Use of oligomeric globulins to efficiently fabricate nanoemulsions: Importance of enhanced structural stability by introducing trehalose

Food-grade nanoemulsions using plant proteins as the sole emulsifier has attracted increasing interest in the food field. However, plant proteins present limitations in emulsification performance owing to their extensive aggregation and unfavorable adsorption behavior, when applied to stabilize emulsions. In the current work, a novel strategy to efficiently form nanoemulsions using plant oligomeric globulins (soy β-conglycinin and glycinin) as the sole emulsifier was proposed through the introduction of trehalose prior to emulsification, in order to overcome the above-mentioned limitations. The formed nanoemulsions were small-sized and well-dispersed, and displayed high stability against flocculation and coalescence. The underlying mechanism for this was largely associated with the enhanced structural stability of protein which contributes to improved interfacial adsorption behavior. Results indicated that the proteins were highly stable during microfluidization and adsorption at the interface in the presence of trehalose. Further research on protein adsorption behavior revealed more rapid diffusion rate, as well as less structural unfolding and rearrangement at oil-water interface of protein particles in trehalose-rich system, than in the trehalose-poor system. Through trehalose coating, oligomeric globulins could perform as outstanding Pickering particles with a strong structural integrity at oil-water interface.