Seiichiro Isobe

National Food Research Institute, Ibaragi, Ōsaka, Japan

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Publications (86)117.48 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Xanthone compounds in mangosteen (Garcinia mangostana Linn.) fruit have been reported to have biological activities including antioxidative and anti-inflammatory effects, and the major xanthone compounds in mangosteen are α-mangostin and γ-mangostin. The objectives of this research were to quantify and qualify the major xanthones in each part of the mangosteen fruit with and without yellow gum from the point of view of effective utilization of agricultural product. Quantitative evaluation revealed that yellow gum had extremely high amounts of α-mangostin and γ-mangostin (382.2 and 144.9 mg/g on a wet basis, respectively) followed by pericarp and aril. In mangosteen fruit with yellow gum inside, xanthones seemed to have shifted from the pericarp and to have concentrated in a gum on the surface of aril, and there was almost no difference between the amounts of α-mangostin and γ-mangostin in whole fruits with and without yellow gum. Pericarp and yellow gum showed much higher radical-scavenging activity and ferric reducing antioxidant potential than the aril.
    Bioscience Biotechnology and Biochemistry 05/2013; 77(5). DOI:10.1271/bbb.120931 · 1.06 Impact Factor
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    ABSTRACT: We studied the hydration properties and enzymatic hydrolysis of micro-sized rice flour obtained by dry jet-pulverization to find new applications for the flour in the food industry. Ultra-fine rice flour (both white and brown) with a mean size of <5 µm was far more dispersible than coarser flours (15–120 µm). Dispersibility increased with finer mean particle size and higher starch damage. The ultra-fine flour also had the highest solubility, swelling power, water absorption index, and glucose release. Dry jet-pulverization to <5 µm mean size and consequent starch damage to (>30%) decreased enthalpy and gave very different hydration properties and enzymatic hydrolysis than in coarser flours.
    Japan Journal of Food Engineering 03/2013; 14(1):37-46.
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    ABSTRACT: Turmeric (Curcuma longa) rhizome contains abundant curcuminoids, which are highly hydrophobic bioactive compounds. This study aimed to extract curcuminoids using edible oil instead of chemical solvents, and a new extraction system using natural medium-chain triacylglycerols (MCTs) was constructed. After grinding turmeric with MCTs, the liquid and solid fractions were separated by pressing and filtering, with the resulting liquid subsequently clarified by centrifuging and heating. The recovery rate of curcuminoids from turmeric to the clarified MCT fraction was ≈ 10%, but the MCT fraction seemed to be practically saturated with curcuminoids. MCT extracts including curcuminoids can be directly used to add yellow color to many kinds of food, as well as curcuminoid functionality together with the physical and biological properties of MCTs.
    Food Science and Technology Research 01/2013; 19(4):655-659. DOI:10.3136/fstr.19.655 · 0.35 Impact Factor
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    ABSTRACT: Abstract The consumption of foodborne pathogens contaminated in food is one of the major causes of diarrheal diseases in Thailand. The objective of this study was to evaluate the prevalence and types of contaminating bacteria in retailed foodstuffs in Thailand. Food from four categories (137 samples total), including meat (51 samples), vegetables (38 samples), fish or seafood (37 samples), and fermented food (11 samples), was purchased randomly from seven different open-markets and seven supermarkets in Thailand from August 2010 to March 2011. Seven types of major foodborne pathogens were identified using conventional culture methods. Approximately 80% of meat samples tested was contaminated with Salmonella spp. In contrast, the Salmonella spp. contamination rate of vegetable (5%) or fermented food (9%) samples was comparatively low. Six strains of Cronobacter sakazakii and two strains of Yersinia enterocolitica were also isolated. A substantially higher rate of contamination by Bacillus cereus was observed in fermented food (82%) than in samples of meat (2%) and fish or seafood (5%). Seven Listeria spp. isolates were obtained from meat and fish or seafood samples. Approximately 39% of samples tested were found to be contaminated with Staphylococcus spp. (54 isolates). The rate of bacterial contamination of meat did not depend on the type of market. However, the contamination rate of Staphylococcus spp. in vegetables was higher in open markets than in supermarkets, and the contamination rate of Salmonella spp. and Staphylococcus spp. in fish or seafood samples purchased in open markets was likewise higher than in those purchased in supermarkets. Therefore, improvement of hygienic practices throughout the food chain may be required to reduce the risk of food poisoning.
    Foodborne Pathogens and Disease 09/2012; 9(9):835-40. DOI:10.1089/fpd.2012.1169 · 1.91 Impact Factor
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    ABSTRACT: The effect of particle size reduction on the pasting properties of rice, wheat, corn (maize), potato, sweet potato, and cassava starches was elucidated. Before pulverizing, the mean particle size and the pasting properties of the starches differed by crop. With increased pulverizing, the mean particle size decreased in all flours (to<10μm) and the pasting properties converged. Commercial flours containing the larger starch granules have the higher starch damage after pulverization.
    Japan Journal of Food Engineering 03/2012; Jpn. J. Food Eng.(1-12):29-35.
  • Food Science and Technology Research 01/2012; 18(6):843-848. DOI:10.3136/fstr.18.843 · 0.35 Impact Factor
  • Nippon Shokuhin Kagaku Kogaku Kaishi 01/2012; 59(10):533-537. DOI:10.3136/nskkk.59.533 · 0.11 Impact Factor
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    ABSTRACT: The loss of quality or quantity of raw foods caused by spoilage bacteria is a major problem, especially in developing countries. Evaluation of the frequency and level of bacterial contamination and/or identification of the contaminating bacteria are keys to solving this problem. The objective of this study was to evaluate the prevalence and types of contaminating bacteria in retail foodstuffs in Thailand. Foods in four categories (137 samples total) including meat (51 samples), vegetables (38 samples), fish or seafood (37 samples) and fermented food (11 samples) were purchased randomly from seven different open markets and seven supermarkets in Thailand from August 2010 to March 2011. Indicator bacteria of fecal contamination or other naturally contaminating bacteria were isolated and identified. More than 90% of each category of collected retail meat, vegetables and fish or seafood was contaminated with coliform bacteria. The contamination rate of fecal coliform bacteria, Staphylococcus spp. and lactic acid bacteria was higher in vegetables from open markets than those from supermarkets, and the contamination rate of Staphylococcus spp. was likewise higher in fish or seafood samples purchased from open markets than those from supermarkets. Improvement in hygienic practices throughout the food distribution may reduce the risk of food poisoning and spoilage of foods purchased in Thai markets.
    Food Science and Technology Research 01/2012; 18(5):705-712. DOI:10.3136/fstr.18.705 · 0.35 Impact Factor
  • The 2nd Asia Pacific Symposium on Postharvest Research, Education, and Extension; 09/2011
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    ABSTRACT: The decontamination effect of milling by a jet mill was investigated by counting the number of bacteria in brown and white rice flour with mean particle diameters of 3, 20, and 40µm prepared by the jet mill. In the jet mill, the particles are crushed and reduced in size by the mechanical impact caused by their collision. Although the brown and white rice grains were contaminated with approximately 10(6) and 10(5) CFU/g bacteria, the microbial load of the rice flour decreased as the mean particle diameter decreased, ultimately decreasing to approximately 104 and 103 CFU/g in the brown and white rice flour. The temperature and pressure changes of the sample were not considered to have an effect on reducing the bacterial count during the milling. Hence, it was thought that the rice flour was decontaminated by other effects.
    Biocontrol science 06/2011; 16(2):79-83. DOI:10.4265/bio.16.79 · 0.75 Impact Factor
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    ABSTRACT: Milling method and particle size affect some properties of rice flour. To prepare ultra-fine rice flour of <30 μm, hammer and dry jet grinding methods were examined and the effect of particle size on starch damage and pasting properties of the flour were elucidated. A jet mill could make finer flour (<10 μm mean size) with a narrower particle size distribution than a hammer mill could. Starch damage increased dramatically at a mean size of <10 μm. Particles of a similar size (<60 μm) had different levels of starch damage between mills. Not only the particle size, but also the milling method affected the level of damaged starch. Flour samples of ≥45 μm mean size had similar viscosity curves, but samples of <20 μm had different curves. Peak viscosity and final viscosity decreased sharply at <10 μm. Setback viscosity for particles of 3 μm from both brown rice and white rice were higher than the peak viscosity. Stability to heat and shearing stress were decreased for <20 μm flours as the breakdown viscosities decreased. Starch damage and pasting properties of flour ground from the nonwaxy japonica cultivar Koshihikari changed dramatically at a mean size of <10 μm.
    Cereal Chemistry 02/2011; 88(1):6-11. DOI:10.1094/CCHEM-04-10-0061 · 1.23 Impact Factor
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    ABSTRACT: Processes of biodegradable molded products were developed. However, to make commercial products to adapted each purpose is still under going. So, this time, to improve the molded products properties, we tested to blend with PLA (polylactic acid) or PBSA (Poly butylenes succinate adipate) into CGM(Corn gluten meal) based agro by-products ingredient.Molded samples were able to make from all tested material and each sample had each physical properties. Finally, we selected suitable condition for practical field test of Large Sapling Pot for Persimmon saplings. Such application will be addressed in our talk and general situation of biodegradable products by biomass resources in Japan will be also introduced.
    MRS Online Proceeding Library 01/2011; 1219. DOI:10.1557/PROC-1219-AA04-01
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    ABSTRACT: The leaching losses of potassium from potatoes during soaking in hot water were measured at four temperatures ranging from 70°C to 100°C. The infinite cylinder diffusion model was used to describe the leaching losses, and the measured data were fitted to a model using a non-linear least squares method. The measured results agreed well with the calculated results. The values determined for the diffusion coefficients were 1.05×10 -6 to 2.05 × 10 -6 (m 2-s -1), and the apparent activation energy determined from an Arrhenius-type equation was 24.4 (kJ-mol -1). The applicability of using microwave for blanching potatoes was also examined. Changes in enzyme (peroxidase) activity, texture and potassium content were measured and compared between blanching by boiling water, microwaves or a combination of microwaves and boiling water. The combination of microwave and boiling water required the least amount of time for inactivation of the enzyme. Blanching using microwave tended to damage samples. Moreover, blanching using microwaves caused significant softening while the combination of microwave and boiling water caused less change in shape and texture. The residual ratio of potassium in the sample blanched using a combination of microwave and boiling was approximately 80% ; similar to that of potatoes blanched using boiling water. These results suggest that the combination of microwave and boiling water can be used for blanching potatoes.
    Nippon Shokuhin Kagaku Kogaku Kaishi 01/2011; 58(7):284-290. DOI:10.3136/nskkk.58.284 · 0.11 Impact Factor
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    Itaru Sotome · Seiichiro Isobe
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    ABSTRACT: Superheated steam (SHS) was applied to food processing because of advantages including efficient heat transfer by latent heat, and prevention of product oxidation. SHS heating solves problems such as water absorption and dissolution of solid content from foods caused by hot water or saturated steam heating; however, it causes low product yield due to its high drying capacity. To fix these problems, a new system using SHS around 115°C and a spray of hot water micro droplets (WMD) has been devel-oped. The SHS+WMD system has simultaneously improved the quality and yield of blanched pota-toes and other vegetables. In addition, it was found that WMD increased the heat transfer efficiency of SHS. This was presumably because WMD reduced the thermal resistance of the condensed water layer on the product surface by stirring the condensate. Due to this effect, the required time for the surface pasteurization of some kinds of raw vegetables decreased. A standard plate count of bacte-rium on cucumber fruit decreased from 10 5 CFU/g to 300 CFU/g with a slight texture change by SHS+WMD heating for 30 s. The SHS+WMD system is currently used in the food industry for cook-ing potato salad, and preprocessing meat, as well as the pasteurization of fishery products in Japan.
    Japan Agricultural Research Quarterly 01/2011; 45(1). DOI:10.6090/jarq.45.69 · 0.44 Impact Factor
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    ABSTRACT: To effectively recover polymethoxyflavonoids (PMFs) from Citrus depressa fruits, different types of extractors were combined in two types of multi-stage extraction systems. The 2-stage extraction system utilized the caterpillar and twin-screw presses, and the 3-stage extraction system utilized the caterpillar, roller, and twin-screw presses. Material balance and distribution of PMFs, extraction rate, and electric power consumption of each stage and total system were evaluated. Compared with single extraction, multi-stage extraction improved the efficiency of PMF recovery in the juice from the fruit; there was no significant difference between the 2- and 3-stage extraction systems. More than 30% of the PMF content was recovered in the juice by these systems. The multi-stage extraction system for Citrus depressa allows production of second- and third-stage juices which contain higher concentration of PMFs and reduction of extraction residue.
    Food Science and Technology Research 11/2010; 16(6):627-630. DOI:10.3136/fstr.16.627 · 0.35 Impact Factor
  • Japan Society of Food Engineering; 08/2010
  • International Conference on Food Applications of Nanoscale Science; 06/2010
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    ABSTRACT: This study demonstrated the effect of extrusion processing on the functional properties of extruded snack foods developed from cereal and legumes, and the by-products from herbs and vegetables. The functional properties considered were antioxidant capacity, total phenolic compounds and resistant starch content. The results showed that Japanese green tea had the highest antioxidant capacity and phenolic content (68.31mmol Trolox/g and 337.58 mg GAE/g, respectively) and egoma leaves had the second highest (8.35 mmol Trolox/g and 60.60 mg GAE/g, respectively). Red kidney beans had the highest resistant starch content (33.78 % w/w) and corn grits had the second highest content (13.67% w/w). The extrusion process slightly decreased the antioxidant capacity (3.61-13.07%) and phenolic content (4.54-29.75%), but substantially decreased the resistant starch content (89.17-96.33%) for all extruded products. The extrusion process was suitable to produce functional snack foods, while retaining their antioxidant capacity.
    Kasetsart Journal - Natural Science 03/2010; 44(2):271-279.
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    ABSTRACT: The applicability of microwave to the drying and blanching of tomatoes was examined. The changes of the drying rate and surface color were first measured and compared between drying by hot air (50°C) or microwave at three radiation powers. The drying rates using a microwave were higher than that using hot air. Both a constant-rate drying period and a falling-rate drying period were observed for each microwave radiation power. Compared to hot air drying, microwave drying resulted in an increase in lightness which is a preferable quality of tomatoes. Next, the changes in temperature, nutrients and surface color were measured and compared between blanching by microwave or boiling water. Microwave blanching required less time, resulted in higher retention of nutrients (ascorbic acid and lycopene) and caused less change in color in comparison with boiling water blanching. These results suggest that a microwave could be applied to drying and blanching tomatoes.
    Nippon Shokuhin Kagaku Kogaku Kaishi 01/2010; 57(5):191-197. DOI:10.3136/nskkk.57.191 · 0.11 Impact Factor
  • Tunisia-Japan Symposium on Science, Society & Technology, P.104; 11/2009

Publication Stats

2k Citations
117.48 Total Impact Points


  • 1999–2013
    • National Food Research Institute
      Ibaragi, Ōsaka, Japan
    • Tsukuba Research Institute
      Edo, Tōkyō, Japan
  • 2000–2012
    • University of Tsukuba
      Tsukuba, Ibaraki, Japan
  • 2004
    • Ochanomizu University
      Tōkyō, Japan
  • 1994
    • Rice University
      Houston, Texas, United States