Effects of gamma irradiation on chemical,microbial quality and shelf life of shrimp

In the present study the combined effect of gamma irradiation (1, 3 and 5 kGy) and storage at two temperatures: refrigeration (+4 °C) and frozen (?18 °C), on the shelf-life extension of fresh shrimp meat was investigated. The study was based on microbiological and physicochemical changes occuring in the shrimp samples. Total volatile base nitrogen values and trimethylamine values for irradiated shrimp samples were significantly lower than non-irradiated samples at both storage temperatures, and the rate of decrease was more pronounced in samples irradiated at the higher dose (p<0.05). Thiobarbituric acid values for irradiated shrimp samples were significantly higher than non-irradiated samples at both storage temperatures (p<0.05). pH values of shrimp samples were affected significantly by both irradiating dose and storage temperatures (p<0.05). Microbial counts for non-irradiated shrimp samples were higher than the respective irradiated samples at both storage temperatures (p<0.05). The results revealed that irradiation at high dose (5 kGy) might enhance lipid oxidation, although the growth of microorganisms and protein oxidation was inhibited.     

Improvement of shelf stability and processing properties of meat products by gamma irradiation

To evaluate the effects of gamma irradiation on the processing properties of meat products, emulsion-type sausage, beef patties and pork loin ham were manufactured. Most contaminated bacteria were killed by 3 kGy-irradiation to raw ground beef, and sausage can be manufactured with desirable flavor, a reduction of NaCl and phosphate, and extension of shelf life using gamma irradiation on the raw meat. The beef patties were manufactured with the addition of antioxidants (200 ppm), BHA, ascorbyl palmitate, -tocopherol, or β-carotene, and gamma-irradiation. Retardation of lipid oxidation appeared at the patties with an antioxidant. A dose of 5 kGy was observed to be as effective as the use of 200 ppm NaNO₂ to provide and maintain the desired color of the product during storage. After curing, irradiation, heating and smoking could extensively prolong the shelf life of the hams.     

Effect of gamma irradiation on polypropylene yarns under air and water

Journal of Radioanalytical and Nuclear Chemistry - Polypropylene (PP) filters are used for the treatment of radioactive liquid waste containing gamma nuclides such as Co-60, and filter physical and...     

The effect of gamma irradiation on the structural properties of olivine

Journal of Radioanalytical and Nuclear Chemistry - Gamma irradiation studies of (Mg0.905Fe0.095)2SiO4 olivine were performed using X-ray fluorescence method, X-ray diffraction, Raman and...     

Effect of gamma irradiation on chemical composition,antioxidant activity,antibacterial activity,shelf life,and cytotoxicity in the peels of two mango varieties grown in Bangladesh

Mango (Mangifera indica) is perhaps the most notable sound natural product, however short-lived. A few synthetic compounds like calcium carbide, pesticides, formalin and calcium-based arrangements have been utilizing for its protection, notwithstanding, those synthetic compounds are perilous for our human wellbeing. Besides, mango strip is a food-handling by-product that is discarded since it isn't economically reasonable. For this study, the nutritional, antibacterial, and antioxidant properties of peels from two mango cultivars (Amrapali, and BARI-11) were analyzed with four doses (0.5, 1.0, 1.5, and 2 kGy) of gamma irradiation. The impacts of radiation on storage quality and life span of usability were likewise investigated. Mango peels were found to have many phytochemicals. Be that as it may, radiation altogether impacted tested parameters like fat, protein, carb, fiber, sugar, energy, soluble solids, etc. in both of the mango peels. On the other hand, the peel samples showed 50% DPPH scavenging activity at varied dosages. Moreover, samples exposed to 1.5 kGy of radiation showed higher antioxidant activity. At a radiation dose of 1.5 kGy, amrapali peel proved to be less hazardous to brine shrimp lethality assay than other samples. The widest inhibitory zones against Pseudomonas sp. were obtained at a dosage of 150 µg/disc. After two weeks of storage, the 1.5 kGy radiation dosage left the mangoes' texture firm, indicating that it was extending the fruit's shelf life by greatly reducing the microbial attack. Thus mangoes could be preserved using radiation without significantly affecting their nutritional value.     

Pectin- and gelatin-based film: effect of gamma irradiation on the mechanical properties and biodegradation

Agricultural by-products, pectin and gelatin, were used to prepare a biodegradable film. The film casting solution including the pectin and gelatin was irradiated at 0, 10, 20, and 30 kGy to investigate the irradiation effect on the mechanical properties of the film. The tensile strength of the 10 kGy-irradiated film was the highest among the treatments but the elongation at break, water vapour permeability, and swelling ratio were the lowest. Hunter color L^*- and a^*-values decreased but the b^*-value increased as the irradiation dose increased. The total organic carbon content produced from the Paenibacillus polymyxa and Pseudomonas aeruginosa also showed that the film of 10 kGy-irradiated was lower than those of 0, 20, and 30 kGy-irradiated films. In conclusion, irradiation of the film casting solution at 10 kGy increased the mechanical properties of the pectin and gelatin based film. To manufacture the film by agricultural by-products, however, the irradiation dose of the film casting solution should be determined to achieve better mechanical properties.     

Partitioning of minor actinides: Effects of gamma irradiation on the extracting capabilities of a selected calixarene-based picolinamide ligand

The ligand [3-N-(6-carboxymethylpicolinamide)propyloxy]calix[6]arene (1) has been selected among a series of calixarene-based picolinamide ligands as a possible candidate to be used in a small-scale process for the An/Ln separation under the option of the advanced reprocessing of irradiated nuclear fuel. In this frame, due to the high radioactivity of the nitric solutions to be treated, the behaviour of the ligand under irradiation conditions is undoubtedly of key importance.Liquid–liquid extraction tests were performed, in order to ascertain the extracting capabilities of the calixarene ligand 1 before and after γ-irradiation. A wide range of absorbed doses was investigated, and the tests were performed both in reactive and inert (N₂) atmosphere.The determination of distribution coefficients for actinides and lanthanides, and of the separation factors between elements of the two families was carried out by using γ-spectrometry (as for ²⁴¹Am and ¹⁵²Eu) and ICP-mass spectrometry (MS) (as for all the lanthanides of interest).Contrarily to what observed in the case of other previously and currently studied ligands [Baaden, M., Berny, F., Muzet, N., Troxler, L., Wipff, G., 2000. In: Lumetta, G., Rogers, R., Gopolan A. (Eds.), Calixarenes for Separation. A.C.S. Symposium Series No. 757. American Chemical Society, Washington, DC, pp. 45–55], the extraction efficiency (distribution coefficients) of the calixarene ligand 1, increases by a factor of 2–10 after γ-irradiation on a significant range of absorbed doses.     

The effect of gamma irradiation on physicochemical and microbiological quality of fresh pork loins

Radiation treatments were carried out under air on fresh pork loins at doses of 2, 4 and 8 kGy and the loins were evaluated for deamidation, solubility, sulphydryl content and surface hydrophobicity. Deamidation was significantly (P0.05) affected by the treatment with 98% deamidation at a dose of 8 kGy. No significant changes (P>0.05) were noted in sulphydryl content under the same conditions. The increase in deamidation was accompanied by a decrease in hydrophobicity and an increase in protein solubility. γ-Irradiation also reduced the number of microorganisms in the meat. Mesophiles were more resistant to the irradiation treatment than psychrotrophs and Pseudomonas.     

The effect of gamma irradiation and surfactants on the size distribution of nanoparticles based on soluble starch

The effect of three kinds of surfactants (anionic, cationic and nonionic) on the shape and size distribution of nanoparticles based on soluble starch fabricated under gamma irradiation was studied. Aqueous solution of soluble starch was irradiated with a dose of 20 kGy. The TEM micrograph and size distribution plots showed that when irradiations were made in presence of surfactants the smaller and more distinct nanoparticles were created in comparison to pure starch solution.     

The effect of neutron and mixed gamma and neutron irradiation on the solar properties of borosilicate glass

Neutron and mixed gamma and neutron irradiation, at different absorbed doses, of borosilicate glass with four different chemical compositions was conducted to investigate the effects on the solar properties of the glass. Irradiation was performed in the tangential beam tube and central thimble of a nuclear reactor. The effect of thermal and epithermal neutrons on such solar properties as secondary heat-transfer factor, solar factor (the total solar energy transmittance), and shading coefficient of the borosilicate glass were investigated to determine the effect on the solar properties of borosilicate glass, because of its neutron absorbance property.     

The effect of gamma irradiation on the viscosity of two barley cultivars for broiler chicks

Seeds of two barley cultivars (Local Black and Shoaa) were gamma irradiated at 0, 10, 50, 100, 150 and 200 kGy doses using Cobalt-60 source to decrease the viscosity. The viscosity was determined in the flour of the seeds using Ostwald U-tube viscometer. The viscosity values were reduced by 25%, 50%, 65%, 72% and 74% in Local Black barley cultivar, while, in Shoaa cultivar the reductions were 15%, 30%, 52%, 69% and 67% at 10, 50, 100, 150 and 200 kGy, respectively. The chemical compositions of the seeds were determined in all treatments.     

Effect of gamma irradiation combined with hot water dip and transportation from Thailand to Canada on biochemical and physical characteristics of Thai mangoes (Nahng Glahng Wahn variety)

Two lots of mangoes of the Nahng Glahng Wahn variety from Thailand were irradiated at the Thai Irradiation Center (TIC) at 0.49 to 0.77 kGy. Following this, one batch was retained in Thailand (TIC) while the other was shipped to the Canadian Irradiation Center (CIC) for investigation of the same variables during storage. This way, it was hoped to compare the effects of gamma radiation with hot water dip (HWI) or without (I) before and after transportation, on the respiratory activity, rotting, texture, ph, titratable acidity and on the total soluble solids in mangoes. Irradiation stimulated carbon dioxide (CO₂) production early in the study but delayed ethylene (C₂H₄) production which peaked later. The production of CO₂ and C₂H₄ occurred later at CIC than at TIC. The I and particularly HWI treatments also delayed the rotting of the mangoes. The texture of the mangoes declined earlier and more rapidly during storage in Thailand than in Canada. The irradiated samples developped a softer texture early during storage and the rise in pH was less marked than the controls. The control showed lower values of total soluble solids during the first 10 days of storage but increased later.     

Effects of gamma irradiation on solid and lyophilised phospholipids

The effects of gamma irradiation (25 kGy) as a sterilisation method for phospholipids (distearoylphosphatidylcholine and distearoylphosphatidylglycerol) were investigated. ³¹P-NMR revealed minor chemical degradation of the phospholipids but lower dynamic viscosity and pseudoplasticity, lower turbidity, higher diffusion constant, smaller size, more negative zeta potential and changes in the phase transition behaviour of the subsequently produced liposomes were observed. The observed changes could to some extent be explained by the irradiation-induced degradation products (distearoylphosphatidic acid, fatty acids, lysophospholipids).     

The decontamination effects of gamma irradiation on the edible gelatin

The decontamination effects of gamma irradiation on the edible gelatin were studied. The results indicated that the bacterium and mold in the gelatin decreased significantly with the dose of 5 kGy treatment. However, the content of crude protein, microelement, amino acid in the gelatin remained unchanged under the irradiation of 4 and 8 kGy. The viscosity of the gelatin decreased with the increase of the irradiation dose, but the gelatin with a dose of 5 kGy treatment still accorded with the standard of the second-order class. These results suggested that the optimum irradiation dose for edible gelatin for the purpose of decontamination was in the range 3–5 kGy.     

The effect of gamma irradiation and particle size of CaCO3 on the properties of HDPE/EPDM blends

Mechanical blends formed of 50 wt% of high-density polyethylene (HDPE) and 50 wt% of ethylene–propylene–diene-monomer (EPDM) elastomer have been loaded with 50 wt% of three different particle size of CaCO₃, namely CaCO₃ 300, CaCO₃ 700, and CaCO₃ 2000 whereby the latter has the smallest particle size of ～311, 82 μm. Mechanical, physico-chemical and thermal properties were followed up as a function of irradiation dose for loaded and unloaded blends. The results obtained indicated that the values of tensile strength, tensile modulus at 50% elongation, gel fraction and decomposition temperature increase with increasing irradiation dose. On the other hand elongation at break, permanent set and swelling number were found to decrease with increasing irradiation dose. Moreover, the effect of particle size of CaCO₃ was observed in a limited but apparent upgrading of mechanical, physico-chemical, and thermal properties. The order of semi-reinforcing capacity of three different types of CaCO₃ is as follow: CaCO₃ 2000 > CaCO₃ 700 > CaCO₃ 300 > unloaded blend. Whereby CaCO₃ 2000 has the smallest particle size.     

The effect of irradiation temperature on the quality improvement of Kimchi,Korean fermented vegetables,for its shelf stability

The present study was conducted to evaluate the effect of irradiation temperature on the shelf stability and quality of Kimchi during storage at 35 °C for 30 days. Kimchi samples were N₂-packaged and heated at 60 °C and then gamma irradiated at 20 kGy under various temperatures (room temperature, ice, dry ice, and liquid nitrogen). In the results of microbial, pH, and acidity analysis, combination treatment of heating and irradiation was able to sterilize microbes in Kimchi regardless of irradiation temperature. When Kimchi was irradiated under frozen temperatures, especially dry ice, the softening of texture and the deterioration of sensory quality of Kimchi were reduced. Also, ESR signal intensities were weakened due to the decrease of irradiation dose and temperature.     

Effects of gamma and electron beam irradiation on polymer electrolytes

Polymer electrolytes based on poly(ethylene oxide) and lithium salts have been widely studied in recent years. In order to enhance the room temperature ionic conductivity of PEO-LiX complexes, various techniques, such as addition of plasticizers and crown ether, and also irradiation by γ and electron beams have been investigated. The enhancement of the conductivity by irradiation has been accounted for the decreasing of the crystallinity of PEO-LiX. We reviewed these results and have investigated the degradation processes of PEO using Tb³⁺ fluorescence probes. We have also studied on the effects of irradiation of polymers such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA) and PEO using Tb⁺³ fluorescence probe. Various monomers containing SO₃H and COOH have been grafted on poly(ethylene oxide) using irradiation technique. The structures and ionic conductivities of Li and Na salts of irradiated products were investigated in detail.     

Effect of gamma irradiation on trichromatic values of spices

The effect of γ-irradiation on trichromatic color values L*, a*, and b* was determined in black pepper, oregano, and allspice samples irradiated at average doses from 5 kGy to 30 kGy. Trichromatic values a* measured in methanol extracts of treated spices immediately after the irradiation process were significantly changed, but the subsequent storage of allspice and oregano caused much more distinctive alteration of these color values than the irradiation itself. Additionally, the differences in redness between the reference (non-irradiated) allspice and oregano samples and samples treated by γ-radiation gradually disappeared during the storage period. On the contrary, the post-irradiation storage of black pepper samples did not reveal any changes of a* values. Presented at the XVIIIth Slovak Spectroscopic Conference, Spišská Nová Ves, 15–18 October 2006.