Flavour release from pectin gels: Effects of texture, molecular interactions and aroma compounds diffusion

Model jam-like systems at increasing High Methoxylated Pectin content were developed in order to observe flavour release from gelled matrix at very low hydrocolloid concentration. The addition of pectin modified the release of the most volatile and hydrophobic aroma compounds. This phenomenon was strictly related to the formation of a gel network that, even at a concentration of 0.1% pectin, led to a decrease of volatile mobility. No specific molecular interactions were found between flavour compounds and pectin in water solution without sugar; moreover no significant difference was observed in diffusion coefficient values for all aroma compounds at the pectin levels used (0.1% to 0.4%). The predominant cause of aroma retention in gelled systems might thus be due to a hindered molecule migration through the three-dimensional structure.