CHEM 98T Lecture 3: Week 2 articles
8 Feb 2017
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Document Summary
Effect of potassium, sodium, and calcium on the microstructure and rheological behavior of kappa-carrageenan gels. Balance between fine/coarse gel strands was dependent on potassium concentration. In contrast to potassium form, sodium-kappa-carrageenan formed weak gels/showed no dependence on sodium ion concentration. Sodium form had network structure with flexible superstrands. Calcium-kappa-carrageenan formed weak gels in limited ca conc. range. Calcium induced gels had fine network without coarse superstrands seen in na or k forms. Type of cations used impacts gel characteristics: monovalent cations give gels with decreasing shear/elastic moduli in order. Coil-helix transition necessary for gels to form found that helixes of potassium-kappa-carrageenan formed only under conditions that promoted aggregation. Mea(cid:374)s there"s stro(cid:374)g li(cid:374)k (cid:271)etwee(cid:374) heli(cid:454) for(cid:373)atio(cid:374)/gel for(cid:373)atio(cid:374: microstructure/rheological behavior revealed transient state on gelation of k form of kappa-carrageenan. In presence of k, sharp initial max during cooling/gel formation.
