The thermal properties of buckwheat (Fagopyrum esculentum Moench) proteins with different lipid contents (2.5, 6.5 and 17.8%) were studied by differential scanning calorimetry (DSC)
under various medium conditions. From DSC curves, many DSC characteristics including denaturation temperature (Td), enthalpy change (ΔH) and the width at half peak height (ΔT1/2) of endothermic peaks were obtained and evaluated. The DSC curves of various buckwheat proteins (BWPs) in the 0.05 M phosphate
buffer (pH 7.0) showed a major endotherm at about 102°C and a minor endotherm at about 80°C, attributed to thermal transitions
of 13S and 8S globulins, respectively. Td and ΔH of the globulins of BWPs were independent of their lipid contents, while the presence of high lipid content (17.8%) to some
extent increased the ΔT1/2. The progressive increase in Td of 13S globulins with increase in NaCl concentration, suggests a more compact conformation with higher thermal stability.
The influence of chaotropic salts on the DSC characteristics of 13S globulins was also independent of their lipid contents.
Thermal analysis of the 13S globulins in the presence of protein perturbants (including urea, sodium dodecyl sulfate, ethylene
glycol, dithiothreitol and N-ethylmaleimide) indicated that hydrophobic and hydrogen bondings are the major interactions for
stabilizing protein conformation of buckwheat 13S globulins and the SS-SH interchange also attributes to the stabilization
of the protein conformation.
Authors:M. Germ, B. Breznik, N. Dolinar, I. Kreft, and A. Gaberščik
, M., Gaberšcik, A., Kreft, I. 2005. Combined effects of elevated UV-B radiation and the addition of selenium on common ( Fagopyrumesculentum Moench) and tartary ( Fagopyrum tataricum (L.) Gaertn.) buckwheat. Photosyntetica 43 :583
The use of buckwheat as a source of rutin for medicine or food supplement requires a high content of this component in pimary row materials. The study was aimed at the investigation of the influence of stand density and sowing dates on the rutin content in the aboveground parts at the stage of flowering and achenes of two buckwheat species (Fagopyrum esculentum and Fagopyrum tataricum). The rutin content in the aboveground parts of buckwheat was significantly higher in plants sown in mid-May. The sowing date did not influence the rutin content in the achenes. The whole buckwheat plant contained the highest content of rutin in 25 cm rows with a sowing ratio of 200 achenes per square metre. However, the final rutin amount obtained from a buckwheat stand depended on the production of biomass. Common buckwheat provided a higher rutin yield because it produced a higher amount of biomass of inflorescences, the part rich in this flavonoid. Therefore 12.5 cm rows with 400 seeds per square metre are suitable for rutin production because of the higher number of plants. We can recommend tartary buckwheat for achene production as a source of rutin for human nutrition or food supplement because it provides twenty-fivefold more rutin than common buckwheat.