Functionalisation of pectin by ultra high pressure homogenisation

Pectin is well-known plant-based hydrocolloid extensively used in food and beverage industry for formation and/or enhancement of product texture and stability. Versatile functionalities of different pectin types (e.g. gelling, thickening, colloidal stabilization) are predetermined by their structure. The aim of this work was to explore possibility to alter structure of pectin by pilot-scale ultra-high dynamic pressure treatment, as a physical modification approach, and potentially enhance its functionality.

Therefore, high esterified apple (AP) and citrus pectin (CP) were treated by ultra-high pressure homogenizer (UHPH) at three different pressure levels and characterized with respect to their apparent viscosity, gelling behavior (gelation time, temperature and melting point), gel strength, molecular weight (MW) and on-line viscosity using size-exclusions chromatography coupled to refractive index, light scattering and online differential viscometer. The results of the study indicated that UHPH impacted the MW in a source dependent manner. Treated CP and AP pectin exhibited a small decrease in the average MW and a more pronounced decrease in the intrinsic viscosity, likely due to more significant UHPH effect on the larger pectin molecules. In addition the smaller (in volume) AP pectin presented a more compact conformation in solution. On the macroscopic level, those changes resulted in decreased gelation time and increased gelation temperature. Even though treatment caused decrease in apparent viscosity and gel strength of CP pectin, it had not significant effect on AP pectin.

From the results, it can be concluded that UHPH process has a potential to modify the functionality of pectins, but further research is needed in order to elucidate all the changes and potential benefits of this ubiquitous and multifunctional hydrocolloid.