The Effect of Sucrose on the Thermo-Reversible Gel-Sol Transition in Agarose and Gelatin

Abstract

The effects of sucrose on the elasticity and thermo reversible gel-sol transition in agarose and gelatin gels were studied. The concentration and temperature dependence of the elastic modulus was analysed by current theories of gel elasticity. The gel-sol transition observed by differential scanning calorimetry was discussed or the basis of a zipper model approach. It was suggested that the number of junction zones increased, the size of each junction zone decreased, and the rotational freedom of a link in a zipper decreased by the addition of sucrose.

Effect of sugars on aging of gelatin gels by vacuum-ultraviolet circular dichroism and rheological measurements

“…Their analysis of the shear modulus as a function of gelatin concentration based on an equation derived from the rubber elasticity theory showed that the junction zones of the gelatin gels become smaller but at the same time more numerous by the addition of sucrose [2]. Nishinari et al applied a zipper model approach to the analysis of differential scanning calorimetry (DSC) data for gelatin gels containing sucrose and the obtained results are consistent with those of Oakenfull et al [3].…”

“…An aqueous solution of 0.5 M KSCN was used as a solvent [13]. Dilute solutions for SLS measurements were prepared at four concentrations near c = 1.0, 2.0, 3.0 and 4.0 × 10 -3 g/cm 3 . SLS measurements were carried out over the angular range of 30° to 135° at intervals of 15° with vertically polarized incident light at 632.8 nm of He-Ne laser.…”

“…Sugars are known to modify the gelation properties of gelatin, increasing the gel strength and melting point [2][3][4]. Oakenfull et al demonstrated that the addition of sucrose increases the shear modulus, rate of gelation, melting point and enthalpy of melting of gelatin gels.…”

Gels: model systems for soft matter food physics

“…Sugars dissolve in water and restructure by hydration shells the water molecules locally, rather than using the models as discussed by [69]. Thus water is not an inert background of good solvent, which manifests itself by the change of the gelling properties when different sugars are added.…”

Rheological and related studies on industrially important polysaccharides and proteins

“…Solutions of some biopolymers such as methyl cellulose [7] , xyloglucan from which galactose residues are removed [8] , curdlan [9−10] , glycinin and β-conglycinin [11−12] form a gel on heating, while solutions of other biopolymers such as agarose [13] , carrageenan [14] , gelatin [13,15] and gellan [16−17] form a gel on cooling. The gelation mechanism of heat-set gels has been recently reviewed [18] .…”