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Six cultivars (Franquette, Marbot, Mayette, Mellanaise, Lara, and Parisienne) of walnuts (Juglans regia L.) were collected during the 2001 crop, from Braganç a, Portugal. Chemical composition, including moisture, total oil content, crude protein, ash, carbohydrates, and nutritional value, was evaluated. Fat was the predominant component, ranging from 62.3 to 66.5%. Total oil was extracted and analyzed for fatty acids, sterols, oxidative stability, and peroxide value. Fatty acids and sterols were determined by gas-liquid chromatography coupled to a flame ionization detector. Eighteen fatty acids were quantified. Polyunsaturated fatty acids and, in particular, linoleic acid were predominant. -Sitosterol, ∆ 5 -avenasterol, and campesterol were the major sterols found. Differences were observed among the studied cultivars, especially in peroxide values and in the sterol profile.

The main objective of the present work was to optimize the extraction conditions for simultaneous maximization of total reducing (TRC) and antioxidant (AC) capacities for lettuce (Lactuca sativa L.) by-products extracts, using response surface methodology. For this, a design of experiments (DOE) with different combinations of solvents (water, methanol and acetone) extraction temperatures (30-60 ºC) and time (10-60 min) on the TRC and AC was applied. Higher and consistent fittings using second order polynomial models of the experimental data with regard to TRC (R 2 =0.529, p lack of fit >0.05) and AC (R 2 =0.900, p lack of fit >0.05) were obtained with methanol. The optimum extraction conditions based on combination responses for TRC and AC were: 30 % methanol (v/v), 60 ºC and 60 min. A close agreement between experimental and predicted values was found when applying these conditions. Furthermore, when aqueous extracts were prepared (e.g. 45 °C, 10 min), these presented similar TRC and AC properties to those obtained by the above optimum extraction conditions, having the advantage of applying mild extraction conditions and avoiding the use of organic solvents in their preparation.

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The chemical composition and nutritional value of five wild edible mushroom species (Agaricus arvensis, Lactarius deliciosus, Leucopaxillus giganteus, Sarcodon imbricatus, Tricholoma portentosum) commonly consumed in the Trás-os-Montes region of Northeast Portugal was determined. Chemical composition evaluation included moisture, total oil content, crude protein, ash, carbohydrates, and nutritional value determination. The macronutrient profile in general revealed that the wild mushrooms were rich sources of protein and carbohydrates, and had low amounts of fat. On the basis of the proximate analysis, it can be calculated that an edible portion of 100 g of these mushrooms provides, on average, 28 kcal (118 kJ). The analysis of fatty acid composition, performed by gas-liquid chromatography coupled to a flame ionization detector, allowed the quantification of fifteen fatty acids. Unsaturated fatty acids and, in particular, oleic and linoleic acids, were predominant. The composition in individual sugars was also determined by high performance liquid chromatography coupled to a refraction index detector, mannitol and trehalose being the most abundant sugars.

Over the last few years, several aspects of Senegalese sole (Solea senegalensis) culture have been developed and optimised but the dietary lipid level for optimal growth has never been determined. Hence, five isonitrogenous diets (56 % dietary protein) with increasing dietary lipid levels (4,8,12, 16 and 20 % DM) were fed to satiation to triplicate groups of twenty fish (mean initial weight 10 g). Fifteen tanks were randomly assigned one of the five diets. Feed was distributed using automatic feeders, and fish were fed over a 16-week period. At the end of the experiment the fish fed on diets containing the two lowest dietary lipid levels (4 and 8 %) showed a 3-fold body-weight increase with a significantly higher daily growth index than fish fed higher lipid levels (1·2 v. 0·8). Moreover, these fish displayed a significantly lower dry feed intake (12 g/kg per d) and feed conversion ratio (1·0) compared with fish fed higher lipids levels (16-19 g/kg per d; feed conversion ratio 2·0). Low dietary lipid levels (,12 %) significantly improved nutrient retention and gain and hence growth, without major effects on whole-body composition. Despite the slight alteration in n-3 PUFA muscle content in the fish fed low-fat-diets, this fish fed low dietary lipid still remains a rich n-3 PUFA product and generally maintained its nutritional value. These results evidenced a low lipid tolerance of Senegalese sole juveniles and suggest a maximal dietary inclusion level of 8 % lipids for both optimal growth and nutrient utilisation without compromising flesh quality.Lipid nutrition: Flatfish: Dietary lipid tolerance: Protein-sparing effectThe aquaculture industry has expanded in Europe over the last decades, but few marine fish species have contributed to this growth. The successful development of Southern European aquaculture has resulted in increased production of gilthead seabream (Sparus aurata), sea bass (Dicentrarchus labrax) and turbot (Psetta maxima), leading to market saturation and reduced prices. For these reasons, great efforts have recently been devoted to find new candidate species, to improve diversity and to ensure sustainable development of the industry.Senegalese sole (Solea senegalensis) is a promising flatfish species for marine farming, especially due to its high market value. Over the last few years significant advances have been accomplished on Senegalese sole weaning techniques and larvae feeding (1 -3) . However, little is known about the nutritional needs of this flatfish species during its juvenile stage (4,5) . The protein requirement for maximum protein accretion in Senegalese sole has been estimated at 600 g/kg diet (5) , but, so far, no studies concerning the optimal dietary lipid level have been carried out.Dietary formulations in aquaculture tend to increase lipid content as a non-protein source for enhancing growth and sparing protein, and for reducing organic matter and N losses (6 -10) . Nevertheless, in flatfish species positive results on protein sparing are limited and controversial. High ...

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