[Value of the "amylose number" in determination of starch damage]

The author demonstrated column and paper chromatographically that no or very little amylose is extracted when using HAMPEL's method for the colorimetric determination of starch damage ("amylose number"). The actually extracted substances are mainly other starch components which form a violet colour on addition of a dilute iodine solution. Further starch components which form a violet colour on addition of a dilute iodine solution are extracted by rewashing with the different components of HAMPEL's solvent mixture. The most distinct results were obtained with distilled water. It is suggested to rewash the filter residue with distilled water to extract all the damaged starch and to use the combined extracts for the determination. In consideration of the fact that HAMPEL's solvent mixture extracts not only amylose from the damaged starch, the term of "amylose number" should be rejected and replaced by the term of formamide ammonium sulphate sulphosalicylic acid (FAS) method or formamide sodium sulphate sulphosalicylic acid (FNS) method.