CARBOHYDRATE-BASED SURFACTANTS FOR FORMING AND STABILIZING COLLOIDAL SYSTEMS AS EMULSIONS AND FOAMS

Carbohydrate-based surfactants (CBS) constitute a class of amphiphilic molecules with particular and common interests. These surface-active compounds can be produced from the most abundant renewable materials allowing large product concept possibilities, and may occur in a large structural range with one or more hydrophilic head groups and hydrophobic chains with various linkers/spacers, thanks to numerous reactive functional groups in their basic structure. It is then possible to design a quasi-unlimited number of new compounds by (bio)-synthesis from various raw materials. This structural diversity can generate a wide range of properties, which could be developed in food and non-food applications. Our challenge is now to find out the most suitable molecular structures for the post-development of CBS, mainly for colloidal systems like emulsion, foam, and suspension. A pre-screening of the dynamic and equilibrium interfacial tensions and interfacial rheology properties of various CBS prepared by chemical, enzymatic, or chemo-enzymatic synthesis routes from the derivatives of bio-renewable substrates is carried out. Then, the characterization of emulsifying and foaming properties of pre-selected molecules is performed. These investigations are completed by the characterization of thermal properties of liquid suspensions and powders. Homologous series of two derivative compounds of glucuronic and galacturonic acids with mono- or bicatenar hydrophobic chains and different linkages (linear or cyclic ester, amide) have been chosen as CBS starting compounds. These were full characterized by spectroscopic techniques (RMN, SM, IR). The effect of the hydrophobic chain length and number, polar head group, and the linker on whole properties investigated is easily deduced.