Flavonoids as stabilizers of fish oil: An alternative to synthetic antioxidants

The antioxidant activities against fish oil oxidation of six commercially available flavonoids and of five flavonoids purified from two Chilean native plants were compared to those ofdl-α-tocopherol and of two synthetic antioxidants, butylated hydroxytoluene and butylated hydroxyanisole. Among the commercial flavonoids, catechin, morin and quercetin showed a higher activity when fish oil oxidation (either spontaneous or Fe²⁺-induced) was assessed from the formation of peroxides or thiobarbituric acid-reactive substances. Among the native flavonoids, the 5,3′,4′-trihydroxy-7-methoxy flavanone (designated as Pt-2) showed the highest antioxidant activity. Mixtures of quercetin or of Pt-2 withdl-α-tocopherol produced better inhibitory effects when compared to that of each substance assayed by itself. Also, when Pt-2 and quercetin were assayed in combination (0.3 g/kg oil and 0.7 g/kg oil, respectively), a synergistic antioxidant effect was observed. Results indicate that several flavonoids could be used as natural antioxidants as a means to replace those synthetic antioxidants, the use of which has been questioned.     

Noxiustoxin 2, a novel K+ channel blocking peptide from the venom of the scorpion Centruroides noxius Hoffmann

A novel peptide called Noxiustoxin 2 (NTX2) was purified from the venom of the scorpion Centruroides noxius and characterized chemically and functionally. It is composed of 38 amino acid residues linked by three disulfide bridges and its primary structure is 61% identical to that of Noxiustoxin (NTX). It is not toxic to mice (using up to 200 micrograms/20 g mouse weight) and crustaceans (up to 30 micrograms/g of crayfish), but has a paralysing effect on crickets (30 micrograms/g animal). It displaces the binding of [125I]NTX to rat brain synaptosome membranes with a Ki of 0.1 microM, in comparison NTX has a Ki of 100 pM. Similarly, using single Ca2+ activated K+ channels of small conductance obtained from cultured bovine aortic endothelial cells it was shown that NTX2 is over two logarithm units less potent than NTX in producing 50% blockade of the probability of opening the channels. NTX2 is not recognized by a panel of six distinct monoclonal antibodies against NTX, however it is recognized by polyclonal antibodies raised in mouse, with native NTX. Primary structure comparison of both NTX and NTX2 suggests that the N-terminal segments of these peptides are important for channel affinity.     

Determination of Shelf Life of Sous Vide Salmon (Salmo Salard) Based on Sensory Attributes

ABSTRACT:  Sous vide  technology permits precooked dishes of high sensory and nutritional quality to be obtained with a longer shelf life than is possible using other cooking–cooling methods. Salmon portions (200 g; 0.5, w:w; greased with olive oil) were par-roasted (300 °C/3 min), cooked using  sous vide  technology (80 °C/43 min), and maintained in anaerobic conditions at 2 °C for 0, 4, 8, 12, 15, 18, 22, and 25 d. At each control day,  Enterobacteriaceae  counts were made and the attributes of sensory spoilage were determined (3 visual, 2 odor, 2 flavor, and 3 texture attributes) by a panel of trained judges. A loss of smell, taste, color, and juiciness was detected during storage, along with the appearance of off-odors and off-flavors. The shelf life of the  sous vide  salmon based on sensory analysis was established at 18 d.     

Effect of ozone on bacterial flora in poultry during refrigerated storage

The effect of ozone on the microbiological and sensory quality of poultry during refrigerated storage was studied. Ozone facilitates the oxidation of lipids, but no alterations were observed in the sensory characteristics of the meat. Ozone has a pronounced effect on the flora causing deterioration and hence prolongs the useful life of poultry in refrigerated storage. It was also observed to exert a powerful bactericidal effect on coliforms, Escherichia coli, and Salmonella.     

Thermal conductivity of five hydrocarbons along the saturation line

The paper presents the results of new, absolute measurements of the thermal conductivity of five alkanes as a function of temperature at their saturation vapor pressure. The alkanes studied include the four normal alkanes n-octane, n-nonane, n-undecane, and n-tetradecane as well as the branched alkane, iso-octane. The results, which extend over the temperature range 282–373 K, have an estimated uncertainty limit of 1.5% deriving mainly from a correction for the effects of radiation absorption in the measurement process. The results are employed to generate effective core volumes for the fluids studied which may be employed to predict the density dependence of the thermal conductivity by means of an existing correlation.     

Slug, a zinc finger gene previously implicated in the early patterning of the mesoderm and the neural crest, is also involved in chick limb development

The great advances made over the last few years in the identification of signalling molecules that pattern the limb bud along the three axes make the limb an excellent model system with which to study developmental mechanisms in vertebrates. The understanding of the signalling networks and their mutual interactions during limb development requires the characterisation of the corresponding downstream genes. In this study we report the expression pattern of Slug, a zinc-finger-containing gene of the snail family, during the development of the limb, and its regulation by distinct axial signalling systems. Slug expression is highly dynamic, and at different stages of limb development can be correlated with the zone of polarizing activity, the progress zone and the interdigital areas. We show that the maintenance of its expression is dependent on signals from the apical ectodermal ridge and independent of Sonic Hedgehog. We also report that, in the interdigit, apoptotic cells lie outside of the domains of Slug expression. The correlation of Slug expression with areas of undifferentiated mesenchyme at stages of tissue differentiation is consistent with its role in early development, in maintaining the mesenchymal phenotype and repressing differentiation processes. We suggest that Slug is involved in the epithelial-mesenchymal interactions that lead to the maintenance of the progress zone.