Nondestructive determination of soluble solids content of persimmons by using dielectric spectroscopy

Abstract

To explore the feasibility of dielectric spectroscopy in predicting soluble solids content (SSC) of persimmons during postharvest storage period, the dielectric constant spectra and dielectric loss factor spectra of 105 'Shui' persimmons were measured from 20 MHz to 4500 MHz. Based on the joint x-y distances algorithm, the persimmon samples were divided into two sets: 70 samples in calibration set and 35 samples in prediction set. One hundred and seventyfour, 14, and 24 variables were extracted as characteristic variables from full dielectric spectra (FS) by uninformative variables elimination (UVE), successive projection algorithm (SPA), and competitive adaptive reweighted sampling (CARS), respectively. Partial least squares (PLS) and least squares support vector machine (LSSVM) were applied to build SSC prediction models using FS and characteristic variables extracted by UVE, SPA, and CARS. The results indicated that LSSVM models offered better performance than PLS models at same input variables. CARS-LSSVM had the best SSC determination performance with the correlation coefficient and root-mean-square error of prediction set of 0.970 and 0.494°Brix. This study indicates that dielectric spectroscopy technique combined with characteristic variables selection methods is promising for determining SSC of persimmons. ARTICLE HISTORY

Non‐destructive sugar content assessment of multiple cultivars of melons by dielectric properties

“…8,9 The dielectric spectra in the range 20-4500 MHz can be successfully applied to assess the sugar content of fruits with a thin rind, such as kiwifruit, 10 apples, 11,12 pears 13 and persimmons. 14 These studies demonstrate that dielectric spectroscopy can be applied as an alternative technique for detecting the internal qualities of fruits.…”

“…Moreover, most studies using the dielectric spectroscopy technique have taken one cultivar as the sample and built a model that could only be applied for the specific cultivar. 13,14 This means that different cultivar melons corresponded to the different structures of the models, which will increase the development cost and the runtime of the instrument in the actual application. Therefore, it is necessary to investigate the feasibility of dielectric spectroscopy with respect to detecting the internal qualities of large-sized and thick-rind fruits such as melon, and it will also be interesting to investigate which model, the individual-cultivar model or the multi-cultivar model, has the best sugar content prediction performance.…”

Nondestructive Analysis of Internal Quality in Pears with a Self-Made Near-Infrared Spectrum Detector Combined with Multivariate Data Processing

“…In addition, we also calculated the ratio of the standard error in prediction to the standard deviation of the samples, which is the RPD. An RPD > 2.5 meant excellent model predictions, 2.5 ≥ RPD ≥ 2 meant very good, 2 > RPD ≥ 1.8 meant good, 1.8 > RPD ≥ 1.4 meant fair, 1.4 > RPD ≥ 1 meant poor, and RPD < 1 meant very poor [42]. Generally, a good model had higher Rc, Rp, and RPD values and lower RMSECV and RMSEP values, but the difference between RMSECV and RMSEP also was small [43].…”

Quality Attributes and Dielectric Properties of Sea Buckthorn Berries under Differing Freezing Regimes and Their Interrelationships

“…Dielectric properties could predict quality indices of kiwifruit during storage [ 12 ]. Dielectric properties could also be used as a method for determining SSC of persimmons [ 13 ]. There exists a mathematical relationship between the total soluble solids content and the impedance (Z), resistance (R), admittance (Y) and conductance (G) of apple juice, and these dielectric parameters could be used to determine the TSS of apple juice [ 14 ].…”