kGy Irradiated Samples Research Articles

Estimate the lifetime of thermoluminescence traps in general-orders of kinetics model of chilli powder samples by using the R package TGCD

The kinetic parameters of thermoluminescene (TL) glow peaks of chilli powder irradiated by gamma rays with the different doses of 0, 4 and 8 kGy (i.e. activation energies (E), order of kinetics (b), trapping and recombination probability coefficients (R) and frequency factors (s)) have been determined and evaluated by glow curve deconvolution (GCD) method using the glow curve data to estimate lifetime of TL traps. The kinetic parameters of TL glow peaks are calculated by modeled first-, second-, generalorders of kinetics (GOK) thanking to the computer by using the R package TGCD. The results obtained as comparing the lifetime values of the three samples showed that the values of the 8 kGy irradiated-samples were the lowest whereas the 4 kGy irradiated-samples’value were greater than the non-irradiated samples’ one time.

Gamma radiation treatment applied to microbial decontamination of products derived from eggs collected from the retail market in São Paulo

ABSTRACT The quality of products derived from eggs depends on the quality of the raw material source and the industrial production. The contamination by fungi and bacteria can occur after exposure of the product in the retail market. The objective of this study was to evaluate the microbiological quality of 60 samples of derivated egg products and evaluate the effects of gamma radiation of cobalt-60, using the dose of 5 and 10 kGy, for decontamination of products collected in the retail market in the São Paulo city. The bacterial count was performed by the most probable number (MPN) and the fungal counts by serial dilution after plating surface. It was observed a decrease in the humidity and water activity (Aw) values of irradiated whole egg powder and white egg powder samples (p<0.05), but there was no significant change in the pH of the same samples irradiated with 5 and 10 kGy (p>0.05). In the powdered yolk the values of pH and Aw presented a significant difference (p<0.05), but no significant difference in the humidity values of 5 and 10 kGy irradiated samples (p>0.05). Effective microbial sterilization of all products occurred at the dose of 10 kGy.

English

The present study aimed to evaluate the efficiency of the irradiation process in the control of Campylobacter spp. in chilled chicken heart samples, since this microorganism is related to the contamination of meat and chicken giblets and is responsible for enteritis in humans. The methodology and standards recommended by RDC no. 12 (Brazil, 2001) were applied for the bacteriological analyses. The chilled chicken heart samples were acquired in an industry that undergoes sanitary inspection, located in the West Zone of Rio de Janeiro. Samples were divided into two groups, non-contaminated (NC - originally from the industrial plant) and contaminated (CAMPY– contaminated with C. jejuni ATCC 33291/CCAMP/FIOCRUZ 00262 strains by CCAMP/LABZOO/IOC/FIOCRUZ), subsequently separated into four groups: NC and CAMPY control groups and samples irradiated at 1.5, 3.0 and 4.5 kGy. The eight subgroups were analyzed for the presence of Campylobacter sp. No statistically significant difference was observed between the four groups namely the non-irradiated controls and the 1.5, 3.0 and 4.5 kGy irradiated samples (p> 0.05). Elimination of Campylobacter sp. was observed, with no bacterial growth in any of the irradiated, non-contaminated (CN) and infected (CAMPY) samples. Thus, the efficiency of the Co60 irradiation process of chilled chicken heart for the elimination of the surveyed microorganisms was proven. The lowest dose applied was sufficient to eliminate the enteric pathogen which is of great significance in a public health point of view. However, it should be noted that the Brazil legislation determining the microbiological standards for food does not include a microbiological standard for Campylobacter sp. This means that any amount of this enteric pathogen may bring public health risks. Key words: Food irradiation; chicken heart; Campylobacter sp.; Foodborne illness; public health.

Modulation of Pb chemical state of epitaxial lead zirconate titanate thin films under high energy irradiation

The chemical states of epitaxial PbZrxTi1-xO3 films were investigated by an X-ray photoelectron spectroscopy as a function of the gamma-ray doses. An anomalous behaviour was observed in Pb4f states, and a core level of Pb4f shifts towards a higher binding energy at 50 kGy and towards a lower binding energy at 200 kGy. The behaviour can be explained by a radiation induced reduction of PbO to metallic Pb. The metal-insulator-metal electrodes were fabricated by lithography, and the current-voltage characteristics were measured. A negative differential resistance (NDR) was observed in the leakage currents at room temperature. A higher current and disappearance of NDR characteristics were found in the 200 kGy irradiated samples, which further confirms the presence of metallic Pb.

Effect of Irradiation on Shelflife and Microbial Quality of Cold-Stored Sous-Vide Mackerel Fillets

The combined effect of irradiation on microbial quality and shelflife of sous-vide mackerel fillets was investigated. Fillets were vacuum packaged, pasteurized (70C, 10 min) and rapidly cooled. Sous-vide fillets were separated into three groups as nonirradiated (control) and irradiated at the doses of 2.5 and 5.0 kGy, respectively. Samples were stored at 2 ± 1C. Sensorial, physical, chemical and microbial analyses were carried out weekly. According to the sensory results, 5.0 kGy irradiated samples were acceptable until the eighth week of cold storage while control and 2.5 kGy irradiated samples were unacceptable by the seventh week. Total mesophilic and psychrophilic bacterial counts and TVB-N values of control samples exceeded the limits on the sixth week; however, irradiated samples never exceeded the limits. Irradiation of sous-vide fillets provides microbial safety and longer shelflife to consumers who prefer both safe and quick food. Practical Applications Ready-to-eat foods are preferred by most of the consumers having not enough time to spend for cooking. Sous-vide technique, which is also popular in ready-to-eat foods, is generally a low temperature-short time process protecting texture, juiciness and flavor of fish. However to reduce or eliminate the risk linked to the possibility of inadequate pasteurization of sous-vide cooking, an additional hurdle like irradiation would be useful. In the present study microbial limits were exceeded while sensory scores were still acceptable for non-irradiated group which may mislead the consumers preferring sous-vide fish and cause food poisoning. Sous-vide cooking combined with irradiation technology enhances microbial quality, provides food safety and increases the shelflife of sous-vide fillets.

Effect of gamma radiation on microbiological changes in dry salted ribbon fish (Lepturacanthus savala, Cuvier, 1829)

A study was conducted to determine the effects of gamma radiation on microbiological qualities of dry salted ribbon fish ( Lepturacanthus savala ) collected from fish drying yard. Results of microbiological analysis showed that total plate count in non-irradiated ribbon fish was 6.9±0.15 log cfug -1 which was significantly reduced by 1 logs at 1.0 kGy, 2 to 3 logs at 3.0 kGy and 3 to 4 logs at 5.0 kGy gamma radiation. Maximum staphylococci count was noted in non-irradiated ribbon fish (3.17±0.17 log cfug -1 ) compared to irradiated with 1.0 kGy (2.63±0.50 log cfug -1 ), 3.0 kGy (2.35±0.35 log cfug -1 ) and 5.0 kGy (1.95±0.50 log cfug -1 ) on 0 th day. At the end of experiment, the halophilic count was 4.98±0.40 log cfug -1 in control while in 5.0 kGy irradiated fish sample it was 1.49±0.49 log cfug -1 . Vibrio cholera, Salmonella and Shigella and E.coli were not detected in experimental fish samples during investigation. Total fungal count recorded was 2.48±0.03 log cfug -1 in non-irradiated ribbon fish but it was totally eliminated in 5.0 kGy irradiated fish samples. Gamma irradiation doses (1.0, 3.0 and 5.0 kGy) had no significant effect (P>0.05) on sensory properties (appearance, colour, odour and texture) of dry salted ribbon fish sample neither at zero time nor during nine month storage periods. It can be concluded that, gamma irradiation dose of 3.0 and 5.0 kGy had a significant (P<0.05) effects on decreasing microbial load and improve the microbiological safety of dry salted ribbon fish without any adverse effects on their sensory quality.

Effect of combination treatment of gamma irradiation and ascorbic acid on physicochemical and microbial quality of minimally processed eggplant (Solanum melongena L.)

Gamma irradiation alone and in combination with ascorbic acid was tested for preventing the surface browning and maintaining the quality attributes of minimally processed eggplant. Eggplant samples after preparation were subjected to treatment of gamma irradiation in the dose range of 0.25–1.0kGy and to combination treatments of ascorbic acid dip at a concentration of 2.0% w/v and gamma irradiation (dose range 0.5–2.0kGy) followed by storage at 3±1°C, RH 80%. Studies revealed inverse correlation (r=−0.93) between the polyphenol oxidase (PPO) activity, browning index and the treatments of ascorbic acid and gamma irradiation. Combinatory treatment of 2.0% w/v ascorbic acid and 1.0kGy gamma irradiation proved to be significantly (p≤0.05) effective in inhibiting the PPO activity, preventing the surface browning and maintaining the creamy white color and other quality attributes of minimally processed eggplant up to 6 days of refrigerated storage. Sensory evaluation revealed that control and 0.25kGy irradiated samples were unacceptable only after 3 days of storage. Samples irradiated at 0.5kGy and 0.75kGy were unacceptable after 6 days of storage. Microbial analysis revealed that radiation processing of minimally processed eggplant at 1.0kGy with and without ascorbic acid resulted in around 1 and 1.5log reduction in yeast and mold count as well as bacterial count just after treatment and 6 days of storage therefore, enhances the microbial safety.

The Effect of Ionizing Radiation on Multi-drug Resistant Pseudomonas aeruginosa Isolated from Aquatic Environments in Egypt

Aims: This study was conducted to determine the effect of different doses of gamma radiation on Multi-drug resistant Pseudomonas aeruginosa isolated from River Nile at Rosetta branch and associated drains in Egypt. Place and Duration of Study: The study was started with samples collection in August 2010 through April 2011 in the Microbiology Dep., Central Laboratory for Environmental Quality Monitoring (CLEQM), National Water Research Center (NWRC), Cairo, Egypt and the National Centre for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority (EAEA), Cairo, Egypt. Methodology: Water samples were processed using membrane filtration, 144 strains of P. aeruginosa were isolated and identified and their antibiotic susceptibility was determined against 20 different antibiotics using agar disc diffusion method. Irradiation of bacterial isolates was processed using gamma irradiation unit of cobalt (Co) and the Original Research Article British Microbiology Research Journal, 4(8): 856-868, 2014 857 D10-value was calculated from the survival curve. Results: Isolates were categorized as multi-drug resistant Pseudomonas aeruginosa (MDRPA). 125 (86.8%) were found to be extensively drug resistant (XDR) and 19 (13.2 %) were characterized as possible pan drug resistant (PDR). The highest resistance (100%) was mostly directed to amoxycillin/clavulanic acid, ampicillin, carbenicillin, methicillin, cephalothin, kanamycin, vancomycin, tetracycline, erythromycin, clindamycin, trimethoprim/sulfamethoxazole, nitrofurantoin and chloramphenicol. More than 75% of isolates were sensitive to norfloxacin (82.6%), piperacillin (81.2%), amikacin (79.2%) and tobramycin (77.8%). 63.2%, 26.4% and 14.6% of isolates were sensitive to ofloxacin, cefotaxime and ceftriaxone, respectively. The viable counts of MDRPA decreased with increasing radiation doses of gamma rays up to the lethal dose (3 kGy). The counts of 0.5, 1.0, 1.5, 2.0, 2.5 kGy irradiated samples were respectively 7.8, 6.5, 4.7, 2.3& 1 log10 and the D10-value calculated from the survival curve was 0.27 kGy. Conclusion: Contaminated fresh water may act as reservoirs for antibiotic resistant pathogens. Regular monitoring of Multi-drug resistant pathogens in aquatic environments should be adopted constantly. Gamma radiation demonstrates a potential value for wastewater treatment and pollution control.

Enhancement of Antioxidant Properties and Increase of Content of Vitamin D2 and Non-volatile Components in Fresh Button Mushroom, Agaricus bisporus (Higher Basidiomycetes) by γ-irradiation

Agaricus bisporus is a popular culinary-medicinal mushroom in Taiwan, and γ-irradiation could extend its shelf life. Our objective was to study the content of vitamin D2 and the taste components and antioxidant properties of ethanolic extracts from A. bisporus with various doses of γ-irradiation. After irradiation, the vitamin D2 content of 5-10 kGy irradiated mushrooms was in the range of 5.22-7.90 µg/g, higher than that of the unirradiated control (2.24 µg/g). For all treatments, the total content of soluble sugars and polyols ranged from 113 to 142 mg/g, and the monosodium glutamate-like components ranged from 6.57 to 13.50 mg/g, among which the 2.5 kGy irradiated sample has the highest content of flavor 5'-nucleotide. About antioxidant properties, 10 kGy irradiated samples exhibited lower EC50 values than did other samples. EC50 values were less than 5 mg/mL for ethanolic extracts. Total phenols were the major antioxidant components and the total content was 13.24-22.78 mg gallic acid equivalents/g. Based on the results obtained, γ-irradiation could be used to improve the vitamin D2 content and intensity of umami taste in fresh mushrooms. In addition, γ-irradiation not only maintained the antioxidant properties of mushrooms but also enhanced the antioxidant properties to some extent.

시판 유통 중인 냉동 다진 마늘의 사전 살균 및 조사처리 여부 판별 모니터링

시판 냉동 다진 마늘 5종(중국산 3종, 국산 2종)을 대상으로 DEFT/APC, 전자코 분석, PSL, TL 및 ESR 분석을 이용하여 사전살균처리 및 조사 여부를 모니터링 하였다. DEFT/APC 분석 결과 중국산 시료에서 DEFT값(생균수+사균수)은 7.9~8.3 log CFU/g으로 높은 값을 나타내었으나, APC(생균수)는 4.2~4.8 log CFU/g으로 낮은 값을 나타내어 사전살균처리 가능성이 확인되었다. 그러나 국산 시료는 DEFT값과 APC 값의 차이가 크게 나타나지 않아 사전살균처리되지 않은 것으로 판단되었다. 전자코를 이용한 조사여부 스크리닝 결과, 중국산 시료는 미지시료와 1 kGy 조사시료간에 있어서 차이가 불분명하여 조사여부 확인이 어려운 반면, 국산 시료는 그 차이가 명확히 구분되어서 사전 조사처리 되지 않았음을 확인할 수 있었다. PSL 분석 결과, 미지시료 5종 모두 700 이하의 PCs(-)을 나타내었으며, 1 kGy의 선량으로 재조사하여 얻은 PSL ratio 역시 10배 이상으로 나타나, 모든 시료가 사전 조사되지 않은 시료로 확인되었다. 한편 TL 분석에서 TL1 발광곡선은 국산 2종의 미지시료는 300°C 이상에서, 중국산 3종은 240~250°C에서 약한 발광곡선을 나타내었다. 이상의 결과를 검증하기 위하여 재조사(1 kGy)에 의한 TL2 발광곡선을 측정한 결과, 국산 및 중국산 모두 150~250°C에서 발광피크를 나타내면서 TL ratio(TL1/TL2)가 0.1 이하로 비 조사(negative)로 나타났다. 그러나 중국산 3종의 TL1 발광곡선의 온도범위를 고려해 본다면 조사처리의 가능성이 높게 나타났다. 그리하여 ESR 분석을 실시한 결과, 중국산 3종 시료는 미지시료 및 1 kGy 조사시료 모두 방사선 유래의 특이적인 cellulose signal이 관찰되어 TL1 결과를 잘 뒷받침하였다. 이와 같이 냉동 다진 마늘의 조사여부를 효과적으로 확인하기 위해서는 물리적 분석법의 다중적 활용이 필요한 것으로 나타났다.

Interactions of montmorillonite and electron beam irradiation in enhancing the properties of alumina trihydrate–added polyethylene and ethylene vinyl acetate blends

This study aims at investigating the effects of electron beam irradiation on the montmorillonite and alumina trihydrate–added low-density polyethylene and ethylene vinyl acetate blends. The mechanical, flammability and electrical resistivity of the montmorillonite and alumina trihydrate–added low-density polyethylene and ethylene vinyl acetate blends were investigated. The addition of montmorillonite provided the reinforcing effect to the alumina trihydrate–added low-density polyethylene and ethylene vinyl acetate, whereby the tensile strength of 150 kGy and 250 kGy irradiated samples gradually increased with increasing of montmorillonite composition (i.e. 5 phr to 20 phr). Furthermore, the addition of montmorillonite into low-density polyethylene and ethylene vinyl acetate blends increased the limiting oxygen index and thermal decomposition temperatures of samples, thus improving the flame retardancy and thermal stability. The increasing of montmorillonite and irradiation dosage promoted the char formation during combustion. Besides, the increasing of montmorillonite loading levels gradually decreased the surface and volume resistivities of the polymer blends. The high irradiation dosages (i.e. 150 kGy and 250 kGy) were found to slightly decrease the electrical resistivity of the alumina trihydrate–added low-density polyethylene and ethylene vinyl acetate blends especially at high loading of montmorillonite. The irradiation effect improved the mobility of montmorillonite ions in polymer matrix, subsequently causing the reduction of the electrical resistivity of the polymer blends. The storage capacity of electrical charges of samples was slightly declined with the increasing of montmorillonite loading levels and irradiation dosages as shown by the dielectric constant results. The dielectric loss tangent of samples slightly increased at the increasing of montmorillonite loading level. However, the dielectric loss tangent was declined with increasing of irradiation dosages.

2-Dodecylcyclobutanone as an irradiation dose indicator to identify and estimate original dose in irradiated ground beef

2-Dodecylcyclobutanone (2-DCB), as a chemical marker of irradiated lipid-containing foods, was used to detect whether ground beef patties were irradiated and to estimate the original absorbed dose. The ground beef patties (70/30) were irradiated at five targeted absorbed doses of 0.5, 1.0, 3.0, 5.0, and 7.0 kGy and stored for 0, 7, 14, 21, and 28 days, respectively at 4 °C. A rapid analytical method based on direct solvent extraction (DSE)/gas chromatography–mass spectrometry (GC–MS) was developed to analyze 2-DCB in γ-ray irradiated ground beef patties. The samples were extracted with acetonitrile via DSE using a tissue-mashing instrument, and then purified with a 1-g silica cartridge and analyzed via GC–MS. The results indicate a linear relationship between irradiation dose and the amount of 2-DCB produced in the irradiated samples (y = 0.0608x–0.0004, R² = 0.9899). In addition, a linear relationship was observed between the loss (%) of 2-DCB and storage time (L = 1.958d–1.6596, R² = 0.9597). Thus, a method for estimating the initial dose of irradiated food was developed based on these two line equations; this method explored the establishment of a determination model of the original irradiation dose of lipid-containing foods. The method was used to successfully estimate 2–7 kGy irradiated beef samples within 28 days with minimal deviation within ±15 %.

전자선 조사한 자두의 휘발성 유기성분 변화

The changes in the volatile organic compounds in plum after its electron beam irradiation and storage were determined using the simultaneous distillation extraction method and gas chromatograph-mass spectrometry. There were 44, 46, 45, 47, and 38 volatile compounds in the 0-, 0.25-, 0.5-, 0.75-, and 1 kGy irradiated samples, respectively. Also, the volatile flavor components of the plum that was stored for 30 days were identified as 48, 40, 40, 39, and 40 components. The compositions of the volatile compounds of the control and irradiated samples showed a similarity after the storage. Especially, the more important volatile flavor of the plum was identified as hexanal of the C6compounds, (E)-2-hexenal and (Z)-3-hexenal. In particular, hexanal, (E)-2-hexenal, and (Z)-3-hexen-1-ol increased in all the doses, where as hexanol and (E)-2-hexen-1-ol decreased. Among the lactone compounds, -hexalactone, -octalactone, and -decalactone were identified during the storage period in the raw samples. Hexanonic acid and 2-hexenoic acid were not identified during the storage of the samples, and 2-methylprrole was detected only when the storage samples were irradiated at a dose higher than 0.5kGy. Therefore, it was shown that there was no effect on the variation of the volatile organic component suntil 1 kGy in the plum was irradiated with an electron beam.

Electron paramagnetic resonance investigation of different plant organs after gamma irradiation

Total reactive oxygen species (ROS) signals in irradiated Arabidopsis plants were examined by electron paramagnetic resonance (EPR) analysis. At 10 kGy, the EPR signal intensity was highest in the root, whereas relatively low intensity levels were observed in the leaf and stem. The relative unit (r.u.) of control plants was 0.38 in the leaf, which was gradually increased to 0.51, 0.71, and 0.95 r.u. at 1, 5, and 10 kGy, respectively. In the stem, the intensity in all irradiated samples was lowest compared with that in other plant organs such as the leaf and root. The r.u. in the root sharply increased from 0.13 r.u. in control samples to 1.58 r.u. at 10 kGy, with 0.30-0.42 r.u. observed in 1-5 kGy irradiated samples. Stem and leaf extracts showed remarkably high levels of radical scavenging activity at 89.12 and 71.45%, respectively, compared with the very low level of activity in the root at 10.75%. These findings were in good agreement with the extraction yield of each plant organ, which was 20.0, 14.8, and 10.0% in the stem, leaf, and root, respectively. Order of EPR signal intensity and radical scavenging activity was as follows: EPR signal intensity: 1) leaf > root > stem at 1 and 5 kGy, 2) root > leaf > stem at 10 kGy; radical scavenging activity: stem > leaf > root. Results showed high or low levels of EPR signal intensity in different plant organs could be caused by the ROS removal power of extracts from different plant organs.

Analysis of volatile organic compounds of ‘Fuji’ apples following electron beam irradiation and storage

The volatile organic compounds of non-irradiated and electron-beam irradiated ‘Fuji’ apples (Malus domestica Borkh.) at 0, 0.5, and 1kGy were isolated through simultaneous distillation extractions and analyzed using gas chromatograph–mass spectrometry. A total of 53 volatile organic compounds were characterized in 0 and 1kGy irradiated samples, whereas two more compounds related to ketone and terpenoid group were identified in 0.5kGy irradiated samples. The contents of volatile compounds were 24.33, 36.49, and 35.28mg/kg in 0, 0.5, and 1kGy irradiated samples, respectively. The major compounds identified were butanol, hexanal, [E]-2-hexenal, and hexanol in all samples. The relative content of alcohol increased after 30 days of storage in all samples, whereas that of aldehyde decreased. Although the contents of some volatile compounds were changed by electron-beam irradiation, the total yield and major flavor compounds of irradiated ‘Fuji’ apples were similar to, or even greater than, those of the control. Therefore, the application of e-beam irradiation if required for microbial decontamination of ‘Fuji’ apples is an acceptable method as it does not bring about any major quantitative changes of volatile organic compounds.

Quality attributes of Pleurotus eryngii following gamma irradiation

Quality attributes (appearance, color, texture, weight, and volatile compounds) of irradiated (0, 1, 2, and 3) king oyster ( Pleurotus eryngii) mushrooms, packed in polystyrene trays and covered with polyvinylchloride (PVC) film, were evaluated over a storage period of 4 weeks at 5 ± 1 °C. Hunter L values (lightness) increased upon irradiation and remained high throughout the storage period in 1 kGy-irradiated samples, whereas a values showed a slight decrease, and b values exhibited an increasing trend following irradiation. Mushroom texture decreased in firmness with increasing dose, but 1 kGy-irradiated samples maintained an overall better texture than all other samples. A similar trend was observed for weight loss during storage. The control samples developed mold, whereas 3 kGy-irradiated mushrooms were soft at the 3rd week of storage. Scanning electron microscopy showed micro-structural changes in the irradiated samples, which were probably the cause for increased weight loss and poor texture at the high 3 kGy dose. A principal component analysis of E-nose data showed dose-dependent differences in volatile profiles of all samples. Irradiation at 1 kGy was most effective for the extension of postharvest storage with added advantages.

Physicochemical and sensory properties of irradiated dry-cured ham

To determine the effect of different irradiation doses on ready-to-eat (RTE) dry-cured shoulder hams, physicochemical and sensory attributes were analyzed during 8 weeks of refrigerated storage. The results show that irradiation reduced the redness value and increased the 2-thiobarbituric acid-reactive substance (TBARS) value as well as the irradiation aroma during storage. However, ham samples irradiated with 2.5 and 5.0 kGy did not show significant changes in lightness values compared to the control sample during 8 weeks of storage. TBARS values were lower in the sample irradiated with 2.5 kGy than in the other irradiated samples. The total plate counts of the 5.0 kGy-irradiated samples were not measured after 0 weeks. Sensory panels found that the 2.5- and 5.0 kGy-irradiated samples had better overall acceptability scores than the other irradiated samples. It was concluded that treatments with lower levels of irradiation (≤5.0 kGy) can enhance the microbial safety and sensory acceptance of dry-cured shoulder hams.

THE COMBINED EFFECT OF IRRADIATION AND ANTIOXIDANT PACKAGING ON SHELF LIFE EXTENSION OF GOAT FISH (PARUPENEUS INDICUS): MICROBIAL, CHEMICAL AND EPR SPECTRAL ASSESSMENT

The present study was carried out to evaluate the efficiency of gamma radiation (1–10 kGy) in combination with antioxidant wrapping (butylated hydroxyanisole [BHA], curcumin, ethylenediaminetetraacetic acid [EDTA]) for extending the quality and shelf life of goat fish Parupeneus indicus Quality assessment was studied by monitoring the chemical (total volatile base nitrogen, trimethyl amine [TMA] and thiobarbituric acid reactive substances), microbiological (total bacterial count) and electro paramagnetic resonance (EPR) spectral analysis. A dose-dependent reduction of TVB and TMA was contemplated with irradiated samples. Lowest TVB (21 ± 1.52) and TMA (3.8 ± 0.7) were seen in 10 kGy irradiated samples compared with control TVB (79 ± 2.5) and TMA (22 ± 1.1) values. Antioxidant coated samples exhibited lower t-bars values indicative of higher antioxidant activity than the control. A final t-bars value of 0.346 ± 0.04 was seen for control, while it was 0.25 ± 0.03, 0.31 ± 0.04 0.31 ± 0.03 for BHA, curcumin and EDTA coated samples, respectively. Scavenging potential of selected antioxidants was measured in EPR using a stable radical 1-diphenyl-2-picrylhydrazyl. Infusion of fish samples with antioxidants diminished the intensity of EPR radical peak in irradiated samples. Outcome of the study proposes irradiation along with antioxidant wrapping as an efficient tool in preservation of foods from the sea. PRACTICAL APPLICATIONS Ever since the global necessity for fishery products is expanding, there is a call for efficient preservative approaches. In countries like India, the serious outstanding puzzle with respect to distribution of fishery products is their vulnerability to spoilage, chiefly due to the contamination of spoilage microorganisms. Because of the boycott on chemical and antibiotic preservatives, many countries have had to limit the export of some fishery commodities resulting in solemn economic loss. In this circumstance, food irradiation tenders a momentous alternative method for slashing storage losses. Though irradiation and frozen storage may essentially stop the growth of pathogenic microorganisms, deterioration of quality brought about by chemical and physical origins can happen. The study conducted was of prime importance as the antioxidant treatments along with irradiation displayed the evident of fruitful reduction in inhibiting the negative shades of food spoilage and allows international trade requirements to be met.

SAXS Studies on the Structure Behaviors of Crosslinked PTFE Irradiated by Gamma Ray

The structural changes of crosslinked polytetrafluoroethylene (XPTFE) by gamma ray irradiation in air at room temperature were studied by thermal analysis and SAXS techniques. The chain scission of irradiated XPTFE was predominant in room temperature and increased with an increase of dose. The crystallization is enhanced by chain scission during irradiation. The melting temperature and melting heat of XPTFE irradiated by gamma ray increased with the adsorbed dose. The scattering intensity of samples decreased with increasing dose. The fractal dimension of sample decreased but the thickness of transition layer parameter becomed smaller before 100 kGy gamma ray dose, and then it increased with dose above 100 kGy Irradiated XPTFE samples exhibited self-similarity structure. Chain scission of XPTFE is responsible for its structural change after XPTFE irradiated by gamma ray in air.

Irradiation of sangari ( Prosopis cineraria): Effect on composition and microbial counts during storage

Fresh dried and old dried sangari ( Prosopis cineraria) were treated with 0, 2.5, 5.0, and 7.0 kGy of irradiation and subsequently stored at ambient temperatures. Proximate values and total bacterial counts were evaluated immediately after irradiation and at regular intervals of 1 month during 3 months of storage. No significant changes were found in moisture, fat, protein, ash and fiber contents. Total sugar content was increased in both control and irradiated samples possibly due to conversion of starch into sugars. Irradiation treatment reduces total bacterial counts of dried samples of both fresh and old dried sangari. However, a dose of 5.0 kGy completely decontaminated both sangari and there was no microbial growth in 5.0 kGy irradiated samples during the storage period. Irradiation at 5.0 kGy was enough to extend the shelf-life of dried sangari up to 3 months without any significant change in the nutritional qualities.