By Hanne K. Ludvigsen, Product Manager Dairy and Ice cream, Palsgaard A/S. Chocolate milk is a well-known and popular product around the world. Except for a few products where a visible sedimentation is desired, chocolate milk is expected to be a homogeneous product without visible sedimentation and creaming. Most of the cocoa powder is insoluble in milk and water meaning that if no precautions are taken, the cocoa particles settle at the bottom and the text ‘shake before use’ will have to be written clearly on the packaging. This labelling has a negative impact on the consumer. Further, for long shelf life products creaming occurs over time - a process which can also be delayed by taking appropriate action. Forming the thixotropic system Chocolate milk usually contains up to 2% cocoa powder. In order to make a homogeneous suspension of the cocoa particles in the milk, a three-dimensional network has to be formed. The cocoa particles are entrapped herein. When shear is applied to the chocolate milk the network is broken and the viscosity decreases. When the shear is removed the threedimensional network is restored. It is a so-called thixotropic system. The ingredients used to form this thixotropic system are generally mono- and diglycerides carrageenan and microcrystalline cellulose. Mono- and diglycerides further have an important function in preventing creaming in the product. The effect of emulsifiers in chocolate milk Mono-and diglycerides are emulsifiers produced by reaction of edible vegetable fats/oils and glycerol. The result is a molecule with Figure 1. Chocolate milk with and without sedimentation. a hydrophilic and a lipophilic part and consequently it is placed at the interface between the fat/protein and water. This happens during homogenisation and ageing of the chocolate milk. The monoand diglycerides form complex with the whey proteins, making the fat globule membrane more resistant towards coalescence. Hence they reduce fat separation in the product. However, they also reduce the net charge of the fat globule membrane and thereby increase the flocculation of the fat globules forming a three-dimensional network, which increases the creaminess in the milk. The effect of carrageenan in chocolate milk Carrageenan is by far the most commonly used stabilizer in chocolate milk. Carrageenan is extracted from seaweed. In Europe carrageenans are divided in 2 groups, refined carrageenan (E-407) and semirefined carrageenan (E-407a). Both types are applicable in chocolate milk. Carrageenans are further grouped in Kappa-, Lambda- and Iota carrageenan according to their chemical composition. It is especially Kappa carrageenan, which has found use in chocolate milk due to its ability to react with the milk proteins and form a three-dimensional network. The carrageenan Palsgaard Technical Paper, October 2010 2 How to make a delicious chocolate milk
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