Rheological Matchup of Real and Plant-based Mayo: Gel Strength, Strain Overshoot, and Yielding, plus the Extended Cox-Merz Rule

Abstract

Mayonnaise is a dense oil-in-water emulsion with over 65% oil, vinegar (or lime juice), and egg as an emulsifier or stabilizer. Conventional mayonnaise, an animal-based (AB) formulation, has flow behavior suitable for dispensing, spooning, spreading, consuming, and use as a salad dressing, dip, and base for sauces. Emulating its texture, flavor, stability, rheology, processability, and sensory attributes is challenging with egg-free recipes that often include plant-based (PB) proteins and hydrocolloids, such as xanthan gum, guar gum, and starch in the aqueous phase. Here, we contrast the rheological responses of commercially available AB and PB mayos under oscillatory strain to assess their linear and nonlinear viscoelastic properties and to assess why the addition of hydrocolloids provides an egg-free alternative with suitable shelf-life and processability. Also, responses assess texture and the first-bite impression and help contrast the mouthfeel that encompasses holistic and dynamic sensations throughout consumption. All mayos display gel-like responses in oscillatory shear at low strain and liquid-like responses beyond the yield stress. All AB mayos show a strain overshoot in the plots of loss modulus against strain, which is absent in the response of vegan mayos that use polysaccharides as hydrocolloids. We contrast the apparent yield stress values from the shear flow curve, the onset of strain softening in the elastic modulus beyond a critical strain, and dripping experiments. Hydrocolloids and proteins with dissimilar interfacial and bulk properties contribute to the contrasting moduli, yielding, and strain overshoot response of real and vegan mayo.