Effect of thermal treatment on potato starch evidenced by EPR, XRD and molecular weight distribution

Effect of heating of the potato starch on damages of its structure was investigated by quantitative electron paramagnetic resonance (EPR) spectroscopy, X-ray diffraction and determination of the molecular weight distribution. The measurements were performed in the temperature range commonly used for starch modifications optimizing properties important for industrial applications. Upon thermal treatment, because of breaking of the polymer chains, diminishing of the average molecular weights occurred, which significantly influences generation of radicals, evidenced by EPR. For the relatively mild conditions, with heating parameters not exceeding temperature 230 °C and time of heating equal to 30 min a moderate changes of both the number of thermally generated radicals and the mean molecular weight of the starch were observed. After more drastic thermal treatment (e.g. 2 h at 230 °C), a rapid increase in the radical amount occurred, which was accompanied by significant reduction of the starch molecular size and crystallinity. Experimentally established threshold values of heating parameters should not be exceeded in order to avoid excessive damages of the starch structure accompanied by the formation of the redundant amount of radicals. This requirement is important for industrial applications, because significant destruction of the starch matrix might annihilate the positive influence of the previously performed intentional starch modification.

EPR spectroscopy as a tool for investigation of differences in radical status in wheat plants of various tolerances to osmotic stress induced by NaCl and PEG-treatment

Two kinds of wheat genotypes with different tolerance to osmotic stress (NaCl and PEG-treatment) were investigated with biochemical analyses, including the measurements of total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power and starch content. The results were compared with electron paramagnetic resonance (EPR) data concerning the nature and amounts of stable long lived radicals present in the control and stressed plants. In addition, the changes in manganese content upon stress conditions were monitored. Different mechanisms of protection against PEG stress in sensitive and tolerant wheat genotypes were postulated. In sensitive genotypes, electrons were created in excess in stress conditions, and were stabilized by polysaccharide molecules, whereas in tolerant genotypes, protection by antioxidants dominated. Moreover, the quinone-semiquinone balance shifted towards semiquinone, which became the place of electron trapping. NaCl-treatment yielded significant effects mainly in sensitive genotypes and was connected with the changes of water structure, leading to inactivation of reactive oxygen species by water molecules.

Selenium-induced protection of photosynthesis activity in rape (Brassica napus) seedlings subjected to cadmium stress. Fluorescence and EPR measurements

Fluorescence and electron paramagnetic resonance measurements were used to study selenium influence on photosystem activity in rape seedlings affected by Cd stress. Water cultures containing Hoagland nutrients were supplemented with 400 microM of CdCl(2), 2 microM of Na(2)SeO(4) and a mixture of both CdCl(2) and Na(2)SeO(4). The seedlings were cultured till the first leaf reached about 1 cm in length. Cadmium-induced changes in the activity of both photosystems were partly diminished by Se presence in the nutrient medium. Electron microscopy photographs confirmed less degradation in chloroplasts of plants cultured on media containing Se. It is suggested that sucrose groups of starch, which is deposited in greater amounts in Cd-stressed plants, may act as traps for free radicals produced under those conditions.

Effect of Sweeteners on Radical Formation in Starch Studied by Electron Paramagnetic Resonance Spectroscopy

The process of radical generation occurring upon thermal treatment of potato and corn starch containing sweeteners: saccharose, acesulfam K, aspartame, and sorbitol was investigated by electron paramagnetic resonance spectroscopy, using Cu2+ ions as a paramagnetic probe. It was found that the influence of acesulfam K and sorbitol on radical formation is stronger than that of other additives. Acesulfam K increased the amount of radicals in the starch compared to native starch, whereas sorbitol significantly decreased their concentration. The influence of sweeteners on radical processes in the starch is because of differences in their molecular structures and presence or absence of OH groups.

Phosphate Positioning and Availability in the Starch Granule Matrix as Studied by EPR

Cu(2+) was introduced as an EPR probe into the starch granules isolated from different starch crop genotypes including transgenically modified potatoes generated for extreme amylose and starch phosphate monoester concentrations. Several discrete copper adducts bound to the starch matrix with different strength was revealed. It was found that phosphate has a significant influence on the type of these species, their number, location in the structure, and strength of binding. Well dispersed Cu(2+) complexes with axial symmetry are formed in the semicrystalline part of the starch linked through O-P- bonds in the phosphorylated starches. In the amorphous part of the starch, freely rotating hexaaqua complexes of Cu(2+) and complexes coupled antiferromagnetically are formed. The amount of the former increases with content of phosphate indicating enhanced binding of water in the granules. The results complement previous experimental data and molecular models for the starch granule with respect to the location and effects of phosphate and crystalline matter.

Electron paramagnetic resonance study of water distribution in starch granules

An electron paramagnetic resonance (EPR) study was performed for potato and wheat starch containing Cu2+ ions as a paramagnetic probe. Distribution of water in the starch granules as well as the interactions between the copper and starch matrix of different crystalline structures were determined. EPR spectra of the native starches consisted of two different centers of Cu2+. One of them, giving at 293 and 77 K an EPR signal of axial symmetry with a well-resolved hyperfine structure (HFS), was assigned to the Cu2+ -starch complex in which Cu2+ ions strongly interacted with oxygen atoms of the starch matrix. Another Cu2+ species, exhibiting an isotropic signal at 293 K and an axial signal with resolved HFS at 77 K, was attributed to a [Cu(H2O)6]2+ complex freely rotating at room temperature and immobilized at low temperatures. Interaction of Cu2+ with the starch matrix and the relative number of the particular copper species depended on the crystallographic type of starch. Dehydration at 393 K resulted in elimination of the rotating complex signal and decrease of the total intensity of the EPR spectrum caused by clustering of the Cu2+ ions. Freezing at 77 K and thawing led to restoring of the spectrum intensity and reappearing of the signal of the [Cu(H2O)6]2+ complex. This effect, related to liberation of water molecules from the granule semicrystalline growth rings on freezing/thawing, was especially visible for wheat starch, indicating differences in the water retention ability of starch granules of different crystallographic structure.

Catalytic Activity of MCM-48-, SBA-15-, MCF-, and MSU-Type Mesoporous Silicas Modified with Fe3+ Species in the Oxidative Dehydrogenation of Ethylbenzene in the Presence of N2O

MCM-48, SBA-15, MCF, and MSU mesoporous silicas were used as supports for a deposition of Fe oxide species. Iron was introduced using two different methods: the wetness impregnation and the molecular designed dispersion (MDD). The obtained catalysts were characterized with respect to their textural parameters (BET), chemical composition (electron microprobe analysis), and reducibility (TPR). The coordination environment of Fe was determined using EPR and UV-vis/DRS. The samples were tested as catalysts in the oxidative dehydrogenation of ethylbenzene to styrene in the presence of N(2)O. An influence of Fe dispersion and reducibility on the catalytic activity was discussed. Isolated Fe(3+) species appeared to be more selective in the styrene formation, whereas iron oxide clusters showed a higher selectivity in total oxidation of aromatic hydrocarbons. The reaction system was well described by the Mars- van Krevellen mechanism.

Electron paramagnetic resonance study of V2O5 deactivation in the course of catalytic oxidation of SO2 to SO3

The influence of reagents interactions with V2O5 catalyst on its activity in the reaction of SO2 oxidation has been investigated by electron paramagnetic resonance (EPR) method. It was found that the deactivation of V2O5 is caused by the diminishing of the number of adsorption centers able to interact with reagent molecules and with the creation of elements of the VOSO4 phase.

[Disability among patients with affective disorders]

In a group of patients with affective disorder it was found that the frequency of formal handicap occurred in 29.8% of those subjects. This was observed mainly in women and mostly with those diagnosed as bipolar affective disorder (43.6%). Patients with an alcohol problem more often were on social security pension.

[Results of using tricyclic antidepressive drugs in the treatment of endogenous depression (comparative analysis of 7 drugs)]

A group of 250 patients with endogenous depression was studied. Amitriptyline proved to be the most effective drug (51% positive responses) followed by noxiptilin (50%), imipramine (42%), dibenzepin (43%). Clomipramine, desipramine, and nomifensine appeared to be the least effective. Demographic or clinical factors such as age, sex, type of affective illness, severity of depressive syndrome or its particular symptoms (depression, fear, anxiety, psychomotor impairment or biological rhythm alteration) did not show any potential for prediction of the treatment outcome. Worse therapeutic results were observed in patients who had already been given antidepressant treatment for the current depressive cycle before the assessment.

[Early results of the treatment of endogenous depression with tricyclic antidepressive drugs and prognosis of their effectiveness]

Evaluation of a group of 250 patients with endogenous depression in the course of affective illness suggest that reactions of patients to tricyclic antidepressants in an early phase of the treatment may supply interesting prognostic data. Improvement of mental state (reduction of the Hamilton Depression Scale score) on the seventh day and especially on the 14th day of treatment points to a high probability of positive response to the treatment. Lack of such a reaction or worsening of the mental state in the early phase of pharmacotherapy (on the seventh day) frequently is an early sign of lack of positive response to the treatment. The survey considered following antidepressant drugs: amitriptyline, noxiptilin, clomipramine, dibenzepin and desipramine.

[Reaction to sleep deprivation as a prognostic factor in the treatment of endogenous depression]

Studies conducted on a group of 38 patients with endogenous depression demonstrated that a reaction to sleep-deprivation presenting as improved well-being has a significant predictive potential for treatment with imipramine. Patients who displayed the reaction also significantly more frequently displayed improvement of clinical course (remission; good response). Risk of switching from depression to mania also increased among these patients. Patients responding to sleep-deprivation with improved well-being belonged mainly to the bipolar affective disorder. Neither clinical manifestations of depression, nor the number of relapses, nor the duration period of the disorder, nor basic demographic patterns did show distinct features; nor did they differ significantly from patients who did not respond to sleep-deprivation with improved well-being.

[Social adaptation of patients with bipolar disorder in relation to the problems of alcoholism (pilot studies)]

89 patients (52 women and 37 men) with bipolar affective disorder was separated on two groups: with alcohol problems (n = 30) and without alcohol problems (n = 59). Both groups were tested using Scale of Adaptation and Activity of Puzyński (SAA III). The bipolar affective illness discriminates patient's social functioning (especially married life and emotional relation to the closest relatives). The bipolar patients with alcohol problems did show worse social adaptation than the other group; it concerns mainly masculine patients.

[Drug resistance and various selected demographic and clinical characteristics of patients with endogenous depression]

The influence of some selected demographic and clinical characteristics on the formation of resistance to antidepressant drugs were studied in the group of 115 patients with affective disorders. Drug resistance occurs as frequently in women as in men. It appears much frequently in patients after 40 (about 30%). Persons under 30 are not or very rarely affected. Type I of bipolar affective disorder and the occurrence of affective disorder in relatives are positive prognostic factors. The long relapses (greater than 20 weeks) are of the worse prognostic value than shorter ones (less than 3 months). Previous poor efficiency of antidepressant drugs predicts very often an identical response during current episode. Alcohol abuse is an unfavourable prognostic factor in men with endogenous depression.

[Blood MAO/DBH index and the results of the treatment of endogenous depression]

In the group of 115 endogenous depression patients 84 responded to tricyclic antidepressant medication and 31 remained drug-resistance. The changes of platelet MAO activity and serum DBH activity in the latter group were found. Among drug-resistant patients, 40% showed low MAO/DBH index (.6) and in 36% the index was within the medium range (.6-1.9). The low value of the index is predominantly connected with the increase of DBH and decrease of MAO activity, and it may become the potential predictive factor for the pharmacotherapy in endogenous depression. The results show the influence of the disturbances of catecholamines synthesis and degradation on the phenomenon of drug-resistance to tricyclic antidepressants.