Compositional and functional differences of ewe and goat’s milk and dairy products with regard to cow’s milk and dairy products

Abstract

As the substitute of human milk in infant food, milk from cattle and smallruminants species has been studied extensively to address their nutritionalvalue. In the last 20 yr, proteomics gave a great contribution inunderstanding the proteins component, including isoforms, posttranslational modification, interaction, functional properties, to evaluatecasein fractions, whey fractions, and milk fat globule. The study ofpolymorphisms of caseins at the protein level are key characteristics to bespecifically considered in the cheese-manufacturing industry. Differentgenotypes of αS1-casein have been observed depending on species andbreeds. These types have been associated with allergic processes and mayaffect digestibility, milk and cheese properties. Higher levels of some of theessential amino acids observed in goat milk may play an important role onthe intestinal absorption. Lower size of fat globule in goat milk has beenassociated with higher digestibility. Regarding to immune variables, nodifferences in milk immunoglobulins (IgG and IgM) have been describedwhen sheep and goat milk are compared with cow’s milk. Proteomicselucidated also some differences in proteins with immune function betweencow, sheep and goat milk whey. The IgG heavy chain C region showedhigher intensity in sheep than in the other 2 species while lactoperoxidasewas higher in cow milk whey. Conversely, the polymeric immunoglobulinreceptor isoform 1 was higher in small ruminants whey milk than in bovine.Concerning fatty acid composition, concentrations of C6:0, C8:0, andC10:0, responsibles for the flavor of cheeses, are much higher in sheep andgoat’s milk and dairy products than in cows. The opposite occurs with thecontent of cis-9 C18:1, which is lower in caprine and ovine milk fat. CLA andtrans-11 C18:1 contents seem to be slightly higher in ewe’s products.Another important achievement is the study the specific composition of themilk microbiota that directly impacts on the subsequent development ofdairy products. Microorganisms can bring about the fermentation of milkthrough the production of lactate and have a variety of different impacts onthe sensory, texture, flavor and organoleptic properties of resultantproducts.