Polysaccharide gels as oil bulking agents: Technological and structural properties

• Various polysaccharide gel matrices containing olive oil were development.
• Stability and texture were evaluated in polysaccharide gels with oil incorporated.
• Lipid and polysaccharide interactions were investigated using Raman spectroscopy.
• Structural behaviour of polysaccharides may explain the differences in texture.

Lipid and polysaccharide interactions in various polysaccharide gels prepared for use as oil bulking agents were investigated using Raman spectroscopy. Two different polysaccharide gel matrices containing olive oil were prepared using mixed biopolymer systems of alginate with inulin (OM-A/I) or dextrin (OM-A/D). Stability and textural properties were also evaluated in these matrices. Thermal stability of the different matrices was optimal. The textural behaviour of polysaccharide matrices with olive oil incorporated differed depending on the polysaccharide gels used in their formulation. OM-A/I presented the highest (P < 0.05) hardness, adhesiveness, and chewiness. These matrices were stabilized by hydrogen bonding between oil carbonyl groups and water and/or carbohydrate molecules. Lipid acyl chains are relatively fixed through hydrogen bonding and intermolecular order upon micelle formation. Raman spectroscopic results also showed carbohydrate-water hydrogen bonding, in which inulin seemed to be more strongly bonded to water than dextrin. This difference in the structural behaviour of inulin and dextrin in terms of hydrogen bonding to water may explain the differences in textural properties.

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