Tiger Nut Oil-Based Oil Gel: Preparation, Characterization, and Storage Stability

Area of Science:

• Food science and technology
• Materials science
• Biopolymer applications

Background:

• Oleogels offer a promising alternative to solid fats, addressing health concerns associated with traditional fats.
• Tiger nut oil, rich in unsaturated fatty acids, presents unique challenges for oleogel formulation due to its oxidative instability.
• Whey protein isolate (WPI) and xanthan gum (XG) are food-grade polymers with potential for structuring liquid oils.

Purpose of the Study:

• To prepare and characterize tiger nut oil-based oleogels using WPI and XG via the emulsion template method.
• To investigate the influence of WPI and XG concentrations on the microstructure, rheological properties, and stability of the resulting oleogels.
• To evaluate the potential of these oleogels as solid fat substitutes.

Main Methods:

• Preparation of high internal phase emulsions (HIPEs) using tiger nut oil, WPI, and XG.
• Microstructural analysis using optical and laser confocal microscopy.
• Rheological testing to assess viscoelasticity and gel strength.
• Characterization of texture, oil holding capacity, and oxidative stability.

Main Results:

• Xanthan gum alone did not form oleogels; WPI concentration was more influential.
• Complexation of WPI and XG enhanced HIPE viscoelasticity and stability.
• Increased WPI concentration improved emulsion stability, viscoelasticity, oil holding capacity, and oleogel strength.
• XG addition significantly enhanced emulsion stability and viscoelasticity (p < 0.05).
• Oleogels with >0.3% XG exhibited high gel strength (>15,000 Pa) and good thixotropic recovery.
• Optimal WPI (2.0%) and XG (>0.3%) yielded oleogels with minimal oil loss, good viscoelasticity, thixotropic recovery, and temperature stability.
• Tiger nut oil oleogels showed lower oxidative stability compared to the oil alone due to polyunsaturated fatty acids.

Conclusions:

• WPI and XG effectively form stable tiger nut oil oleogels with desirable physicochemical and rheological properties.
• The synergistic interaction between WPI and XG is crucial for enhancing emulsion and oleogel characteristics.
• Optimized oleogels demonstrate potential as functional solid fat substitutes in food applications.
• Further research into improving the oxidative stability of tiger nut oil oleogels is warranted.