Functional and structural characteristic of plant protein isolates as emulsifier by ultrasound-assisted extraction: A review

Depletion of natural-based resources is a common problem in many countries. This worse condition is in line with the people suffering from malnutrition when consuming food. The Sustainable Development Goals (SDGs) challenge ensuring global food security. More exploration of underutilized sustainable protein resources is required to preserve the protein sources. Ultrasound-assisted extraction (UAE) is a model-promoting extraction to isolate the plant-based protein effectively. UAE is a green extraction technique that provides high-performance results with power and time variation of protein isolates. This study aims to review the impact of UAE on functional and structural characteristics of plant protein isolation (PPI). The previous review reveals the optimum condition of extraction variables, whereas the contribution of UAE in protein isolate. The mechanism of UAE focused on extracting plant protein isolates such as protein yield, solubility, water or oil holding capacity, surface hydrophobicity, foaming capacity, emulsifying activities, and zeta potential. The UAE effect successfully maintains emulsion stability by lowering surface tension and increasing protein solubility in the aqueous phase. The aggregation of protein film at the interface between hydrophilic and hydrophobic media affects its stability in obtaining homogeneous mixtures. The findings clarified that the UAE can enhance the functional characteristics of PPI to fit and proper processing in food industries and support SDGs.