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    Near infrared spectroscopy as an alternative method for rapid evaluation of toluene swell of natural rubber latex and its products
    (2018-06-01)
    Lim, Chin Hock
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    Toluene swell or equilibrium swelling is universally used by rubber factories to measure the degree of crosslink of their compounded or prevulcanized latices at different stages of production. To apply near infrared spectroscopy for rapid and accurate quality control, spectral acquisition of prevulcanized latex, thin film and thick film was performed using a Fourier transform near infrared spectrometer in diffuse reflection mode across the wavenumber range of 12,500–3600 cm<sup>1</sup>. For prevulcanized latex an effective model was developed using partial least squares regression with preprocessing (first derivative + straight line subtraction method). The coefficient of determination (r<sup>2</sup>), root mean square error of cross validation and bias of the validation set were 0.71, 3.93% and 0.005%, respectively. For the thin film model the r<sup>2</sup>, root mean square error of cross validation and bias were 0.65, 4.01% and 0.028%, respectively. Whereas for the thick film model the r<sup>2</sup>, root mean square error of cross validation and bias were 0.70, 4.00% and 0.006%, respectively. Three models including prevulcanized latex, thin film and thick film were validated by 23 unknown samples, providing standard error of prediction and bias of 5.357 and 2.494, 4.565 and 1.001 and 3.641 and 0.961%, respectively, for prevulcanized latex, thin film and thick film. The model developed for the thick film spectra gave the best results.
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    Potential of near infrared spectroscopy as a rapid method to detect aflatoxins in brown rice
    (2019-06-01)
    Dachoupakan Sirisomboon, C.
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    Wongthip, P.
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    Brown rice is a main popular health food with high nutritional value and health benefits. As a result of poor post-harvest drying and inappropriate storage conditions, rice grains are often damaged through fungal spoilage as well as mycotoxin production. The objective of this research was to evaluate the possibility of using the near infrared spectroscopy, with a wavenumber range between 12500 and 4000 cm<sup>−1</sup> (800–2500 nm), as a rapid method for detection of aflatoxins in brown rice. Firstly, storage trials were carried out to generate representative of samples contaminated and non-contaminated with aflatoxins. These data were used to create a partial least squares regression model using 120 brown rice samples with the required near infrared spectral data and aflatoxin concentration levels that were determined using a standard enzyme-linked immunosorbent assays method. The accuracy of developed models was externally validated using the test set. The statistical model developed from the treated spectra (vector normalization; SNV) provided the best accuracy in prediction with a coefficient of determination of prediction (r<sup>2</sup>) of 0.95, a root mean square error of prediction of 415.00 µg kg<sup>−1</sup> and a bias −54.00 µg kg<sup>−1</sup>. The model developed showed good predictive performance which suggests that it could have practical applications as a rapid method to detect aflatoxins in brown rice.
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    Determination of dry matter and soluble solids of durian pulp using diffuse reflectance near infrared spectroscopy
    (2015-01-01)
    Onsawai, Phalanon
    ;
    Fourier transform near infrared spectroscopy was used as a non-invasive technique for the determination of dry matter and soluble solids of durian pulp. A set of 25 fruit was randomly harvested every 10 days, starting from 80 days until 127 days after the onset of fruit development covering six levels of maturity (80 days, 90 days, 100 days, 110 days, 120 days and 127 days). After applying ethephon on the fruit stems, the fruits were kept for 3 days at room temperature and allowed to ripen. Only the pulp of the durian was scanned. The dry matter and soluble solids reference values of the samples were determined by a hot-air-oven method and using a refractometer, respectively. Prediction models using half the samples related the spectral data, and dry matter and soluble solids data were subsequently established using partial least-squares regression and validated using the other half of the samples in a prediction set. A full cross-validation was also generated using all 149 samples. Both the half-of-the-samples model and the all-sample model were then validated using a true validation set of samples collected in a later year. When tested against the validation half of the samples, the halfof- the-samples model predicted dry-matter content with a coefficient of determination (r2) and root mean square error of prediction (RMSEP) of 0.89 and 3.60%, respectively, and for soluble solids content 0.55 and 1.63 °Brix (Bx), respectively. When tested on samples from a later season, the model for dry-matter content returned an r2, RMSEP and bias of 0.26, 6.10% and 2.16%, respectively, and for soluble solids content 0.27, 1.25 °Bx and 1.09 °Bx, respectively. The cross-validated model for dry matter yielded a slightly better r2 and root mean square error of cross-validation (RMSECV) of 0.90 and 3.58%, respectively, however, the model for soluble solids did not provide a better r2 and RMSECV: 0.51 and 1.81 °Bx, respectively. When tested on samples from a later season, the cross-validated models gave, r2, RMSEP and bias of 0.15, 5.17% and 1.49%, respectively, for dry-matter content, and for soluble solids content 0.37, 1.32 °Bx and 1.23 °Bx, respectively. The poor results obtained when predicting dry matter in samples in later seasons indicate that samples from several seasons must be included in the set of calibration samples. This is the first report on the application of NIR spectroscopy to evaluate the dry matter and soluble solids of durian pulp and could be useful to customers, exporters, importers and also postharvest technologists. However, prediction accuracy was not demonstrated in the model for durian pulp soluble solids, possibly because of the effect of ethephon applied after harvesting to induce ripening within 3 days to make the fruit suitable for consumption. In addition, it was found that the vibration bands of cellulose and fat, and those of aromatic, CH2 and sucrose highly affected the predictions of dry matter and soluble solids in the durian pulp, respectively.
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    Application of near infrared spectroscopy to detect aflatoxigenic fungal contamination in rice
    (2013-09-01)
    Dachoupakan Sirisomboon, C.
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    Putthang, R.
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    The objective of this research was to apply the near infrared spectroscopy (NIRS), with a wavelength range between 950 and 1650 nm, to determine the percentage of fungal infection found in rice samples. The total fungal infection and yellow-green Aspergillus infection, which is often indicative of aflatoxigenic fungal infection, are the focus of this research. Spectra were obtained on 106 rice samples, by reflection mode, including 90 naturally contaminated samples, and 16 artificially contaminated samples. Calibration models for the total fungal infection were developed using the original and pretreated absorbance spectra in conjunction with partial least square regression (PLSR). The statistical model developed from the untreated spectra provided the greatest accuracy in prediction, with a correlation coefficient (. r) of 0.668, a standard error of prediction (SEP) of 28.874%, and a bias of -0.101%. For yellow-green Aspergillus infection, the most accurate predictive statistical model was developed using a pretreated (maximum normalization) NIR spectra, with the following statistical characteristics (. r = 0.437, SEP = 18.723% and bias = 4.613%). Therefore, the result showed that the NIRS could be used to detect aflatoxigenic fungal contamination in rice with caution and the technique should be improved to get better prediction model. However, there is an evident from NIR spectra that the moisture and starch content in rice affects the overall extent of fungal infection. © 2013 Elsevier Ltd.
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    Nondestructive estimation of maturity and textural properties on tomato 'Momotaro' by near infrared spectroscopy
    (2012-10-01) ;
    Tanaka, Munehiro
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    Kojima, Takayuki
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    Williams, Phil
    Near infrared spectroscopy offers the possibility to classify and predict the internal quality of fruits and vegetables. The objective of this study was to evaluate the ability of near infrared spectroscopy to classify the maturity level and to predict textural properties of tomatoes variety "Momotaro". Principal component analysis (PCA) and Soft independent modeling of class analogy (SIMCA) were used to distinguish among different maturities (mature green, pink and red). Partial least squares (PLS) regression was used to estimate textural properties, alcohol insoluble solids and soluble solids content of the tomatoes. The PCA calibration model with mean normalization pretreatment spectra of mature green tomatoes, gave the highest distinguishability (96.85%). It could classify 100.00% of red and pink tomatoes. The SIMCA model could not give better accuracy in maturity classification than individual PCA models. Among the textural parameters measured, the bioyield force from the puncture test with the near infrared (NIR) spectra (between 1100 and 1800 nm) pretreated by multiplicative scatter correction (MSC) had the highest correlation coefficient between NIR predicted and reference values (r = 0.95) and lowest standard error of prediction (SEP = 0.35 N) and bias of 0.19 N. The ratio of standard deviation of reference data of prediction set to standard error of prediction (RPD) was 2.71. In the case of Momotaro tomato, NIR spectroscopy by using PLS regression could not predict alcohol insoluble solids in fresh weight accurately but could predict soluble solids content well with r of 0.80, SEP of 0.210 %Brix and bias of 0.022 %Brix. © 2012 Elsevier Ltd. All rights reserved.
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    Determination of the gamma-aminobutyric acid content of germinated brown rice by near infrared spectroscopy
    (2014-01-01)
    Kaewsorn, K.
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    Rice rich in gamma-aminobutyric acid (GABA) has been increasing in popularity worldwide, particularly within the commercially important health food market. The aim of this research was to develop a near infrared (NIR) spectroscopic method to evaluate the GABA content of germinated brown rice. Germinated brown rice (GBR) from two groups was used in this study. The first group contained GABA adjusted rice samples produced from germinated rough rice, which had been soaked for 24 h and 48 h and then incubated for 0 h, 6 h, 12 h, 18 h, 24 h, 30 h and 36 h (GBR samples). The second group was the GBR purchased from local markets (MGBR samples). The GABA content of each sample was subsequently determined by high performance liquid chromatography (HPLC). A prediction model for the GABA content was subsequently established using the NIR spectral data in conjunction with partial least square regression (PLSR), which was validated using test set validation. There were three optimal models obtained from GBR samples, MGBR-Khao Dawk Mali 105 samples and MGBR-various varieties. The first model was established using spectral data pre-treated with first derivative + multiple scatter correction and the second and third models were from first derivative + vector normalisation pre-treated spectra. The coefficient of determination (r2), root mean squared error of prediction (RMSEP) and a bias of 0.97-0.98 mg, 0.21-0.52 mg per 100 g dry matter and -0.285-0.067 mg per 100 g dry matter, respectively, were obtained. This is the first report on the application of NIR spectroscopy to evaluate the GABA content of the germinated brown rice, which could prove useful in an industrial applications and consumers. © IM Publications LLP 2014.
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    Near-infrared spectroscopy, hyperspectral, multispectral imaging principles and applications in energy properties of biomass
    (2023-08-21)
    Posom, Jetsada
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    Shrestra, Bijendra
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    Maraphum, Kanvisit
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    Pitak, Lakkana
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    Saengprachatanarug, Khwantri
    Biomass is renewable energy which is zero neutrality carbon energy. It is used for generating heat energy and electrical energy. Therefore, the use of biomass with high efficiency is important and the quality of biomass related to its energy should be measured before utilization and trading. The measurement of energy indexes of biomass is necessary to the thermal conversion process and the trading of biomass. However, the conventional measurement methods are laborious and take a long time, with a lot of costs. In recent years, near infrared spectroscopy (NIR) and imaging technologies (hyperspectral and multispectral images) have been widely investigated and applied as non-destructive, reliable and accurate techniques to monitor the quality and composition of biomass. This chapter contains the principle of NIR and imaging technique including essential component principles, NIR and imaging technique procedures, novel model development methods and applications. The non-destructive measurement of biomass quality as the real time and non- contact measurement will be represented. Moreover, this chapter will describe the application of NIR and imaging techniques for analysing the energy indexes of biomass, such as heating value or calorific value, proximate data, elemental composition, combustion index, pyrolysis characteristics, mechanical properties and so on.
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    Evaluation of total solids of curry soup containing coconut milk by near infrared spectroscopy
    (2016-01-01) ;
    Nawayon, Jutharat
    The aim of this research was to perform a feasibility study of the potential of near infrared (NIR) spectroscopy to evaluate the total solids content of instant curry soups containing coconut milk; these included green curry, red curry, massaman curry and panang curry. The soup samples were collected from mixing tanks, water adjusting tanks, ultra-high temperature process line and laminated cartons. Adjusted samples were made from the same recipe as in the processing line but with the total solids increased by 30%, 60% and 90%, and reduced by 30%, 60% and 90% total solids from normal levels. Each sample was scanned with a Fourier transform NIR spectrometer. A prediction model for total solids was established using NIR spectral data in conjunction with reference data using partial least squares regression, which was validated using leave-one-out validation and test set validation. The test set validation showed better prediction performance as proved by using an unknown sample set. The test set validation model was developed using multiplicative scatter correction of spectra for the 6102-5446.3 cm<sup>-1</sup> and 4605.4-4242.9 cm<sup>-1</sup> regions, and provided a coefficient of determination for prediction (r<sup>2</sup>), root mean square error of prediction (RMSEP), bias and ratio of standard error of prediction to the standard deviation (RPD) of 0.92, 0.95%, -0.20% and 3.71, respectively. It was shown that NIR spectroscopy could be applied in an instant curry soup production line for process control and quality assurance.
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    Rapid non-destructive evaluation of moisture content and higher heating value of Leucaena leucocephala pellets using near infrared spectroscopy
    (2016-07-15)
    Posom, Jetsada
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    Shrestha, Amrit
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    The MC (moisture content) and HHV (higher heating value) of Leucaena leucocephala pellets using NIR (near infrared) spectroscopy was investigated in this study. The MC of the pellets was adjusted by subjecting the samples to different relative humidity environments. The samples were scanned in diffuse reflection mode at wavenumbers of 12,500-4000 cm<sup>-1</sup>. Partial least squares regression models correlating the MC and HHV with the NIR spectra were developed and validated by full cross validation. The model for MC and HHV provided coefficients of determination (R<sup>2</sup>) of 0.995 and 0.964, a root mean square error of cross validation (RMSECV) of 0.187%wb and 79.2 J g<sup>-1</sup>, bias of -0.0008%wb and 1.29 J g<sup>-1</sup> and a RPD (ratio of prediction to deviation) of 13.9 and 5.30, respectively. The models had excellent accuracy. This rapid quality evaluation method may be used for trading of biomass pellets. An equation related MC and HHV was also developed.
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    Primary assessment of macronutrients in durian (CV Monthong) leaves using near infrared spectroscopy with wavelength selection
    (2024-01-05) ;
    Jaisue, Natthapon
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    Worphet, Akarawhat
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    Tawinteung, Nukoon
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    Farmers would be able to regulate fertilization and produce quality durian if they knew the nutrient concentration in durian leaves. A long period of time for traditional nutritional content determination is needed. Therefore, near-infrared spectroscopy is a good method for nondestructive and quick nutrient content evaluation. The leaf sample matrices (fresh leaves, dried ground leaves, and dried ground leaf pellets) were scanned by Fourier transform near-infrared (FT-NIR) with a wavelength of 12,500–3,600 cm<sup>−1</sup>. Regression models were developed using partial least squares (PLS) with full wavelength, short wavelength, and selected wavelength by successive projections algorithm (SPA). In this study, the model for N and K concentration was acceptable and the prediction was considered good but for P content not had succeeded. As a result, the PLS-SPA model using fresh leaf samples for evaluating N content in durian leaves exhibited performance of r<sup>2</sup> = 0.852, SEP = 0.14%, RPD = 2.63 and bias = −0.020%. The PLS-SPA model using dried ground leaf samples for evaluating K content in durian leaves exhibited performance of r<sup>2</sup> = 0.820, SEP = 0.13%, RPD = 2.36 and bias = 0.006%. This research found that it is possible to apply NIR waves to predict N and K concentrations in durian leaves. It is not necessary to predict directly from the wavelengths associated with -N or -K bonds. Instead, NIR can measure them indirectly from the bonding of proteins, which are products formed by N and K. In addition, selecting the wavelength that is related to the value to be measured can produce results that are not significantly different from using full or short wavelengths. These models can assist farmers in rapidly predicting N and K content in durian leaves for immediate fertilizer adjustment.