Ingredients | IDM 10 2016 | international-dairy.com · 39 ing new products with added vitamins, iron, oat fibres, calcium, conjugated linoleic acids (CLA), magnesium and more. The same issue, however, raises its ugly head: adding most things to milk will destabilise the product and endanger both on-the-shelf appeal (for bottled products) and consumer enjoyment (for both bottled and carton products). Even coffee milk, while not widely considered a healthdriven product, suffers from the same effect. And a related problem, in long shelf-life products, is the phenomenon known as ‘creaming’. Sedimental blues Sedimentation begins the moment the drink has been produced. But, of course, it really starts to work its dark magic once on the shelf. At worst, two distinct layers can appear. In chocolate milks, the bottom one is an (appropriately) dark chocolate colour, while the one just above it has been described as having a “white-livered” appearance by at least one source*. In assessing the sedimentation aspect of such drinks, sensory evaluations tend to focus upon: • The amount of sedimentation • The fineness of the sediment • The ease or resistance with which it remixes with the milk when shaken While some particle-containing drink manufacturers have managed to work out how to achieve a consistent and strong suspension, many others, however, have not. For this latter group, there is much to be gained by deploying up-to-date techniques to combat the problem. Four networks acting in concert Essentially, any drink containing insoluble particles is prone to sedimentation. Their resistance to sedimentation, if it is to be effective throughout the shelf-life of the product, first requires manufacturers to consider the choice of milk and particle type. To reduce the likelihood of sedimentation, state-of-the-art recipes for chocolate drinks based on fresh milk can make the most of four distinct, yet interacting networks that together enable an extremely robust suspension, keeping cocoa particles in their place while ensuring emulsion stability, creaminess and other benefits. Four of the five networks we’ll discuss in this article are physical effects enabled by: 1. Emulsifiers, which increased flocculation of fat globules to form a three-dimensional network 2. Stabilizers, forming the essential carrageenan network 3. Microcrystalline cellulose (MCC), whose effect on the formation of hydrogen bonds forms yet another network 4. In chocolate milks and other enriched milk drinks that may contain cocoa powder, the tannin component in the powder bonds proteins to add further strength to the drink’s suspension If all four of these networks are present, as they may be in a sophisticated product, the combined result will hold the cocoa particles – or other particles contained in enriched drinks – tightly in suspension, 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 preshear 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. 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 Figure 1. Formation of carrageenan network in chocolate milk (source: Palsgaard) Figure 2. MCC/CMC network (source: Palsgaard)
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