Physical properties, microstructure, intermolecular forces and oxidation stability of soybean oil oleogels structured by different cellulose ethers

Abstract

Edible oleogels were prepared by different kinds of hydroxypropyl methyl cellulose (HPMC) and methylcellulose (MC) through emulsion-templated method. Physical properties of the oleogels such as rheological behavior and oil binding capacity were evaluated. Polarizing light microscope (PLM) as well as scanning electron microscope (SEM) was used to gain information on the microstructure of the samples. Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were used to evaluate intermolecular forces between the polysaccharides in the oleogels. It was found that oil-water interface layers of the emulsions were strengthened by polysaccharides (HPMC and xanthan gum (XG) or MC and XG), and it prohibited oil droplets from coalescing during drying. The formation of semi-crystalline structure of oleogels to trap the oil was attributed to intramolecular/intermolecular hydrogen bonding between the polysaccharides. The higher viscosity grade resulted in better structure with respect to emulsions, vacuum dried emulsions, and oleogels compared to that of lower viscosity grade for HPMC or MC. The mechanical strengths of vacuum dried emulsions and oleogels stabilized by HPMC were harder compared to that of MC. The study would provide guidance for the production of functional fat products with zero trans and low saturated fatty acids.

Practical applications: HPMC and MC, two types of dietary fiber, are two kinds of the most commonly used cellulose ethers which are food-approved additives. The oleogels prepared by HPMC and MC using an emulsion-templated method can be used to produce functional fat products with zero trans and low saturated fatty acids, which would be beneficial to human health. The properties of oleogels structured by different HPMC and MC with the different degree of polymerization (DP) and substitution (DS) were different. The physical properties, microstructure and intermolecular forces for oleogels were evaluated in order to lay the basis for the application of the oleogels.

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