Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
605461 | Food Hydrocolloids | 2009 | 8 Pages |
The gelatinization of native wheat starch granules in some monovalent salt solutions (i.e. sodium and potassium chlorides and nitrates) was studied as a function of type and concentration of electrolyte by different techniques. The granular swelling at different temperatures was derived on a macroscopic scale from the swelling volume, whereas particle size analysis yielded information on a microscopic scale. Crosscorrelation revealed a close relationship between both approaches. Differential scanning calori-metry (DSC) indicated that all studied monovalent salts had a similar (protective) effect at 0.1 M concentration. However, at higher concentrations, a markedly different effect was observed for chlorides as compared to nitrates. A highly similar tendency was also observed from the gelatinised starch viscosity: whereas the consistency coefficient gradually decreased with increasing chloride concentration, it displayed a minimum value at low nitrate concentrations followed by a steady increase at higher concentrations. The sensitivity of the swelling of native wheat starch granules to ions could be explained from a combination of a general electrolyte effect at low concentrations and specific ion effects (in line with the Hofmeister anion series) at higher concentrations.