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

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.

HortScience ◽  
1991 ◽  
Vol 26 (10) ◽  
pp. 1303-1305 ◽  
Author(s):  
Gerald G. Dull ◽  
Richard G. Leffler ◽  
Gerald S. Birth ◽  
Arthur Zaltzman ◽  
Ze'ev Schmilovitch

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.


1998 ◽  
Vol 6 (A) ◽  
pp. A163-A170 ◽  
Author(s):  
B. Barabás

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.


1993 ◽  
Vol 281 (2) ◽  
pp. 259-264 ◽  
Author(s):  
Salvador Garrigues ◽  
Máximo Gallignani ◽  
Miguel de la Guardia

2019 ◽  
Vol 1 (2) ◽  
pp. 246-256
Author(s):  
Benjamaporn Matulaprungsan ◽  
Chalermchai Wongs-Aree ◽  
Pathompong Penchaiya ◽  
Phonkrit Maniwara ◽  
Sirichai Kanlayanarat ◽  
...  

Shredded cabbage is widely used in much ready-to-eat food. Therefore, rapid methods for detecting and monitoring the contamination of foodborne microbes is essential. Short wavelength near infrared (SW-NIR) spectroscopy was applied on two types of solutions, a drained solution from the outer surface of the shredded cabbage (SC) and a ground solution of shredded cabbage (GC) which were inoculated with a mixture of two bacterial suspensions, Escherichia coli and Salmonella typhimurium. NIR spectra of around 700 to 1100 nm were collected from the samples after 0, 4, and 8 h at 37 °C incubation, along with the growth of total bacteria, E. coli and S. typhimurium. The raw spectra were obtained from both sample types, clearly separated with the increase of incubation time. The first derivative, a Savitzky–Golay pretreatment, was applied on the GC spectra, while the second derivative was applied on the SC spectra before developing the calibration equation, using partial least squares regression (PLS). The obtained correlation (r) of the SC spectra was higher than the GC spectra, while the standard error of cross-validation (SECV) was lower. The ratio of prediction of deviation (RPD) of the SC spectra was higher than the GC spectra, especially in total bacteria, quite normal for the E. coli but relatively low for the S. typhimurium. The prediction results of microbial spoilage were more reliable on the SC than on the GC spectra. Total bacterial detection was best for quantitative measurement, as E. coli contamination could only be distinguished between high and low values. Conversely, S. typhimurium predictions were not optimal for either sample type. The SW-NIR shows the feasibility for detecting the existence of microbes in the solution obtained from SC, but for a more specific application for discrimination or quantitation is needed, proving further research in still required.


2011 ◽  
Vol 65 (9) ◽  
pp. 1056-1061 ◽  
Author(s):  
Sharon L. P. Sakirkin ◽  
Cristine L. S. Morgan ◽  
James C. MacDonald ◽  
Brent W. Auvermann

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