Eizo Taira

Automated Quality Evaluation System for Net and Gross Sugarcane Samples Using near Infrared Spectroscopy

Sugar content is the most important index of sugarcane quality in the payment system. A quality evaluation technique for shredded sugarcane was investigated using an automatic and high-speed near infrared (NIR) spectroscopy system. In this study, net and gross canes were tested in order to assess the potential for labour saving and cost reduction by the NIR measurement. NIR reflectance spectra ranging from 1100 nm to 2498 nm were collected to evaluate the cane quality of the shredded cane. A calibration equation for the pol in cane (PIC) of net cane was developed using a modified partial least squares (MPLS) regression. The accuracy of the PIC calibration for net cane was satisfactory with standard errors of prediction (SEP) of 0.21% and a bias of −0.06% in the range 1100–1848 nm wavelength. To eliminate the trash removal, a PIC calibration for gross cane was also examined. Results of the PIC calibration in the 1100–1848 nm wavelength range showed the highest accuracy (SEP=0.46%, bias=0.01%), although the accuracy for gross cane was lower than that for net cane. The NIR instrument could be used as an evaluation tool for the quality of net and gross sugarcane in a practical payment system.

Application of support vector regression for simultaneous modelling of near infrared spectra from multiple process steps

Near infrared (NIR) spectroscopy in combination with partial least-squares regression (PLS) is widely applied in process control for non-destructive measurement of quality parameters during production. PLS assumes an approximate linear relationship between the parameter to be estimated and the intensity of its absorption bands. Spectra, however, may contain non-linearities for various reasons such as differences in viscosity, temperature, pH, particle size and chemical composition of the sample matrix. In such cases, PLS might not predict the parameter of interest sufficiently well, and one must find other methods for the calibration task. Support vector machine regression (SVR) has been gaining interest within chemometrics in recent years. SVR is capable of modelling highly non-linear data, also when data are of very high dimensions. The aim of this study was to develop calibration models of NIR spectra from four different process steps in a raw-sugar factory. The models were intended for monitoring two quality parameters at the individual process steps. Our goal was to obtain global calibration models covering all four process steps in order to obtain simple calibration maintenance. SVR was used for the calibration task, since all of the above-mentioned sources of non-linearities were present. SVR results were benchmarked against PLS. SVR had a better prediction performance than PLS (1) for models built on individual process steps, (2) for global models covering all four process steps and (3) when the global models were evaluated on the individual process steps. Moreover, the majority of SVR models had prediction errors close to reference uncertainty and hence were close to being optimal. Finally, the global SVR models predicted the individual process steps better than the corresponding local PLS models. We conclude that the nonlinear modelling method SVR was able to model non-linearities caused by pooling NIR spectra from multiple different process steps. Implementation of the global SVR models would have several advantages over the local PLS models. First, they would allow simple calibration maintenance because only one model per quality parameter would have to be maintained. Second, they would allow more precise estimation of the quality parameters and therefore better process monitoring.

Direct sugar content analysis for whole stalk sugarcane using a portable near infrared instrument

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.

Relationships between nutrients and sucrose concentrations in sugarcane juice and use of juice analysis for nutrient diagnosis in Japan

Abstract Sugarcane is an important economic crop in southwest Japan, but its production is decreasing. To increase sugar production, both sugarcane yield and quality should be improved. Fertilizer management is one of the factors that influence sugarcane quality. We accordingly focused on nutrients present in sugarcane juice and attempted to identify the key factors affecting sugarcane quality. We collected sugarcane samples from 2013 to 2015 from all of the sugar mills in Japan and examined the relationships between juice nutrients and sucrose concentration. Juice analysis over 3 year showed that potassium (K+) and chloride (Cl−) were the most abundant cation and anion in the juice and that both negatively correlated with the sucrose concentration. K+ and Cl− concentrations significantly varied depending on production areas and those with higher K+ and Cl− concentrations had a low sucrose concentration. This finding suggests that sugarcane in those areas may have been supplied with these two ions in excess. Electrical conductivity (EC) in the juice always positively correlated with K+ and Cl− concentrations. EC may thus be a reliable indicator of K+ and Cl− concentrations and could be used for nutrient diagnosis because of its ease of measurement. For improving sugarcane quality, we recommend that potassium chloride, which supplies both K+ and Cl− and is a commonly used potassium fertilizer for sugarcane production in Japan, should be used in lower quantities in a year following one in which the EC of sugarcane juice at harvest is found to be high.

Measurement of Soil Deformation at the Ground Contact Surface of a Traveling Wheel

Abstract In order to clarify the soil deformation at the ground contact surface, traveling tests using a rubber-coated rigid wheel were carried out with -5%, 5%, 10%, 20% and 40% slip using a sophisticated soil bin test apparatus. The displacement of soil particles at the ground contact surface was observed through the movement of acrylic wires (1 mm in diameter) laid down on the soil surface. PTV (Particle Tracking Velocimetry), an effective image processing technique, was employed to detect the movement of the acrylic wires using image processing of a series of pictures. The detected movement is assumed to coincide with that of soil particles at the same position. Accordingly, the movement of soil particles could be successfully measured and analyzed. In addition, the soil deformation under the wheel was also measured using PIV (Particle Image Velocimetry). Both measures were then analyzed and the characteristics of soil deformation clarified. The mathematical model for the soil displacement at the ground contact surface showed good agreement with the measured values, except for at high slip.

Networking system employing near infrared spectroscopy for sugarcane payment in Japan

A cane quality evaluation system using near infrared (NIR) spectroscopy for determining payments to growers was developed and introduced to raw sugar mills in southern Japan. The evaluation system consists of a cutter grinder for sample preparation, an NIR instrument and a networking system. We investigated a calibration model for the determination of sugar index [Pol in cane, (PIC)] for shredded cane samples using a modified partial least squares regression with and without a repeatability file. The accuracy of the model developed using the repeatability file was adequate [root-mean square error of prediction, (RMSEP) = 0.30%] and the pooled standard error (P-SE) between master and eight slave instruments was 0.14%. In contrast, calibration models without a repeat ability file incurred large P-SE and pooled bias (P-bias) values, although the RMSEP values were very similar to the repeatability file model in cases using the first derivative and standard normal variate (SNV) spectral pre-treatment. The evaluation system was installed in 17 raw sugar mills on 13 islands involved in sugarcane cultivation in southern Japan. The system is presently used to measure the PIC value of cane samples that are supplied by farmers to mills. All data obtained are collected and compiled into a central facility via the Internet. The NIR networking system for sugarcane has been implemented in all raw sugar factories in Japan as an official method for determining cane prices.

Influence of Soil Surface Coverage on Soil Deformation by a Traveling Wheel

A model roller was traveled repeatedly along a soil bin with low traveling slip under 3 different coverage conditions; uncovered, and covered by a 1-mm or 3-mm thick rubber sheet. Soil displacement during each traveling was recorded by taking series of pictures through the transparent acrylic soil bin wall and application of image processing. Soil surface coverage affects the size and shape of the soil displacement trajectory for each travel. The soil particles at the deeper layers under coverage by the 3-mm sheet were displaced the furthermost downward among the 3 sets of conditions after only one travel. Coverage by a thick sheet significantly decreased the horizontal displacement of the soil during travel repetition, while that by the thin sheet had the opposite result. The results showed that consideration of soil surface coverage would help in the control of soil compaction.

Soil Deformation beneath a Wheel during Travel Repetition

Abstract To elucidate the phenomenon of the soil compaction observed during actual machine operation, a model wheel was traveled repeatedly and the subsequent soil deformation was analyzed. As repetitive travel progressed, soil particles drew similar trajectories with accompanying changes in the size and shape of the trajectories leading to the formation of spiral-like patterns. The changes depended on traveling slip and depth of the soil layer. The void ratio increased in with repetitions in the shallow layers, but decreased in the deeper layers. The change in void ratio in high slip conditions was larger than those in low slip conditions, indicating that repetitions in high slip caused more deformation and compaction than did those in low slip.

Effect of waxy material and measurement position of a sugarcane stalk on the rapid determination of Pol value using a portable near infrared instrument

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 R2 of 0.78–0.82, r2 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 R2 of 0.73–0.82, r2 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.

Alterations in the morphological, sugar composition, and volatile flavor properties of petai ( Parkia speciosa Hassk.) seed during ripening

Petai seeds are one of the well-known strong-smelling foods of the Southeast Asian region that have been harvested and commercially offered in different ripening forms. The current study focused on alterations in the size, color, sugar composition, and volatile flavor properties of petai seeds in the four ripening stages (unripe, mid ripe, ripe, and over-ripe). The ripening process was mainly indicated by the increase in size and weight as seed color turned paler and less greenish. The total sugar content gradually increased during ripening, and then elevated from 1.60 g/100 g (ripe seed) to the level of 2.82 g/100 g in the over-ripe seed. Ripening also altered the volatile flavor composition of petai seed, wherein the predominant aldehydes (hexanal and acetaldehyde) were decreased, and the sulfuric compounds (hydrogen sulfide, methanethiol, and 1,2,4-trithiolane) tended to increase. Additionally, gas chromatography-olfactometry (GC-O) analysis revealed alterations in the perceived odor strength and sensation of each volatile compound and demonstrated volatile flavor profiles, viz. detection percentages of volatile group odor strengths and descriptive odors, of petai seed. These results provide valuable information for monitoring alterations in the physical appearance, sugar composition, and aroma that represent the flavor quality in seasonal petai seed.