基于生物阻抗特性的苹果新鲜度无损测定

Non-destructive Detection of Freshness Grade for Apple Fruit Based on Bio-impedance Properties

摘要:

以红富士苹果为试材，在室温下贮存得到失重率0、5%、10%、15%和果心褐变果实，分别定义为1、2、3、4、5级新鲜度，采用LCR阻抗仪测定各等级共424个果实的14个生物阻抗参数在9个频率点下的126个特征值。通过稀疏主元分析-线性分类器（SPCA-LDC）模型试验，得出适宜的选样比例（训练样本数与测试样本数之比）为9∶1，主元数达到前39～45个时分级正确率达到最大值；构成至少39个主元的生物阻抗特征参数为44个；50次重复试验的分级正确率平均值为87.90%。

Abstract:

Bioimpedance properties of Fuji apple fruit with different freshness were investigated. Fruit with weight loss of 0, 5%, 10%, 15% and core-browning under room temperature were chosen as samples corresponding to descending freshness grades of 1,2,3,4,5, respectively. 126 observations of 14 bio-impedance parameters under nine frequencies of total 424 fruit from each grade were measured fruit by fruit with LCR impedance meter. Data were computed by using the sparse principal component analysis-linear classifier (SPCA-LDC) model. Results indicated that classification accuracy reached to maximum stably when the ratio of training sample to test sample of 9∶1 and former 39～45 principal component (PC) were adopted. The least 39 PCs were consisted of 44 from the 126 observations. Average rate of classification accuracy reached to 87.90% within 50 test repeats. 