Significance of milk fat in cream products

Abstract

Cream is a Xuid milk product, comparatively rich in fat, in the form of an emulsion of fat-in-skimmed milk, obtained by physical separation from milk (Codex Alimentarius Commission, 2003). This simple deWnition does not reXect that the word "cream" has for a long time been considered a premium product or a value-enhancing ingredient in milk products and other foods. The special "creaminess" results from the Wne dispersion of the fat globules in the hydrophilic phase and depends strongly on the fat content. In separated cream, the diameter of fat globules ranges from ca. 1 to 8mm. During further processing to the diVerent cream products, this typical oil-in-water (o/w) emulsion is modiWed or even converted into another physical state. ModiWcation can be achieved by homogenization, which markedly reduces the average fat globule size and improves creaminess. On the other hand, mechanical treatment of chilled cream causes destabilization (i.e., coalescence of the fat globules). This treatment and the concurrent entrapment of air are essential for whipping cream into a stable foam. The fat content of cream products varies from about 10-50%. Products with a low, internationally not-yet standardized, fat content are "coffee cream" (≥10% fat, Germany), "half-and-half cream" (≥10.5% fat, USA), "half cream" (≥12% fat, UK) or "light cream" (≥12% fat, France). Traditional whipping cream has 30 to 40% fat, whereas double cream contains about 50% fat. Creams of high fat content are also essential ingredients in dairy or non-dairy products such as some fresh cheese varieties or cream liqueurs. Butter is manufactured from cream (30-80% fat) by phase inversion. Reviews on cream, cream processing and cream products have been published by Towler (1994), Early (1998), Kessler (2002) and HoVmann (2003). Two IDF Bulletins (IDF 1992, 1996) deal with pasteurized and UHT creams. In summary, the signiWcance of milk fat in the diVerent cream products is based on fat content, fat distribution, the physical state of the fat, and last but not least, the chemical, physical, and sensory properties of the non-fat ingredients. In the following, interactions between these factors are described for the most important cream products.