基于介电特性预测苹果的损伤体积

Prediction of Damage Volume on Apple Basing the Dielectric Property

水果的介电特性与其损伤密切相关,可利用其对苹果的损伤程度进行快速评价。用万能实验机对红富士苹果施加不同大小的压力,在常温(22±1)℃贮藏29 d的过程中测试其损伤体积和介电参数。结果表明:受伤苹果的损伤体积和相对介电常数随贮藏时间的延长而增大,且受压力越大其损伤体积和相对介电常数越大;受伤苹果在贮藏期间的损耗因数呈波动变化,且不同程度压伤果ε″差异不显著,用损耗因数不能预测伤果的损伤体积。伤果的相对介电常数和损伤体积间呈显著正相关(r=0.921),用相对介电常数对损伤体积进行预测的方程为VB=-1.374+0.227ε'(R2=0.848)。对方程的验证发现,预测结果与测定结果间的平均偏差为23.37%。为快速评价水果的受伤程度提供检测方法,也将为利用介电特性法评价水果品质奠定基础。

Dielectric property was used to rapidly evaluate the degree of damage basing the obviously correlation between dielectric property and damage of fruit.Fuji apples which were pressed in different static pressure by universal testing machine were stored 29 days in room temperature（ 22 ± 1） ℃ and monitored the change of damage volumes and dielectric parameters.The results showed that the damage volume and relative dielectric constant of damaged apple increased with the prolongation of storage time,which were bigger with the increasing of pressure,and the loss factor ＇s change of apple was variable during storage and could＇t be used to predict the damage volumes because of the difference of ε″ was non-significant on the degree of damage.The equation,which was built basing the significant positive correlation between relative dielectric constant and damage volume（ r = 0.921） to predict damage was VB=-1.374 ＋ 0.227ε＇（ R2= 0.848）. By relative dielectric constant and the mean variation between prediction result and experiment result was 23.37%. The research result could provide new method for evaluating fruit quickly and build the basement for evaluating fruit by dielectric property.