An investigation and identification of polysaccharides isolated from archeological specimens
SummaryPolymeric compounds have been isolated from archeological specimens (fragments of Central Asian paintings of the 2nd-19th centuries). A comparison of their IR spectra with the spectra of plant gums has shown that they are polysaccharides which have remained undestroyed for up to 1800 yr. In some cases it has been possible from the IR spectra and composition of the extracted polysaccharides to provisionally identify sourcherry or apricot gum, of which these polysaccharides were components.
Thin-layer chromatographic analysis of sugar mixtures
Abstract Some general remarks are made concerning the difficulties experienced in the quantitative determination of the composition of complex sugar mixtures in solution. The application of thin-layer chromatography to this analytical problem is discussed. A technique for obtaining a satisfactory separation of nine to ten sugars has been worked out. Methods of determining reducing sugars and keto-sugars in amounts of 0 to 100 μg are mentioned, as well as a technique for removing the sugar-containing area from the thin-layer plate. Figures illustrating the quantitative aspects of the method are given.
On the fractionation of β-lactoglobulin and α-lactalbumin
Abstract Existing methods for the preparation of α-lactalbumin and β-lactoglobulin are examined critically. It is proposed that the most satisfactory method for the preparation of the whey protein fraction from bovine milk is (NH 4 ) 2 SO 4 fractionation. A number of new gentle procedures for the fractionation of the whey proteins are compared with some existing methods. The distribution of total protein at various stages is determined by total Kjeldahl nitrogen and the kind of protein by starch-gel electrophoresis. The effect of variables, such as pH, salt concentration and temperature on the separation of α-lactalbumin and serum albumin from β-lactoglobulin is studied. Differences in the behavior ( e.g. solubility) of genetic variants of β-lactoglobulin are noted. The solubility of each of the major whey proteins, under similar conditions to those used in the fractionation, is compared with its solubility in the whey protein mixture. The understanding gained of factors important in the fractionation is used in recommending new procedures for α-lactalbumin and β-lactoglobulin isolation.