sion, preventing them from migrating to the bottom of the container. It’s a ‘thixotropic’ network, referring to the fact that if shear is introduced to the suspension, for example by stirring, the network will be broken down, but will tend to revert to its pre-shear state again once the disturbance stops. Of course, gravity means the network is also subject to subsidence under its own weight, but this is countered by adherence to the inside of the container. And at the same time, the stabilized network improves the drink’s mouth-feel. Figure 1. Formation of carrageenan network in chocolate milk. NETWORK NO. 1: CARRAGEENAN Extracted from seaweed, carrageenan is by far the most commonly used stabilizer in chocolate milk. In Europe, carrageenans are divided into two distinct groups: Refined carrageenan (E-407); and semi-refined carrageenan (E-407a), both of which can be used in chocolate milk. And it’s a sub-group of these, namely Kappa carrageenan, whose chemical composition has proved useful in chocolate milk because of the way it reacts with milk proteins to form a three-dimensional network. Essentially, the carrageenan forms a helix with negatively charged sulphate groups turning outwards. This helix interacts with the positively charged casein micelle. When carrageenan is used as a stabilizer, and in order for the network to be formed, the chocolate milk must be cooled to below 25°C before filling, or below 25°C during constant rotation if in-can or in-bottle sterilisation is used. It’s important to store the product at temperatures below 30°C, as the network will start to break down in the heat. Figure 1 shows how this network is formed in a carrageenan-stabilized chocolate milk. Dosaging carrageenan is somewhat like walking a tightrope. And it’s a fine line indeed: A dosage that’s just a little too low will quickly produce undesirable levels of sedimentation. Slightly overdo the dosage, on the other hand, and the product is likely to acquire a heavy, gelated body. So the margin between the two states is narrow. Unless, that is, the stabilizer is accompanied by mono- and diglycerides. This increases the dosage margin, and has the useful effect, due to the creation of a network between fat globules and whey proteins, of reducing the amount of carrageenan required to form a stable product. But more on that in a moment. Another factor to be taken into account, of course, in determining the right dosage of carrageenan, is the variation that may occur in the composition of the milk, depending on the season. But there’s more still to the dosage decision. It also depends, for example, on: • The milk’s fat content, as more fat requires less stabilizing • The cocoa content, because more cocoa demands less stabilizer • The choice of heat treatment (Sterilisation requires less stabilizer than UHT, which in turn requires less than a pasteurised product) Carrageenan is extracted from seaweed and is the most commonly used stabilizer in chocolate and enriched milk to prevent sedimentation of particles. It is, however, difficult to dosage as adding too much will cause gelation and too little will cause sedimentation. Photo source: https://en.wikipedia.org/wiki/Carrageenan 3
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