The powdery ingredients of an instant ready meal differ significantly from one another; some are dusty fine, others are agglomerated, others may be slightly lumpy. Some are greasy, others are extremely hygroscopic. Some are easy to dose, others are present as a semi-solid mass. Freeze-dried meat preparations, dried vegetables, pre-treated saturated side dishes such as rice, potato flakes or pasta are more or less lumpy, with particle sizes of 2 cm and more
Note/Question from a customer: It is sometimes complicated to achieve agglomerate-free wetting and at the same time ensure that the mixture remains cold and free-flowing when liquid admixtures have to be blended into the powder.
Any agglomerates that form should be broken up; on the other hand, the mixing tools should only introduce a small amount of energy into the mixture. The coarse components should be retained and look good.
Depending on the type of instant meal, 40 individual components and more are involved in the recipe. Such heterogeneous compositions can be prepared in the amixon mixer in batches. Then they have ideal instant properties, look good and the end consumer receives the goods undamaged and segregation-free.
A good approach is as follows:
First, a number of "fine and robust" powders are fed into the mixer and mixed intensively. After 60 to 120 seconds, liquids are added while continuing the mixing operation to wet the powders completely. In this way, dusts are effectively bound. Then the mixing tools stop and more powder components are added to the mixer. These coat the previously wetted particles. Now other powders and other liquids are added.
Some liquids are of low viscosity, others are highly viscous and should be heated in advance. Others again are structurally viscous or even dilatant. Depending on the rheology of the respective liquid and the factory's own handling regime, a wide variety of nozzles and dosing systems are used.
If you would like to read more on the subject of powder wetting/humidification, then please read influencing factors for successful liquid distribution into the powder.
Sometimes there are also separately prepared powder premixes that are added in a stop-and-go process. Finally, the chunky, sensitive components are added. These are, for example, freeze-dried meat preparations, dried vegetables, pre-treated saturated side dishes such as croutons, rice, potatoes or pasta.
The latter are "folded in" for only 10 to 20 seconds. The product is then ideally mixed without the chunky components being damaged. In this way, one and the same twin-shaft mixer works in completely opposite ways, from intensive, aggressive deagglomeration with high energy input to extremely gentle "underlifting" with minimal agitation. In this way, vertical twin-shaft mixers achieve premium qualities with ideal mixing quality.
The dead-space-free discharge valve is then opened. The mixing tools now rotate extremely slowly and discharge the mix particularly gently. This works absolutely segregation-free without particle breakage down to the last remains.
If you would like to find out more about tests in the amixon technical centre, please read here.