Raw material expansion and expansion process on the impact of particle hardness through the expansion of raw materials and expansion processing, can destroy the anti-nutritional factors in the raw material, remove the toxins in the raw material, kill bacteria, eliminate harmful substances, so that the raw material in the protein denaturation, starch fully pasted, pasted starch on the hardness of the particles after the impact is significant. At present, puffed raw materials are mainly used in the production of high-grade dairy pig food and special aquatic material. For special aquatic material, raw materials through the expansion, starch paste degree increases, the hardness of the formed particles also increased, which is conducive to improve the stability of the particles in the water. For suckling pig feed, the particles are required to be crispy, not too hard, which is good for suckling pig's feeding. However, the hardness of pelletized granules is larger because of the greater degree of starch dextrinization, so the hardness of pelletized granules is also larger, and the hardness of the granules should be reduced by other means.
Raw material mixing, adding water, oil spraying process on the impact of particle hardness of raw materials can improve the uniformity of various particle size components, is conducive to maintaining the basic consistency of particle hardness, improve product quality.The process of adding water in the mixer is still a problem that is being actively explored. In the production of hard pellet feed, adding 1% to 2% of water in the mixer is conducive to improving the stability and hardness of pellet feed particles.However, due to the increase of moisture, it brings negative effect to the drying and cooling of the pellets, and it is also unfavorable to the storage of the products.In the production of wet pellet feed, up to 20% to 30% moisture can be added to the powder, and it is easier to add about 10% moisture in the mixing process than in the tempering process.The pellets formed from high moisture materials are less hard, wet and soft, with good palatability, which can improve the production performance of livestock and poultry. This wet pellet feed can be used in large-scale breeding enterprises. Wet pellets generally can not be stored, generally require that the production that is fed. In the mixing process to add fat is currently a feed production workshop commonly used in a fat addition process. Adding 1% to 2% of fats and oils to reduce the hardness of pellets is not significant, but adding 3% to 4% of fats and oils can significantly reduce the hardness of pellets.