Influence of gamma irradiation and storage on the microbial load,chemical and sensory quality of chicken kabab

Influence of gamma irradiation and storage on the microbial load, chemical and sensory quality of chicken kabab was investigated. Chicken kabab was treated with 0, 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated samples were kept in a refrigerator (1–4 °C). Microbiological, chemical and sensory characteristics of chicken kabab were evaluated at 0–5 months of storage. Gamma irradiation decreased the microbial load and increased the shelf-life of chicken kabab. Irradiation did not influence the major constituents of chicken kabab (moisture, protein and fats). No significant differences (p>0.05) were observed for total acidity between non-irradiated (control) and irradiated chicken kabab. Thiobarbitric acid (TBA) values (expressed as mg malonaldehyde (MDA)/kg chicken kabab) and volatile basic nitrogen (VBN) in chicken kabab were not affected by the irradiation. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples.     

Effect of gamma irradiation on microbiological,chemical and sensory characteristics of licorice root product

Licorice root products were irradiated at doses of 0, 5, 10, 15 and 20 kGy in a ⁶⁰Co package irradiator. Irradiated and unirradiated samples were stored at room temperatures. Microbial population on product, chemical changes and sensory properties of produced solution of licorice root products were evaluated after 0 and 12 months of storage. The results indicated that gamma irradiation reduced the counts of microorganisms on licorice root products. D₁₀ of total count and klebsiella spp. were about 1.4 and 0.7 kGy, respectively. The mineral ions (Na, Ca and K) concentration in solution produced from irradiated products were lower than non-irradiated ones. Glycyrrhezinic acid and maltose concentration in solution produced from irradiated products were higher than non-irradiated ones. Sensory evaluation indicated that no significant differences (P<0.05) were found between solution produced from irradiated and unirradiated products in color, flavor, texture, or taste.     

Effect of gamma irradiation on microbiological,chemical, and sensory properties of fresh ashitaba and kale juices

Due to the popularity of health effects upon intake of fresh fruits and vegetables, the demand for fresh vegetables and fruit juices has rapidly increased. However, currently, washing is the only procedure for reducing contaminated microorganisms, which obviously limits the shelf-life of fresh vegetable juice (less than 3 days). In this study, we examined the effects of irradiation on the microbiological, chemical and sensory properties of ashitaba and kale juices for industrial application and possible shelf-life extension. Freshly made ashitaba and kale juices already had 2.3×10⁵ and 9.5×10⁴ CFU/mL, respectively. Irradiation of 5 kGy induced higher than 2 decimal reductions in the microbial level, which was consistently maintained during storage for 7 days under refrigerated conditions. Total content of ascorbic acid in vegetable juice decreased upon irradiation in a dose-dependent manner. However, the content of flavonoids did not change, whereas that of polyphenols increased upon irradiation. In sensory evaluation, the ashitaba and kale juices without irradiation (control) scored lower than the irradiated samples after 1 and 3 days, respectively. This study confirms that irradiation is an effective method for sterilizing fresh vegetable juice without compromising sensory property, which cannot be subjected to heat pasteurization due to changes in the bioactivities of the products.     

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.     

Effect of gamma irradiation on microbial load,physicochemical and sensory characteristics of soybeans (Glycine max L. Merrill)

Gamma irradiation is highly effective in inactivating microorganisms in various foods and offers a safe alternative method of food decontamination. In the present study, soybeans (Glycine max L. Merrill) were treated with 0, 1.0, 3.0, 5.0 and 10.0 KGy of gamma irradiation. Microbial populations on soybeans, isoflavone, tocopherol contents, raffinose family oligosaccharides, color and sensory properties were evaluated as a function of irradiation dose. The results indicated that gamma irradiation reduced aerobic bacterial and fungal load. Irradiation at the doses applied did not cause any significant change (p>0.05) in the contents of isoflavone of soybeans, but decreased tocopherol contents. The content of key flatulence-producing raffinose family oligosaccharides in irradiated soybeans (10.0 kGy) decreased by 82.1% compared to the control. Sensory analysis showed that the odor of the soybeans was organoleptically acceptable at doses up to 5.0 kGy and no significant differences were observed between irradiated and nonirradiated samples in flavor, texture and color after irradiation.     

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 effects of gamma irradiation on the microbiological, physical and sensory qualities of diced tomatoes

Diced Roma tomatoes were treated with gamma irradiation and evaluated for changes in microbial, physical, chemical and sensory properties. Dosages for Trial 1 were 0.0, 0.39, 0.56 and 1.82 kGy and in Trial 2, 0.0, 0.50, 1.24 and 3.70 kGy. Irradiation at 3.70 kGy resulted in no aerobic populations through day 12 and significantly fewer colonies through day 15 whereas yeast and mold populations experienced a 2 log reduction through day 12. Color, titratable acidity, and °Brix were not significantly affected by irradiation. Tissue firmness decreased with increasing dose but not with storage time. Treatment with 3.7 kGy decreased firmness by 50% and 20% with 0.5 kGy, however, the reduced firmness induced by 0.50 kGy was undetected by a 9 member trained sensory panel. A significant (p0.05) inverse correlation between changes in texture and water-soluble pectin (WSP) was determined while total pectin remained relatively constant and oxalate soluble pectin content decreased slightly with irradiation dose. The significant inverse correlation between the loss of firmness and WSP indicates that the changes in WSP play an important role in the tissue softening of tomatoes, This study indicates that irradiation at 0.5 kGy can reduce microbial counts substantially to improve microbial shelf life without adverse effects on sensory qualities.     

Effect of combination processing on the microbial, chemical and sensory quality of ready-to-eat (RTE) vegetable pulav

Effect of irradiation in combination with retort processing on the shelf life and safety aspects of an ethnic Indian food product like vegetable pulav was investigated. Gamma irradiation of RTE vegetable pulav was carried out at different dosage rates with ⁶⁰Co followed by retort processing. The combination processed samples were analysed for microbiological, chemical and sensory characteristics. Microbiological analysis indicated that irradiation in combination with retort processing has significantly reduced the microbial loads whereas the chemical and sensory analysis proved that this combination processing is effective in retaining the properties even after storage for one year at ambient conditions. The results also indicated that a minimum irradiation dosage at 4.0 kGy along with retort processing at an F₀ value of 2.0 is needed to achieve the desired shelf life with improved organoleptic qualities.     

Effect of gamma irradiation on the microbial load,nutrient composition and free radical scavenging activity of Nelumbo nucifera rhizome

The assurance of microbial quality is necessary to make plant materials suitable for human consumption and commercialization. The aim of the present study was to evaluate the possibility to apply the gamma radiation treatment on the rhizome samples of Nelumbo nucifera for microbial decontamination. The radiation processing was carried out at dose levels of 1, 2, 4 and 6 kGy. The irradiated and control samples were analyzed for microbial load, organoleptic acceptance, extraction yield, proximate composition, phenolic contents and DPPH scavenging activity. The results indicated that gamma radiation treatment significantly reduced microbial load and increased the storability of the irradiated samples. The treated samples were also acceptable sensorically. The extraction yield and phenolic contents increased with the increase of radiation dose. Gamma radiation also enhanced the DPPH scavenging activity.     

Effects of gamma irradiation on microbial contamination and extraction yields of Korean medicinal herbs

Effects of gamma irradiation on hygienic quality and extraction yields in twenty-one kinds of Korean medicinal herbs were investigated. Gamma irradiation at 5–10 kGy inactivated contaminating microorganisms. The total extraction yield in fifteen kinds of the investigated medicinal herbs increased by 5–25% by a dose of 10 kGy.     

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.     

Effect of gamma irradiation on quality of dried potato

The objectives of this study were to obtain the effect of gamma irradiation on the quality of dried potato. Experiments were conducted to study the influence of different doses, air temperatures, slice thickness of potatoes on the dehydration rate, appearance quality (L-values), vitamin C content, and the rehydration ratio of dried potatoes. The greater the dose, the higher the dehydration rate, the lesser the vitamin C content, and the lower the rehydration ratio. The L-values for low-dose irradiation was greater than that for non-irradiated potatoes.     

Effects of gamma irradiation on chemical composition and ruminal protein degradation of canola meal

Gamma irradiation of canola meal (at doses of 25, 50 and 75 kGy) could alter its ruminal protein degradation characteristics by cross-linking of the polypeptide chains. This processing resulted in decrease (linear effect, P<0.001) of ruminal protein degradation and increase (linear effect, P<0.001) of intestinal protein digestibility. The results showed that gamma irradiation at doses higher than 25 kGy can be used as a cross-linking agent to improve protein properties of supplements in ruminant nutrition.     

Microbial quality evaluation and effective decontamination of nutraceutically valued lotus seeds by electron beams and gamma irradiation

Lotus seeds are nutraceutically valued natural plant produce, which succumbs to microbial contamination, predominantly to toxigenic moulds. Results of the present study revealed seed coat portion to harbor higher proportion of microbial load, particularly fungi than cotyledon portion. Among the mycotoxins analyzed, aflatoxins (B₁, B₂, G₁ and G₂) were below detectable limits, while the seeds were devoid of Ochratoxin-A (OTA). Application of different doses of electron beam and gamma irradiation (0, 2.5, 5, 7.5, 10, 15 and 30 kGy) for decontamination purpose revealed significant dose-dependent decrease in the fungal contaminants (P<0.05). However, the contaminant yeasts could survive up to 10 kGy dose, which could be completely eliminated at 15 kGy. From the results obtained, a dose range between 10 and 15 kGy is recommended for complete decontamination, as these doses have also been shown earlier to have minimal effects on nutritional and functional properties of lotus seeds.     

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...     

Effect of gamma radiation on microbial population of natural casings

The high microbial load of fresh and dry natural casings increases the risk of meat product contamination with pathogenic microorganisms, agents of foodborn diseases.

The aim of this work is to evaluate the killing effect of gamma radiation of the resident microbial population of pork and beef casings, to improve their hygiene and safety.

Portions of fresh pork (small intestines and colon) and dry beef casings were irradiated in a Cobalt 60 source with with absorbed doses of 1,2,5 and 10 kGy.

The D₁₀ values of total aerobic microorganisms in the pork casings were 1.65 kGy for colon and 1.54 kGy for small intestine. The D₁₀ value found in beef dry casings (small intestine) was 10.17 kGy. Radurization with 5 kGy was able to reduce, at least, 6 logs the coliform bacteria in pork casings. The killing effect over faecal Streptococci was 4 logs for pork fresh casings and 2 logs for beef dry casings. Gamma radiation with 5 kGy proved to be a convenient method to reduce substantially the microbial population of pork fresh casings. Otherwise, the microbial population of beef dry casings still resisted to 10 kGy.     

Application of gamma irradiation to reduce microbial contamination in herbal cosmetic products

This study addresses the decontamination of herbal powder cosmetics by gamma irradiation to reduce the total microbial colony count in facial herbal powder, herbal rose brush on and talcum. Pre-irradiated samples showed total colony counts of 3.00×10⁴, 2.70×10⁴ and 1.00×10³ CFU/g. At 3rd day after application, irradiation reduced the total colony counts to 1.90×10², 6.00×10² and 1.20×10² CFU/g. Moreover, the total colony counts of the three samples were found to be less than 100 CFU/g after 3 months storage. The non-uniformity of ΔE^? revealed that time affected the color of brush on and talcum, which differed from their original color; however, irradiation affected the colors of the brush on only (P<0.05), by reducing its brightness and increasing redness and yellowness of the products. Paired preference tests were conducted in facial herbal powder and herbal rose brush on. The results showed no significant preferences between the non irradiated and irradiated of the two products at P max=75%, α=0.05, β=0.10. This concludes that the irradiation does not affect the preference of the products, and it can be an alternative technology to reduce microbial decontaminations in herbal products.     

Effect of gamma irradiation on antioxidant activity of Amoora rohitaka

The effect of a medium dose of gamma radiation on antioxidant activity of Amoora rohitaka was studied. Radiation doses were 0, 1, 3 and 5?kGy. Antioxidant activity was screened by using different assay. With increasing dose the formation of Maillard reaction products (MRPs) contributes to the increase in the antioxidant activity. MRPs are formed as a result of Maillard reaction. In ABTS [2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid di-ammonium salt] assay, ethanol extract showed increase in scavenging activity. It also showed a marked increase in polyphenolic contents. The present study reveals that gamma irradiation can be an efficient process to increase antioxidant activity of Amoora rohitaka.     

Effect of gamma irradiation on ethylene–octene copolymers

Two ethylene–octene copolymers (POE) were irradiated with ⁶⁰Co gamma radiation and influence of irradiation atmosphere, absorbed dose and heat treatment of samples on the crosslinking were studied. Thermal properties and crystalline morphology of non-irradiated and irradiated POE were determined by using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXS), respectively. The Charlesby–Pinner equation was used to describe the relationship between absorbed dose and sol fraction. The gel fraction of irradiated POE was lower and decreased with the increase of octene content when irradiated in oxygen, compared to irradiation in nitrogen atmosphere. The gel fraction increased significantly with the increasing of absorbed dose for the two copolymers. Heat treatment of samples prohibited the crosslinking of irradiated POE. The DSC results indicated that a subtle change of thermal properties of POE was observed before and after gamma irradiation at low dose. No change was found from the WAXS spectra of non-irradiated and irradiated POE. For heat-treating samples, the Charlesby–Pinner equation can not fit perfectly with the relationship between the sol fraction and absorbed dose, but it fits well with the crosslinking reaction of POE pellets.     

Effect of gamma irradiation on gas-ionic liquid and water-ionic liquid interfacial stability

The effect of γ-radiation on gas-ionic liquid (IL) and water-IL interfacial stability was investigated. Three phosphonium-based ILs, which vary considerably in their viscosity, conductivity and miscibility with water, were examined. The gas phase above the IL samples (headspace gas) was analyzed using gas chromatography with a mass spectrometer detector while the changes in the IL and aqueous phases were followed by conductivity measurements and Raman spectroscopy. For the gas-IL systems, the headspace samples showed trace amounts of the radiolytic decomposition products of the ILs that were small and volatile enough to become airborne. The type of cover gas, air or Ar, had no effect on the gas speciation. Negligible changes in the conductivity and the Raman spectra of the IL phase due to irradiation indicate that γ-irradiation induces negligible chemical changes in the IL phase when it is in contact with a gas phase. For the water-IL systems, the initially immiscible layers slowly developed an interfacial emulsion layer, even in the absence of radiation. This layer started at the water-IL interface and then grew downwards, eventually converting the entire IL phase to an emulsion. Gamma-irradiation accelerated the conversion of the IL phase to an emulsion. The development of the emulsion layer was accompanied by changes in the conductivity and the Raman spectra of both the IL and water phases. Based on these results, a mechanism involving the formation of micelles at, or near, the water-IL interface has been proposed to explain the development of an emulsion layer. We also suggest that radiolytic decomposition of ILs produces surfactants that can accumulate at the interface and, even at low concentrations, accelerate the emulsification process.