食品科学 ›› 2018, Vol. 39 ›› Issue (19): 103-113.doi: 10.7506/spkx1002-6630-201819017

• 食品工程 • 上一篇    下一篇

树莓果片微波膨化机理

苏晓琳1,2,薛宏坤1,刘成海1,郑先哲1,*   

  1. 1.东北农业大学工程学院,黑龙江 哈尔滨 150030;2.黑龙江民族职业学院食品学院,黑龙江 哈尔滨 150066
  • 出版日期:2018-10-15 发布日期:2018-10-24
  • 基金资助:
    国家自然科学基金面上项目(31271911)

Mechanistical Study of Microwave Puffing of Raspberry Fruit Chip

SU Xiaolin1,2, XUE Hongkun1, LIU Chenghai1, ZHENG Xianzhe1,*   

  1. 1. College of Engineering, Northeast Agricultural University, Harbin 150030, China; 2. College of Food, Heilongjiang Vocational College for Nationalities, Harbin 150066, China
  • Online:2018-10-15 Published:2018-10-24

摘要: 为了揭示微波加热树莓果片的体积膨胀机理,对树莓果片微波膨化特性进行研究,根据电磁场、传热场、结构力学及稀物质传递理论,建立了树莓果片微波膨化四场耦合模型,选取微波强度和初始水分质量分数作为影响参数,得到了膨化过程中树莓果片的温度分布、水分质量分数及膨胀变形的变化规律,并与实验结果进行对比分析。结果表明:微波加热条件下,果片内部的水分蒸发使得果片内产生较高的压力,推动果片膨胀,果片表面水分的蒸发使得果片发生收缩行为,膨胀和收缩这两种相反的趋势最终决定树莓果片的体积变化。果片的温度分布主要由微波穿入果片的渗透深度决定,随着微波加热时间的延长,果片的水分质量分数逐渐降低。温度的升高和水分质量分数的降低导致树莓果片弹性模量的增大,弹性模量的变化影响着果片体积的膨胀。当微波强度为20~40 W/g、果片初始水分质量分数为26%时,膨化后树莓果片的品质较好,且膨化率也比较高,最大膨化率可达到3.91。

关键词: 树莓果片, 初始水分质量分数, 微波强度, 微波膨化, 膨化机理

Abstract: The present study concentrated on the volume expansion mechanism of raspberry fruit chip during microwave heating. To investigate the puffing characteristics of raspberry fruit chips, four-filed coupling models based on the theories of electromagnetic field, heat transfer, structural mechanics and the Transport of Diluted Species physics were established to describe temperature distribution, moisture content and expansion deformation as a function of microwave intensity and initial moisture content, respectively, and they were evaluated by comparison with the experimental results. The results obtained indicated that high pressure inside fruit chips was generated due to water evaporation from the interior during microwave heating, leading to expansion of the chips. On the other hand, water evaporation from the surface resulted in shrinkage of fruit chips. The volume change of raspberry fruit chips was dependent on both expansion and shrinkage. The temperature distribution was mainly dependent on the penetration depth of microwave into the material. The moisture content was decreased gradually with the increase of microwave heating time. The increased elastic modulus of raspberry fruit chips was due to the increase of temperature and the decrease of moisture content, which influenced the volume expansion of fruit chips. Microwave intensity of 20–40 W/g and initial moisture content of 26% gave a better product with a higher expansion percentage of 3.91.

Key words: raspberry chips, initial moisture content, microwave intensity, microwave puffing, puffing mechanism

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