葡萄冷藏中电学参数与质地特性变化规律

    Law of dielectric parameters and texture properties for grape during cold storage

    • 摘要: 为了探讨采后葡萄电学参数与质地特性的变化规律,以红地球葡萄为材料,利用HIOKI 3532-50型LCR测量仪和自制平行板铜电极,在0.1~3?980 kHz频率范围内选取24个频率点,对采后冷藏果实进行了电学参数的动态测定,并研究了其与果实质地参数硬度、咀嚼性、黏着性和弹性之间的相关性,筛选出了电学参数较佳测试频率,建立了电抗X与质地参数的二元二次回归方程。结果表明,葡萄果实复阻抗Z、电感Lp、电抗X和电阻Rp随测试频率升高呈指数形式下降;在同一频率下,果实Z、Lp、X和Rp随着贮藏时间的增加呈线性下降趋势。随着果实的衰老,质地参数硬度和咀嚼性逐渐下降,黏着性绝对值和弹性呈上升趋势。在较佳测试频率0.1 kHz下,电学参数与质地参数呈现较高相关性,其中电抗X与硬度、弹性、黏着性呈现显著相关性(P<0.05),同时与咀嚼性达到较高相关性,并建立了二者之间的关联方程,为实现葡萄无损检测提供了依据。

       

      Abstract: Dielectric parameters were non-destructively measured over frequency range from 0.1 kHz to 3980 kHz with a parallel-plate copper electrode and HIOKI 3532-50 LCR meter in order to study the law of dielectric and texture parameters of Red Globe grape during cold storage at 0℃. Firmness, chewiness, springiness and adhesiveness of grape were measured as texture attributes for correlation with the dielectric properties. The optimum frequency for dielectric properties test was identified and the regression equation was built. The results showed that fruit impedance, resistance, inductance and reactance decreased gradually by exponential form with the increase of frequency and 0.1 kHz was the optimum frequency for dielectric properties test. At the optimum test frequency, impedance, resistance, inductance and reactance decreased linealy with the extension of storage time. At the same time, firmness and chewiness decreased gradually with the time went on, springiness and the absolute value of adhesiveness went up contrarily. At 0.1 kHz frequency, the high correlation was found between dielectric and texture parameters, such as reactance with texture parameters (P<0.05). At last, the regression equation was built for dielectric and texture parameters, reactance could be used as sensitive dielectric parameter marking variations of texture properties.

       

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