Polyglycerol fatty acid esters are a general term for a series of products, also known as polyglycerol esters, polyglycerol monomeric fatty acid esters, and fatty acid polyglycerol esters. The characteristic is that there are many hydrophilic hydroxyl groups. Polyglycerol fatty acid esters are a new type of highly efficient and high-performance polyhydroxy ester nonionic surfactants, which are applied in fields such as food, daily chemicals, petroleum, textiles, coatings, plastics, pesticides, rubber, and medicine