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Irradiation Treatment (irradiation + treatment)
Selected AbstractsOPTIMIZING ELECTRON BEAM IRRADIATION OF "TOMMY ATKINS" MANGOES (MANGIFERA INDICA L.)JOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2007MARIA A. MORENO ABSTRACT We determined the optimum irradiation treatment for decontamination of physiologically mature fresh "Tommy Atkins" mangoes, without detriment to the fruits' sensory and chemical properties. Mangoes were irradiated at 1.0, 1.5 and 3.1 kGy using a 10-MeV linear accelerator (14-kW LINAC, double beam mode). Mangoes were stored for 21 days at 12C and 62.7% relative humidity with nonirradiated fruits as controls. Dose distribution within the fruit was determined using Monte Carlo techniques. Irradiation did not affect the overall sensory quality of mangoes at doses up to 1.5 kGy. Only fruits irradiated at 3.1 kGy were unacceptable by the panelists. Irradiation at 3.1 kGy enhanced the fruit's aroma characteristics. Irradiation at all levels caused a significant (P , 0.05) decrease (,50,70%) in ascorbic acid content by the end of storage. Mangoes irradiated at 1.5 and 3.1 kGy had slightly higher levels of phenolics than the control (27.4 and 18.3%, respectively). E-beam irradiation of Tommy Atkins mangoes up to 3.0 kGy causes no detriment to the fruit's overall sensory and chemical quality. [source] Phenolic compounds and the colour of oranges subjected to a combination treatment of waxing and irradiationJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2004Mostafa Moussaid Abstract The effects of waxing, irradiation doses and storage on phenolic compounds and colour of irradiated oranges were investigated. Mature oranges (Citrus sinensis (L) Osbeck var Maroc late) waxed or unwaxed were treated with 0, 1 or 2 kGy radiation and stored up to 9 weeks at 20 °C and 40,50% RH. Colour of the oranges, total phenols and flavones in the peel were measured. Phenolic compounds increased with irradiation dose and storage time. Hue angle, L* value and chroma of the orange colour were more affected by waxing and storage time than the irradiation treatment. Changes in the phenolic compounds were linked with changes in the redness and saturation of the orange colour. Irradiation stimulated synthesis of flavones; waxing controlled changes induced by irradiation. These results may aid in maintaining the quality and safety of oranges during storage. Copyright © 2004 Society of Chemical Industry [source] Effect of environmental stresses on the sensitivity of Enterobacter sakazakii in powdered infant milk formula to gamma radiationLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2008T. Osaili Abstract Aim:, To evaluate the effect of starvation, heat, cold, acid, alkaline, chlorine and ethanol stresses on the resistance of Enterobacter sakazakii in powdered infant milk formula (PIMF) towards gamma radiation. Methods and Results:, Stressed cells of E. sakazakii ATCC 51329 and four other food isolate strains were mixed individually with PIMF, kept overnight at room temperature, and then exposed to gamma radiation up to 7·5 kGy. The D10 -values were determined using linear regression and for the stressed E. sakazakii strains these values ranged from 0·82 to 1·95 kGy. Conclusions:, Environmental stresses did not significantly change the sensitivity of most E. sakazakii strains to ionizing radiation. Significance and Impact of the Study:, Data obtained established that most forms of environmental stress are unlikely to significantly enhance the resistance of E. sakazakii strains to lethal, low dose irradiation treatment. [source] The Relationship of Phthalocyanine 4 (Pc 4) Concentrations Measured Noninvasively to Outcome of Pc 4 Photodynamic Therapy in MicePHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2009Lihua Bai The ability to noninvasively measure photosensitizer concentration at target tissues will allow optimization of photodynamic therapy (PDT) and could improve outcome. In this study, we evaluated whether preirradiation tumor phthalocyanine 4 (Pc 4) concentrations, measured noninvasively by the optical pharmacokinetic system (OPS), correlated with tumor response to PDT. Mice bearing human breast cancer xenografts were treated with 2 mg kg,1 Pc 4 iv only, laser irradiation (150 J cm,2) only, Pc 4 followed by fractionated irradiation or Pc 4 followed by continuous irradiation. Laser irradiation treatment was initiated when the tumor to skin ratio of Pc 4 concentration reached a maximum of 2.1 at 48 h after administration. Pc 4 concentrations in tumor, as well as in Intralipid in vitro, decreased monoexponentially with laser fluence. Pc 4-PDT resulted in significant tumor regression, and tumor response was similar in the groups receiving either fractionated or continuous irradiation treatment after Pc 4. Tumor growth delay following Pc 4-PDT correlated with OPS-measured tumor Pc 4 concentrations at 24 h prior to PDT (R2 = 0.86). In excised tumors, OPS-measured Pc 4 concentrations were similar to the HPLC-measured concentrations. Thus, OPS measurements of photosensitizer concentrations can be used to assist in the scheduling of Pc 4-PDT. [source] Effects of gamma irradiation on the life stages of yellow flower thrips, Frankliniella schultzei (Trybom) (Thysanoptera: Thripidae)ANNALS OF APPLIED BIOLOGY, Issue 3 2001JULIANA A YALEMAR Summary Irradiation at a minimum absorbed dose of 250 Grays (Gy) has been approved by the USDA as a quarantine treatment for certain fruits in Hawaii to control four species of tephritid fruit flies. Subsequent research must determine whether this dose is sufficient to control other quarantine pests, such as mealybugs, thrips, mites, beetles, moths, and scale insects, on other commodities with export potential that are approved for irradiation treatment for fruit flies. This study demonstrated that irradiation at 250 Gy caused non-emergence of eggs and pupae, failure of larval development, and sterility of adults of yellow flower thrips, Frankliniella schultzei (Trybom). Adults were the most resistant stage tested, with 100% mortality at 57, 36 and 30 days post-treatment for the 250, 350 and 400 Gy treatments, respectively. Untreated adults survived up to 66 days. After receiving an irradiation dose of 250 Gy, no one- to two-day old eggs hatched successfully, while 3,4-day old eggs hatched but did not develop beyond the larval stage. Of the controls, 96.0% of 1,2-day old eggs and 75.9% of the 3,4-day old eggs hatched and survived through pupation. No first or second instar larvae treated with a target dose of 250 Gy were able to pupate. When pupae were irradiated at 250 Gy, 37% emerged as adults and all were sterile compared to 88.3% emergence of controls. [source] Electrophoretic patterns of microwaved and ,-irradiated beef liver proteinsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2001S Farag Abstract The effects of ,-irradiation treatments (2.5, 5 and 10,kGy) and microwaves generated from an oven at low and defrost power settings for 0.5, 1 and 2,min on the total proteins and protein patterns of beef liver immediately after treatment and during frozen storage (,18,°C) for different periods were studied. Chemical analyses indicated that the protein content of beef liver was reduced after exposure to ,-radiation or microwaves and also during frozen storage. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used to illustrate the changes in protein bands of different molecular weights and their percentages before and after exposure to gamma and microwave radiation. The main effect of ,-radiation on the protein patterns of beef liver was the disappearance of some high-molecular-weight protein bands and the development of other bands characterised by moderate and low molecular weights. This finding indicates the degradation of beef liver proteins by ,-irradiation. In contrast, microwave treatment caused an increase in the levels of high-molecular-weight protein bands with a concomitant decrease in low-molecular-weight protein bands. This phenomenon demonstrates the polymerisation of low-molecular-weight proteins under the influence of microwaves. © 2001 Society of Chemical Industry [source] | |||||||||||||