NUTRITIONAL ASPECTS OF MILK PRODUCTS USED FOR INFANT FEEDING

The nutritional problems in design of satisfactory food for infants and the need for more research and development is discussed. The high infant mortality in the first decade of this century is noted, while the value of heat treatment and modification of cows' milk formulations in reducing infant mortality and disease is discussed. The properties of butterfat and solids-not-fat are assessed and the functions of whey protein in human and in cows' milk evaluated. Modifications to the recommendations for composition of infant foods over the last decade with the change in the contribution of the dairy foods industry are shown.     

THE PRESENT NUTRITIONAL STATUS OF MILK PROTEINS

The role of milk and milk products as a source of protein required for human needs is assessed and various methods of determining the nutritional value of protein described. Biological value of milk protein and amino acids composition are compared and the importance of concentrated lysine is emphasized. The effect of heat treatment on whey proteins is discussed with the possibility of Maillard reaction. The future developments in milk protein with its high nutritional value and the necessity for new ways of using it as a food are stressed.     

THE NUTRITIONAL IMPORTANCE OF MILK AND MILK PRODUCTS IN THE NATIONAL DIET

The average consumption of milk and milk products is related to their composition and to the recommended intakes for nutrients, and the nutritional importance of dairy products is considered. The major contribution to the average diet is in the protein, calcium, riboflavin and vitamin A contained in dairy products.     

RHEOLOGICAL ASPECTS OF THE RENNETING OF MILK CONCENTRATED BY ULTRAFILTRATION

The kinetics of clotting by rennet of ultrafiltrated milk were studied by determining induction and clotting times, and development of the rigidity modulus as a function of rennet concentration and protein content in the sample. Creep cmpliance-time studies were conducted on the resultant gels at three different stresses. Clotting time increased with protein content and decreased with rennet concentration. The protein effect on clotting time decreased with increasing rennet concentration and was practically nil at 200 mg enzyme/kg sample. The ultimate rigidity and the viscoelastic parameters of gels depended on the protein concentration in a double logarithmic relationship. The calculated values of the constants indicated that the viscosities were influenced to a greater degree by the protein concentration than were the elastic moduli. The renneted milk gels exhibited creep compliance-time response at low shear stresses indicative of the viscoelastic behaviour of an interlinked three-dimensional network. Gelation followed a second order reaction in its initial stages and an approximately third order reaction in the final stage. The results are discussed in terms of potential mechanism and type of bonds involved.     

小米营养乳生产工艺

以营养丰富的小米为原料，对小米乳饮料的生产工艺、配方及产品质量进行研究，指出了酶反应最佳条件、稳定剂对产品质量的影响及工艺条件对小米营养乳饮料稳定性的影响，得出了色、香、味及组织状态俱佳的小米营养乳饮料。     

牛乳中主要蛋白过敏原研究现状

牛乳蛋白过敏原的研究成为近几年国内外的研究热点之一.依据有关牛乳中过敏原的研究报道.对牛乳中的主要过敏原酪蛋白、B-乳球蛋白(p-LG)及á一乳白蛋白(á-LA)的结构特征、表位、改性等的研究现状进行介绍,并对牛乳蛋白过敏原的研究进行展望.     

微波消解-凯式定氮法测定牛奶中蛋白质含量

建立微波消解-凯式定氮法测定牛奶中蛋白质含量的方法,采用密闭微波消解样品,优化微波消解条件.方法的相对标准偏差RSD为1.82%,回收率在98.8%～101.7%之间.