Maciej Fiedorowicz

Molecular characterization of wheat amylopectins by multiangle laser light scattering analysis

ABSTRACT Weight-average molecular weight (Mw) and chain length of eight amylopectins isolated from one Australian, two United States, and five Korean wheats were measured using multiangle laser light scattering (MALLS) and refractive index (RI) detectors operated in a microbatch mode, and in a high-performance size-exclusion chromatography (HPSEC) mode. The Mw of amylopectins measured in the microbatch mode ranged from 29 × 106 to 349 × 106. Three amylopectins (Geuru, Tapdong and WW) showed significantly high Mw values over 200 × 106. The Mw measured by HPSEC mode with MALLS-RI detectors (42 × 106 to 73 × 106) were significantly less than those obtained in the microbatch mode with exception of dark northern spring hard wheat (DNS) amylopectin, indicating the possible variation of Mw by the analysis mode. Root-mean square of the radius of gyration (Rg) also was greater when the microbatch mode was used (122–340 vs. 95–116 nm). Chain length distributions of debranched amylopectins of different cultivars, me...

Molecular Distribution and Pasting Properties of UV‐Irradiated Corn Starches

Suspension (30%, w/w) of corn starch (25 % amylose) in water was irradiated by UV-light with wavelength greater than 250 nm at 25 °C, under a stream of nitrogen or air, for time intervals ranging from 5 to 25 h. Effects of the irradiation on the transition enthalpy and temperature for melting, and the pasting viscosity profile of the irradiated starch were examined. Weight-average molecular weight (M w ) and radius of gyration (R g ) of the irradiated starch molecules were measured by high performance size exclusion chromatography coupled with multiangle laser light scattering and differential refractive index detectors (HPSEC-MALLS-RI). In the case of starch irradiated under nitrogen, the transition enthalpy (ΔH) decreased with increasing irradiation time whereas the melting temperature was not changed. Similarly, the peak paste viscosity (P v ) decreased from 97 to 56 RVU by 25h irradiation. Average M w and R g of amylopectin and amylose fractions, which were 93 x 10 6 and 144nm, and 2.0 x 10 6 and 104nm, respectively, were decreased by irradiation to 32.2 × 10 6 and 93.7 nm, and 0.7 x 10 6 and 83.6 nm by the irradiation for 15 h under nitrogen, respectively. When the starch was irradiated with aeration, sharp drops of all measured parameters were observed in 5 h of irradiation (ΔH 11.4J/g, P v 53.2 RVU, amylopectin M w 50 x 10 6 ). After 15 h under air, however, all measured values increased (ΔH 16.8J/g, P v 65.5 RVU, amylopectin M w 63.1 × 10 6 ). Molecular size distribution profiles confirmed oxidative the photodegradation in the early stage (up to 5 h), and cross-linking reactions in the late stage (5-15 h) of irradiation under aeration.

Formation of nanometal particles in the dialdehyde starch matrix.

Environmentally friendly method of the preparation of dialdehyde starch (DAS) based composites containing nanosilver (DAS/Ag) and nanogold (DAS/Au) as reducing and protecting agents was developed. UV-vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed formation of about 10nm ball shaped Ag and Au nanoparticles situated within the polysaccharide template. Thermal properties of the composites were characterized involving differential scanning calorimetry (DSC), whereas molecular weights of polysaccharide chains of the matrix were estimated with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Formation of nanosilver and nanogold containing composites led to induction of the polymerization and/or crosslinking reactions of DAS molecules, resulting in a significant rise of molecular weight of polysaccharide chains constituting DAS/Ag and DAS/Au composite templates.

Polarized light-stimulated enzymatic hydrolysis of chitin and chitosan

Illumination with white linearly polarized light (WLPL) stimulated chitinase and chitosanase in their degradation of chitin and chitosan, respectively. Enzymes were illuminated at room temperature in separate vessels, then admixed in reactors containing polysaccharides. Hydrolysis of chitosan to glucosamine followed first order kinetics whereas hydrolysis of chitin to N-acetylglucosamine deviated from the first order kinetics. In both cases, an increase in the rate of hydrolysis depended on the illumination time. Efficient degradation required up to 60 min exposure of the enzyme to WLPL.

THE PHOTODYNAMIC EFFECT OF VICTORIA BLUE BO ON PERIPHERAL BLOOD MONONUCLEAR AND LEUKEMIC CELLS

Abstract— The photodynamic effect of Victoria blue BO (VB‐BO) and photoirradiation on peripheral blood mononuclear cells was studied. The cells were preincubated with VB‐BO followed by photoirradiation and overnight culture. The highest percentage of dead cells (propidium iodide assay in flow cytometry) was seen in the monocyte population. The lymphocytes showed a lower sensitivity to VB‐BO photodynamic action than the monocytes (12%vs 80% of Pi‐positive cells). The effect of VB‐BO and phototreatment on lymphocyte function was studied using a mitogen‐induced proliferation assay. A decrease of mitogen response was observed. The VB‐BO and photoirradiation were also used on leukemic cells. The leukemic cells from acute myeloid leukemia and B precursors leukemia were sensitive to VB‐BO photodynamic action. The high VB‐BO sensitivity of monocytes and leukemic cells (myeloid and lymphoid B derived) suggests possible application of VB‐BO for selective depletion of monocytes or sensitive leukemic cells.

Microwave-assisted solid-state sulphation of starch

Abstract Starch was sulphated with pyridine.SO3 complex in the microwaveassisted solid state processes in multimodal microwave oven and, for comparison, also on convectional heating blends of solid reagents. Starch was less hydrolysed in microwave-assisted reactions. The degree of the esterification of the sulphuric acid anhydride depended to a lesser extent on the reaction time and the power applied, and more essentially on the reagent ratio, that is, dose of the sulphating agent. Its higher doses favoured depolymerization and esterification leading to diesters, that is, crosslinking.

Polarized-Light-Stimulated Enzymatic Hydrolysis of Xylan

The 1‐ to 2‐h illumination of xylanase with visible polarized light (PL) prior to the action of that enzyme upon beechwood xylan significantly increased its activity. The activity only negligibly decreased on 3 months storage. The hydrolysis of xylan proceeded in three well‐distinguished stages. In the first and fastest stage the effect of illumination was only slightly positive. The effect of the stimulation was noted in the second, slower stage. Enzyme stimulated with PL, preferably by means of the 2‐h illumination, performed better than enzyme stimulated with nonpolarized light and non‐stimulated enzyme. In the last, the slowest stage, the rates of the reaction were nearly the same using either stimulated or non‐stimulated enzyme.

Formation and properties of hyaluronan/nano Ag and hyaluronan-lecithin/nano Ag films

A facile and environmentally friendly method of the preparation of silver nanoparticles embedded in hyaluronan (Hyal/Ag) and hyaluronan-lecithin (Hyal-L/Ag) matrix was developed. Thin, elastic foils were prepared from gels by an in situ synthesis of Ag in an aqueous solution of sodium hyaluronate (Hyal), using aq. d-(+)-xylose solution as a reducing agent. The gels were applied to a clean, smooth, defatted Teflon surface and left for drying in the air. The dry foils were stored in a closed container. UV-vis spectroscopy, transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectra confirmed formation of about 10nm ball-shaped Ag nanoparticles situated within the polysaccharide template. Thermal properties of the composites were characterized involving differential scanning calorimetry (DSC) and thermogravimetric (TGA) analyses, whereas molecular weights of polysaccharide chains of the matrix were estimated with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). An increase in the molecular weight of the hyaluronate after generation of Ag nanoparticles was observed. The foils showed specific properties. The study confirmed that silver nanoparticles can be successfully prepared with environmentally friendly method, using hyaluronan as a stabilizing template. Hyaluronan and hyaluronan-lecithin matrices provide nanocrystals uniform in size and shape. The composites demonstrated a bacteriostatic activity.

Formation of cyclodextrins with cyclodextrin glucosyltransferase stimulated with polarized light

After illumination with white, linearly polarized light (WLPL), cyclodextrin glycosyltransferase produced mixture of α‐, β‐, and γ‐cyclodextrins (CD) with higher overall yield than did that enzyme when nonilluminated. The illumination also influenced the ratio of those CD and that effect depended on concentration of enzyme and illumination time. At a high enzyme concentration (0.64 U/cm3), regardless the illumination time, formation of β‐CD predominated. The highest yield of β‐CD was afforded after 1 h illumination and 2 h illumination led to a significant increase in the yield of γ‐CD. Three‐month storage of enzyme illuminated with WLPL did not reduce its enhanced activity.

Distarch Phosphate as a Matrix for the Generation of Quantum Dots

Generation of ZnS, CdS, CaS and MgS quantum dots (QDs) was attempted in the matrix of distarch phosphate, an anionic polysaccharide. Based on the analysis of FTIR spectra, thermograms and Differential Scanning Calorimetry, interactions of QDS with the matrix could be excluded. On generation of MgS QDs and also, to a certain extent, CaS QDs, hydrolysis of the salts generating these QDs took place. That process had an impact on the partial destruction of the matrix. Molecular weight and radii of gyration of the products showed that the generation of QDs was dependent on the properties of the matrix polysaccharide. The elasticity, plasticity and viscosity of the gels containing QDs were significantly lower than those of plain distarch phosphate. Generally these values changed with time similarly to gels free of QDs.