Mara Grube

Infrared spectra of some fructans

The FT–IR spectra of fructan – inulin (RAFTILINE), widely applied in the food industry and crystalline fructose as the main component of fructans, were studied. Special interest was to study the spectra of the levan precipitate and fructan syrup – produced by Zymomonas mobilis during the fermentation on sucrose–based medium.

Comparative investigation of the macromolecular composition of mycelia forms Thielavia terrestris by infrared spectroscopy

Using analytical and infrared spectroscopic methods, the differences between the composition of diffuse and pellet forms of mycelium of the ascomycete Thielavia terrestris were described. Quantitative estimates of the amounts of protein, nucleic acids and carbohydrates in T. terrestris showed a predominance of catabolic processes in the metabolism of the pelleted form, in comparison to the diffused form.

OATS AND FAT-FREE MILK BASED FUNCTIONAL FOOD PRODUCT

The present study addresses problems and solutions related to new functional bio-active food product creation. Commercial rolled oats and fat-free milk were used as raw materials. Limited enzymatic hydrolysis of oat starch was carried out by α-amylase. The lactic acid bacteria strains Lactobacillus acidophilus, Bifidobacterium sp., and commercial starter cultures ABT-1 were cultivated in enzymatically hydrolysed oat mash. Lactobacillus acidophilus was a more active producer of lactic acid, while Bifidobacterium sp. improved the taste properties. A fat-free milk additive was applied to stabilise the texture of the oat mash, and increase the protein content of the final product. All procedures ensured the preservation of beta-glucan, and the number of active lactic acid bacteria in the final product reached 109 per ml. A yogurt-like oat based product “Oat bio Lacto” supports oat beta-glucan, oat lipid unsaturated fatty acids and living probiotic lactic acid bacteria, and can be considered as polyfunctional nutrition.

Carbohydrates in Jerusalem artichoke powder suspension

Purpose – The aim of this study was to evaluate the influence of temperature and action time on the extraction rate of carbohydrates of Jerusalem artichoke concentrate powder and inactivation of inulin during boiling and sterilization.Design/methodology/approach – Water suspension of Jerusalem artichoke concentrate (5g/100ml) at 25, 50 and 100○C was tested after 5, 15, 30 and 60min to determine the content of inulin, glucose, fructose and sucrose and evaluate the extraction rate. The stability of inulin was studied after boiling and sterilization at 120○C during 1, 2 and 3h. The extraction rate was evaluated by Fourier‐Transform Infrared (FT‐IR) spectroscopy as well.Findings – It was shown that extraction of soluble carbohydrates – fructose, glucose, sucrose and inulin, from water suspension of Jerusalem artichoke concentrate was practically completed in 5min at 25○C. The extraction rate was not significantly influenced by temperatures lower than 100○C. Inulin was stable during boiling for 1h but steriliz...

Effect of plant extract on the degradation of nitroaromatic compounds by soil microorganisms

Remediation of soils contaminated by nitroaromatic compounds and nitramines, i.e. explosives, is known as very important, complicated, and rapidly developing area of biotechnology. A search for optimal growth conditions for soil bacteria is of a great importance in order to isolate various xenobiotic degraders. Bacteria consortium A43 was isolated from soils contaminated with explosives. In the presence of carbohydrate and plant extract, an addition of TNT to the solidified minimal medium stimulated the growth of the tested bacteria, as compared to other bacteria consortium isolated from the same soils. Reducing sugars as carbohydrates, and cabbage leaf extract as a plant extract were used in these experiments. Cultivation of the A43 in liquid medium of the same content showed that addition of cabbage leaf extract alone to medium is much more efficient for TNT degradation by growing biomass as compared to addition of carbohydrate alone.

DNA-binding studies of AV-153, an antimutagenic and DNA repair-stimulating derivative of 1,4-dihydropiridine

UNLABELLED The ability to intercalate between DNA strands determines the cytotoxic activity of numerous anticancer drugs. Strikingly, intercalating activity was also reported for some compounds considered to be antimutagenic. The aim of this study was to determine the mode of interaction of DNA with the antimutagenic and DNA repair-stimulating dihydropyridine (DHP) AV-153. DNA and AV-153 interactions were studied by means of UV/VIS spectroscopy, fluorimetry and infrared spectroscopy. Compound AV-153 is a 1,4 dihydropyridine with ethoxycarbonyl groups in positions 3 and 5. Computer modeling of AV-153 and DNA interactions suggested an ability of the compound to dock between DNA strands at a single strand break site in the vicinity of two pyrimidines, which was confirmed in the present study. AV-153 evidently interacted with DNA, as addition of DNA to AV-153 solutions resulted in pronounced hyperchromic and bathochromic effects on the spectra. Base modification in a plasmid by peroxynitrite only minimally changed binding affinity of the compound; however, induction of single-strand breaks using Fentons reaction greatly increased binding affinity. The affinity did not change when the ionic strength of the solution was changed from 5 to 150 mM NaCl, although it increased somewhat at 300 mM. Neither was it influenced by temperature changes from 25 to 40°C, however, it decreased when the pH of the solution was changed from 7.4 to 4.7. AV-153 competed with EBr for intercalation sites in DNA: 116 mM of the compound caused a two-fold decrease in fluorescence intensity. FT-IR spectral data analyses indicated formation of complexes between DNA and AV-153. The second derivative spectra analyses indicated interaction of AV-153 with guanine, cytosine and thymine bases, but no interaction with adenine was detected. CONCLUSIONS The antimutagenic substance AV-153 appears to intercalate between the DNA strands at the site of a DNA nick in the vicinity of two pyrimidines.

Hydrogen‐producing Escherichia coli strains overexpressing lactose permease: FT‐IR analysis of the lactose‐induced stress

The lactose permease gene (lacY) was overexpressed in the septuple knockout mutant of Escherichia coli, previously engineered for hydrogen production from glucose. It was expected that raising the lactose transporter activity would elevate the intracellular lactose concentration, inactivate the lactose repressor, induce the lactose operon, and as a result stimulate overall lactose consumption and conversion. However, overexpression of the lactose transporter caused a considerable growth delay in the recombinant strain on lactose, resembling to some extent the “lactose killing” phenomenon. Therefore, the recombinant strain was subjected to selection on lactose‐containing media. Selection on plates with 3% lactose yielded a strain with a decreased content of the recombinant plasmid but with an improved ability to grow and produce hydrogen on lactose. Macromolecular analysis of its biomass by means of Fourier transform‐infrared spectroscopy demonstrated that increase of the cellular polysaccharide content might contribute to the adaptation of E. coli to lactose stress.

Influence of growth conditions on hydrophobicity of Lactobacillus acidophilus and Bifidobacterium lactis cells and characteristics by FT-IR spectra

In this study we have found, that the values of cell surface hydrophobicity (CSH) of L. acidophilus LA5 and B. lactis Bb12 cells change in response to varied growth conditions – phase of growth, concentration or type of carbon source, presence of oxygen. An evaluation of FT-IR spectra using cluster and quantitative analyses revealed substantial changes of the chemical composition depending on the CSH level of L. acidophilus LA5 and B. lactis Bb12 cells. Decrease of the carbohydrate level was observed in proportion to the increased CSH values alongside with the elevated protein content of more hydrophobic cells of both cultures. The results of present study could help to specify the appropriate physiological state and environment for L. acidophilus LA5 and B. lactis Bb12 to ensure their probiotic properties.

Fermentation of Jerusalem artichoke by Zymomonas and Saccharomyces

Purpose – The aim of this study is to find out the appropriate fermentation conditions of Jerusalem artichoke powder (JAP) based media to obtain light beverage containing inulin.Design/methodology/approach – JAP water suspension or filtrate were used for preparation of growth media with or without enzymatic hydrolysis of inulin for fermentation by Zymomonas mobilis 113 “S” or Saccharomyces cerevisiae.Findings – If enzymatic hydrolysis of inulin was not used significantly higher amount of inulin (7.42 per cent) was unconverted by Z. mobilis than by S. cerevisiae (2.22 per cent) while the ethanol concentration was much higher (2.86 per cent) after S. cerevisiae fermentation than after Z. mobilis fermentation (1.21 per cent). Considerably more ethanol was produced by Z. mobilis during co‐fermentation with Fructozyme L of JAP suspension filtrate (5.98 per cent) and suspension (4.96 per cent). Analyses of volatile components of fermentation broths showed that for production of inulin containing light beverages...

Micro-Raman scattering and infrared spectra of hemoglobin

Confocal micro-Raman and FT-IR spectroscopies have been used for detection of radiation influence of hemoglobin of patients examined by radio-isotopes diagnosis (Tc99m). After irradiation we observed some little changes of the Raman scattering bands which connected with out of plane porphyrine bending vibrations, also we observed additional band due to methemoglobin. Radiation of blood lead to the transition from hemoglobin (Fe2+) to methemoglobin (Fe3+) with a delocalization of iron from porphyrine plane. It was shown that FT-IR spectra indicate the radiation effects on hemoglobin.