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.     

Connectivity Based k-Hop Clustering in Wireless Networks

In this paper we describe several new clustering algorithms for nodes in a mobile ad hoc network. The main contribution is to generalize the cluster definition and formation algorithm so that a cluster contains all nodes that are at distance at most k hops from the clusterhead. We also describe algorithms for modifying cluster structure in the presence of topological changes. We also proposed an unified framework for most existing and new clustering algorithm where a properly defined weight at each node is the only difference in otherwise the same algorithm. This paper studied node connectivity and node ID as two particular weights, for k=1 and k=2. Finally, we propose a framework for generating random unit graphs with obstacles.     

Validation of the rancimat test for the assessment of the relative stability of fish oils

The induction periods for the peroxidation of various fish oils at 55–90°C were studied by the Rancimat test. The natural logarithms of the induction periods varied linearly with respect to temperature, with a mean coefficient of −7.5×10⁻²°C⁻¹, which was significantly different from that reported for vegetable oils. The activation energy for the formation of volatile acids had a mean value of 38.9 kJ/mol and was independent of the fish oil source. Peroxide formation under Rancimat test conditions followed first-order kinetics. The same kinetics were followed under Schaal Oven test conditions (forced-air oven, 60°C). On the basis of the results obtained, the Rancimat test appears to be useful in determining the relative stabilities of fish oils without the change in peroxide decomposition kinetics that may occur at elevated temperatures.     

ODDLS: A new unstructured mesh finite element method for the analysis of free surface flow problems

This paper introduces a new stabilized finite element method based on the finite calculus (Comput. Methods Appl. Mech. Eng. 1998; 151 :233–267) and arbitrary Lagrangian–Eulerian techniques (Comput. Methods Appl. Mech. Eng. 1998; 155 :235–249) for the solution to free surface problems. The main innovation of this method is the application of an overlapping domain decomposition concept in the statement of the problem. The aim is to increase the accuracy in the capture of the free surface as well as in the resolution of the governing equations in the interface between the two fluids. Free surface capturing is based on the solution to a level set equation. The Navier–Stokes equations are solved using an iterative monolithic predictor–corrector algorithm (Encyclopedia of Computational Mechanics. Wiley: New York, 2004), where the correction step is based on imposing the divergence‐free condition in the velocity field by means of the solution to a scalar equation for the pressure. Examples of application of the ODDLS formulation (for overlapping domain decomposition level set) to the analysis of different free surface flow problems are presented. Copyright © 2008 John Wiley & Sons, Ltd.     

Improving the moisture resistance of adobe structures

Mud plasters or soil stuccos are commonly used to protect adobe walls from water erosion. Due to drying shrinkage cracks and high permeability, the commonly used soil stuccos are not durable. Stucco stabilizers such as Portland cement, lime and asphalt are expensive. An experimental study undertaken to evaluate some of the locally available, inexpensive, stucco stabilizers is reported here. Crack-resistant stucco compositions made with a cactus solution are described and techniques to make the stucco surface impervious to water are discussed. The results of durability tests involving simulated rainfall on stucco panels, and stucco applied to adobe walls, are presented. Recommendations for field practice are also given.     

Minimal Cuts up to Third Order in a Planar Graph

This paper presents a new algorithm to determine all minimal cuts up to third order that isolate some sink node from all source nodes in a planar graph. The algorithm has the advantage of having a linear complexity, which makes the problem tractable as opposed to path oriented methods, where path determination grows exponentially with the size of the graph. This algorithm can be used when the size of the graph requires computer assistance, and it can simplify the application to large systems, of reliability evaluation techniques based on minimal cuts. The limitation of cuts up to third order has a numerical reason since cuts of higher order often negligibly affect the system indexes. A computer application to a graph that models an urban power distribution network shows the algorithm's capacity to handle complex problems and reduce CPU time.     

Protein isolates from two Mediterranean legumes: Lathyrus clymenum and Lathyrus annuus. Chemical composition,functional properties and protein characterisation

Protein isolates were analysed from two Mediterranean legumes, Lathyrus clymenum and L. annuus. Protein isolates were prepared by alkaline extraction, including sodium sulphite and acid precipitation of Lathyrus proteins at their isoelectric point (pH 4.5). The percentage of proteins recovered from L. annuus and L. clymenum flours during the preparation of the protein isolates was around 60%. Chemical composition, nutritional parameters, main functional properties and protein composition of Lathyrus protein isolates were studied. L. annuus and L. clymenum protein isolates contained 81.07% and 82.4% of proteins, respectively, and they have a balanced content of essential amino acids, except for sulphur amino acids, with respect to the FAO pattern. The in vitro protein digestibility increased in the protein isolates to 93% and 95% in L. annuus and L. clymenum, respectively. Functional properties were similar to those observed in other legumes protein isolates. These results confirm the interest of local crops as sources of high value protein products obtained after convenient protein extraction procedures and the removal of antinutritional components. These high added value protein isolates are of interest for the food industry and for the revalorisation of L. annuus and L. clymenum favouring the bioconservation of Lathyrus.     

Application of raman spectroscopy to monitor and quantify ethyl esters in soybean oil transesterification

Biodiesel (FA esters) has become very attractive as an alternative diesel fuel owing to its environmental benefits. Transesterification is the most usual and important method to make biodiesel from vegetable oils. This article investigates the potential for using Raman spectroscopy to monitor and quantify the transesterification of soybean oil to yield ethyl esters. The differences observed in the Raman spectra of soybean oil after transesterification were a peak at 2932 cm⁻¹ ( ), the displacement of the v _C=O band from 1748 to 1739 cm⁻¹, and the bands at 861 (v _R-C=O and v _C-C) and 372 cm⁻¹ (δ _CO-O-C). Uni- and multivariate analysis methods were used to build several analytical curves and then applied in known samples, treated as unknowns, to test their ability to predict concentrations. The best results were achieved by Raman/PLS calibration models (where PLS=partial least squares regression) using an internal normalization standard (v _=C-H band). The correlation coefficient (R ²) values so obtained were 0.9985 for calibration and 0.9977 for validation. Univariate regression analysis between biodiesel concentration and the increasing intensity of band or v _C=O displacement showed R ² values of 0.9983 and 0.9742, respectively. Although spectroscopic methods are less sensitive than chromatographic ones, the data obtained by spectroscopy can be correlated with other techniques, allowing biodiesel yield and quality to be quickly assessed.     

Quality and Safety Models and Optimization as Part of Computer‐Integrated Manufacturing

This article is part of a collection entitled “Models for Safety, Quality and Competitiveness of the Food Processing Sector,” published in Comprehensive Reviews in Food Science and Food Safety. It has been peer‐reviewed and was written as a follow‐up of a pre‐IFT workshop, partially funded by the USDA NRI grant 2005‐35503‐16208. ABSTRACT: Mathematical models are the basis of modern process engineering methods. Mathematical optimization is at the kernel of systematic and efficient tools for (1) experimental design, model development, and identification, (2) development of optimal operating procedures, and (3) implementation of those procedures by means of model‐predictive controllers. Here, we review and discuss how these model‐based optimization techniques can be used at the core of computer‐integrated manufacturing systems for the food industry. These systems will be able to bring the operation of food processing plants closer to the best possible product quality and safety, at a reduced cost and with minimal environmental impact.