Chapter One

H.C. Deeth and J. Hartanto

1.1 Introduction

This chapter discusses the relevance of major milk components to concentrated and dried products, the chemical composition of the various products and some of the quality issues of the products associated with the various components. Knowledge of the chemical composition of these products is essential for understanding their manufacture, applications, nutritional attributes, essential chemical differences and functional properties, as well as the changes that occur during their manufacture and storage. Several comprehensive reviews of the chemical composition of milk are available in dairy chemistry texts and other publications (e.g. Walstra & Jenness, 1984; Wong et al., 1988; Fox & McSweeney, 1998; Varnam & Sutherland, 2001; Anonymous, 2003; Walstra et al., 2006).

Many factors affect the composition of milk. These include the species and breed of animal from which the milk is derived, the stage of lactation, the season and the nutritional status and health of the animal. In addition, changes to the milk occur after it is harvested and before it is processed, which may affect its processibility. Therefore, it is impossible to provide accurate compositional data. In Table 1.1, `textbook values' of the major constituents, water, fat, protein, carbohydrate (lactose) and minerals or ash are given for whole milk and skimmed milk, that is, milk from which fat has been removed. Table 1.1 also gives compositional data for a range of concentrated and dried milk products selected from a range of sources. As for the