Food processors requirements met by radiation processing

Processing food using irradiation provides significant advantages to food producers by destroying harmful pathogens and extending shelf life without any detectable physical or chemical changes. It is expected that through increased public education, food irradiation will emerge as a viable commercial industry. Food production in most countries involves state of the art manufacturing, packaging, labeling, and shipping techniques that provides maximum efficiency and profit. In the United States, food sales are extremely competitive and profit margins small. Most food producers have heavily invested in equipment and are hesitant to modify their equipment. Meat and poultry producers in particular utilize sophisticated production machinery that processes enormous volumes of product on a continuous basis. It is incumbent on the food irradiation equipment suppliers to develop equipment that can easily merge with existing processes without requiring major changes to either the final food product or the process utilized to produce that product. Before a food producer can include irradiation as part of their food production process, they must be certain the available equipment meets their needs. This paper will examine several major requirements of food processors that will most likely have to be provided by the supplier of the irradiation equipment.     

Food irradiation in Hungary: commercial processing and development work

The result of an experiment with irradiated frozen poultry meat is presented. The purpose of the experiment was to prove the benefit of irradiation treatment for elimination of pathogenic bacteria such as Salmonella and Campylobacter. We found that an average dose of 4.5 kGy kills the bacteria in the meat. Agroster was involved in an EU project on the identification of irradiation treatment of spices and data from this project are presented. Commercial irradiation of spices has been used for more than 15 years in Hungary, proving the benefit of this technology     

Low-energy electrons and X-ray irradiation effects on plasma-polymerized allylamine bioactive coatings for stents

Radiation used in biomedical applications causes chemical changes to biomedical materials. This work is an ex situ simulation of the influence of low-energy electron (LEE) impact and X-ray irradiation on the chemical properties of plasma-polymerized allylamine (PPA) bioactive and biocompatible stent coatings. Preliminary X-ray photoelectron spectroscopy (XPS) results show that PPA coatings oxidize in contact with ambient air by the detection of C-O and CO bonds which are typical of polymer oxidation. Chemical changes after LEE and X-ray irradiation are mainly a loss of oxygen, assuming a surface deoxidizing and not a complete destruction of the surface. XPS survey analyses show that the amine groups remain stable during irradiation. LEE impact measurements by TOF mass spectrometry show that the main ionic losses are H⁻ ions. It appears that CN groups are stable under irradiation and we observe a loss of hydrogen and oxygen as the main chemical modifications. In conclusion, these results suggest that PPA coatings are stable under biomedical radiation, and they can therefore be used for bioactive and biocompatible stent coatings.     

Thermal Properties of E-beam Cured Epoxy/Thermoplastic Matrices for Advanced Composite Materials

The aim of this work is to investigate the possibility to improve the thermal behaviour of epoxy based systems, cured by ionizing radiation, in order to produce matrices for advanced carbon fibres composites. Blends of two epoxy monomers, difunctional and trifunctional, have been polymerized by e-beam irradiation and the dynamic mechanical thermal properties have been investigated. The increase of the concentration of the trifunctional epoxy monomer in the blend causes a marked increase of the Tg, but strongly decreases the reactivity. Subsequently, blends of the same epoxy monomers with a high Tg thermoplastic toughening agent have been considered and their reactivity and the thermal properties of the obtained materials have been also studied. The experimental results show that the thermoplastic component increases the reactivity of the difunctional/trifunctional blends, without a significant decrease of the glass transition temperature which still satisfies the requirements for advanced composite materials.     

Analytical methods and monitoring system for E-beam flue gas treatment process

The results of reliable and precise measurement of gas composition in different key points of e-beam installation are necessary for its proper operation and control. Only the composition of flue gas coming into installation is adequate to composition of flue gas emitted from coal-fired boiler. At other points of e-b installation the gas composition is strongly modified by process conditions therefore specific measuring system (sampling and conditioning system and set of gas analyzers) for its determination are required. In the paper system for gas composition measurement at inlet and outlet of e-b installation are described. Process parameters are continuously monitoring by CEM system and occasionally by the grab sample system. Both system have been tested at pilot plant at EPS Kaw czyn.     

Sensorial analysis evaluation in cereal bars preserved by ionizing radiation processing

Gamma-rays utilized as a food-processing treatment to eliminate insect contamination is well established in food industries. Recent troubles in Brazilian cereal bars commercialization require a special consumer's attention because some products were contaminated by insects. To solve the problem, food-irradiation treatment was utilized as a safe and effective solution. The final product was free of insect contamination. The aim of this study was to determine the best radiation dose processing utilized to disinfestations and detect some change on sensorial characteristic by sensorial analysis in cereal bars. In this study, three different kinds of cereal bars were purchased in São Paulo (Brazil) in supermarkets and irradiated with 1.0, 2.0 and 3.0 kGy at “Instituto de Pesquisas Energéticas e Nucleares” (IPEN-CNEN/SP). The samples were treated with ionizing radiation using a ⁶⁰Co gamma-ray facility (Gammacell 220, A.E.C.L.). That radiation doses were used successfully as an anti-insect treatment in the cereal bars, since in some food industries doses up to 3.0 kGy are used to guarantee at least a dose of 1.0 kGy in internal cereal bars package. Sensorial analysis was necessary since cereal bars contain ingredients very sensitive to ionizing radiation process.     

Low-energy electron and X-ray degradation of biomedical plasma-fluoropolymer

Plasma-deposited thin films of fluoropolymer on metallic substrates were degraded by low-energy (1-100 eV) electrons and X-ray irradiation to simulate irradiation conditions of implanted coated stents in the human body during diagnostic procedures using high energy radiation. The desorption of anions and cations from the surface of the films induced by 1-100 eV electrons was recorded by mass spectrometry. The electron energy dependence of the emission of F⁻ exhibited a resonant peak at 12.9 ± 0.4 eV, showing the formation of a transient excited anion and a monotonic rise at higher energies, associated to dipolar dissociation. In the positive ion mode, the fragments F⁺, CF⁺, CF₂⁺, CF₃⁺, C₃F₃⁺, C₂F₄⁺ and C₂F₅⁺ were observed. Emission thresholds were measured and laid above 25 eV. The shape of the cation emission curves versus electron energy showed no resonant process. X-ray degradation was studied by X-ray photoelectron spectroscopy for different exposure times. Loss of fluorine in -CF₂ groups was observed and damage mechanisms were proposed.     

Effects of X-ray radiation on the surface chemical composition of plasma deposited thin fluorocarbon films

Different thin fluorocarbon (FC) films were deposited on Si(111) using plasma polymerisation and then exposed to X-ray radiation. Changes in the chemical composition of the deposited fluorocarbon films as a function of irradiation time were investigated in situ using X-ray photoelectron spectroscopy. The evaluation of the C1s and F1s core level induced emission as a function of exposure to X-ray radiation (Mg Kα, hν = 1253.6 eV) reveals changes in the surface chemical composition of the FC polymer structure. The presented results indicate a high defluorination under X-ray irradiation. Additionally, binding energy shifts of the F1s and C1s peaks during the exposure associated with surface charging effects were observed. With ongoing exposure the surface charging decreases continuously and the FC surfaces become more conductive due to changes in the polymer structure. Different models have been used to describe the decomposition kinetics and surface composition.     

Gamma radiation, cold and four different wrappings to preserve ginger rhizomes, Zingiber officinallis Roscoe

After irradiating with a single dose of 50 Gy, ginger rhizomes were dipped into paraffin for coating, wrapped in a plastic film of low-density polyethylene, on perforated or non-perforated polivinyl chloride film, and compared with non-wrapping and non-irradiation as the controls. After treatments the rhizomes were maintained refrigerated at 13°C and 80% relative humidity. As a main result it could be observed that dipping into paraffin and wrapping with plastics resulted in smaller weight loss of the rhizomes.     

Poly(epsilon-caprolactone) biomaterial sterilized by E-beam irradiation

The effects of ionizing radiation (electron beam) on poly(epsilon-caprolactone) (PCL) were studied by analyzing changes in viscosity-average and weight-average molecular weight and radius of gyration, and by performing sol-gel analysis and swelling tests. Samples were irradiated under various conditions: solid and molten PCL in the presence or absence of air. The overall efficiency of crosslinking is higher for samples irradiated in the molten state than in the solid state, and is reduced in the presence of oxygen. Based on three kinds of experiments (molecular weight dependence on the dose in the pre-gelation region, sol-gel analysis, and swelling study), radiation-chemical yields of intermolecular crosslinking and scission were determined and are discussed in terms of the mechanism of radiation-induced reactions in PCL. Properties of the gels formed by high-dose irradiation and mechanical properties of irradiated PCL were analyzed. Irradiation causes an increase in the compression modulus of PCL. This process occurs at the pre-gelation stage and continues in the gel-containing system. We have demonstrated, for the first time, that irradiation of solid PCL is accompanied by a pronounced post-effect, which manifests itself by changes in the average molecular weight. EPR data indicate that this effect, at least in part, is caused by the presence of long-lived radicals trapped in the crystalline regions. Irradiation with the sterilizing dose does not cause a statistically significant change in the biocompatibility of PCL after subsequent storage for 79 d, as determined by preliminary osteoblast vitality tests.     

X-ray fluorescence imaging with polycapillary X-ray optics

X-ray fluorescence spectrometry imaging is a powerful tool to provide information about the chemical composition and elemental distribution of a specimen. X-ray fluorescence spectrometry images were conventionally obtained by using a μ-X-ray fluorescence spectrometry spectrometer, which requires scanning a sample. Faster X-ray fluorescence spectrometry imaging would be achieved by eliminating the process of sample scanning. Thus, we developed an X-ray fluorescence spectrometry imaging instrument without sample scanning by using polycapillary X-ray optics, which had energy filter characteristics caused by the energy dependence of the total reflection phenomenon. In the present paper, we show that two independent straight polycapillary X-ray optics could be used as an energy filter of X-rays for X-ray fluorescence. Only low energy X-rays were detected when the angle between the two optical axes was increased slightly. Energy-selective X-ray fluorescence spectrometry images with projection mode were taken by using an X-ray CCD camera equipped with two polycapillary optics. It was shown that Fe Kα (6.40 keV) and Cu Kα (8.04 keV) could be discriminated for Fe and Cu foils.     

X-ray Peltier cooled detectors for X-ray fluorescence analysis

The recent results on development of X-ray Si(Li), Si-planar and CdTe p-i-n detectors cooled by Peltier coolers for fabrication of laboratory and portable XRF analysers for different applications are discussed.

Low detection limits of XRF analysers are provided by increasing of detectors sensitive surface; improvement of their spectrometrical characteristics; decreasing of front-end-electronics noise level; Peltier coolers and vacuum chambers cooling modes optimization.

Solution of all mentioned tasks allowed to develop Peltier cooled detectors with the following performances:

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Advantages and disadvantages of all types of detectors for X-ray fluorescence analysis are compared. Spectra are presented. Application of different XRF analysers based on developed detectors in medicine, environmental science, industry, cryminalistics and history of art are demonstrated.     

A new facility for X-ray irradiation and its application

In February 1998, located at Izumiohtsu-Osaka, the West-Japan Irradiation Service Co. Ltd (W-JISCO) opened the new facility “Kansai Electron Beam Irradiation Center” which is the irradiation service center by Electron Beam and X-ray (Bremsstrahlung). The distinguishing feature of this facility is the No. 2 beam line for X-ray conversion.     

Accelerators for cancer therapy

The vast majority of radiation treatments for cancerous tumors are given using electron linacs that provide both electrons and photons at several energies. Design and construction of these linacs are based on mature technology that is rapidly becoming more and more standardized and sophisticated. The use of hadrons such as neutrons, protons, alphas, or carbon, oxygen and neon ions is relatively new. Accelerators for hadron therapy are far from standardized, but the use of hadron therapy as an alternative to conventional radiation has led to significant improvements and refinements in conventional treatment techniques. This paper presents the rationale for radiation therapy, describes the accelerators used in conventional and hadron therapy, and outlines the issues that must still be resolved in the emerging field of hadron therapy.     

E-beam radiation synthesis of xanthan-gum/carboxymethylcellulose superabsorbent hydrogels with incorporated graphene oxide

In this study the electron beam (e-beam) radiation synthesis in “paste-like condition” and characterization of the network structure of acrylic acid (AA) sodium salt/xanthan gum (XG)/carboxymethylcellulose (CMC) superabsorbent hydrogels incorporating graphene oxide (GO) was investigated. The effects of the AA concentration on gel fraction, sol-gel analysis, swelling degree and network parameters, as well as the relationship between these parameters and radiation dose was also established.

Gel fraction exceeds 90%, and the p₀/q₀ ratio shows a moderate degradation process. The swelling kinetic data were used to determine, first the swelling degree, second the diffusion characteristics, and third the average molecular weight between crosslinks (Mc), as well as. The diffusion data revealed a Fickian mechanism transport, for each hydrogel compositions. The network parameters (Mc and ξ) increased with absorbed dose, while cross-linking density and the radiation-chemical yields were decreased.     

Total reflection X-ray fluorescence and grazing incidence X-ray spectrometry — Tools for micro- and surface analysis. A review

A review of Total Reflection X-ray Spectrometry and related methods covering literature of four decades is presented. History, theory, instrumentation, sample preparation, and applications are summarized and some examples are given. New developments and trends are discussed with respect to emerging nano-technologies in all fields of sciences.     

Simultaneous small-angle X-ray scattering and wide-angle X-ray diffraction

The simultaneous SAXS/WAXD technique is shown to provide an unambiguous method for following structural changes taking place during the programmed heating of a range of multiphase polymeric materials. Results are given for polyethylene, block copolyurethanes and block copolyesters containing liquid crystalline hard segments. UK Thermal methods Group Award Lecture     

X-ray waveguiding for micro- and nanofocusing

Recently it was shown that X-ray focusing efficiency may achieve a submicron spot-size level; further diminish in X-ray beam sizes requires novel nano-technology based solutions. In this work the wave features of X radiation propagation both in ultra-narrow collimators and at glancing reflection from plane and curved surfaces can be described within the unified theory of X-ray trapped propagation: surface channeling in micro-guides and bulk channeling in submicron guides.     

Multivariate curve resolution applied to in situ X-ray absorption spectroscopy data: An efficient tool for data processing and analysis

Large datasets containing many spectra commonly associated with in situ or operando experiments call for new data treatment strategies as conventional scan by scan data analysis methods have become a time-consuming bottleneck. Several convenient automated data processing procedures like least square fitting of reference spectra exist but are based on assumptions. Here we present the application of multivariate curve resolution (MCR) as a blind-source separation method to efficiently process a large data set of an in situ X-ray absorption spectroscopy experiment where the sample undergoes a periodic concentration perturbation. MCR was applied to data from a reversible reduction–oxidation reaction of a rhenium promoted cobalt Fischer–Tropsch synthesis catalyst. The MCR algorithm was capable of extracting in a highly automated manner the component spectra with a different kinetic evolution together with their respective concentration profiles without the use of reference spectra. The modulative nature of our experiments allows for averaging of a number of identical periods and hence an increase in the signal to noise ratio (S/N) which is efficiently exploited by MCR. The practical and added value of the approach in extracting information from large and complex datasets, typical for in situ and operando studies, is highlighted.     

Detection of Phakopsora pachyrhizi by polymerase chain reaction (PCR) and use of germination test and DNA comet assay after e-beam processing in soybean

Soybean harvest is the main agribusiness in Brazil, which is the second largest exporter in the world and has a revenue of billions of dollars. Asian dust is caused by the fungus Phakopsora pachyrhizi and its dissemination is difficult to control, since it occurs through wind dispersion. Actually P. pachyrhizi is found in different parts of the world. Electron beam treatment could be an alternative process to minimize these losses, especially for the grains exportation industry. Besides the possibility of being disconnected when not in use, this source does not need to be reloaded, is easily available and, streamlines the process and reduces logistics costs. The present work aims to identify, by the polymerase chain reaction technique (PCR), the P. pachyrhizi fungus presence in the irradiated soybeans and the possibility to use radiation treatment as a sanitary alternative. Doses 0, 1.0, 2.0, 5.0, 6.0, 7.0, 8.0, 9.0 and 10.0 kGy (IPEN-CNEN/SP Electron Accelerator) were applied and two fast-screening methods were performed: DNA comet assay (for the detection of DNA damage) and germination test (for the measurement of roots inhibition). These tests are very easy to carry out and measure damage response depending on radiation dose.