Response surface evaluation of the stability enhancement of a sago palm weevil (Rhynchophorus ferrugineus) larvae-based protein emulsion by soy protein isolate and guar gum

• Rhynchophorus ferrugineus (Sago worm) was used to develop the whole Sago worm emulsion (SWE) system. • The emulsion system of the Sago worm was developed by using soy protein isolate (SPI) as emulsifier and guar gum (GG) as stabilizer. • Response surface methodology was used to achieve the highest emulsion stability from each formulation. • The most impact on SWE was GG higher than SPI. Sago palm weevil ( Rhynchophorus ferrugineus ) larvae (“sago worms”) are widely consumed in Southeast Asia because of their favorable taste. This consumption also reduces pest populations that threaten economically important crops, highlighting the potential of insect protein as a sustainable and nutritious food source in regions facing ecological and nutritional challenges. This study investigated the effects of combining soy protein isolate (SPI) and guar gum (GG) with a sago worm emulsion (SWE) on the stability, rheological properties, and microstructure of the resulting emulsions. Regression models and surface plots were created using response surface methodology. The viscoelasticity and microstructure of the emulsions were investigated using rheological property determinations and scanning electron microscopy. Both SPI and GG significantly improved emulsion stability, with higher concentrations leading to greater stability. Rheological analysis revealed shear-thinning behavior, which intensified with increasing GG levels, whereas microstructural analysis indicated smaller, more uniformly distributed oil droplets at higher SPI and GG concentrations. The optimal formulation, containing 10% SPI and 4% GG, demonstrated the highest emulsion stability and uniformity. This research highlights the synergistic effect of SPI and GG in improving SWE stability and provides valuable insights into the development of insect-based emulsion products for food applications.