Sumio Kawano

Development of a calibration equation with temperature compensation for determining the Brix value in intact peaches

The influence of sample temperature on the performance of a near infrared (NIR) calibration equation was evaluated and then the development of a calibration equation, which can compensate for a variation of sample temperature, was examined. The results obtained are as follows. (i) The calibration equations developed using samples at constant temperature were not stable in predicting when the sample temperature varied. (ii) NIR spectra were affected by sample temperature; as sample temperature increased, absorption became stronger at 841 and 966 nm. A similar phenomenon is exhibited by water. (iii) Water absorption is easily influenced by a variation in temperature, therefore it was considered that water was an important factor causing a bias when the sample temperature varied. (iv) The calibration equations developed using samples which had a temperature range from 21 to 31°C, showed a high accuracy in prediction, even if the sample temperature changed in that range. In consequence, it was concluded that a calibration equation with temperature compensation could be developed using a combined calibration sample set which covered a variation in temperature of the samples in the future.

Near infrared spectral patterns of fatty acid analysis from fats and oils

A near infrared (NIR) spectral pattern of oil contains information about fatty acid composition, because NIR absorption bands around 1600–1800 nm and 2100–2200 nm are due to the straight carbon chain andcis double bonds, respectively. This study was undertaken to build a foundation for the rapid determination of the fatty acid composition in oil by an NIR method. First, NIR spectra of pure triglycerides were measured and characterized. Fatty acid compositions could be estimated roughly by comparing the spectra of fats and oils (butter fat, pig milk fat, soybean oil and palm oil) with those of pure triglycerides. Secondly, the NIR spectra of these fats and oils were reconstructed by summation of the triglyceride spectra, which are multiplied by factors corresponding to the fatty acid composition of the sample determined by gas chromatography. The calculated spectra agree with the originals, especially for that of soybean oil. However, in order to reconstruct spectra precisely, it may be necessary to reevaluate the loading weight of each triglyceride, which was equal in this study.

Non-Destructive NIR Quality Evaluation of Fruits and Vegetables in Japan

Using the interactance method, it is very difficult to determine the composipeaks. Thus the peak at 906 nm was considered to be the key absorption band for measuring the Brix value in peaches. To analyse the relationship between the correlation coefficient and the absorption of sugars, NIR spectra of amorphous sucrose and water (Figure 3) were recorded since sucrose accounts for at least 80 % of the total sugars in peach fruits. In the NIR spectrum of amorphous sucrose, three characteristic absorption bands were observed at 918, 1002 and 1175 nm. The band at 1002 and 1175 nm, however, overlapped those of water that occurred at 978 and 1162 nm. In the vicinity of 918 nm, the fact that the absorption due to water was comparatively weak, accounted for the large downward peak observed at 906 nm in the correlation plot. Multiple linear regression analyses based on NIR spectral data and chemical data of Brix value, revealed high correlations between NIR Brix value and actual Brix value. The highest multiple correlation coefficient (R) was 0.97 with a standard error of calibration (SEC) of 0.48 °Brix. The standard error of prediction (SEP) and bias were 0.50 °Brix and 0.01 °Brix, respectively (Figure 4). It was concluded that this method was relatively accurate for nondestructively measuring sugar content of peaches. _ 0515 w 956 . 680 759 839 918 997 1076 1156 1235

An overview of research and development of near infrared spectroscopy in Japan

This paper presents an overview of research and development of near infrared (NIR) spectroscopy in Japan. The application of NIR spectroscopy in Japan only stretches back to the early 1980s. Thus, the history is rather short, but progress in the research and development of NIR spectroscopy is extremely fast. The history and present status of NIR spectroscopy in Japan are described and a number of representative applications carried out in Japan are introduced.

Calibration of somatic cell count in milk based on near-infrared spectroscopy

Abstract A PLS model for prediction of somatic cell count (SCC) based on near-infrared (NIR) spectra of unhomogenized milk is presented in the study. Samples of raw milk were collected from cows in the early lactation period (from 7th to 29th day after parturition). The NIR spectra were measured in the region 400–1100xa0nm. As reference method a fluoro-opto-electronic method was applied. Different preprocessing methods were investigated. The robust version of PLS regression was applied to handle outliers present in the dataset and the uninformative variable elimination–partial least squares (UVE–PLS) method was used to eliminate uninformative variables. The final model is acceptable for prediction of SCC in raw milk.

A study on the universality of a calibration with sample temperature compensation

The applicability and universality of a sample combination method to develop a calibration with sample temperature compensation [J. Near Infrared Spectrosc. 3, 211 (1995)] was investigated from mathematical and theoretical points of view. From a theoretical analysis it is clear that the development of the calibration will be successful when two conditions are satisfied. One condition is that the vectors whose elements are constituent values should be orthogonal to the vector whose elements are the dot product of spectral change and calibration coefficients. The other is that the inverse vectors of the spectrum related to chemical components should be orthogonal to the vector of spectral change. The first condition is always satisfied when we make a calibration following this method, but whether the second condition is satisfied or not is completely dependent on the regression algorithm. From a mathematical analysis, we concluded that simple multiple linear regression is not completely adequate to develop a calibration with temperature compensation.

Nondestructive determination of tannin content in intact individual acorns by near-infrared spectroscopy

To examine the effects of tannin content in acorns of Quercus serrata on the fate of individual seeds, we developed a system for nondestructive chemical analysis of single acorns by near-infrared spectroscopy. We modeled the relationship between the normalized second-derivative spectra and tannin content by partial least squares regression. We obtained the best calibration model (r2xa0=xa00.836; standard error of calibrationxa0=xa01.90; standard error of validationxa0=xa01.43; biasxa0=xa00.10). The regression coefficient plots showed that the key band for the model was 938xa0nm, close to the absorption band of tannic acid in aqueous solution.

Near infrared spectroscopy for mastitis diagnosis: Two-dimensional correlation study in short wavelength region

We describe the application of two-dimensional correlation spectroscopic (2DCOS) technique for mastitic diagnosis. Seven average spectra in the short wavelength region (700–1100 nm) of mastitic levels separated from healthy to disease were subjected to 2DCOS analysis. Synchronous correlation map clearly showed water and fat bands. Asynchronous correlation map indicated the dynamical variations of milk constituents in milk occurred when a cow gets mastitis.