| Project/Area Number |
16560178
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | KANAZAWA UNIVERSITY |
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Principal Investigator |
TADA Yukio Kanazawa University, Graduate School of Natural Science and Technology, Associate Professor, 自然科学研究科, 助教授 (20179708)
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| Co-Investigator(Kenkyū-buntansha) |
TAKIMOTO Akira Kanazawa University, Graduate School of Natural Science and Technology, Professor, 自然科学研究科, 教授 (20019780)
ONISHI Hajime Kanazawa University, Graduate School of Natural Science and Technology, Research Associate, 自然科学研究科, 助手 (80334762)
YOSHIOKA Hideaki Toyama National college of technology, Associate Professor, 商船学科, 助教授 (80259845)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2005: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2004: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Freezing / Ultrasound / Ice formation / Ultrasonic cavitation / Food / Freezing injury / キャビテーション |
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| Research Abstract |
Freezing can slow down or stop some biological reactions for preserving food. It is also true that the freezing is lethal to keeping the taste of food. During freezing, the extra- and intra-cellular ice formation, osmotic water permeation through cell membrane, deformation of the cell and other behavior occur at microscale and they bring serious injuries connecting to drip and denaturation of protein.
A method to actively controlling crystallization is one of promising technique for cryopreservation. The object of this project is to study the effects of ultrasonic irradiation on ice formation during freezing of biological materials. In the experiments, agar gel and/or potato tissue was frozen under irradiation of ultrasound at frequency of 28kHz. The measurements of temperature and the microscopic observation of ice crystals by using fluorescent indicator were carried out.
Firstly, the cooling rate of sample augmented according to the increase of the ultrasonic power, since acoustic streaming and flow disturbance due to acoustic cavitation increased. Secondly, it was found that ice structure size decreased with increasing ultrasonic power in case of rapid cooling. Furthermore, the ultrasonically induced effects on freezing was analyzed using local cooling rate defined at freezing front. It was clarified that smaller ice crystals were formed by irradiating ultrasound, comparing with case without ultrasound, under being the same local cooling rate. Therefore, there are effects on ice formation through not only enhancing local cooling rate due to acoustic streaming, but also other relevant phenomena. The mechanism of sonocrystallisation in biological tissue was discussed in relation to ultrasonic power and cooling rate.
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