AMP 4448 is delaying the increase in the measured value – or in other words delaying the thickening effect caused by the increasing water content in the coating during a production day. When lecithin or Palsgaard® AMP 4448 is added to chocolate it will reduce the plastic viscosity more than the YV, and as water especially increase the YV, lecithin and Palsgaard® AMP 4448 on its own seem to be a feasible but not an optimal solution. the added benefit of pgpr Polyglycerol Polyricinoleate – PGPR (E476) also known as Palsgaard® PGPR 4150 is an excellent emulsifier to add when a decreased YV is required or an increased YV to be avoided. PGPR is mainly reducing the YV in the chocolate and is therefore always used in combination with either lecithin or Palsgaard® AMP 4448 to achieve a pumpable product with a low YV. To read more about PGPR and its functionality please look at the end of this article**. One could say that the functional effect of PGPR on the YV in chocolate is the opposite of the effect of adding water, and therefore PGPR will be ideal for ice cream coatings. Graph 2 shows the increase in viscosity at shear rate 2 [1/s] (speed of the chocolate) when applying various amounts of ice cream mix to a coating containing 0.7% lecithin or Palsgaard® AMP 4448 and 0.3% PGPR (Palsgaard® PGPR 4150). When adding the mixture of lecithin and PGPR, the thickening effect of the added ice cream mix is reduced very much compared to the ice cream coating with no emulsifier added. The thickening effect at higher water content has been reduced by adding both lecithin and PGPR. Graph 2: Rheology on ice cream coating - The effect of added water. 3500 0.7% lecithin + 0.3% Palsgaard® PGPR 4150 0.7% Palsgaard® AMP 4448 + 0.3% Palsgaard® PGPR 4150 3000 2500 2000 mPa∙s 1500 1000 500 0 0% ice cream mix 1% ice cream mix 2% ice cream mix It is interesting to see that the mixture of Palsgaard® AMP 4448 and Palsgaard® PGPR 4150 show no or only a little thickening effect when adding the ice cream mix to the ice cream coating. When adding this combination, the coating will be very robust towards increases in water content, and this clearly shows that it will be stable and uniform during a production day. In the conclusion examples of additional use of coating as a result of the higher measured values are shown. aCtual appliCation tests: The curves clearly show the differences in the rheology at various water contents and emulsifier additions but it is difficult to imagine what these differences mean in an actual production. To convert the differences shown in the graphs, we have conducted a series of realistic application tests. The method and results are described in the following: Test setup: An ice cream coating base is produced, emulsifiers and the defined amount of ice cream mix (1 and 2%) added. The temperature of the ice cream coating is kept at a dipping temperature of 37°C. The ice creams are kept at minus 18°C. A series of ice creams are taken out of the freezer, weighed – dipped and weighed to establish the average amount of coatingpickup. Typical ice cream coating pickup on this type of ice cream lollies is approximately 6.5 grammes - equivalent to approx. 25 w/w %. The aim of the test is to imitate the possible changes in ice cream coating-pickup during a production day. The recipe shown below in table 1 containing approx. 60% fat is designed to give a thin and crispy layer on moulded ice cream and is a good and realistic test recipe for the following trials. Recipes based on speciality fat or cocoa butter will provide similar test results. results of dipping tests Graph 3 shows the result of the dipping tests and this enable us to compare the viscosity analysis with the actual results of the dipping operation. Table 1: Recipe of ice cream coating base ingredient Cocoa Powder – low fat Skim milk powder Sugar Coconut oil Rape seed oil % 10 3 28 50 9 Palsgaard Technical Paper - August 2012 Moisture caused problems in ice cream coating - a problem of the past 4
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