A Gel Chromatographic Study of Molecular Weight Distribution in Native Wheat Starch and Its Oxidation Products

Abstract

AbstractThe distribution of molecular size of the native starch prepared according to a new method and of oxidised products of starch has been investigated with the help of agarose gel filtration. It has been noticed that the curve of the molecular distribution of the native wheat starch (product A) shows a big peak excluded by the gel with M̄W > 2 · 106 comprising about 58% of the sample and a part fractioned by the gel within the area 1 · 104 < M̄W < 2 · 106. Comparative gel filterings of native maize, tapioca and potato starch have shown that the distribution of molecular size of wheat starch (A) most resembles that of maize starch. Tapioca starch and especially potato starch have a somewhat lower percentage of molecules within the part fractioned by the gel than wheat starch (A). Native wheat starch, product B has a somewhat higher percentage of molecules within the area 1 · 105 > M̄W > 2 · 104 than the other native types of starch.Heat‐treatening and oxidation of native starch causes a decrease or a disappearance of the macromolecular excluded part of the sample and instead increases the molecules within the fractioning area of the gel, M̄W < 2 · 106. The used gel chromatographic method is thus very suitable when investigating the distribution of molecules of oxidised starch products and in product control.