文摘
Two fractions of carob galactomannans (GM25 and GM80) were extracted at respectively 25 °C and 80 °C from crude locust bean gum. Those fractions having slightly different chemical structures, previously characterized, were studied for their viscosity properties over a wide range of concentrations: diluted solution, unperturbed state and gel state. For each of the physical properties, links to the chemical fine structure could be established, expanding knowledge on the topic: in dilute solution, GM25 is more soluble in water while GM80 seems to tend to self-association due to its structure as highlighted by intrinsic viscosity measurements ([η]GM25 = 9.96 dL g−1 and [η]GM80 = 4.04 dL g−1). In unperturbed state, initial viscosities η0 were more important for GM80 fractions at 1% and 2% due to greater hyperentanglements (η0(GM80,1%) = 9.9 Pas; η0(GM80,2%) = 832.0; Pa.s η0(GM25,1%) = 3.1 Pas; η0(GM25,2%) = 45.1 Pas). In gel state, hydrogels obtained from GM80 were also stronger (hardness GM80 (2%) = 0.51 N and hardness GM25 (2%) = 0.11 N), suggesting a much more important number of junction areas within the gel network. The findings discussed herein demonstrate the potential for new applications.