Influence of electrolytes on the heat-induced swelling of aqueous dispersions of native wheat starch granules

• Published in: Food hydrocolloids Vol. 23; no. 8; pp. 2204 - 2211
• Main Authors: Zhu, W.X., Gayin, J., Chatel, F., Dewettinck, K., Van der Meeren, P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2009; [New York, NY]: Elsevier Science; Elsevier
• Subjects: aqueous solutions; Biological and medical sciences; chemical concentration; chlorides; dispersions; DSC; electrolytes; Food additives; Food industries; Fundamental and applied biological sciences. Psychology; gelatinization; General aspects; heat treatment; Hofmeister; Ions; nitrates; Particle size; potassium chloride; potassium nitrate; sodium chloride; sodium nitrate; Starch; Starch and starchy product industries; starch granules; swelling (materials); temperature; Viscosity; volume; wheat starch; Viscosity; Ions; Particle size; Hofmeister; Starch; DSC; Differential scanning calorimetry; Electrolyte; Polysaccharide; Wheat starch; Aqueous dispersion
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2009.05.002

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.