02 Puffed corn flour processing equipment Corn is an important energy source in feed, and its grain component contains 70-75% starch. Since the starch molecules in raw corn are integrated into a dense starch grain structure, a considerable proportion of the crystal structure of antacid and enzyme is present in the starch grains, which is not conducive to animal digestion and utilization, and the crystal structure must be disintegrated (that is, gelatinized) to be fully hydrolyzed by enzymes to improve digestibility. Young animals, especially early weaned piglets, have not yet developed their digestive organs and digestive enzyme activity is very low. Studies have shown that piglets have insufficient amylase secretion within 42 days of birth, and that digestive enzyme activity growth regresses due to weaning stress, often due to starch, which affects production performance. When the corn is expanded, the starch gelatinizes, the starch crystal structure is irreversibly destroyed, and the water absorption and expansion in the small intestine of the animal are rapidly absorbed and expanded, the action area and penetrating ability of amylase are greatly increased, the hydrolysis speed and digestion degree of starch are improved, and the gelatinized starch greatly improves the sensitivity of α-amylase, and makes the action more rapid. In addition, gelatinized starch stimulates lactic acid production in the stomachs of young animals, which prevents the production of pathogenic microorganisms, thereby alleviating and eliminating diarrhea in piglets. For aquatic animals, the effect of gelatinized starch is also great. The utilization rate of raw starch for rainbow trout is only 20-24%, while cooked starch is 52-70%; the digestibility of cooked starch in carp is as high as 96%, while raw starch is 38%. The gelatinized starch in aquatic feed also enhances the bonding performance of the feed and improves its stability in water. Precisely for the above reasons, gelatinized starch is widely used in young livestock feed, special feed, and aquatic feed, and extrusion expansion has also become an important method of starch gelatinization. In fact, not only corn needs to be expanded in these feeds, but other grains used as energy feed need to be expanded. 2. Extruded and expanded corn process Let's take a look at the typical extruded corn process. Maize puffing is a starch gelatinization process under the combination of moisture, heat, mechanical shear and pressure difference. When the material is mixed with steam and water, the non-crystalline zone of the starch begins to absorb water, and through the expansion cavity, the rapidly rising temperature and the kneading of the spiral blade accelerate the starch absorption, the crystal structure begins to disintegrate, the hydrogen bond breaks, the expanded starch grains begin to break, and become a sticky melt, and at the outlet due to instantaneous pressure drop, the moisture flash causes a large number of expanded starch grains to disintegrate. Starch gelatinization. Compared with the conventional cooking process, the plant cell wall can be broken, the starch chain is shorter, and the digestibility can be improved more effectively. There are many factors that affect the expansion of corn, mainly moisture, expansion temperature, differential expansion pressure and mechanical shear force in the cavity. These are also several factors that can be controlled in puffing production at present. Currently, there are two types of corn produced by extrusion and expansion: dry method and wet method. Many users think that adding water is a wet method, and without adding water is a dry method, which is actually a misunderstanding. The so-called wet method refers to steam pre-quenching and then expanding. The dry method is direct expansion without steam pre-quenching. Even if water is added, it is a dry method. There is also information on wet and dry expansion, and this article is omitted. Generally, wet production is better than dry production, but steam boilers are required, and the investment is greater than dry. When producing puffed corn, whether it is dry or wet depends on the specific situation of the user and the product requirements, and some products can only be expanded dry. 3. Puffed corn indicators Almost all users will ask, to what extent can you puffed corn? We have also summarized this issue, so let's first discuss evaluating puffed corn. It can be seen from the foregoing that puffed corn for feed requires maturation (that is, the degree of gelatinization). As for puffing, it is an inevitable result of starch particles breaking and moisture flash. Generally, the degree of puffing is characterized by the material capacity. Therefore, there are two requirements for puffed corn. The degree of ripening and puffing is measured by starch gelatinization and material capacity, respectively. The degree of starch gelatinization is measured by the starch glucosidase method, while the material volume can be measured with a volumetric weight meter. The degree of ripening and swelling are interrelated. A high degree of ripening does not necessarily mean a high degree of swelling, but a high degree of swelling will have a high degree of ripening. For most feed companies, there are no conditions for measuring gelatinization, but the capacity is easy to measure, and the ripening degree reflected by the volume is also relatively accurate. Therefore, weight capacity has become an important indicator for feed companies to evaluate puffed corn at present. Puffed corn flour processing equipment