Effects of homogenization and heat treatment on camel milk: Physicochemical properties, microstructure, and digestibility in infants

Abstract

Milk is typically processed through homogenization and heat treatment, which alter its physicochemical properties and digestibility. This study investigated the effects of homogenization and heat treatment on the microstructure and functional characteristics of camel milk. The fatty acid profiles of camel milk as well as the sequences, protein origins, and bioactivities of different peptides derived from camel milk were compared after different treatments through an in-vitro simulation of the infant gastrointestinal tract. Homogenization and appropriate heat treatment enhanced the protein interface properties of camel milk and also reduced its zeta potential, particle size, and protein and lipid aggregation after digestion, leading to improved stability and digestibility. Furthermore, homogenization and ultra-high temperature (UHT) treatment led to significant changes in the fatty acid profile during the digestion stage, decreasing the saturated fatty acid content by 7.67% while increasing the unsaturated fatty acid content (i.e., C17:1, C18:1n9t, C18:1n9c, C18:2n6c, C20:1, C20:3n6, C22:1, and C24:1). Heat treatment facilitated the release of digestive peptides, most of which were derived from β-casein. UHT-treated camel milk yielded several specific peptides during digestion, of which LLFR, IQDAQDKLFLSWVEWKR, FLK, and GSLDEFFHR showed a range of biological activities, including antimicrobial, antihypertensive, and neuromodulatory effects. These bioactive peptides demonstrated the potential to synergistically promote the development of a robust gut microbiome in infants and enhance immunity, effectively preventing disease occurrence. Collectively, the findings indicated that homogenized and UHT-treated camel milk is easily digested and absorbed by infants and provides more nutrients, thereby promoting infant growth and development.