The objective of this study was to investigate conditions under which inulin gels were formed, as well as to determine their properties using an example of a FRUTAFIT TEX formulation. The gel-forming properties of inulin were studied with regard to: its concentration in water solutions, temperature (40–90°C) of water used to dissolve the inulin preparation, pH value (3 to 8), and NaCl concentrations (from 0 to 3%). The study comprised the determination of the following parameters: degree of gel formation using a VGI index of gelation, hardness of gels formed, degree of their reversibility, and melting temperature. It was stated that the gelation potential depended statistically significantly on the solution temperature and the inulin concentration. No gel structures were formed using solvents of low concentrations (below 15%). However, when the solution temperature was increased to 80°C, and the inulin concentration in the solvent was 15%, the gel-forming properties of the preparation were evidently decreased (VGI = 93.2%). Next, when the preparation was dissolved at 90°C, no gel could be formed (VGI = 0%) after the sol was cooled down. The pH value had a statistically significant effect on the gel forming process. This gel forming process was the weakest in the acidic environment (ph from 3 to 4), and under such conditions, a concentration exceeding 20% was necessary to enable gels to be formed. If NaCl was added, the gelforming properties of inulin were significantly enhanced. The hardness of inulin gels depended on the concentration of inulin applied. However, it was stated that the addition of NaCl did not significantly impact the hardness of gels formed. Basing on the results obtained, it was also confirmed that inulin could be applied as a fat substitute in non-limpid food products with pH below 5.
inulin, gel properties, gelation