Miniaturized NIR spectroscopy for the determination of main carbohydrates in syrup

NIR news ◽  
2017 ◽  
Vol 28 (2) ◽  
pp. 3-6 ◽  
Author(s):  
Raphael Henn ◽  
Christian G. Kirchler ◽  
Christian W. Huck

This article gives an insight into the advances of miniaturized spectrometers on their way to success dealing with the determination of main carbohydrates in syrups. To evaluate the performances of such portable spectrometers, a comparison of the prediction ability, applying Partial Least Squares Regression models, was carried out. Spectra were recorded using a commercially available handheld and a conventional benchtop spectrometer. This work shows that NIR spectroscopy (both benchtop and handheld) can be used for the determination of the main carbohydrates sucrose, glucose and fructose in syrups. Measuring these main constituents in syrups is of great importance in the producing industries. Usually, these sugars are determined via enzymatic hydrolysis with high accuracy, but this method is expensive, time- and resource-consuming. These drawbacks brought up the question of possible alternatives which, if possible, are not restricted to a laboratory environment. NIR spectroscopy fulfills those requirements and was therefore considered to be an attractive alternative for this application.

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.


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