Physico-chemical characterization and stability of inulin gels

The ability of three commercial inulins (Raftilose ®P95, Frutafit IQ®, and Frutafit TEX®) with different chemical composition (oligo-polysaccharides profile) to form gels (at 25 and 50 °C) was evaluated. Raftilose®P95 (rich in mono-disaccharides) did not form gels, Frutafit IQ® (mainly oligosaccharides) gelatinized in the 30-60% w/w concentration range and Frutafit TEX ® (mainly long-chain saccharides) in the 20-40% w/w range. Textural and thermal properties of the gels were studied and their stability was evaluated during storage at 4 °C. Frutafit TEX® gels (both fresh and during storage) were harder, more adhesive, and less cohesive than Frutafit IQ® gels (40% w/w). At 40% w/w, Frutafit TEX ® gels had a significantly higher amount of freezable water than Frutafit IQ®, and the DSC thermogram line shapes indicated that ice melting was more uniform and occurred at higher temperatures in Frutafit TEX® than in the Frutafit IQ® gels. Ice melting profile was not significantly affected by both gelification temperature and storage time. Frutafit IQ® gels were more stable than Frutafit TEX® gels during storage.