[Milk and dairy products for human nutrition: contribution of technology]

The complex composition of milk has led to the development of innovative technological processes such as membrane separation. The dairy industry is now able to offer consumers safe classical products (liquid milk, raw-milk cheeses) with little or no heat treatment. Indeed, heat treatment undermines the organoleptic qualities and bioactivity of many molecules found in milk. New technologies, and especially membrane microfiltration, have allowed researchers to identify two groups of milk proteins in terms of their human absorption kinetics: slow micellar casein and fast whey proteins. The highly purified products thus obtained are used for infant foods and slimming aids, and as functional ingredients. The same technologies have been applied to colostrum, yielding a sterile "serocolostrum" containing biologically active immunoglobulins, growth factors, and polypeptides. Combined with other separation techniques, membrane technologies should soon allow the separation and purification of minor milk proteins described as having essential roles in bone calcium uptake and vitamin transport, for example. The use of enzymatic membrane reactors has led to the identification of several bioactive peptides, such as--kappa-caseinomacropeptide, which induces CCK (cholecystokinin) secretion and thus regulates food intake and lipid assimilation,--alpha(S1) CN (91-100), a compound with benzodiazepine activity,-- kappaCN (106-116), which has anti-thrombotic activity by inhibiting blood platelet binding to fibrinogen, and--alpha(S) and beta casein phosphopeptides, which are thought to increase iron and calcium absorption.