Determination of hydroxyproline in cured pork sausages and dry cured beef products by NIRS technology employing a fibre–optic probe

In the present work a study was made of the use of near infra-red spectroscopy (NIRS) technology with a remote reflectance fibre–optic probe for the analysis of hydroxyproline in cured pork sausages (salchichón and chorizo) and dry cured beef (cecina). The presence of the amino acid hydroxyproline was used as an analytical criterion to assess the amount of collagen from connective tissues versus lean meat (muscle). The fibre–optic probe was placed directly on the sample with no previous treatment or manipulation.The regression method employed was that of modified partial least squares (MPLS). The equation developed for a total of 80 samples (salchichón, chorizo and cecina) allowed the determination of the hydroxyproline content within a range of 0–0.74%. The multiple correlation coefficient (RSQ) and standard error of prediction corrected (SEP(C)) obtained were respectively 0.772 and 0.05%. The predicted values of hydroxyproline in unknown samples using NIRS technology and applying the fibre–optic probe directly on the sample without previous treatment were comparable to those obtained using the chemical method.     

Colour and viscosity of milk and soybean vanilla beverages. Instrumental and sensory measurements

BACKGROUND: Differences in instrumental measurements of colour and viscosity were analysed in six commercial samples of vanilla beverages, three of milk and three of soybean. Sensory differences between them were assessed and an analysis was made of whether the perceived differences had any influence on consumer preferences with respect to these attributes. RESULTS: The milk beverages were a stronger yellow in colour (45.05≤b*≤60.02) than the soybean beverages (18.46≤b*≤21.96). The flow of all samples was Newtonian, showing viscosity values in the range 4.34–7.92 mPa s. Significant differences in viscosity were detected between samples. Sensory results revealed that the vanilla milk samples were perceived as having a stronger yellow colour and being thicker than the vanilla soymilk samples. The majority of people surveyed (n = 142) preferred the samples that were deeper yellow in colour; moreover, the thickness of milk samples was significantly more acceptable than that of soymilk samples. CONCLUSION: The instrumental measurement of colour relates well to the perceived differences in the colour of these products and explains the differences in consumer preferences. However, the instrumental viscosity values do not relate well to the thickness perceived or to the differences in acceptability of the beverages. Copyright © 2007 Society of Chemical Industry     

Effect of salt content on the rheological properties of salad dressing-type emulsions stabilized by emulsifier blends

The effects that salt content and composition of emulsifier blends exert on the rheological properties of salad dressing-type emulsions were studied. Binary blends of egg yolk and different types of amphiphilic molecules (Tween 20, sucrose laurate and pea protein), in several proportions, were used to stabilize emulsions. Salt concentration was ranged from 0 to 2.3% w/w. Steady-state flow tests and small-amplitude oscillatory shear measurements within the linear viscoelastic region were carried out. Rheological tests were complemented with droplet size distribution measurements. Rheological properties and physical stability of the emulsions studied were significantly influenced by salt content and the nature of binary emulsifier blends. In general, the values of rheological parameters studied increased with salt content. However, salt affects in much higher extent the properties of emulsions stabilized by high proportions of egg yolk or pea protein in the emulsifier blend, rather than those mainly stabilized by non-ionic low-molecular-weight surfactants, which are less sensitive to changes in the ionic strength. In this sense, the increase observed in the values of viscosity and linear viscoelastic functions of emulsions is more important when a protein is predominant in the emulsifier blend. This effect was explained on the basis of a more apparent increasing interdroplet interactions and viscosity of the continuous medium, both of them induced by salt addition, which lead to the consecution of an extensively flocculated state and improved creaming stability. On the contrary, different blends of pea protein and egg yolk showed a quite similar evolution of the rheological parameters with salt concentration.     

“Special Issue on Latin-American Research” Maritime Networks,Services Structure and Maritime Trade

This paper aims at investigating the relationship between maritime trade and maritime freight rates at sectoral level. These rates and their effect on international trade will be estimated using highly disaggregated data of shipments from five Spanish ports to seventeen destinations, 78.34% of the tonnage exported by Spain. The paper focuses on the effect of maritime networks, services structure and port infrastructure variables on maritime freight rates. The relationship between freight rates and trade is then analysed by applying a gravity model for sectoral exports. We investigate the endogeneity of the trade and freight rate variables by estimating both equations by using instrumental variables methods. The main findings of this study should contribute significantly in explaining the variability of maritime freight rates and to quantifying the impact of maritime freight rates in maritime trade.     

Fired clay masonry units production incorporating two-phase olive mill waste (alperujo)

This work deals with the use of alperujo, the main residue from the two-phase olive oil extraction process, as a raw material in fired clay masonry units production. Different amounts (3, 6 and 12 wt%) of clay were substituted by alperujo, and the properties of the resulting ceramic units were compared to those of conventional products. Results show that a number of advantages can be obtained. At 12 wt% alperujo addition, masonry units present lower density (1710 kg m^?3 compared to 1850 kg m^?3 reference value) and higher thermal insulation effectiveness (18% reduction in the bulk of fired clay thermal conductivity). With respect to mechanical properties, the fired bending strength attained of approximately 14 N mm^?2 is sufficiently high for this type of unit. In addition, the heating value obtained from the organic content of the added alperujo can cause a decrease in the heating requirements in the firing process.     

Magnetite Production from Steel Wastes with Concentrated Solar Energy

In order to achieve a balanced development in the application of materials for structural or functional purposes, one of the priority objectives of future work is to achieve the goal of “zero waste” in the different production lines. As would be expected from what was agreed in the Kyoto Protocol and the meetings of Copenhagen 2009 and Cancun 2010, the production of clean energy will be strongly encouraged in the future, and indeed that is already the case now. Taking that into consideration, while the promotion of clean energy production is mainly directed toward electricity, solar thermal is quite interesting because of its direct application to metal mining and the chemical processes used in the sustainable development of materials. The combination of both objectives, “zero waste” and “clean energy,” may pose an interesting challenge in the development of primary iron and steel, as well as in other areas of metal production and even in the field of mining. The help of solar thermal energy, which can be concentrated to reach high temperatures, is a tool that could support both the direct production and the recycling of waste steel, in particular waste which is physically and chemically the worst for the environment. This would mean that the environment itself, solar energy, is in fact the key to environmental protection.