Differentiation of rye and wheat flour as well as mixtures by using the kinetics of Karl Fischer water titration.

The aim of this study was to find a simple way to differentiate between rye and wheat flour and their mixtures by using the kinetic parameters of Karl Fischer water titration (KFT). Consequently, the water content and type of molecules in rye and wheat mixtures used in Romanian bread making have been investigated by means of volumetric KFT. Further, the kinetics of KFT have been determined and novel kinetic parameters corresponding to "surface" and "strongly-retained" water molecules have been identified to discriminate between rye and wheat flour and their mixtures. The "surface" and "strongly-retained" water reaction rates well correlate with the rye content in the flour mixtures, especially at higher temperature analysis (r>0.95). These parameters can be used as indicators for quality evaluation of such type of mixtures, as well as to identify adulteration by improper use of the rye-wheat flour ratios in bread making.

Thermal and oxidative stability of the Ocimum basilicum L. essential oil/ß-cyclodextrin supramolecular system.

Ocimum basilicum L. essential oil and its ß-cyclodextrin (ß-CD) complex have been investigated with respect to their stability against the degradative action of air/oxygen and temperature. This supramolecular system was obtained by a crystallization method in order to achieve the equilibrium of complexed-uncomplexed volatile compounds in an ethanol/water solution at 50 °C. Both the raw essential oil and its ß-CD complex have been subjected to thermal and oxidative degradation conditions in order to evaluate the protective capacity of ß-CD. The relative concentration of the O. basilicum L. essential oil compounds, as determined by GC-MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the ß-CD complex is quite different in comparison with the raw material. An increase of the relative concentration of linalool oxide from 0.3% to 1.1%, in addition to many sesquiterpene oxides, has been observed. ß-CD complexation of the O. basilicum essential oil modifies the relative concentration of the encapsulated volatile compounds. Thus, linalool was better encapsulated in ß-CD, while methylchavicol (estragole) was encapsulated in ß-CD at a concentration close to that of the raw essential oil. Higher relative concentrations from the degradation of the oxygenated compounds such as linalool oxide and aromadendren oxide were determined in the raw O. basilicum L. essential oil in comparison with the corresponding ß-CD complex. For the first time, the protective capability of natural ß-CD for labile basil essential oil compounds has been demonstrated.