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Near-infrared (NIR) spectrophotometers with different optical arrangements were used to measure the diffusely reflected electromagnetic radiation of different types of food additives in polyethylene (PE) foils. Eight compounds, frequently used in food process – but also in other industries –, were measured by different NIR spectrophotometers. The detected (‘as is’) and mathematically transformed (by scatter correction, second derivative combined with smoothing) NIR spectra were processed with multivariate data analysis (MDA). In this matter, unsupervised methods like principal component analysis (PCA) and cluster analysis (CA) were used, which techniques do not require prior information and reference measurements. The aim of the present study was to distinguish food additives by the help of the applied chemometric methods based on NIR spectra detected via the PE foils. Results indicated that distinction of different food additives and compounds with NIR methods is possible not only with the conventional sample preparations and handlings, but also without breaking the packaging.

Open access

Abstract

The purpose of this paper is to present a way to develop a technical e-laboratory for students interested in their continuing training. It presents hardware and software aspects regarding design of a LabVIEW-Based Soundcard Interface for E-Laboratory. To realize an e-learning laboratory we used web publishing tool from LabVIEW and the connection between server and remote computer is realized with a VPN software to pass through any router or a NAT device and realise a secure tunnel between remote computers and LabVIEW web-server. Also, the web publishing tool from LabVIEW allows concurrent access from different remote computers to e-laboratory. For example paper offers a LabVIEW application for acquisition and generation of signals using the sound card.

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Abstract

Soybean seeds were germinated on an industrial scale after soaking for 0–56 h to produce a special additive for food industrial use. The germination process of three soybean varieties was monitored with near-infrared (NIR) spectroscopy based on changes in the amount, status, or character of the water. This paper evaluates the “waterless” NIR spectra of sound, germinated, and heat treated seeds to try to follow the fine details of the germination process. The germination process was analysed with the help of cluster analysis (CA), principal component analysis (PCA), and polar qualification system (PQS) as statistical and chemometric methods. PCA proved to be the most sensitive spectrum evaluation method to follow the fine details of germination. The applied NIR method is suitable for non-destructively, real-time monitoring of the non-linear nature of germination.

Open access
Acta Alimentaria
Authors:
M. Hódsági
,
Á. Jámbor
,
E. Juhász
,
S. Gergely
,
T. Gelencsér
, and
A. Salgó

Resistant starches (RSs) are broadly investigated as appropriate additives in starch-based products due to their well-known and proved health benefits. However, it was shown in previous studies that these starches are sensitive of the different heat treatments used in the food processing, which can cause changes, especially in the resistance. There is an increasing trend to use microwave (MW) energy in food processing; therefore, our aim was to investigate the changes of RSs compared to native starches caused by MW heating. Maize, wheat, RS2 and RS4 starches were MW-treated according to a 2×2 experimental design (300 and 600 W of power, 30 and 150 s of time). The changes of in vitro digestibility, rheological properties (rapid visco analyser, RVA) and near infrared (NIR) spectroscopic characteristic were studied. Two spectrophotometers were applied (dispersive and Fourier-transform (FT)) to compare their sensitivity in the analysis of the MW-treated starches.Results showed that the digestibility of starches did not show any tendencies when increasing the microwave energy of treatments, the characteristics of the kinetic curves remained unchanged. The RVA analysis showed that the RSs did not gelatinize after the heat-treatments. The MW heating weakened the rheological properties of all starches. The NIR analysis was the most sensitive device for the detection of the effects of MW treatments. The analysis of the most characteristic carbohydrate regions (2080–2130 and 2270–2290 nm) highlighted structural alterations of the starches; moreover, the dispersive spectrophotometer was found to be more sensitive in the analysis of starches than the FT-one.

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