食品科学

• 基础研究 • 上一篇    下一篇

利用低场核磁共振技术分析冬瓜真空干燥过程中的内部水分变化

李 娜,李 瑜*   

  1. 河南农业大学食品科学技术学院,河南 郑州 450002
  • 出版日期:2016-12-15 发布日期:2016-12-21

Analysis of Internal Moisture Changes of Benincasa hispida during Vacuum Drying Using Low-Field NMR

LI Na, LI Yu*   

  1. College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China
  • Online:2016-12-15 Published:2016-12-21

摘要: 为研究冬瓜真空干燥过程中内部水分的含量、分布及状态变化,应用低场核磁共振(low-field nuclearmagnetic resonance,LF-NMR)技术,测定不同干燥条件下冬瓜真空干燥过程中的横向弛豫时间T2反演谱,进而分析冬瓜样品内部的水分状态及其变化规律。结果表明:在真空干燥过程中,冬瓜干基含水率与NMR信号幅值之间呈显著的线性关系;真空干燥过程改变了样品的横向弛豫时间T2,增加了冬瓜内部不易流动水的含量、降低了水分的流动性;不同干燥温度条件下,结合水所占比例、自由水所占比例随着干燥时间的变化分别呈指数模型、多项式模型,且拟合方程的决定系数均大于0.95,拟合精度较高。该研究为进一步研究产品的保藏提供技术指导,为冬瓜的真空干燥实际产业化生产控制提供理论依据。

关键词: 冬瓜, 真空干燥, 水分, 低场核磁共振, 横向弛豫时间

Abstract: The objective of this work was to explore the water content, distribution and state changes of Benincasa hispida
during vacuum drying. The transverse relaxation time T2 inversion spectra of Benincasa hispida at different temperatures
during the drying process were measured and the characteristics of internal moisture state and changes were analyzed using
low-field nuclear magnetic resonance (LF-NMR). The results showed that the linear relationship between total NMR signal
amplitude and moisture content on a dry base during drying was established. The transverse relaxation time T2 was changed
and moisture mobility was reduced during the drying process. The moisture with high degree of freedom moved to the
moisture with low degree of freedom. The kinetic models describing the percentages of bound and free water versus drying
time followed an exponential function and a polynomial function, respectively, at different drying temperatures. The high
regression coefficients (R2 > 0.95) indicated high fitting precision of the equations. This research can provide a theoretical
basis for industrial production and preservation of Benincasa hispida.

Key words: Benincasa hispida, vacuum drying, moisture, low-field nuclear magnetic resonance (LF-NMR), transverse relaxation time T2

中图分类号: