Application Notes 2 SHIMADZU 3 Biolan Microbiosensores 4 Anton Paar 5 BÜCHI Labortechnik AG 6 Bruker BioSpin 9 Novasina AG © conejota / Shutterstock.com www.newfoodmagazine.com 1 New Food, Volume 18, Issue 6, 2015 Application Note NOVASINA AG Water activity in chocolate Not just for sweet teeth... Introduction to the same level. That sounds easy; but the challenge lies in keeping While enjoying the lovely taste and texture of a chocolate bar or a praline, texture and taste as it's change is not really appreciated by consumers. just a few of us would expect that a lot of science stands behind. Texture, What would you think if the well-known Lindt balls did not melt taste, appearance and organoleptic, all of that have to be brought irresistibly smooth in your mouth? under one roof to obtain a perfect praline which fulfils consumer's expectations. While most of us think about pH, rheology or fat analysis in Finding best formulation connection with analytical technology used to develop new and control To find the best formulation which fulfils customer's expectations on existing chocolate products, it could be shown that one key parameter texture, taste, organoleptic etc. it is wise to keep an eye on water activity. must fit to avoid big problems: Water Activity. Read below to find out why. Having it in the right range will bring consumer's love. Factors which influence water activity of chocolate products are: What is water activity? Temperature As simple as water activity is defined by the relation of vapour pressure of Manufacturing process water over the sample to the saturation vapour pressure over pure water, Homogeneity of filling the more complex it is to fully understand it. It describes the potential Addition of sugars of the free water in a product and not the amount (mass) of the same. Composition of formulations While pure water has the highest potential, each interaction with a substance or a product will lower the potential and thus change the In the case of truffle manufacturing, variation in compounds can water activity. State of the art instruments measure the air humidity influence water activity and all other physical properties dramatically. It over the sample in equilibrium state which corresponds to water is of crucial importance to get the right mix of all ingredients which have activity in the product. initially the following aw-values: Cream: 1.00aw // Butter: 0.98aw // Glucose: 0.71aw // Sorbitol powder: 0.32aw // Couverture: 0.30 aw. Water migration – THE enemy for chocolate! Aside of pure milk chocolate, fancy mixtures are present on the market. Figure 2 illustrates the influence in compound variation: Nowadays it is not enough just adding hazelnut into chocolate – no, from jelly beans to fruits, all is packed into a chocolate bar and with them a lot of problems: unexpected growth of moulds, texture changes, fat oxidation, just to name a few. But why? The answer is: water migration. As two different compounds are mixed, water starts to migrate from the area of high to the one with low water activity and not from high moisture to low moisture. In principle, you can have the following situation, where the dry area is getting drier and wet area more wet: Typical fat-based fillings have a water activity of 0.20-0.35aw, water-based ones have 0.65-0.90aw and pure chocolate 0.40-0.50aw Not respecting this fact can bring or remove a lot of water to or from Figure 2: Influence on water activity value of variation of compounds of truffles1 a place in the product where it is definitely not wished, thus biscuits can As seen, water activity offers much more than just microbial get bent or moulds will grow where they normally do not. Water information for chocolate production. It can help you making the migration can be avoided by adjusting water activity of all components products better, more constant in quality and finally, meet customer's expectations perfectly. Reference 1. G. Sargenti, "Bedeutung der Wasseraktivität in der Confiserie", May 2013 Need more information? Contact us! Figure 1: Water migration in a product with different water activity values www.novasina.ch www.newfoodmagazine.com 9 New Food, Volume 18, Issue 6, 2015