Bulletin of Hiroshima Prefectural Technology Research Institute Food Technology Research Center
Online ISSN : 2435-5909
Print ISSN : 1883-8324
ISSN-L : 1883-8324
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  • Yayoi WATANABE, Sayaka NAKATSU
    2020 Volume 29 Pages 1-5
    Published: March 16, 2020
    Released: October 02, 2020

    We studied the influence of the preliminary solution immersion process on silver salmon specimens dried by hot air. For immersion, NaCl, sodium citrate, calcium lactate, sorbitol, and protease solutions were used. After immersion, the silver salmon specimens were heated at 90°C and dried by air blow at 60°C. The moisture content of the salmon specimens that were dried after immersion in a NaCl, sodium citrate, calcium lactate, or protease solution was lower than that of the control specimens that were not subject to the immersion treatment. The a* value was high in measurements using a chroma meter (L*a*b* value), and the number of breaks was high in the physical property analysis. The number of breaks and maximum load of 20 types of commercially available confectionery were compared with those of the dried salmon specimens in the physical property analysis, and the results were mapped. The drying rate of salmon specimens that were immersed in NaCl and sodium citrate solutions was higher than that of other specimens both in the first half and second half of the drying process. The results suggested that the moisture in the specimens was easily diffusible.

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  • Tomoko FUJIWARA, Kentaro NISHIHAMA, Ritsushi OHDOI, Risa YAMASAKI
    2020 Volume 29 Pages 7-12
    Published: March 16, 2020
    Released: October 02, 2020

    The H16-2 strain of Hiroshima Momiji yeast is a sake yeast derived from crossbreeding. It is characterized by a high fermentative capacity and is capable of producing 7 to 8 ppm of ethyl caproate in brewed sake. To increase the varieties of Hiroshima Momiji yeast, we made improvements to increase the acid productivity while maintaining the characteristics of the H16-2 strain (e.g., fermentative capacity, ethyl caproate productivity). The H16-2 strain was used as the parent strain, and candidate strains with improved acid productivity were obtained from the strain resistant to cycloheximide. Two strains were selected based on the koji extract fermentation test and the small scale brewing test (total rice:1 kg). In the brewing test (total rice: 110 kg), the No. 72 strain was determined to meet the target. The acidity of the sake brewed from the No. 72 strain was 1.1 times that of the H16-2 strain.

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  • Yujin SHIGETA, Mikako NAKANISHI, Masahiro MASTUBARA, Tadahiko SHIONO, ...
    2020 Volume 29 Pages 13-18
    Published: March 16, 2020
    Released: October 02, 2020

    Staining with 5(6)-Carboxyfluorescein diacetate (CFDA) is widely used as a rapid counting method for viable bacteria. However, bacterial spores are not stained by CFDA. We studied a method of staining bacterial spores using CFDA after hydrostatic pressure-induced germination. The B.subtilis spores were stained using CFDA by pressurization at 50 MPa or more. The stained spore counts by fluorescence microscopy were almost equivalent to viable counts measured in the cultivation method. Twelve types of Bacillus spores and Geobacillus stearothermopilus spores were measured using this method. The difference of the measured values between the staining method and the cultivation method was within one log-cycle. We also inoculated B.subtilis spores in a liquid seasoning and measured the counts after hydrostatic pressure-induced germination (100 MPa, 40°C, 15 min) using a commercially available rapid measurement device. The correlation coefficient of the rapid method and the cultivation method was 0.99. The results suggested that the CFDA staining method using pressurization may be used for rapid counting of bacterial spores.

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Technical Report
  • Tomoko FUJIWARA
    2020 Volume 29 Pages 23-26
    Published: March 16, 2020
    Released: October 31, 2020

    I studied a simple and rapid method for measuring the alcohol concentration of miso using an ethanol sensor. The ethanol sensor was capable of accurately measuring an ethanol concentration of 1% (w/v) or less within the temperature range between 15 and 30°C. It was confirmed that the ethanol sensor also detected alcohols other than ethanol. Regarding the measurement method, an ethanol sensor probe was placed in the gas of a vessel containing a mixture of miso and water nine-fold that of miso at room temperature. The value 60 seconds after commencement of measurement was used as the measured value. The regression line, which was obtained based on the oxidation method analysis values of the alcohol concentration of miso using the measured values, was considered to be useful for prediction. Based on the regression coefficient, the alcohol concentration (w/w%) of miso was estimated to be the value measured using the ethanol sensor × 8.7. There was a very strong correlation between the estimated values and the oxidation method analysis values. It was judged that this measurement method is sufficiently useful.

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