Szilveszter Gergely

Changes in moisture content during wheat maturation - What is measured by near infrared spectroscopy?

The aim of the present study was to detect maturation processes in wheat seed non-destructively with special respect to changes in moisture content and natural hydration/dehydration processes. Maturation is a phase of seed development in which a series of biochemical, enzymatic and morphological changes occur under highly hydrated conditions. The role of water is therefore critical to the whole maturation process. The amount and variation in content of different water species [high density water (HDW) with weaker hydrogen bonding and low density water (LDW) with stronger hydrogen bonding] changed considerably during maturation. Characteristic changes in three water absorption bands [1890–1920 nm (water I), 1400–1420 nm (water II) and 1150–1165 nm (water III)] were analysed. It was concluded that the different transitions of water molecules could be followed sensitively through different regions of NIR spectra. In the maturing seed, combination bands (water I and water III) were more sensitive indicators of changes in water molecules than was the first overtone (water II). The polar qualification system (PQS) provided sensitive and informative results regarding the amount and species of water in the developing seed. NIR spectroscopic techniques can be used effectively in monitoring plant physiological processes and the spectra have hidden information for predicting the stage of growth in wheat seed.

Relationship between NIR spectra and RVA parameters during wheat germination

ABSTRACT The process of germination in six different wheat cultivars was monitored using NIR spectroscopy and the Rapid Visco Analyser (RVA) method. Near-infrared spectra provided insight into both chemical and physical changes that occur in the seed, in particular mobilization processes involving carbohydrates. RVA curves also contain physical and chemical information and can be interpreted as physicochemical spectra. The process of germination was followed sensitively through the RVA curves and some rheological parameters (peak viscosity, trough, breakdown, final viscosity, and setback) were highly correlated (R = 0.95–0.98) with predicted values calculated from NIR spectra. Viscosity data calculated from RVA curves collected at 200–480 sec showed the most characteristic changes during the early heat treatment stage of the pasting procedure. Strong intercorrelations were found between viscosity data and NIR spectra from the beginning of the swelling and gelatinization processes in germinating seed. The ...

Comparison of Different Types of NIR Instruments in Ability to Measure β-Glucan Content in Naked Barley

ABSTRACT Importance of β-glucan in human nutrition is mirrored in numerous approval applications registering β-glucan containing products as health beneficial products in accordance with forthcoming EU Health Claims Regulation. In comparison to other cereals, barley contains considerable amounts of β-glucan. Naked barley is of particular interest because it circumvents the costs and loss of beneficial substances related to dehusking. In this study, the potential of near-infrared spectroscopy as an accurate, fast and economic method of determination of β-glucan in naked barley was appraised. Four different near-infrared instruments were used to analyze 107 barley samples, in both whole grain and milled form. Importantly, both black and purple pericarp samples, which are of additional nutritional interest due to high anthocyanin content, and waxy samples, which show an extraordinary high β-glucan content could be analyzed within the same calibration set as the normal samples. All tested dispersive near-infr...

Changes in protein content during wheat maturation—what is measured by near infrared spectroscopy?

The amount and variation in content of different proteins changes considerably during maturation and these changes were non-destructively monitored in developing grain using near infrared (NIR) spectroscopy. Characteristic changes in two protein absorption bands were identified (2055–2065 nm, identified as amide A/II and 2175–2180 nm, identified as amide I/III) and it was concluded that the different dynamics of protein development (accumulation of proteins as well as gluten network formation) could be followed sensitively by monitoring these two different regions of NIR spectra. Amide A/II represents the effect of protein network formation during maturation based on the vibrations of inter-chain hydrogen bonded N–H groups in polypeptides. Amide I/III is the manifestation of protein accumulation, as in the formation of gliadins and glutenins that interact together to form a gluten network. NIR spectroscopy is shown to be effective in monitoring plant physiological processes both qualitatively and quantitatively, and the spectra have more hidden information for predicting the stage of growth in wheat seed.

On-line prediction of the glucose concentration of CHO cell cultivations by NIR and Raman spectroscopy: Comparative scalability test with a shake flask model system

HighlightsNIR and Raman spectroscopy are compared using a shake flask model system.Multivariate models are built for glucose prediction using data from the shake flasks.Both techniques followed the trend of glucose concentration during cultivation.The effect of scale‐up on model performance is tested with bioreactor data.The shake flask model system is appropriate for quick generation of a working model. Abstract In this study, near‐infrared (NIR) and Raman spectroscopy were compared in parallel to predict the glucose concentration of Chinese hamster ovary cell cultivations. A shake flask model system was used to quickly generate spectra similar to bioreactor cultivations therefore accelerating the development of a working model prior to actual cultivations. Automated variable selection and several pre‐processing methods were tested iteratively during model development using spectra from six shake flask cultivations. The target was to achieve the lowest error of prediction for the glucose concentration in two independent shake flasks. The best model was then used to test the scalability of the two techniques by predicting spectra of a 10 l and a 100 l scale bioreactor cultivation. The NIR spectroscopy based model could follow the trend of the glucose concentration but it was not sufficiently accurate for bioreactor monitoring. On the other hand, the Raman spectroscopy based model predicted the concentration of glucose in both cultivation scales sufficiently accurately with an error around 4 mM (0.72 g/l), that is satisfactory for the on‐line bioreactor monitoring purposes of the biopharma industry. Therefore, the shake flask model system was proven to be suitable for scalable spectroscopic model development.

A model system and chemometrics to develop near infrared spectroscopic monitoring for Chinese hamster ovary cell cultivations

Near infrared (NIR) spectroscopy is an ideal tool for biopharmaceutical process monitoring, as it can be used to generate information on key bioprocess variables rapidly online. Mammalian cell cultivation is a rapidly developing field of biopharmaceutical production where one of these key process variables is the glucose concentration. However, calibrations for the NIR-based monitoring of glucose are usually not available in the early phase of process development owing to the lack of sufficient NIR data from small-scale experiments. This article demonstrates the development of calibrations based on NIR spectroscopy (11,988.0–4297.0 cm−1) for the determination of glucose concentration in a novel shake flask model system for mammalian cell cultivation. To generate a homogeneous distribution of glucose concentration in the calibration range and to reduce the correlation between glucose and other metabolites, cultivation samples with low glucose levels were spiked with glucose, and NIR measurements were subsequently performed. Biochemical and physical variability was deliberately induced in the model system to mimic possible matrix effects typically occurring in fed-batch bioreactor cultivation samples. The specificity of the calibration model to glucose was increased by variable selection, so the spectral region between the two water peaks was used for calibration. Four mathematical pretreatments were evaluated by comparing the root-mean standard error of prediction (RMSEP) values of the models; the best preprocessing method was a novel combination of baseline offset method with the deresolve function. Our models predicted the glucose concentration in two test cultivations with an RMSEP of 3.12 mmol L−1 and 5.51 mmol L−1.

Correlation between NIR spectra and RVA parameters during germination of maize

ABSTRACT The physical, chemical, and morphological changes of maize seeds during germination were investigated using near-infrared spectroscopy (NIR) and a method based on the Rapid Visco Analyser (RVA). Near-infrared spectra provide information about both chemical and physical changes that occur in maize seed. The RVA curves make it possible to follow the process of germination. Four RVA parameters (peak viscosity, final viscosity, trough, and setback) were linearly correlated with germination time (R = 0.64–0.96), while the first derivatives of RVA curves contain specific information about starch structure. Water-soluble protein (WSP) content of germinated maize seeds was measured using a flow injection analyser; this technique proved to be suitable for monitoring germination by following the mobilization of proteins. WSP and RVA parameters were highly correlated (R2 = 0.82–0.95) with predicted values calculated from NIR spectra of dry samples. Strong intercorrelations existed between NIR spectra and vi...

Sprouting of soybean: a natural process to produce unique quality food products and additives

Seed germination (sprouting) offers a broad spectrum of quality changes to the design of novel food components/additives/products with improved composition, enhanced nutritional value and/or with dedicated functional properties compared to ungerminated seed. This review summarises the general physiological and compositional changes that occur during the germination process in soybean seed. The changing pattern of macro- and micro components, different bioactive compounds and anti-nutritive factors are highlighted and their nutritional and functional characteristics summarised. Furthermore, the benefits of a strictly controlled short-term germination process (germination time <48 h) are summarised and the potential of an innovative sprouting procedure is discussed. Short-term germination technology and the processed bean materials provide a special quality seed product as raw material or additive, which can be used in a wide variety of sectors, such as the food industry, households, and public and hospital catering. It can also be applied in the healthy and functional food production segment.

Investigation of heat-treated cultivation medium for mammalian cells with near infrared spectroscopy

A chemically defined medium powder for Chinese hamster ovary (CHO) cell cultivation was investigated regarding its response to heat treatments with different exposure times (1 hour, 7 hours and 13 hours) and temperatures (30 °C, 50 °C and 70 °C). The heat treatments were performed according to a design of experiments approach. Spectra of the control and the treated powders were collected to compare the sample groups using a dispersive and a Fourier transform (FT) near infrared (NIR) spectrometer. Multivariate data analysis including unsupervised classification as principal component analysis and supervised classification as soft independent modelling of class analogy was employed to identify the treatment-induced variations in the samples. Samples were separated according to the temperature set points of heat treatments and the control samples were successfully discriminated based on second-derivative NIR spectra. In order to evaluate the impact of the treatments on the growth rate of CHO cells, shake flask cultivation experiments were also performed. The viable cell density results showed that both treatment temperature and treatment duration were significant factors (p = 0.05). Additionally, the sensitivity of change detection for medium powders was higher in the case of NIR and FT-NIR measurement and spectrum analysis compared to traditional shake flask cultivation.

Off-line detection of milling processes of Pannon wheat classes by near infrared spectroscopic methods

The innovations of near infrared (NIR) technology are effectively used in the quality control field of cereal science and technology. The aim of this study was to elaborate NIR methods for testing and recognition of chemical components and quality in ‘Pannon wheat’ milling fractions as well as to develop spectroscopic methods following the milling processes and evaluate the milling actions, the stability of the milling technology by different types of milling products. Milling fractions of the ‘Pannon Standard’ and the ‘Pannon Premium’ wheat categories were produced from allied (i.e. true to variety or variety identical) wheat under industrial conditions where samples were collected versus sampling times and maximum or minimum yields. The changes of the main chemical components (starch, protein, lipid) and physical properties of fractions were analysed by dispersive spectrophotometers using visible and/or NIR regions of the electromagnetic radiation. Close correlations were obtained between the data of sp...