Biochemistry and Biophysics

Effect of the Addition of Chitosans with Different Molecular Structure on Fermentation Process and Viscosity Changes During Sour Cream Storage

2013-06

Effect of the Addition of Chitosans with Different Molecular Structure on Fermentation Process and Viscosity Changes During Sour Cream Storage

Pages 13-21
Author Jelena ZagorskaAlexander PelnikGarry Kerc
Abstract The effect of different health promoting chitosan-based additives (high molecular weight chitosan, carboxymethyl chitosan, chitosan oligoosaccharide) with different molecular structure on pH changes during cream fermentation process and viscosity changes of sour cream during storage were studied. The inhibition of cream fermentation is much higher for chitooligosaccharide with low molecular weight and higher degree of deacetylation than for high molecular weight chitosan with lower degree of deacetylation especially at a higher concentrations of additives. The increase of viscosity of sour cream with the increase of concentration of high molecular weight chitosan and decrease of viscosity with the increase of concentration of chitooligosaccharide have been observed. It was demonstrated that the effect of additives on viscosity can be explained by changing the interaction forces between negatively charged casein micells and by the start of gel formation during cream fermentation process at higher pH.

2013-06

Influence of Mobile Phone Radiation on Membrane Permeability and Chromatin State of Human Buccal Epithelium Cells

Pages 22-28
Author Galyna B. SkamrovaAnastasia O. LantushenkoYuriy G. ShckorbatovMaxim P. Evstignee
Abstract The results obtained in the present study indicate a statistically significant response of human buccal epithelium cells to the mobile phone radiation in terms of changes in the number of heterochromatin granules in nucleus and membrane permeability. The observed changes are qualitatively similar, indicating certain threshold exposure time of about 1 min and a saturation at exposure times longer than 30 min. These changes may serve as a marker of alteration in functional activity of human cells after electromagnetic radiation (EMR) action. The major effect of mobile phone radiation on cells was dependent upon the exposure time, whereas the specific absorption rate (SAR) level of mobile phone radiation appeared to be relatively unimportant. As our experiments were conducted using limited number of subjects, the data obtained in this study are preliminary and more extensive studies are needed.

2013-06

Stability Study of Multiwalled Carbon Nanotube/κ-Casein Dispersion

Pages 29-34
Author Bao-Guang MaYong-Qiu LiJia-Bao LiangLi-Ming ZhangJu-Zhen Y
Abstract As one of the most promising materials, multiwalled carbon nanotubes (MWNTs) are being developed for bioapplications. However, the poor dispersion in either water or organic solvents has largely restricted the research and applications of MWNTs. In this study, MWNTs were homogeneously dispersed in aqueous solution ofκ-casein without chemical modification. Techniques including Zeta potential, transmission electron microscopy, circular dichroism have been employed to study the influencing factors on the stability of the dispersion. The results indicated that the dispersion of MWNTs in 0.05 %wt κ-casein is the most stable when the concentration of MWNTs is 0.1 %wt. The exposure of phenylalanine in κ-casein has a significant impact on the dispersion of MWNTs because of the π-π stacking and strong van der Waals attractions between the phenylalanine and MWNTs. The high stability of dispersion may open a new and economic way to use this common protein for bioapplication and biomaterial in the future.