By Arne Pedersen, Product & Application Manager, Bakery & Confectionery, Palsgaard A/S. This article describes how an optimal mixture of Emulsifier YN and PGPR efficiently solves moisture caused problems when coating ice cream with chocolate- or compound coatings. By using the special properties of both emulsifiers the negative effect of water in an ice cream coating is neutralized and a stable and uniform production day is secured. liquid filling – or instability due to alcohol content in the filling. All problems and challenges described in numerous articles. iCe Cream Coating One area which is not described very much is ice cream coating. This application differs from the coatings which are to be eaten at normal room temperature and very special production problems rather than subsequent quality issues are related to this application. Ice cream coating is eaten together with the ice cream and during this process the mouth is typically cooled down to a temperature below 30°C which is far below the typical melting point for well tempered chocolate based on cocoa butter. The trick is that the chocolate used for ice cream coating is not tempered and it is cooled very fast to a temperature around minus 18°C. This treatment forces cocoa butter to crystallize in a number of different unstable crystal forms with a low melting point – typically 25°C – which makes the ice cream coating melt nice and easily together with the ice cream when eaten. The typical storage temperature at minus 18°C will keep the crystals from re-crystallizing and therefore secure the desired melt down when eaten through out the shelf life of the product. Alternately a non temper vegetable fat with a melting point around 25°C – e.g. coconut oil can be used, either on its own or in mixtures with e.g. cocoa butter. dipping proCess The dipping/coating process is also different due to the low process temperatures and the very short time from liquid to solid. In a traditional coating process the crystallization takes several minutes. Equally, there is plenty of time to regulate the layer thickness and shape by blowing/vibrating. When coating an ice cream it is a matter of seconds before the coating is fixed into a non-moveable layer, and the layer thickness is defined by the rheology of the chocolate, the crystallization speed of the fat used and the temperature of the ice cream and the chocolate. It is therefore important to be in control of the rheology of the coating in order to get the desired layer thickness and shape, and to use the optimal temperatures in the ice cream and in the chocolate coating. One could think that this would solve the problem and secure a production free of problems, but it is unfortunately not so. identifying the Cause of moisture problems in iCe Cream Coatings During a production run the ice cream coating will change its rheological properties due to the fact that it is impossible to avoid water from getting into the chocolate. The fact is that an almost water free 35°C hot chocolate is exposed to ice cream containing more than 60% water, preferable at minus 15°C. Melted ice cream mix will therefore migrate to the hot choco- Creating a Coating ChoColate Chocolate is a valued product to be used as coating on many different products and the functions are many. A typical confectionery coating will protect and keep the filling inside the praline and protect it from drying out. It will enable customers to hold it without getting greasy fingers but when eaten the chocolate will melt nicely and together with the filling provide an excellent taste. This is due to the very special properties of confectionery fats like cocoa butter which is unique in the sense that it is hard and brittle at temperatures below 30° C (room and hand temperature) and completely melted at 35° C which is the temperature in the mouth. traditional Coating Challenges Challenges arising from using chocolate as a coating are also many as the result depends on the interaction between the filling and the coating – mainly on long term basis as the problems typically shows after a storage period. Migration of fat from the filling to the chocolate causing the grey layer called bloom is one big problem (see figure 1) – another is leaking Figure 1: Chocolate bloom caused by migration of fat. Palsgaard Technical Paper - August 2012 Moisture caused problems in ice cream coating - a problem of the past 2
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