Mixing, blending, stirring
mixing operations can be distinguished in the food industry:
- solid/solid mixing as, for example, carried out during the production of animal feed or food products, such as blends of tea and coffee, dried soup, cake mixes, custard, ice-cream mixes, malt blends etc.
- solid/liquid mixing as, for example, carried out during the production of canned foods, dairy products, etc. This type of mixing is also used in the production of chocolates and sweets, where the ingredients are mixed in a more or less liquid state then and solidify on cooling
- liquid/liquid mixing, used during the production of emulsions like mayonnaise, margarine and mixtures of solutions. This type of mixing is also used to blend different wines or mineral water with each other or with additives or extra ingredients.
- liquid/gas mixing, used, for example, in making ice-cream, whipped-cream and some sweets. During spray drying the liquid-phase is mixed in a stream of gas.
For viscous solid/liquid mixing, kneading machines are used.
For low viscous solid/liquid mixtures and liquid/liquid mixtures various types of stirrers, impellers and agitators are applied.
For liquid/gas mixing, atomisers are used to produce small liquid droplets, which are brought into contact with a stream of gas. In making ice-cream, whipped-cream or a foam, small gas bubbles are fed into a liquid.