Effect of gamma radiation on optical properties of PVA/PEG/EY blend, and radiochromism.

Effect of gamma radiation on the physicochemical properties of ciprofloxacin in solid state

Effects of gamma-irradiation, variety and storage on physicochemical properties of brown rice from three Louisiana rice varieties: Mars, a medium grain variety, Lemont and Tebonnet, long grain varieties, were determined. Cooking time was significantly reduced in Mars and Lemont at doses of 200 and 300 Krads. Irradiation increased cooking rate, water uptake at 80$\sp\circ$C, water uptake ratios, total solids content in residual cooking liquid and starch damage from 100 to 300 Krad samples. Water uptake at 96$\sp\circ$C generally decreased with increasing dose levels. Evidence indicated alterations in the rice grain structure and composition. The component drastically affected by gamma-irradiation was starch as shown by reduced cooking time, increased water uptake, increased amounts of starch and protein in residual cooking liquid, reduced volume expansion, increased damaged starch and changes in amylographic pasting characteristics. Scanning electron microscopy showed more simple starch granules in irradiated samples than in nonirradiated samples. Structural changes in the bran layer due to gamma-irradiation were not evident from electron micrographs. Amylose, moisture, fat and protein content were not significantly affected by gamma-irradiation. Total color difference values indicated that brown rice darkened on irradiation and, became lighter on storage. Some changes in irradiated samples on storage were similar to those in nonirradiated samples but the degree of these changes was dependent upon dose. Fat acidity values for irradiated Mars and Lemont samples were generally lower than nonirradiated samples. 100 Krad samples of Tebonnet were higher than that of 0 and 200 Krad samples. Fat acidity values of nonirradiated and irradiated samples of Mars, and nonirradiated samples of Lemont increased on storage while irradiated samples were not significantly affected. Values for Tebonnet were not significantly affected by storage. TBA values for Lemont decreased from that at 0 to 100 Krads and then increased at 200 Krads. There was no definite trend in TBA values for Mars. Dose effects on TBA values were insignificant for Tebonnet. On storage, irradiated samples of Lemont and Tebonnet had lower values than nonirradiated samples. Stored irradiated samples of Mars tended to have higher values than nonirradiated samples.

Effects of gamma and electron-beam irradiations on the stability of free radicals, bioactive compounds and microbial characteristics of turmeric powder

Groundnut is a perishable crop and is subject to quality losses during storage through insect pests, rodent infestation and fungal development. Gamma (γ) irradiation has emerged as a promising technique which could effectively be used for disinfestations of stored food products therefore presenting alternative to chemical preservatives. This research investigated the effect of gamma irradiation on nutritional quality and shelf life of groundnut species produced in Benue State Nigeria. The seeds of Bernarda 1 groundnut (BE1G), Local groundnut (LOG) species were irradiated at varying doses (0, 200, 300, 400 and 500 Gy) using Cobalt-60 Gamma Irradiator. The irradiated and non-irradiated samples were each divided into two portions. The first portion was used for proximate analysis while the second was stored for a period of four months under the same ambient temperature and conditions in a polythene bags and its percentage weight loss were determined. Proximate analysis revealed no significance difference at (p≥0.01) in moisture, protein, crude fibre and fats composition of BE1G species between non irradiated and irradiated samples, however a significant variation (p≤0.01) was observed in its ash and carbohydrate across 200 Gy, 300 Gy and 400 Gy. The result also revealed no significant difference in the proximate composition of LOG species for 400 Gy and 500 Gy doses. After four months storage, percentage weight loss analysis indicated a significant difference between irradiated and control seeds of samples. The 500 Gy dose exhibited the least weight loss in the samples. These findings suggest 500 Gy as gamma irradiation dose for BE1G and LOG, highlighting the optimal effective doses for their preservation.

This paper examines the relative permittivity of irradiated and non-irradiated crude oil samples in the frequency range 0.1 – 100.0MHz and room temperature regulated at 25 ± 1oC. Samples of crude oil of mean specific gravity 0.780 ± 0.015 were irradiated for periods of two, four, six, eight and ten months respectively using a gamma radiation source (Cobalt 60) at a dose rate of 0.65mSv per hour. Dielectric measurements were made by using a Boonton RX meter type 250A admittance bridge manufactured by central research Laboratories, Inc, Red, Wing, Minnesota. Analysis of the resulting dielectric data revealed that both the irradiated and non-irradiated samples exhibited dielectric dispersion over the frequency range investigated. However, the relative permittivity values of the irradiated samples were found to be higher than those of the non-irradiated sample. This difference is understandable as it can be attributed to the ionization of atoms and weakening of molecular bonds in the irradiated samples. The increase in relative permittivity for the irradiated samples was observed to be time dependent as the longer the time of irradiation of sample the higher the value of its relative permittivity. Also, in this study, it was observed that the non-irradiated crude oil sample has longer relaxation time than the irradiated ones. The relaxation time decreases gradually with increasing irradiation time. This has physical significance on the basis of the molecular theory of matter and the fact that relaxation time is inversely proportional to relaxation frequency. These results are comparable with the work of other researchers for which similar trends have been observed.

Comparing the efficacy of γ- and electron-irradiation of PBMCs to promote secretion of paracrine, regenerative factors

The aim of this study was to evaluate the effect of gamma irradiation (1, 2 and 3 kGy) on the bacteriological quality and sensory perception of refrigerated raw whole milk. Moreover, physiochemical and bacteriological parameters were monitored during 60 days of storage at 4C. All of the irradiated samples, mainly 2 and 3 kGy, exhibited a lower (P < 0.05) bacterial load than the nonirradiated samples. During storage, the mesophilic count and titratable acidity did not increase in the irradiated samples. The consumers were able to differentiate all of the irradiated samples from the control group (P < 0.05); however, positive attributes were used to describe the irradiated samples. The present study indicates that the 2 kGy irradiation dose improved the bacteriological quality of raw whole milk and likely did not negatively affect sensory characteristics by maintaining a constant mesophilic count and titratable acidity over the 60 days of refrigerated storage. Practical Applications The prevalence of foodborne diseases and huge economic losses from food industries in developing countries has markedly increased. Taking into account the dairy products, raw milk represents the main source of foodborne infections. To investigate an alternative conservation method, three gamma irradiation doses (1, 2 and 3 kGy) were applied in refrigerated raw whole milk. After, bacteriological and sensory qualities of this milk were investigated. In addition, mesophilic count and titratable acidity were analyzed during 60 days of storage under refrigeration (4 ± 1C). On 0 day, all irradiation doses decreased (P < 0.05) the bacterial load of raw whole milk compared with nonirradiated samples. Moreover, both parameters evaluated during storage period (mesophilic bacterial count and titratable acidity) were stable in samples treated with 1, 2 and 3 kGy. However, rancid odors and flavors were perceived on the samples irradiated with 3 kGy. Therefore, in our study, the 2 kGy dose was recommended for raw whole milk because of the positive effects on bacterial quality and minimal sensory changes.

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

Food-grade PVC and PVDC/PVC films containing 28.3% dioctyladipate (DOA) and 5.0% acetyltributylcitrate (ATBC) plasticizers, respectively, were brought into contact with olive oil and were irradiated with gamma-radiation [60Co] at doses equal to 4 kGy and 9 kGy corresponding to "cold pasteurization". Irradiation was carried out at 8-10 degrees C and samples were subsequently stored at 4-5 degrees C. Contaminated oil samples were analysed for DOA and ATBC at intervals between 7 h and 97 h of contact, using an indirect GC method. Identical nonirradiated (control) samples were also analysed for DOA and ATBC content. Results showed no statistically significant differences in migrated amounts of DOA and ATBC between irradiated and non-irradiated samples. Neither were differences observed between samples irradiated at 4 kGy and 9 kGy. This was supported by identical IR spectra recorded for irradiated and non-irradiated samples and leads to the conclusion that at such intermediate radiation doses (< or = 9 kGy) the migration characteristics of both PVC and PVDC/PVC films are not affected. The amount of DOA that migrated into olive oil was dependent on time, reaching equilibrium after approximately 47 h of contact (302.8 mg/l). The amount of ATBC that migrated into olive oil was non-detectable (< 1 mg/l) for all samples stored at 4-5 degrees C after 97 h. In non-irradiated samples (PVDC/PVC in contact with oil) stored at 20 degrees C, small amounts of migrated ATBC were determined (3.3 and 5.1 mg/l after 29 h 94 h of contact respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

The present research studied the influence of gamma radiation doses on the optical properties and parameters of the tested composite samples consisting of polystyrene polymer as a matrix filled with different concentrations of ultrafine iron particles (0, 10, 20, and 30 wt.%) with an average thickness of 2 µm. Using a UV-1800 Shimadzu spectrophotometer, the optical absorbance and transmittance values of the tested composite samples were measured at room temperature in the wavelength range of 200–800 nm. Optical parameters such as the excitation energy for electronic transitions, optical energy gap, dispersion energy, static dielectric constant, static refractive index, moments of the optical spectrum, optical oscillator strengths, linear optical susceptibility, third-order nonlinear optical susceptibility, carrier concentration to the effective mass ratio, high-frequency dielectric constant, nonlinear refractive index, plasma frequency and long wavelength refractive index were calculated and discussed at different doses of gamma radiation (1, 2, and 6 kGy). The results demonstrate that the optical properties and parameters of the gamma-irradiated composites vary with increasing gamma doses. This variation in values was observed after increased irradiation due to enhanced metal–polymer bonding and due to an increase in the density of the free charges within the metal polymer composites.

The objective of the present study was to investigate the effect of gamma radiationon phytochemical compounds in faba bean. Samples of faba bean seeds were exposed to gammaradiation at doses of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 kGy. Then the contents of total phenolic andflavonoid compounds in non-irradiated and irradiated samples were determined. The contents of totalphenolic compounds in samples of non-irradiated faba bean was found to be 220.55 ± 0.040 μg gallicacid equivalent/g dry matter, while the total flavonoids in non-irradiated samples were found to be106.33 ± 0.450 μg quercetin equivalent/g dry matter. Exposing faba bean seeds to ascending doses ofgamma irradiation induced significant gradual increases in the contents of total phenolic and flavonoidcontents. The maximum increases were observed in samples irradiated at dose of 9 kGy showingincrease by about 183% and 283% in phenolic and flavonoid contents, respectively. Based on theseresults, phenolic and flavonoid compounds in the ethanolic extracts of non- irradiated faba bean seedsand those irradiated at dose of 9 kGy were fractionated and quantified by High Performance LiquidChromatography (HPLC). The results showed that 21 phenolic and 14 flavonoid compounds couldbe separated and quantified from the extract of non-irradiated faba bean seeds by HPLC. The samecompounds were identified in the extract of seeds irradiated at 9 kGy dose but at increasedconcentrations. The effect of gamma irradiation on the contents of macronutrients in seeds as well astheir water absorption properties was also determined. Significant differences were observed in theproximate chemical composition between samples of non-irradiated faba beans and those irradiated atdoses up to 10 kGy. However, irradiation treatments generally induced slight, but statisticallysignificant, increases in the values of water absorption properties as measured gravimetrically(hydration properties) and volumetrically (swelling properties). From the obtained results for totalphenolic and flavonoid contents in non-irradiated and irradiated faba bean, it is clear that irradiationdose of 9 kGy can be selected as an optimal dose for increasing of these phytochemicals in faba bean.

Effect of gamma radiation processing on the quality characteristics of anthocyanin rich ethnic rice cultivars

Al-doped ZnO (AZO) thin films were grown on quartz substrates by the sol-gel method. The effects of the Al mole fraction on the structural and optical properties of the AZO thin films were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-VIS spectroscopy. The particle size of the AZO thin films decreased with an increase in Al concentrations. The optical parameters, the optical band gap, absorption coefficient, refractive index, dispersion parameter, and optical conductivity, were studied in order to investigate the effects of Al concentration on the optical properties of AZO thin films. The dispersion energy, single-oscillator energy, average oscillator wavelength, average oscillator strength, and refractive index at an infinite wavelength of the AZO thin films were affected by the Al incorporation. The optical conductivity of the AZO thin films also increased with increasing photon energy.

Gamma irradiation is known as an effective method to reduce microbial contamination in food products. Its application in seafood food not only enhances safety and quality but also extends shelf life, thereby minimizing post-harvest losses. This study focuses on evaluating the combined effect of low dose gamma irradiation and low-temperature storage on the quality and shelf life of fresh Sutchi Catfish (Pangasius hypophthalmus). The fish samples were subjected to different gamma irradiation doses (0.0 kGy, 1.0 kGy, 3.0 kGy, and 5.0 kGy) and then stored under refrigerated conditions (4°C) and frozen conditions (-18°C). Both non-irradiated and irradiated samples were periodically analyzed for microbial counts, including coliforms (total and fecal), total mesophilic bacteria, Salmonella, E. coli, and Staphylococcus aureus. The biochemical quality indices such as total volatile base nitrogen (TVB-N), pH, peroxide value (PV), and thiobarbituric acid reactive substances (TBARS) were also assessed at regular intervals. The findings revealed that the gamma irradiation and storage at low temperatures significantly (p &lt; 0.05) reduced microbial populations, with higher irradiation doses resulting in greater reductions. Chemical quality indicators in irradiated samples were notably better maintained compared to the control samples under both storage conditions. The study concluded that combining gamma irradiation with refrigeration or freezing effectively minimized microbial loads and preserved biochemical quality. This approach extended the shelf life of the fish up to 21 days in refrigeration and 90 days under frozen storage conditions.

Postharvest loss of inherently perishable fruits is a matter of serious concern for the farmers and traders. Reduction of postharvest loss is one of the key components for ensuring food security. A study was carried out to reduce the postharvest loss of BAU Kul, an improved variety of jujube fruit (Ziziphus mauritiana), by using gamma irradiation. Different doses of gamma irradiation (0.5, 1.0 and 1.5 kGy) was applied to the jujube fruit samples and the microbiological quality, antioxidant content and shelf life of those fruits were evaluated. Gamma irradiation initially caused significant reduction of the total heterotrophic bacteria, coliform as well as yeast and mold counts. However, the counts increased in both irradiated and non-irradiated fruit samples with the passage of storage period but the increment was significantly less in the 1.5 kGy irradiated samples. Irradiation played active role in the enhancement of total phenolics and flavonoids contents. The concentration of these antioxidants remained higher in irradiated samples in comparison to non-irradiated control samples throughout the storage period. However, the ascorbic acid content decreased gradually with the increase of radiation dose and storage period. The overall acceptability of the fruit samples was determined by the taste-taking panelist. The irradiated (1.0 and 1.5 kGy) fruits were acceptable up to 8 days whereas control and 0.5 kGy irradiated fruits lost their acceptability during storage. The study revealed that 1.5 kGy irradiation can improve microbiological quality and extend the shelf life of jujube fruits (cv. BAU Kul) without significant loss of overall antioxidant content and sensory attributes.