Study On The Correlation Between Bio-Impedance Parameters And Inner-Browning Of Fujiapple Fruit

Using’Chang-Fu II’apple fruit as material, impedance parameters, physical-chemical indices、inner-browning rate as well as ethylene peoduction rate were measured under different treatments of temperature and package (refrigeration with high CO2、storing at room temperature with high CO2、refrigeration with bare-naked fruits、storing at room temperature with bare-naked fruits、refrigeration with PVC).Statistic correlation were analyzed between impedance and other group of properties of fruit to investigate the correlation between the changes of impedance and the variation of quality indice,inner-browning,respectively.The aim of this study is to probe the possibility and approach to indicate inner-browning of apple fruit with impedance parameter.All result were as following.(1)The determination of quality which storing at room temperature with high CO2showed that, With the prolonging of the storage time, firmness and soluble solid content presented a fluctuated trend, soluble solid/titratable acid increase gradually, density and titratable reduce gradually. In the ten of impedance parameters,Z、Cs、Ls、0、X reduce, D、 B、ε’、ε" increase gradually, but Rs did not change regularly with the prolonging of the storage time.(2)Related analysis shows that density and impedance parameters have a highest correlation, followed by soluble solid/titratable acid, redox potential. The equation of regression about the correlation of quality indices and impedance parameters are established: Y1(soluble solid/titratable acid)=-16.295+8.429*1010Cs(P<0.05R2=0.833); Y2(density)=-113.235-0.049ε"-8.956deg (P<0.01R2=0.998); Y3(redox potential)=102.991+0.016ε’(P<0.05R2=0.816). After the verification of test samples, the relative error of evaluation of three quality indices were8.65%(Y1),38.43%(Y2),7.27%(Y3), respectively.(3) The characteristic value of impedance parameters increase or decrease gradually with the increase of browning level at the same frequency, presented a correlation between impedance parameters and fruits browning. The difference between serious browning and sound fruits is most obviously. The serious browning and moderate browning, mild browning, sound fruits can be distinguished by using value Z, Ls, X with0.1K～1000KHz, Rs with10K～100KHz, D with39.8K～1000KHz,θwith1K～3980KHz, B with39.8K～398KHz, ε’with3.98K～1000KHz, ε" with1KHz and3980KHz.(4)The impedance parameters at low temperature change with days in the same as room temperature, but the rate of its rise or descend slow significantly. The package of high CO2at room temperature significantly reduce the characteristic value of Cs、B、ε’ under the different frequency, but significantly promote the characteristic value of Cs、B、ε’. Other logarithm of impedance parameters response irregular to different packaging.(5)The ethylene production peak of high CO2packaging at cold storage and bare fruit at room temperature storage was significantly higher than the packaging at room temperature in high CO2, low CO2(mPVC) packaging low temperature and low temperature bare fruit. There was a poor correlation between ethylene production peak and the vast majority of the fruits of impedance parameters characteristic value. At the end of storing, there was a high correlation between soluble solids content and the impedance parameters of the different packaging fruit. Firmness, titratable acid and the part of impedance parameters have a correlation. Z、Cs、Ls、 B、X、ε’ reverse turning caused by fresh browning.