A NMR RELAXOMETRY METHOD FOR DETERMINING THE RECONSTITUTABILITY AND THE WATER-HOLDING CAPACITY OF PROTEIN-RICH MILK POWDERS

The reconstitutability and the water-holding capacity are regarded as important factors among the functional characteristics of dried foods. The kinetic NMR method described in this work gives a complete pictur e of the reconstitution process in water, close td industrial conditio ns, by determining both the rate of solution and the delay for a compl ete reconstitution of milk powders. Furthermore, the technique gives a n available value of the water-holding capacity which provides some cl ear understanding of the mechanisms of solubilisation of native casein micelles. Effects of concentration and mixing rate were studied. The poor reconstitutability of native casein micelles concentrated by micr ofiltration can be significantly improved by adding before drying Suit able additives such as whey proteins or polydextroses which would incr ease the lability of particles.