Fouad Zaki Saleeb

INTERACTIONS OF SURFACTANTS WITH PROTEINS I. MICROCALORIMETRY AND FOAMING

The interactions between an ionic surfactant, dioctyl sodium sulfosuccinate, and scdium caseinate have been investigated by microcalorimetry, foam studies and zeta potential measurements. The binding has been categorized into two major types. At low surfactant/protein ratios, the binding was predominantly hydrophobic in nature, while at higher concentrations, ionic binding occured and was dependent upon pH. The foaming properties of protein surfactant solutions could be interpreted in view of the hydrophobic and ionic regions of binding.

A TECHNIQUE FOR THE DETERMINATION OF VOLATILE ORGANIC COMPOUNDS UNDER EQUILIBRIUM AND NON-EQUILIBRIUM CONDITIONS

The DuPont 916 Thermal Evolution Analyzer (TEA) was modified for studying the concentration of volatile organic compounds (aromas) under dynamic as well as equilibrium conditions. The modified instrument is capable of measuring aromas in the gaseous phase, in aqueous and non-aqueous fluids, and in solid substrates continuously as a function of time and/or temperature. In this new technique, the nitrogen flow system of the TEA is diverted prior to entry into the flame ionization detector and allowed to pass through the appropriate sample cell. This allows the following measurements to be carried out: (a) the partition coefficients of various single aroma components between air/water and air/oil. The calculated coefficients are in good agreement with published data obtained by gas chromatography.