was not affected by diets. Inclusion of grape seed extract and C. ladanifer in diets did not change the sensory properties of meat.
Asunto(s)
Antioxidantes/metabolismo , Dieta/veterinaria , Ácidos Grasos Insaturados/metabolismo , Calidad de los Alimentos , Carne/análisis , Músculo Esquelético/metabolismo , Oveja Doméstica/metabolismo , Tejido Adiposo Blanco/química , Tejido Adiposo Blanco/crecimiento & desarrollo , Tejido Adiposo Blanco/metabolismo , Animales , Animales Endogámicos , Antioxidantes/administración & dosificación , Antioxidantes/análisis , Cistus/química , Dieta/efectos adversos , Ácidos Grasos Insaturados/efectos adversos , Almacenamiento de Alimentos , Extracto de Semillas de Uva/química , Extracto de Semillas de Uva/metabolismo , Humanos , Aceite de Linaza/efectos adversos , Aceite de Linaza/metabolismo , Peroxidación de Lípido , Músculo Esquelético/química , Músculo Esquelético/crecimiento & desarrollo , Pigmentación , Hojas de la Planta/química , Aceites de Plantas/efectos adversos , Aceites de Plantas/metabolismo , Tallos de la Planta/química , Portugal , Sensación , Oveja Doméstica/crecimiento & desarrollo , Aceite de GirasolRESUMEN
The effect of gamma radiation processing on the lipid content, fatty acid composition and conjugated linoleic acid (CLA) profile in frozen lamb meat was investigated. Samples of longissimus thoracis muscle from lambs fed lucerne basal diets either unsupplemented or supplemented with polyunsaturated vegetable oils were irradiated (7kGy) and analysed. CLA contents in lamb meat did not affect (P>0.05) the levels of lipid oxidation induced by the irradiation. No significant differences (P>0.05) were observed for fatty acid composition, related nutritional indexes (n-6/n-3 and PUFA/SFA), as well as for total lipid and CLA contents, between non-irradiated (control) and irradiated meat samples. In contrast, meat irradiation affected the relative proportions of total trans,trans and cis/trans CLA isomers (P<0.001), in addition to the percentage of some minor individual CLA isomers (t11,t13 and t9,t11, with P<0.05 and P<0.001, respectively). The percentage of total cis/trans CLA isomers slightly decreased in irradiated samples, while the relative proportion of total trans,trans isomers slightly increased. This observation may be explained by the higher susceptibility to autoxidation of the cis double bond relative to the trans configuration.