Modification of milk fat globule membrane composition by selective adsorption and its effect in functionality

A study for the selective removal of milk fat globule membrane components was carried out in order to study the possibility of modification of the functional properties of dairy creams and their application into the manufacture of low-fat dairy products. A procedure for the treatment of dairy creams with adsorbents of biological origin (i.e. diatomaceous earths) intended for the selective removal of milk components and the subsequent modification of the creams functional properties was therefore developed and the properties of the modified creams studied. Low-fat dairy spreads were prepared with the modified creams and their physical properties studied and compared to those of commercially available products.; Calcined diatomaceous earths, synthetic calcium silicates and synthetic magnesium silicate were used as adsorbents for the treatment of dairy creams. Washed and unwashed creams were treated with the adsorbents. Proximal analysis, lipid and protein profiles of creams and adsorbents, emulsion stability of the treated creams and electron microscopy analyses of the creams and low-fat dairy spreads prepared with them were carried out.; The removal of milk proteins by washing the creams prior to treatment was responsible for the most significant differences, since it decreased the total solids, ash and protein content of the creams as well as those of the adsorbents used.; Amount and type of proteins removed from the creams during treatment pointed to differences between the adsorbents used. Phospholipid analysis indicated that these lipids were preferentially removed by synthetic magnesium silicates.; Treatment of dairy creams with the silicate adsorbents showed that differences in functional properties of the creams could be obtained by selective interaction of the silicates with some of the cream components. The modified creams were successfully used in the manufacture of low-fat dairy spreads and their textural and rheological properties demonstrated that treatment with the different types of silicates were responsible for their characteristics.