Starch–metal complexes and their rheology

Abstract

Changes in conductivity of 5 w/w% starch gels was studied on their titration with 0.1 M aqueous solutions of selected metal salts. Starch gels usually trapped around 10 mg metal ions per 1 g starch [Co(II), Cu(II), Fe(III), Ni(II)] and that value was only slightly dependent on starch origin (amaranthus, corn, potato, tapioca, waxy corn). Among salts studied (acetates, chlorides, nitrates) FeCl 3 and NiCl 2 were likely to be used because they hydrolyzed increasing conductivity of the solutions and formed micelles of corresponding hydroxides adhering to starch micelles and increasing amount of trapped metal. Addition of metal salts to starch gels had a devastating effect on pseudoplasticity and viscosity of starch gels and only potato starch gel was to a certain extent, exceptional in that respect.

Study of quantitative interactions of potato and corn starch granules with ions in diluted solutions of heavy metal salts

“…Our results demonstrated that the granular structure, resulting from starch biological origin, and the starch water content are important factors impacting accumulation of metal ions in the granules. These findings are contrary to the opinion of Ciesielski and Krystyjan (2009), who reported that the amount of cations entrapped by starch does not depend on either the starch origin or the salt anions.…”

“…Other authors postulated that the entire salt molecules penetrate the granules where alkaline metal cations form the metal alcoholates (Oosten, 1990) while cations of high non-transition and transition groups coordinate to the polysaccharide hydroxyl groups creating the starch-metal complexes (Ahmad & Williams, 1999, Ciesielski & Tomasik, 2004a. Formation of such complexes has been confirmed for gels of different starches as well as for amylose and amylopectin (Ciesielski et al 2003;Ciesielski & Tomasik, 2004a, 2004bCiesielski & Krystyjan, 2009). The structure and stability of the complexes of some transition metals has been already estimated by quatum-mechanical simulations (Ciesielski, 2009).…”

“…Such interactions, in particular the ion specific effects depending on the ion hydration, are essential for the structure, properties and functionality of biological systems and foods (Lo Nostro, Lopes, Ninham & Baglioni, 2002;Lo Nostro et al, 2006;Collins, 2006;Collins, Neilson & Enderby, 2007;Kunz, 2010;Bechtold et al, 2013). Metal ions could be collected in starch granules as hydrated cations [Me(H 2 O) n ] m+ and the starch -metal complexes Ciesielski & Krystyjan, 2009). The first naturally occur in aqueous salt solutions (Neilson, Ansell & Wilson, 1995;Park, Fenter, Nagy & Sturchio, 2006).…”

“…It has been shown that salts have a substantial impact on starch properties. This applies to starch gelatinization and rheological characteristics (Jane, 1993;Ahmad &Williams, 1999;Jyothi, Sasikiran, Sajeev, Revamma, & Moorthy, 2005;Ciesielski & Krystyjan, 2009;Kunz, 2010), dielectric properties and viscosity of starch-water systems (Bircan & Barringer, 1998), starch swelling and retrogradation of starch pastes (Samutsri & Suphantharika, 2012), interactions of starch and hydrocolloids (Sudhakar, Singhal & Kulkarni, 1995, 1996Fumani et al, 2008), as well as starch degradation and caramelisation (Moreau, Bindzus & Hill, 2011, 2011a. Use of salts in food production affects a quality of obtained starch products (Bunger, Moyano & Rioseco, 2003).…”

Preparation and characteristics of mechanical and functional properties of starch/Plantago psyllium seeds mucilage films

“…All examined samples behaved as non‐Newtonian, pseudoplastic liquids (Fig. ) just as other starch systems . Based on the n values obtained from the Ostwald‐de Waele model fitted to the upper flow curves, it was noted that, with the increasing starch concentration in the film‐forming solution, the pseudoplasticity decreased and amounted to 0.64 and 0.71 for H0 and S0, respectively (Table ).…”