Ultrasonication as an emerging technology for processing of animal derived foods: A focus on in vitro protein digestibility

Animal products are sources of highly bioavailable proteins and make a significant contribution to human nutrition and wellbeing. Ultrasonication can induce favourable non-thermal effects in food matrices and this has led to a recent increase in its use in the food industry and related research. In addition to prospective improved quality and sensory attributes of animal products, ultrasonication offers opportunities to improve the digestibility of these foods. However, this beneficial effect of the technology has not been reviewed. The present paper reviews the application of ultrasonication in processing of animal derived foods and examines the effect of ultrasonication on the digestibility of different animal derived food matrices. The underlying mechanisms and optimized conditions for improved protein digestibility of different animal derived food matrices have been critically evaluated and discussed in detail. The review focuses on papers published in the last five years to provide the latest concepts and views on the ultrasonication process. This green and eco-friendly technology has a wide range of applications in the area of animal derived foods. It has been used to accelerate processes such as filtration, extraction, marination, proteolysis, fermentation, decontamination and drying. It can also improve the functional, sensorial and nutritional properties of animal protein-based foods. Ultrasonication can alter the sensorial, especially textural, and other quality attributes of dairy, egg and meat products by affecting the chemical reactions and processes involved in their processing, such as oxidation, Maillard reaction, proteolysis, esterification and production of volatile flavour compounds. It can also modify food structure. There has been recent interest in the application of ultrasonication to improve the digestibility of various animal protein-based foods. Almost all the papers analysed in this review reported a positive impact of ultrasonication on the digestibility of animal proteins. The main mechanisms responsible are related to altered protein structure and changes in the microstructure of food matrices, which improve the digestibility of the animal proteins by making active hydrolytic sites available for digestive enzymes. This technology can be used to develop novel animal protein-based foods with improved digestibility. Future studies should validate this effect in animal models and possibly in human trials.