scholarly journals The Near Infrared Determination of Moisture in Whole Dates

HortScience ◽  
1991 ◽  
Vol 26 (10) ◽  
pp. 1303-1305 ◽  
Author(s):  
Gerald G. Dull ◽  
Richard G. Leffler ◽  
Gerald S. Birth ◽  
Arthur Zaltzman ◽  
Ze'ev Schmilovitch
Keyword(s):  
Moisture Content ◽  
Correlation Coefficient ◽  
Standard Error ◽  
Near Infrared ◽  
Phoenix Dactylifera ◽  
Infrared Spectrophotometry ◽  
Calibration Equation ◽  
Industry Standard ◽  
Calibration Experiment

Whole dates (Phoenix dactylifera L.) were analyzed for moisture content using near infrared spectrophotometry in a direct transmittance geometry. In the calibration experiment using 72 samples, the correlation coefficient was 0.977 and the standard error of calibration (SEC) was 0.89%. When the calibration equation was used to predict the moisture in another set of 72 date samples, the standard error of performance (SEP) was 1.5%. When the method was used to sort these 72 dates into four industry-standard grades, 74% were correctly graded and 15% missed the grade by <1 SEC.

Near Infrared Spectroscopic Determination of Moisture Content in Foods: Extraction Method by Organic Solvents

1998 ◽  
Vol 6 (1) ◽  
pp. 235-240 ◽  
Author(s):  
H. Takamura ◽  
N. Endo ◽  
T. Matoba
Keyword(s):  
Moisture Content ◽  
Organic Solvents ◽  
Extraction Method ◽  
Near Infrared ◽  
Single Step ◽  
Calibration Equation ◽  
Moisture Contents ◽  
Clear Band ◽  
Predicted Values

In order to get a common NIR calibration equation which can be adapted to the determination of moisture content in various types of foods, we have tried to develop a water extraction method from foods by organic solvents. We used various starches and powder foods as the model. NIR spectra of various solvents containing water showed a clear band due to water around 1930 nm. Of the solvents used, this band in N,N-dimethylacetamide (DMA), N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) systems was not shifted by the change of the moisture content. Then, the moisture was extracted from starch by these solvents. Approximately 60% was consistently recovered in a single-step extraction by DMA or DMF. The extraction by DMSO was too viscous to handle. The calibration equation was developed from the results for the extraction from starch by DMA. Then, moisture contents of powder foods were predicted using the calibration equation. For six of eight foods, good correlations were obtained between the laboratory values and the predicted values. These results suggest that this NIR method coupled with extraction is useful for the determination of moisture content with a common calibration equation for various kinds of foods.

scholarly journals Determination of moisture content in lyophilized mannitol through intact glass vials using NIR micro-spectrometers

2011 ◽  
Vol 47 (2) ◽  
pp. 289-297 ◽  
Author(s):  
Cristian Rodrigo Muzzio ◽  
Nicolás Gabriel Dini ◽  
Laura Daniela Simionato
Keyword(s):  
Moisture Content ◽  
Correlation Coefficient ◽  
Standard Error ◽  
Calibration Method ◽  
Nondestructive Method ◽  
Freeze Dried ◽  
Conventional Methods

Determination of moisture content in lyophilized solids is fundamental to predict quality and stability of freeze-dried products, but conventional methods are time-consuming, invasive and destructive. The aim of this study was to develop and optimize a fast, inexpensive, noninvasive and nondestructive method for determination of moisture content in lyophilized mannitol, based on an NIR micro-spectrometer instead of a conventional NIR spectrometer. Measurements of lyophilized mannitol were performed through the bottom of rotating glass vials by means of a reflectance probe. The root mean standard error of prediction (RMSEP) and the correlation coefficient (R²pred), yielded by the pre-treatments and calibration method proposed, was 0.233% (w/w) and 0.994, respectively.

Determination of Degree of Retrogradation of Cooked Rice by near Infrared Reflectance Spectroscopy

1998 ◽  
Vol 6 (A) ◽  
pp. A355-A359 ◽  
Author(s):  
Seung-Yong Cho ◽  
Sung-Gil Choi ◽  
Chul Rhee
Keyword(s):  
Moisture Content ◽  
Standard Error ◽  
Near Infrared ◽  
Reference Method ◽  
Reflectance Spectroscopy ◽  
Multiple Correlation Coefficient ◽  
Enzymatic Method ◽  
Near Infrared Reflectance ◽  
Cooked Rice

Near infrared (NIR) reflectance spectroscopy was used to determine the degree of retrogradation of cooked rice. Cooked rice samples were stored at 4°C for 120 hours, and the degree of retrogradation was measured every six hours during the storage time. Enzymatic method, using glucoamylase, was used as reference method for the determination of the degree of retrogradation. Spectral differences, due to retrogradation of cooked rice, were observed at 1434, 1700, 1928, 2100, 2284 and 2320 nm. 32 samples were used for calibration set and 16 samples were used for validation set. High correlations were achieved between degree of retrogradation determined by enzymatic method and by NIR with multiple correlation coefficient of 0.9753 and a standard error of calibration of 3.64%. Comparable results were obtained with 3.91% of standard error of prediction, when the calibration equation was applied to an independent group of samples. The moisture content of samples tested significantly affected the determination of degree of retrogradation by NIR. The critical moisture content for the determination of degree of retrogradation by NIR was found to be ca. 5% (W.B.). The results suggested that NIR spectroscopy might be used as a potential method for determining both the degree of retrogradation and gelatinization of cooked rice.

A Simple Testing Procedure for near Infrared Instruments

1998 ◽  
Vol 6 (A) ◽  
pp. A163-A170 ◽  
Author(s):  
B. Barabás
Keyword(s):  
Error Compensation ◽  
Near Infrared ◽  
Testing Procedure ◽  
Wheat Protein ◽  
Calibration Equation ◽  
Minimum Number ◽  
Mean Square Difference ◽  
Infrared Instruments ◽  
Protein Measurement

The testing and adjusting procedure of near infrared (NIR) spectrophotometers is based on the measurement of some standards and, if necessary, on the adjustment of the constants in the calibration equation. For this work some use few standards, whereas others use 20 or more. This work was aimed to determine the range of error compensation and the minimum number of standards required. The experiments were applied to wheat protein measurement using two scanning spectrophotometers. The errors in the NIR measurements were characterised as bias, skew, error derived from skew ( Eskew) and standard error of difference corrected for bias and skew ( SEDc) parameters and supposed that errors derived from the change in the wavelength or reflectance of the instrument. The confidence intervals of bias and skew, derived from duplicate measurements of various numbers of wheat standards, were used to determine the minimum number of standards required. The range of error compensation was defined with those bias values, where SEDc was smaller, than an acceptable limit. The range of compensation corresponded to a bias value of ± 8 g kg−1 for wheat protein measurements. The detection of error of measurements required 4 wheat standards. The elimination of errors of bias and skew required 9 standards within the above limits. The developed procedure was tested in case of real instrument error. Diminishing a bias from 5.2 g kg−1 to 0.7 g kg−1 and the root mean square difference ( RMSD) to an acceptable level required the use of 9 standards, similar to the model experiment. The simplicity and rapidity (about 10 min) of the procedure enabled the routine test of NIR instruments. The range of error compensation and the number of standards referred to wheat protein. The simple modelling procedure proved also suitable for the determination of these values for other components and under other measuring conditions.

scholarly journals Comparisons of Karl Fischer Method with Oven Methods for Determination of Water in Forages and Animal Feeds

1999 ◽  
Vol 82 (4) ◽  
pp. 799-808 ◽  
Author(s):  
Nancy Thiex ◽  
Terri Van Erem
Keyword(s):  
Standard Error ◽  
Near Infrared ◽  
Corn Silage ◽  
Infrared Reflectance ◽  
Near Infrared Reflectance ◽  
Karl Fischer ◽  
Animal Feeds ◽  
Karl Fischer Method ◽  
Fischer Method

Abstract In a comparative study of the Karl Fischer method with oven methods for determination of water in forages and animal feeds, oven methods yielded the following relative recoveries (expressed as a percentage of the recovery obtained by the Karl Fischer method) for hay, haylage, and corn silage, respectively: (1) drying at 135°C for 2 h (AOAC 930.15), 113,162, and 133%; (2) drying at 104°C for 3 h (AOAC 935.29), 96,122, and 113%; and (3) drying at 104°C for 6 h, 97, 129, and 117%. Relative recoveries for nonurea-containing and urea-containing feed, respectively, were as fol lows: (1) drying at 135°C for 2 h (AOAC 930.15), 116 and 2746% (2) drying at 104°C for 3 h (AOAC 935.29), 88 and 239%; (3) drying at 95°C for 5 h under vacuum (AOAC 934.01), 83 and 727% (4) drying at 104°C for 6 h, 90 and 427%; and (5) drying at 110°C for 3 h, 94 and 425%. Preliminary near-infrared reflectance calibrations for water (moisture) based on the Karl Fischer method were promising (r2 = 0.98; standard error of calibration = 0.20).

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