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Effect of alkali pretreatment on the rheological properties of concentrated agar-agar gels

1983; Elsevier BV; Volume: 3; Issue: 1 Linguagem: Inglês

10.1016/0144-8617(83)90011-5

1879-1344

Katsuyoshi Nishinari, Mineo Watase,

Polysaccharides and Plant Cell Walls

Differential scanning calorimetry and thermogravimetry in the solid state and dynamic mechanical measurements of gels have been carried out for agar-agars of Chilean and Argentinian origin in order to elucidate the rheological changes in the gel as a result of alkali pretreatment. The elastic modulus of the gel prepared from Chilean agar-agar increased with increasing sodium hydroxide concentration up to 10%, while that of Argentinian agar-agar increased with increasing sodium hydroxide concentration up to 7%, and then began to decrease at higher concentrations. The increase in elastic modulus has been attributed to the structural stabilisation induced by the formation of 3,6-anhydro-l-galactose, while the decrease in elastic modulus in Argentinian agar-agar has been ascribed to chain breakage.