FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Absorption and fluorescence study of amylose complex in cationic detergent using bengal rose as a spectroscopic probe


In order to estimate the detergent influence on the process of amylose-dye complex formation the absorption and fluorescence studies of Bengal Rose in the amylose – Bengal Rose complex in the presence of cationic detergent, tetradodecyltriethylammonium bromide,TDABr, were carried out. The fluorescence quenching study allowed to calculate binding constant between the dye and amylose. Thermodynamic parameters were calculated from the temperature dependencies of binding constant. Fluorescence lifetime measurements allowed to determine the environment and distribution of the dye in both systems. An increasing amount of amylose from 0.1% to 2% led to changes in both, absorption and fluorescence spectra. Observed isosbestic point at 623 nm in the absorption spectrum indicated formation of the static complex between amylose and dye. This was confirmed by the fluorescence spectra where a decrease and shift of fluorescence maximum to longer wavelength was observed. When a cationic detergent above its cmc concentration was added to the system with 1.75% amylose and Bengal Rose the fluorescence maximum shifted to 600 nm and its intensity decreased by 5 times as compared with the system without detergent. Calculated enthalpy and entropy had positive values indicating that not only electrostatic processes took place but also hydrophobic forces participated in the complex formation. Calculated stability constant suggested that the detergent facilitated formation of the amylose complex by the factor of 4.