Comparison of meat quality characteristics and oxidative stability between conventional and free-range chickens

The aim of this research was to evaluate quality traits and oxidative stability of meat products from free range (FR) and conventionally (C) raised chickens as they actually reach consumers in the Italian retail market. FR female and male chickens (n=1500 + 1500), medium growing Isa strain, were raised under commercial conditions for 56 (1.8 kg of live wt.) and 70 d (3.1 kg of live wt.), respectively; C female and male birds (n=5000 + 5000) were a fast growing hybrid (Ross 708) and were separately raised for 39 (1.9 kg of live wt.) and 50 d (3.1 kg of live wt.), respectively. A total of 96 chickens (equally divided by production system and sex) were slaughtered into 2 separate sessions, to obtain the main two commercial categories (rotisserie and cut-up, respectively). After slaughtering, 12 carcasses of each treatment group were randomly selected and used to assess quality properties, chemical composition and oxidation stability of breast and leg meat. C birds had dramatic higher carcass and breast meat yield, whereas FR had higher wing and leg yields. FR birds exhibited higher water holding capacity in both breast and leg meat. Although shear force did not differ in breast meat, legs from FR birds were tougher. Fatty acid composition of FR breast and thigh meat of both categories were characterized by a higher PUFA n-6-/n-3 ratio. In general, a low lipid oxidation level (peroxide value (PV) < 1.3 meq O2/kg of lipid and thiobarbituric acid reactive substances (TBARs) < 0.2 mg MDA/kg of sample) was found in breast and legs, regardless of the commercial category. However, the C system significantly increased PV in rotisserie thigh meat, whereas FR led to a significantly higher TBARs in breast meat. Our results demonstrated that free range can modify the properties of chicken meat and also highlighted the importance of the animal genetic background to select nutritional strategies to improve meat quality traits and oxidative stability in poultry

Effects of multiple abiotic stresses on lipids and sterols profile in barley leaves (Hordeum vulgare L.)

open6siPlants are usually exposed to several types of abiotic stress in regular field conditions. The lipid profile of barley homozygous lines exposed to drought, heat, salinity, and their combinations, was investigated in the present study. Free fatty acids, free sterols, and diacylglycerols were the most abundant classes (∼8.0% of plant material). The genetic background significantly impacted the lipid composition rather than the treatments, and diacylglycerols were the only lipid class affected by salinity (1.84 mg/100 mg plant tissue; ∼33% reduction). However, the genotype × treatment interaction analysis revealed that the lipid and sterol compositions depended on both genotype and environment. Our results suggest that inborn stress tolerance in barley is manifested by enhanced accumulation of most lipids, mainly sterols, especially in heat/drought-stressed plants. In addition, expression of the LTP2 gene may be indirectly involved in the abiotic stress reaction of barley by mediating intracellular transport of some lipid classesopenA. Kuczyńska; V. Cardenia; P. Ogrodowicza; .M. Kempa; M. T. Rodriguez-Estrada; K. MikołajczakaA. Kuczyńska; V. Cardenia; P. Ogrodowicza; .M. Kempa; M. T. Rodriguez-Estrada; K. Mikołajczak

Thermo-oxidation of cholesterol: effect of the unsaturation degree of the lipid matrix

The influence of the unsaturation degree of different triacylglycerols (tristearin, triolein, trilinolein and trilinolenin) on cholesterol oxidation at 180 °C, was evaluated. Cholesterol degraded faster when heated alone than in the presence of triacylglycerols; moreover, the more unsaturated the matrix, the slower the degradation of cholesterol. Both cholesterol and triacylglycerols degradation fit a first order kinetic model (R(2)>0.9), except for the tristearin sample. Cholesterol oxidation products (COPs) and peroxides were formed during the heating treatment. The presence of any type of lipid matrix postponed and decreased the maximum concentration of both oxidation parameters. Maximum total COPs concentrations were achieved at 20 min in neat cholesterol, 120 min in tristearin and triolein and 180 min in polyunsaturated matrix samples. 7-Ketocholesterol was the main COP in most cases during the whole heating treatment. Both the presence of triacylglycerols and their unsaturation degree inhibited cholesterol thermooxidation at 180 °C