No abstract

Cane quality at the farm is important information for both farmers and millers when evaluating cane maturity and determining harvest schedules. We investigated the non-destructive measurement of the sugar content of cane stalks using a portable near infrared (NIR) instrument. A commercially available portable NIR instrument was modified for use in transmittance mode and employed to quantify Pol levels in cane stalks. Calibration models using a partial least squares regression analysis were developed for predicting Pol values from the juice and the cane sample spectra (600-1100 nm). Results of these calibrations, root mean square error of prediction for juice and cane samples, were 1.0% and 1.1% Pol, respectively. Based on the results of this study, the developed measurement method appears to be useful for monitoring cane quality and the planning of harvest schedules.

No abstract

The precision of spectroscopic methods was frequently affected by the identity of the inhomogeneous materials, especially for direct scanning. This research aimed to investigate the effects of waxy types, naturally found on sugarcane surface, on spectral characteristics. A portable Vis/SWNIR instrument with interactance mode across wavelength of 570-1031 nm was used for direct scanning the cane stalk. Principal component analysis (PCA) was applied to examine the differences in the spectra scanned from 180 samples, including 3 types of waxy type: white, black, and mixed black and white. Seven widespread pretreatments were employed to reduce the effect of the waxy types. Results show that the spectra of the samples with each waxy type was separated in groups and standard normal variate (SNV) pretreatment gave the best results. However, it was not able to eliminate the effect compared to the wax-removed samples. Meanwhile, the standard deviation of absorbance values, at the wavelength of 760, 904 and 970 nm of 3 samples, was used for assessing the repeatability and reproducibility. The samples where the waxy covers were removed provided a lower standard deviation of absorbance values of spectra than the best pretreated spectra that used SNV of the samples that retained its waxy covers by one to six times. Thus, the waxy material on cane surface should be removed before collecting spectra.

No abstract

Handheld near-infrared spectroscopy was used to study the effect of integration time and wavelength selection on predicting marian plum quality including soluble solids content (SSC), the potential of hydrogen ion (pH), and titratable acidity (TA). For measurements representing actual conditions, the ontree fruits were scanned under in-field conditions. The assumption was that the robust model might be achieved when the models were developed under actual conditions. The results of the main effect test show that the integration time did not statistically affect SSC, pH, and TA predictions (p-value > 0.05) and the wavelength range had a significant impact on prediction (p-value < 0.01). An integration time of 30 ms coupled with a wavelength range of 670−1000 nm was the optimal conditions for the SSC prediction, while an integration time of 20 ms with 670−1000 nm wavelength was optimal for pH and TA prediction because of the lowest root-mean-square error of cross-validation (RMSECV). The optimal models for SSC, pH, and TA could be improved using spectral preprocessing of multiplicative scatter correction. The effective models for SSC, pH, and TA improved and reported the coefficients of determination (r 2 ) and root-mean-square errors of prediction (RMSEP) of 0.66 and 0.86 °Brix; 0.79 and 0.15; and 0.71 and 1.91%, respectively. The SSC, pH, and TA models could be applied for quality assurance. These models benefit the orchardist for on-tree measurement before harvesting.

No abstract

Near infrared spectroscopy can be applied as a rapid and non-destructive method for monitoring sugarcane quality after determining the precision and accuracy of the approach and model to be used for evaluating stems. In this study, near infrared spectroscopy has been applied to breeding management systems and commercial sugar production. Near infrared spectra were collected using a portable near infrared instrument incorporating a wavelength region of 730-1000 nm. To achieve an effective sampling technique, the investigated cane samples included stems with original cane surface and stems with cane wax removed surface. Results revealed that calibrations based on spectra recorded at only 1-position (1-position spectra) of original samples were poor, while calibrations based on stems with wax removed were acceptable for screening with RMSEP values of 1.2%Pol. Also, the 2-position averaged spectra of non-removed wax samples provided fair models, while 4-and 8-position averaged spectra gave good results with R 2 of 0.78-0.82, r 2 of 0.78-0.82, RMSEP of 1.2%Pol to 1.4%Pol and RPD of 2.1 to 2.4, respectively. The calibration model developed from removed-wax samples at positions 1-, 2-, 4-and 8-averaged spectra rendered effective performances with R 2 of 0.73-0.82, r 2 of 0.73-0.84, RMSEP of 1.2%Pol to 1.5%Pol and RPD of 2.1 to 2.5. Outcomes were not different in performance, even if the scanned positions and number of scans differed. Hence, the author concluded that 1-position spectra with removed-wax samples were convenient and suitable for the measurement of cane stalk Pol value.