Rheological, textural properties and storage stability of mayonnaise formulated with protein hydrolysate derived from yellow mealworm (Tenebrio molitor)

Yellow mealworm (Tenebrio molitor), the larva stage of darkling beetle, confers high nutritional and functional protein and it can serve as a sustainable protein source. The present study therefore evaluated the effect of replacing the egg yolk as emulsifier with yellow mealworm protein hydrolysate powder (YMPH) (0-100%) at 20% increment levels on the rheological and textural properties, colour attributes, emulsion microstructure and storage stability of mayonnaise. The emulsion stability results demonstrated that mayonnaise with up to 60% substitution of YMPH displayed excellent storage stability for 3 weeks (<2% phase separation). In terms of textural properties, all samples showed no significant difference () in firmness whereas consistency decreased steadily with increasing YMPH concentration levels. Microstructure observation of all mayonnaise formulations demonstrated a gradual increase in oil droplet size in parallel with the increase in YMPH concentration. For rheological properties, all mayonnaise exhibited similar gel-like behaviour with greater storage modulus (G’) than loss modulus (G”) and loss tangent (tan δ) less than 1.0. For the colour attributes, increasing YMPH level led to significant decrease () in the L* and b* factors from 73.0 to 27.2 and 23.9 to 8.1, respectively. However, the overall a* factor value increased significantly () from 1.11 to 5.10 as the YMPH concentration increased. This study revealed that insect-based protein hydrolysate has a good potential to serve as an emulsifier.