| 摘要: |
| 超声波可以促进晶核形成，缩短冻结时间并且获得较高的冻结品质，但该技术目前多用于液态样品或浸渍冷冻过程，在固体果蔬样品平板冷冻过程中的应用未见报道。本文设计制作了一种接触式超声波辅助冷冻平板，用于固体果蔬的冷冻过程，并进行了三组实验：1）在﹣1 ℃施加10 s不同功率（0，122.6，178.7，229.8 W）的超声波；2）在﹣1 ℃施加178.7 W超声波，作用0，5，10，15 s；3）在不同阶段（预冷段，相变段，终了段）施加178.7 W的超声波10 s。分别研究了超声波的作用功率、作用时间、作用阶段等参数对胡萝卜冷冻速率的影响，结果表明：在相变阶段作用178.7 W的超声波10 s，能显著降低样品通过最大冰晶生成段的时间tcf和总冻结时间ttf，提高样品的冷冻速率。 |
| 关键词: 超声波 平板冷冻 冷冻速率 胡萝卜 |
| DOI： |
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| 基金项目:国家自然科学基金（51376132）资助项目。 |
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| Influence of Contact Ultrasound Assisted Vibrating Plate on the Freezing Rate of Carrot |
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Zhou Xinli, Teng Yun, Dai Cheng
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| (School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology) |
| Abstract: |
| Ultrasound can promote the formation of crystal nucleus, shorten the freezing time and get a higher quality freeze, but the technology is currently used for the liquid samples or immersion freezing process, and solid samples were barely taken into account. In this paper, the contact ultrasonic assisted vibrating plate was designed and set up, which is used for the freezing process of solid fruits and vegetables. The effects of ultrasound power, exposure time and phase stage on the freezing rate of the carrot were investigated. The experiments are divided into three groups: 1）applying ultrasound with different powers (0,122.6,178.7,229.8 W) for 10s at -1 ℃; 2）applying 178.7 W ultrasound at -1 ℃ for 0,5,10,15 s respectively; 3）applying 178.7 W ultrasound for 10 s during different phase stages. The results showed that the optimum condition is applying 178.7 W ultrasound for 10 s during transition phase，which can significantly reduce the tcf (characteristic freezing times) and ttf ( total freezing times) and increase the freezing rate of samples. |
| Key words: ultrasound plate freezing freeze rate carrot |
