Food exists in a variety of forms - solid food, liquid food, solid-liquid combined food - and different solids, with different physico-chemical properties. This makes pre-treatment of foodstuffs for testing a very complex task, and an important processing requirement is that the foodstuffs must be adequately homogenised. This is why it is necessary to select suitable grinding equipment to crush foods such as tea, coffee and peppers to a small particle size to ensure effective homogenisation before testing.
Depending on the purpose of the test, we can follow the following points.
The feed size is an important criterion for selecting a grinder, for example a whole maize is not the same as a single maize kernel to be processed. There is no fixed particle size standard for homogenisation, for example fishmeal, wheat and vegetable treatments will certainly have a different particle size distribution. Experience has shown that the particle size distribution of substances commonly used for analytical testing is around 20 μm to 2 mm. Depending on the final particle size and the feed size, the appropriate grinder is selected.
Sometimes one grinding instrument is not sufficient to complete the grinding and a multi-step process is required in conjunction with other grinding instruments. When selecting a grinding instrument, the nature of the sample to be processed needs to be fully considered. For example, hardness, viscosity, water content, oil content, etc. It is also important to consider whether the temperature rise and energy rise generated by the grinding process will have an effect on the properties of the sample. Depending on the material to be crushed, different grinders with different crushing principles are available.
Inlet and outlet volumes vary depending on the type of grinder. Open mills with both inlet and outlet ports allow continuous grinding and are therefore suitable for large sample volumes, e.g. jaw crushers, high-speed rotary mills, etc. With closed chamber mills, however, only single batches can be milled.
Grinding instruments often have different accessories, which vary greatly in size and material. What is the best way to choose accessories so that they do not have a wrong influence on the results? That is, the choice of accessories must not introduce new impurities.
Metal accessories: stainless steel, common steel, titanium, etc.
Metal-ceramic accessories: tungsten carbide, zirconium oxide, aluminium oxide, etc.
Accessories made of natural materials: agate
Plastic fittings: PTFE, PC, PP, PE
We should be flexible in our choice according to the actual testing requirements. In terms of the nature of the food and the national testing standards for food, the ultra-fine microgrinder can meet the needs of most food testing pre-treatment crushing. Contact us to learn more.