EFFECT OF CHEMICAL INTERESTERIFICATION ON PHYSICOCHEMICAL PROPERTIES AND INDUSTRIAL APPLICATIONS OF CANOLA OIL AND FULLY HYDROGENATED COTTONSEED OIL BLENDS

Blends of canola oil (CO) and fully hydrogenated cottonseed oil (FHCSO), with 20, 25, 30, 35 and 40% FHCSO (w/w) were interesterified under the following conditions: 0.4% sodium methoxide, 500 rpm stirring, 100C, 20 min. The original and interesterified blends were examined for triacylglycerol composition, melting point, solid fat content (SFC) and consistency. Interesterification caused considerable rearrangement of triacylglycerol species, reduction of trisaturated triacylglycerol content and increase in disaturated-monounsaturated and monosaturated-diunsaturated triacylglycerols in all blends, resulting in lowering of respective melting points. The interesterified blends showed reduced SFC at all temperatures and more linear melting profiles if compared with the original blends. Consistency, expressed as yield value, significantly decreased after the reaction. Iso-solid curves indicated eutectic interactions for the original blends, which were eliminated after randomization. The 80:20, 75:25, 70:30 and 65:35 (w/w) CO: FHCSO interesterified blends showed characteristics which are appropriate for their application as soft margarines, spreads, fat for bakery/all-purpose shortenings, and icing shortenings, respectively.

PRACTICAL APPLICATIONS

Recently, a number of studies have suggested a direct relationship between trans isomers and increased risk of vascular disease. In response, many health organizations have recommended reducing consumption of foods containing trans fatty acids. In this connection, chemical interesterification has proven the main alternative for obtaining plastic fats that have low trans isomer content or are even trans isomer free. This work proposes to evaluate the chemical interesterification of binary blends of canola oil and fully hydrogenated cottonseed oil and the specific potential application of these interesterified blends in food products.     

Effect of cerium additive and secondary phase analysis on Ag<Subscript>0.5</Subscript>Bi<Subscript>0.5</Subscript>TiO<Subscript>3</Subscript> ceramics

Cerium-doped silver bismuth titanate—Ag_0.5Bi_0.5TiO₃ (ABT) ceramics have been synthesized by the high-temperature solid-state reaction method. The structure and elemental examination of the prepared ceramic was analysed by X-ray diffraction (XRD), Fourier transform infrared, scanning electron microscopy and energy-dispersive spectroscopy. XRD analysis showed the presence of pyrochlore structure and secondary phase when more than 5 mol% cerium was added. The impact of temperature on cerium-doped silver bismuth titanate samples was analysed by differential thermal analysis and differential scanning calorimetry. Cerium doping caused the flaky morphology comparing with undoped sample. The homogeneity of all the samples was discussed in detail by diffuse reflectance spectrum. This is the first time the reflection process is analysed for the cerium-doped ABT system to the best of our knowledge.     

Edible Methylcellulose-Based Films as Moisture-Impermeable Barriers in Sundae Ice Cream Cones

An edible bilayer film of methylcellulose and palmitic acid, 3:1 w/ w, and a pure methylcellulose film were tested as moisture-impermeable barriers in a simulated sundae ice cream cone. Circular pieces of film were arranged between the sugar cone and the chocolate layer of samples. Sugar cones of samples containing methylcellulose-palmitic acid films showed no detectable moisture increase for 10 weeks at -23°C and for 4 weeks at -12°C and only negligible increments after that. Moisture increase was greater in samples with pure methylcellulose films. Films retarded moisture transfer from ice cream to the sugar cone keeping its crispness longer than 3 months which is the commercial storage-life of the uncoated product.     

POTASSIUM SORBATE PERMEABILITY of POLYSACCHARIDE FILMS: CHITOSAN, METHYLCELLULOSE and HYDROXYPROPYL METHYLCELLULOSE

Edible coatings controlling preservative migration from surface to food bulk could control surface microbial growth which is often the main cause of spoilage for many food products. In this paper we examine the potassium sorbate permeability behavior of chitosan, methyl cellulose and hydroxypropyl methyl cellulose based films. to gain an understanding of the permeation process, permeability determinations were done at 5, 24, 32 and 40°C. Permeability rates followed the Arrhenius activation energy model. A lack of breaking points in Arrhenius plots indicated that no morphological changes occur within these films in the 5 to 40°C temperature range. Activation energy values were found to be independent of film composition and were affected only by the solvent embedded in the film. This behavior was confirmed by analysis of the same permeability data using a modified Stokes-Einstein equation. Methyl cellulose was the most promising diffusion barrier with a permeability constant of 3.4 and 1.4×10^?8 (mg/s cm²) (cm)/(mg/cm³) at 24 and 5°C, respectively. Electron microscopy was used to examine the morphological characteristics of these films and showed they have no visible pores or channels at magnifications up to 10,000.     

Simultaneous Determination of Sugars and Organic Acids in Cheddar Cheese by High-Performance Liquid Chromatography

In a simple, rapid isocratic HPLC method sugars and organic acids were separated on an Aminex HPX-87 column in the H⁺ form and detected using ultraviolet and refractive index detectors in series. Sugars (lactose, glucose and galactose) and acids (orotic, citric, pyruvic, lactic, uric, formic, acetic, propionic, butyric and hippuric) were identified by retention times. This method affords a simple technique for monitoring starter culture activity and following quality changes during cheese maturation.     

IMPROVEMENTS IN THE SYSTEMS-BASED MODELS GENERATOR SIGEM

Program generators, for us, are computer programs that produce other computer programs. SIGEM is an expert system program generator that can help in the modeling process of real systems. It is associated with a methodology well adapted to modeling practice. In this paper, we present and compare this methodology with other similar ones. Static models (databases), dynamic models, rule-based expert systems, literal and/or numerical variables, probabilistic uncertainty in data and in functions, dimensioned variables, discrete event simulation, and other related problems can be treated with this methodology. We suggest a systems modeling methodology and a programming tool to increase generality of application and easiness of use.     

STRUCTURED REPRESENTATION OF FMS INTEGRATING SI-NETS AND HIGH LEVEL PETRI NETS

In this paper a structured knowledge-based approach to the representation and scheduling of flexible manufactoring systems (FMSs) is described. Our approach is based on a structured conceptual representation (a KL-ONE-like Si-net representation formalism), extended with an instant-based temporal reasoning formalism. Furthermore, the approach integrates a particular extension to high-level Petri nets (PNs), structured timed colored Petri nets (STCPNs), for the modeling and simulation of the FMS. Such a representation scheme allows us to use SI-nets' good properties related to inference (classification and inheritance), which are lacking in PNs, and at the same time provides an extension toward an explicit representation for time. The integration of Si-nets with PNs is necessary because simulation and low-level coordination of FMSs require a procedural approach that is not within the aims of Si-nets. Therefore, procedural and symbolic levels, corresponding to the different hierarchical levels of the representation and control system of the FMS, coexist in the system. Using a qualitative terminology, we may also call them analog and symbolic knowledge. We assume that such a hybrid representation system may be useful, since a procedural representation, integrated within a logic formalism, can increase the expressive power without complicating the notation or the representation itself. The paper describes both the representational aspects and the modeling of the control system of the FMS, focusing on the interaction mechanisms among the different levels of representation. In particular, we show how an STCPN-based model can be automatically derived starting from the symbolic component of the system. A particular FMS case study, regarding a class of problems of resource-constrained multiproject scheduling (where projects are sets of tasks temporally related), is discussed.     

Asymptotic observers for non-linear systems†

Observer design for non-linear systems is discussed. Some recent approaches are based on state and output change of coordinates to transform a non-linear system into a particular observer form, from which an asymptotic observer can be designed ensuring the asymptotic stability of the error dynamics in the new coordinates. In this paper, the stability properties of the error dynamics are studied in the original coordinates. With some examples, it is shown how the asymptotic stability in the new coordinates does not imply, in general, the asymptotic stability in the original ones. Some general results are stated and proved to guarantee the asymptotic stability of the error dynamics in the original coordinates.     

Approximation and realization of Hankel matrices

The approximation of a Hankel matrix by finite rank Hankel matrices is considered. A constructive procedure is proposed for the approximate realization of a linear analytic system by means of bilinear systems.     

Design of spectroelectrochemical cell for in situ X-ray absorption fine structure measurements of bulk solution species

A purpose-built spectroelectrochemical cell for in situ fluorescence XAFS (X-ray absorption fine structure) measurements of bulk solution species is described. The cell performance was demonstrated by the collection of europium L3-edge XANES (X-ray absorption near edge structure) during constant-potential electrolysis of 14.2mmEuCl3.6H2Oin1mH2SO4 aqueous electrolyte. Additionally discussed in this report are the probabilities of 2p3/25d electronic transitions pertaining to Euiii and Euii ions. Implications for the use of XANES in studying intermediate-valence materials, and some potential applications of the presently reported spectroelectrochemical cell are described.