| With Fuping persimmon fruit as research material, used analysis of correlation, analysis of regression and principal component analysis, systematically studying the relationship between the 6 electrical featrues complex impedance Z, parallel equivalent resistance Rp parallel equivalent capacitance Cp, parallel equivalent inductance Lp, paiallel equivalent resistance Rs, complex impedance angle Deg, Conductivityσat the 24 frequency points which were within the range of 0.1 kHz to 3980 kHz of contrast treatment, 1-MCP treatment and fall treatment persimmon fruit during the process of mature and aging, with flesh firmness, titratable acid, soluble solid, soluble tannin , soluble pectin, protopectin, SOD activity, CAT activity, POD activity, MDA content, respiratory rate, ethylene release rate, weight-loss ratio and rate of water content 14 quality features. And finded the characteristic frequency and the sensitive electrical parameters that could be used in nondestructive inspection of postharvest persimmon fruit. Detected the reliability and accuracy of the statistical relationship between sensitive electrical parameters of respective feature frequencies under various treatment, and the quality features using The standard residual values. The results will bring theoretical bases for nondestructive testing using electrical properties of fruit and establishment of fruit grade system.The results are as follows:1) The relationship between electrical parametesr and quality feaures of persimmon fruit related to excitation frequency. The frequency band from 398 kHz to 3980 kHz was the characteristic frequency of physiological property in nondestructive inspection.of persimmon fruit after being plucked under contrast treatment. Z, Rs and Cp were the sensitive electrical parameters marking the mature and aging of postharvest persimmon fruit.2)The best frequency and the sensitive electrical parameters of nondestructive inspection of the persimmon fruit under fall treatmen were different from contrast treatment and 1-MCP treatment. The reason remained to further study.3) At 398 kHz the ICI of the electrical parameter and quality feature for persimmon fruit under contrast treatment ranked first, making 398 kHz the characteristic frequency of physiological property in nondestructive inspection.of persimmon fruit after being plucked under contrast treatment. At 398 kHz, flesh firmness correlated with deg andσsignificantly, with Z, Cp, Lp and Rs very significantly. Ta correlated with Z, Deg, Lp and Rs significantly. TSS correlated with Deg and Cp significantly, with Z, Lp and Rs very significantly, and was under the correlation level withσ. Soluble tannin, soluble pectin, protopectin, rate of water content and SOD activity correlated very significantly with the 6 electrical parameters. POD activity correlated significantly with deg, very significantly with 5 other electrical parameters. MDA content correlated significantly with Rs, very significantly with 5 other electrical parameters. However, weight-loss ratio, respiratory rate, ethylene release rate and CAT activity didn't correlate with the 6 electrical parameters.4) At 3980 kHz the ICI of the electrical parameter and quality feature for persimmon fruit under 1-MCP treatment ranked first, making 398 kHz the characteristic frequency of physiological property in nondestructive inspection of persimmon fruit after being plucked under 1-MCP treatment. flesh firmness, titratable acid, soluble solid, soluble tannin, soluble pectin, protopectin, rate of water content, SOD activity, POD activity, MDA content, weight-loss ratio, ethylene release rate and CAT activity correlated with 5 electrical parameters significantly or very significantly except with deg. However, respiratory rate didn't correlate with the 6 electrical parameters.5) At 0.158 kHz the ICI of the electrical parameters and quality feature for persimmon fruit under fall treatment ranked first, making 0.158 kHz the characteristic frequency of physiological property in nondestructive inspection.of persimmon fruit after being plucked under fall treatment. flesh firmness, soluble solid, soluble pectin, rate of water content, SOD activity and POD activity, correlated withσsignificantly or very significantly, while not with the other 5 electrical parameters.6) Z, Rs, Cp, Lp andσwere the sensitive electrical parameters marking the mature and aging of persimmon fruit under contrast treatment. The mathematic analysis revealed that apply electrical parameters Z could be used to predict the change of flesh firmness, soluble solid and rate of water content after different storage time after being plucked, Rs could predict the change of TSS, soluble pectin and SOD activity, Cp could predict the change of soluble tannin and protopectin, Lp could predict POD activity, andσpredicted MDA content the standard residual values were always within (-2, 2), indicating that Z, Rs and Cp possessed reasonable reliability and accuracy in predicting the quality features after different storage time after being plucked.At the characteristic frequency 398 kHz, weight-loss ratio, respiratory rate, ethylene release rate and CAT activity and the 6 electrical parameter didn't correlated well, thus making us unable to determine the statistical relationship with this 4 quality features, i.e. Failed to figure out the sensitive electrical parameters for the 4.7) Z, Rs and Cp were the the sensitive electrical parameters marking the mature and aging of persimmon fruit under 1-MCP treatment. Electrical parameters Z could be used to predict the rate of eruption of ethelyne after different storage time after being plucked, Rs could predict the change of flesh firmness, titratable acid, soluble solid, SOD activity, CAT activity, POD activity, MDA content, weight-loss ratio and rate of water content. Cp could predict the change of soluble tannin, soluble pectin, protopectin, and the standard residual values revealed that among the 117 standard residual values after being plucked after 12 days, all were within (-2, 2), exccept flesh firmness 2.36 and SOD activity 2.31, indicating that Z, Rs and Cp possessed reasonable reliability and accuracy in predicting the quality features after different storage time after being plucked.At the characteristic frequency 3980 kHz, respiratory rate and the 6 electrical parameters didn't correlated well, thus making us unable to determine the statistical relationship with electrical parameters measured value and respiratory rate. Failed to figure out the sensitive electrical parameters for respiratory rate.8)σwas the the sensitive electrical parameters marking the mature and aging of persimmon fruit under fall treatment.Σcould be used to predict the change of flesh firmness, soluble solid, soluble pectin, SOD activity, POD activity and rate of water content after different storage time after being plucked., and all the standard residual values were within (-2, 2). On the contrary, At the characteristic frequency 0.158 kHz, soluble solid, soluble tannin, protopectin, MDA content, respiratory rate, ethylene release rate, weight-loss ratio and CAT activity and the 6 electrical parameters didn't correlated well, thus making us unable to determine their sensitive electrical parameters of the 8 quality features, neither the statistic relationship with the electrical parameters.9) After being plunked for 21 days of persimmon fruit, the flesh firmness was 2.34 kg·cm-2, soluble solid was 0.61 mmol·100 g-1, soluble solid was 15.96 %, soluble pectin contant was 1.19 mg·g-1. Under these conditions, persimmon fruit were already depunkrised, and possessed the best mouthfeelings. Thus, at the test frequency 398 kH, and using electrical parameter to test online, it could be determined that when cp was above 2.66nF, the soluble pectin contant would be under 1.19 mg·g-1, which meant that persimmon fruit was already depunkrised, and was in the best period for eating.
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