Seiichiro Isobe

Nihon University, Edo, Tokyo, Japan

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Publications (97)118.63 Total impact

  • Toshihiro Ito · Mitsutoshi Nakajima · Seiichiro Isobe
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    ABSTRACT: Cornstarch was extruded using various feed moistures and screw speeds with and without soybean oil. We investigated the effects of each variable and interactions between variables on extrudate characteristics. In starch, the positive linear effect of screw speed and the negative effect of the interaction between moisture and screw speed were significant factors in the degree of gelatinization (DG). The positive linear effect of feed moisture and screw speed and their negative interaction were significant factors in the oil-added extrudates. The water absorption index (WAI) of both extrudates was determined by the linear and quadratic effect of feed moisture and the negative interaction between the two variables. In starch, the positive quadratic effect of moisture and screw speed and their negative interaction affected the water solubility index (WSI). In the oil-added extrudates, the negative effect of feed moisture and the negative interaction of screw speed and feed moisture influenced WSI.
    No preview · Article · May 2015 · Food Science and Technology Research
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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.
    No preview · Article · Jul 2013 · Food Science and Technology Research
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    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.
    Preview · Article · May 2013 · Bioscience Biotechnology and Biochemistry
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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.
    Full-text · Article · Mar 2013 · Japan Journal of Food Engineering
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    ABSTRACT: Soybean curd (Tofu) is a popular food for many people, especially those with health concerns. The objective of this study, therefore, was to evaluate the contamination rate and types of foodborne pathogens and food spoilage bacteria in packaged and unpackaged tofu sold in Thai markets. A total of 133 tofu samples (59 packaged tofu samples and 74 unpackaged tofu samples) were collected from open markets and supermarkets in Thailand. The predominantly identified Gram-negative bacteria were coliforms (67% in tested samples), Pseudomonas spp. (56%) and Escherichia coli (28%) and the predominantly identified Gram-positive bacteria were Enterococcus spp. (77%), lactic acid bacteria (68%), Bacillus cereus (41%) and Staphylococcus spp. (26%). No Listeria spp. were found in any of the tofu samples. The contamination rates of E. coli, Salmonella spp. and Enterococcus spp. in unpackaged tofu were significantly higher than those in packaged tofu (P < 0.05). Three kinds of Gram-negative pathogenic bacteria, Cronobacter sakazakii, Salmonella spp. and Yersinia enterocolitica (serotype 0:5), were found only in unpackaged tofu samples. Of 54 B. cereus isolates, four isolates from three unpackaged tofu samples and one packaged tofu sample were found to produce diarrheal enterotoxin. The most common Enterococcus spp. isolates were Enterococcus faecium and Enterococcus faecalis. These results suggested that the improvement of hygienic practices might be required for reducing the risk of food poisoning and food spoilage of tofu in Thailand.
    No preview · Article · Nov 2012 · Food Science and Technology Research
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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.
    No preview · Article · Sep 2012 · Foodborne Pathogens and Disease
  • T. Orikasa · Y. Ando · T. Shiina · I. Sotome · S. Isobe · T. Yano · A. Tagawa
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    ABSTRACT: The applicability of microwave radiation in the drying and blanching tomatoes was examined. Blanching was performed using hot water (90°C) and microwave radiation (100 W/g dry sample), and the changes in the temperature, nutrient contents, and surface color of the sample were measured and compared. The drying rate with the microwave treatment was greater than that with the hot water treatment, and the constant rate and the falling rate drying periods were observed at each microwave radiation power. Microwave drying caused a greater increase in lightness than hot air drying. Microwave blanching required less time, resulted in higher retention of nutrients (ascorbic acid and lycopene), and caused less change in color than boiling water blanching. These findings suggest the applicability of microwave radiation for the drying and blanching of tomatoes.
    No preview · Article · Jun 2012 · Acta horticulturae
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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.
    Full-text · Article · Mar 2012 · Japan Journal of Food Engineering
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    ABSTRACT: This study focused on the high radical-scavenging activity of onion extract (onion-flavor seasoning made from onion) and aimed to clarify its changing profile. Radical-scavenging activity, amount of major flavonoids, and browning degree during onion extract processing were measured. In heat processing of concentrated onion juice, radical-scavenging activity and browning degree significantly increased, and most flavonoids disappeared. The principal component of the radical-scavenging activity of onion extract was found to be melanoidin. The fractionation of onion extract using solidphase extraction based on hydrophobic interaction showed that the fraction exhibiting higher hydrophobicity had higher radical-scavenging activity and browning degree.
    No preview · Article · Jan 2012 · Nippon Shokuhin Kagaku Kogaku Kaishi
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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.
    No preview · Article · Jan 2012 · Food Science and Technology Research
  • Ye Chen · Ning Zhang · Guan Yu Wang · Yue Du · Seiichiro Isobe
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    ABSTRACT: Blends of Corn gluten meal (CGM) and poly (lactic acid) (PLA) plasticized with glycerol, water and ethanol, were extruded into pellets using single-screw extruder, and the pellets were compression-molded into composites, and the tensile strength, water resistance, thermal stability and morphology of the composite were evaluated. The results showed that PLA reinforced the composite, improved the water resistance. The structure of composite was observed by scanning electron microscopy (SEM), it was showed that PLA formed a network structure, and the modified CGM inlay in network. The result of thermal gravimetric analysis (TGA) considered that the composite could keep thermal stability below 180 °C.
    No preview · Article · Dec 2011

  • No preview · Conference Paper · Sep 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.
    No preview · Article · Jun 2011 · Biocontrol science
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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.
    No preview · Article · Feb 2011 · Cereal Chemistry
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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.
    No preview · Article · Jan 2011 · Nippon Shokuhin Kagaku Kogaku Kaishi
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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.
    No preview · Article · Jan 2011 · MRS Online Proceeding Library
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    ABSTRACT: Superheated steam was applied to food processing because of advantages that include e cient heat transfer by latent heat and the prevention of product oxidation. Superheated steam solves problems such as water absorption and the 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. In order to extend the application of superheated steam to food processing, a new oven system (Aqua-gas ) using superheated steam and micro droplets of hot water has been developed. In this system, a mixture of superheated steam and hot water was achieved under normal pressure by spraying pressurized boiling water into a heating chamber through a nozzle. It was found that Aqua-gas has a higher heat transfer rate than ordinal superheated steam, especially with cold materials. Fresh vegetables have been pasteurized e ectively with little change in texture by heating with this system. The moisture content of the food product processed with this oven system can be controlled by regulating the amount of micro droplets used in the superheated steam. This system is currently used in the food industry for cooking potato salad, preprocessing meat, and in the pasteurization of fish products in Japan.
    No preview · Article · Jan 2011 · Nippon Shokuhin Kagaku Kogaku Kaishi
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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.
    Preview · Article · Jan 2011 · Japan Agricultural Research Quarterly
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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.
    No preview · Article · Nov 2010 · Food Science and Technology Research

  • No preview · Conference Paper · Aug 2010

Publication Stats

2k Citations
118.63 Total Impact Points

Institutions

  • 2015
    • Nihon University
      • Department of Industrial Engineering and Management
      Edo, Tokyo, Japan
  • 2000-2013
    • University of Tsukuba
      • Institute of Agriculture and Forestry
      Tsukuba, Ibaraki, Japan
  • 1999-2013
    • National Food Research Institute
      Ibaragi, Ōsaka, Japan
    • Tsukuba Research Institute
      Edo, Tōkyō, Japan
  • 2011
    • National Agriculture and Food Research Organization
      Tsukuba, Ibaraki, Japan
  • 1994
    • Rice University
      Houston, Texas, United States