JOURNAL of the Tunisian Chemical Society

This paper reports the influence of extraction pH on chain stiffness and gelation properties of polysaccharides from different parts of Opuntia ficus-indica. The different extract presented random coil structure, with the more extended configuration in the case of the acid extract of the nopal peels and basic extract of the fruit peels. Chain stiffness was evaluated for the extracted polysaccharides and compared using calculation from the Kratky-Porod model with two adjustable parameters (persistence length (Lp) and the molar mass per unit contour length (M_L)). These parameters confirm that chain expansion of polysaccharides extracted from nopal peels in acid medium and pear peels in basic medium is related to their rigid structures. Moreover, the viscosimetric study shows that these two polymers form calcium-induced gels and are expected to be useful as thickening or gelation agent in various fields such as food and cosmetic industry.

H. Majdoub, S. Roudesli, A. Deratani

Opuntia ficus-indica, polysaccharide, selective extraction, persistence length, Ca²⁺-gel

Pages: 145-155