[en] The study was done to determine the effect of irradiation on the shelf life and quality of a fish meat jelly product named as Fried-Kamaboko which is sometimes called as Satsumaage. Fresh samples were packed and sealed in cellophane coated polyvinylchloride bag with nitrogen gas, and irradiated at 0, 300 and 500 krad followed by storage at 10⁰C. The results showed that irradiation of 300 krad extended the shelf life of Fried-Kamaboko to be 20 days, in contrast to unirradiated samples which were kept only 3 to 6 days at 10⁰C. The species of main microorganisms which grew in unirradiated samples were Micrococcus, Moraxella-Acinetobacter, lactic acid bacteria, yeasts and molds. Irradiation of Fried-Kamaboko at 300 krad reduced the aforementioned flora to the yeasts. The most radio-resistant microorganisms of Fried-Kamaboko was brownish black Fungi identified as Spicaria, and its D₁₀ value was obtained to be 130 krad. No remarkable difference was observed between the irradiated Fried-Kamaboko and unirradiated ones with respect to the organoleptic evaluation. But off-odor was slightly induced with the dose of 500 krad irradiation. (author)

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[en] Turmeric finger as one of the most popular spices has been widely used for food manufacturing. However, it has also been a major cause of bacterial infestation of food materials especially in curry, ham and sausage manufacturing. In this study decontamination of bacteria in turmeric finger by electron beam irradiation was evaluated by comparing with several other decontamination methods: i.e., boiling, microwave irradiation, treatment by twin screw extruder and gamma-ray irradiation. By estimation of colony counting on nutrient agar plate, turmeric finger without any treatment gave total viable cell at 10⁸/g. Turmeric finger which was irradiated by electron beam at 10kGy dose dramatically reduced thermotolerant cell population below self restriction level (<1000/g), which has been required by food hygiene law. The same level of sterilization effect was obtained only by gamma-ray irradiation at 10kGy and 20kGy. On the other hand, although treatment through twin screw extruder slightly reduced bacterial numbers, neither boiling nor microwave irradiation gave sufficient decontamination effect on turmeric fingers

[en] A method to prepare immobilized urease on the inner wall of a glass tube by radiation-polymerization under frozen state was investigated. As a part of a continuous flow analyzer, i.w.. Technicon Auto Analyzer II, the immobilized urease tube of 1 cm length was set and used for the routine determination of urea. This flow-through system could measure urea concentration of up to 30 mM at rate of 30 samples per hour. The system were possible to assay 2000 to 3000 samples, continuously in practice. The activity of the urease tube stored in a refrigirator maintained 94% of the initial activity after 115 days. (author)

[en] Brazil santos green coffee beans were irradiated with ⁶⁰Co-γ rays at doses of 0, 0.05, 0.5 and 1.5 Mrad respectively and changes of the composition of carboxylic acids in roast beans were analyzed by means of GLC together with those of the organoleptic properties of roast beans during storage by use of the cup testing. The total acid content immediately after roasting was about 6,000 mg/100 g (roast beans) and the composition of carboxylic acids was as follows. Chlorogenic acid: hydroxy-carboxylic acids: mono-carboxylic acid: others = 73 : 18 : 7 : 2. Fresh coffee flavour was influenced markedly especially in acid taste by both irradiation of γ-rays on green beans and storage of roast beans, because of the change of above acids composition. On γ-ray irradiation, the change of the acid composition were more clear than that of stored roast beans. Therefore, the quality of γ-irradiated coffee beans seems to be closely associated with the ratio of hydroxy-carboxylic acids mg/ monocarboxylic acids mg, but little with total acid content. (author)

[en] Changes in the contents of free sugar in onion bulbs of different cultivars and different production areas were investigated during storage and processing by using gas-chromatography. No significant difference was observed in the total free sugar contents among the onions of different cultivars and different production areas except early season's cultivars which showed a slightly lower content of sugar. The free sugar was mainly composed with glucose (1.7 - 3.2%), fructose (1.1 - 2.5%) and sucrose (0.7 - 2.6%), and the composition was somewhat different among the onions of different cultivars and different production areas. During the storage at 4 - 5⁰C, the total free suger contents gradually decreased during the first few months but more markedly to about 30% after sprouting. The middle part of onion bulbs contained more amount of total free sugar than the other parts (middle part, 5.6 → 3.5%, inner part, 5.2 → 3.2%, outer part, 4.8 → 1.5%), and the total free sugar contents in the outer part decreased markedly during the storage. The changes of the sugar contents after the freeze-drying were almost negligible, but showed significant decrease after the hot-air drying, especially for sucrose. The gamma irradiation with 5 - 50 krad gave no appreciable effects on the total free sugar contents though it seemed to make a slight increase in the sucrose content. (author)

[en] Seven kinds of spices were irradiated with gamma-rays at the dose of 5 to 80 kGy. Studies of radiation effect on lipids in each spice were carried out by measuring peroxide value (POV), iodine value (IV), acid value (AV) and analysis of gas-chromatography (GC). POV in each spice was gradually increased with increasing absorbed doses. The increase of POV in nutmeg was higher than those of other spices, and it was suggested that those increase of POV values were related to lipid contents in spices. A little increase of IV and AV were also observed as same amount of POV by the irradiation up to 80 kGy. From the GC analysis of lipids in each spice, components were not changed even irradiated up to 50 kGy of gamma-rays. Radiation effect on components of essential oils in each spice were also analyzed by headspace-GC (HS-GC), and any degradation of components were not observed up to 50 kGy of irradiation even analyzed by GC after separation to hydrocarbon and oxygen compounds. On the contrary, essential oils of cloves sterilized by heat treatment were apparently decreased as compared with irradiated and non-irradiated cloves. (author)

[en] The incubation condition of potato tubers prior to impedance measurement greatly influenced the reliability of detection of irradiated potatoes; the impedance ratio at 5 kHz to 50 kHz (Z_5k/Z_50k) determined at 22degC at an apical region of tuber which was pre-incubated at 22degC for 3 days or longer resulted in the best detection of radiation treatment of potatoes. The impedance ratio was dependent upon dose applied to potato tubers. Potatoes irradiated at 100 Gy could be distinguished from unirradiated potatoes for 10 cultivars of potatoes. The impedance ratio of potatoes irradiated at the same dose was little influenced by the planting locality if the cultivar was the same, although the ratio varied with potato cultivars. These results indicate that irradiated potatoes can be detected if the potato cultivar is known. Potatoes 'Danshaku' commercially irradiated at the Shihiro Potato Irradiation Center could be differentiated from unirradiated 'Danshaku' at different planting localities; the impedance ratio was lower than 2.75 for the unirradiated potatoes and higher than 2.75 for the irradiated ones. (author)