Physical and Chemical Parameters of Emulsifiers and Their Effect on the Process of Food Emulsion Formation
Authors: Tereshchuk Lyubov , Zagorodnikov Konstantin , Starovoitova Kseniya , Viushinskij Pavel 
Published: January 2022

Introduction. Modern food science needs new research of food emulsifiers, their composition, properties and effect on the structural characteristics of emulsions. It looks for modern technological solutions on how to select proper emulsifiers and their mixes to produce emulsions with different mass fractions of fat. The research objective was to study the effect of physical and chemical indicators of surfactants on the properties of food emulsions, as well as to develop practical recommendations for the selection of surfactants for various types of products.

Study objects and methods. The research featured model dairy fat emulsions and laboratory-made vegetable oil, as well as hard and soft mono- and diglycerides of fatty acids and lecithins. The emulsifiers were used to determine the melting point, fatty acid composition, iodine number, and solid triglyceride content at various temperatures. The melting point of emulsifiers was determined by fixing the melting temperature in a capillary oven. To identify the fatty acid composition, the methyl esters of fatty acids were subjected to the chromatogram method. After that, the separated components and their quantity were determined by the area of the peaks. The content of solid triglycerides in the emulsifiers was determined by the method of nuclear magnetic resonance. The hydrophilic-lipophilic balance was obtained from the manufacturer's specifications.

Results and discussion. The solid mono- and diglycerides appeared to have a high content of stearic and palmitic acids. Oleic acid predominated in soft monoglycerides; unsaturated fatty acids (linolenic and oleic) also predominated in the monoglycerides/lecithin complex emulsifier. Solid monoglycerides had a high content of solid triglycerides at 35°C (82.93%), which correlated with the high melting point (80°C) and the lowest iodine number (3 mg I2/100 g) of all the samples. The optimal ratio of vegetable oil and the emulsifier was defined empirically. The emulsifiers were dissolved in refined deodorized vegetable oil at 5–7°C above the melting point of the emulsifier. The resulting ratios were between 6:1 and 10:1. The samples of creamy vegetable spreads were obtained using the studied emulsifiers and their compositions in different doses and ratios. The crystallization temperature and phase transition time were determined when studying the process of emulsion overcooling. The article introduces a list of technological and physicochemical indicators of emulsifiers: the fatty acid composition, the degree of saturation, the melting point, and the content of solid triglycerides. By finding out the physicochemical parameters of emulsifiers, producers can vary the ratio of the components of emulsifying compositions to achieve the desired properties of food emulsions. The hydrophilic-lipophilic balance also proved to be an important index since the proportion of hydrophilic and hydrophobic groups in surfactants affects the type of emulsions and makes it possible to adjust the fat content of the finished product.

Conclusion. The research results can expand the theoretical foundations of food emulsions. The article contains scientifically grounded recommendations on how to select optimal surfactants. The research opens up prospects for further studies of emulsifiers and their effect on the quality of finished products.