Talking about the production and processing of fishmeal
Time：2017/7/20 19:23:22 Clicks：1551
Fish meal is an important animal protein feed, and it is a very popular product in international aquatic products. In recent years, fishmeal production in China has developed rapidly, but the quality is quite different. There are many factors affecting the quality of fish meal, and the production and processing is an important aspect. The production methods of fishmeal are mainly divided into two parts, dry method and wet process, in which dry process is divided into direct drying method and dry pressing method, and wet method is divided into wet pressing method, centrifugal method, extraction method and hydrolysis method.
1 dry processing technology
1.1 direct drying method
This method is characteristic of equipment investment cost is low, and the raw materials of water-soluble components basically all stored in the finished meal. This process not only consume a lot of fuel, and long time high temperature drying, resulting in increasing the extent of lipid oxidation and protein digestion rate also decreased, because without the press, the fat content of fish meal will rise dramatically after drying, affect the quality of fish meal. The dried material is made into fish meal after being crushed and sieved, and the factory can be manufactured before weighing, packing and sampling.
1.2 dry pressing method
This process basically retains the nutrients in the raw material, but because the drying time is longer, can lead to oxidation of raw fish oil, protein decomposition, produce amine and ammonia has special odor and sulfides, affect the quality of fish meal. In order to improve the compression effect, the coarse meal is preheated to 100 degrees, to reduce oil viscosity, increase the rate of oil, and then transferred to the screw press press. As the steam dried fishmeal content has been reduced to about 10%, so at this time, the liquid is squeezed out of fish oil, fish oil can be obtained by refining the finished oil, pressed cake by crushing, sieving, weighing and packaging into finished products.
2 wet processing technology
2.1 wet pressing method
Wet pressing process has low production cost and good product quality advantages, is the use of a more general method. The method is characterized in that the raw material is boiled first, and most of the oil and water are separated and dried by a press, and the quality of the fish meal and the fish oil obtained are better. However, the loss of nutritional value of fish meal is greater, because many useful ingredients in the raw materials, especially water-soluble proteins, free amino acids, B vitamins and minerals, are partially dissolved in aqueous solution.
The characteristics of centrifugation is the largest processing all kinds of raw materials, even for some fresh raw materials with pressing method can not be separated from fish oil, it can also be separated, and the oil content of products is low. The equipment covers a small area. The centrifugal process is similar to the wet press process. Its prominent features: the use of horizontal centrifuges instead of press machines to separate solids, water and oil; instead of steam boilers with hot stoves. After cooking raw materials into slurry, the separation chamber through a hollow tube centrifuge rotating shaft input, by centrifugal pulp is separated into solid and liquid oil and the three part, then, the solid phase was sent to dry, oil refining equipment into further refining, and the liquid phase still contains a part of crude oil and residue. Therefore, the liquid phase separation and further input vertical centrifuge, according to the different relative density, the liquid phase input is divided into coarse slag, oil and juice of three parts, they are basically the same with the recycling of wet pressing method.
2.3 extraction method
Extraction method can make the oil content in fish meal is below 1%, while pressing and centrifugation is not up to the standard. The extraction method is completely skimmed and has high yield of fish oil, but the organic solvent can dissolve a large amount of pigment and make the oil darker. Fish meal is more complete, low fat content, good quality and easy to store for a long time. It is worth noting that, due to flammable organic solvents, even in the air explosion, so in the extraction workshop must adopt explosion-proof and fire prevention measures, strictly prohibited fire into the workshop. Compared with the press method, the process equipment is more complicated, the technical condition is high, and the production cost is high. In addition to consuming fish meal, it is not common to use the extraction method to produce feed fish meal.
2.4 hydrolysis method
By hydrolysis production of is actually the product of protein hydrolysate, the shape of the product is powder, also can make the liquid. The hydrolysis products can completely preserve the original composition of the raw material, but also can make the protein molecules through appropriate hydrolysis, thereby greatly improving the rate of digestion and absorption, so this type of products has been in animal feed, nutritional supplements, bacterial culture, microbial fermentation and functional protein has been applied widely.
In recent years, China has occurred and the use of poor quality fishmeal animal poisoning death phenomenon. So, the quality of fishmeal has attracted great attention, which requires the meal to maintain freshness of the finished meal must be well preserved, but also requirements of fishmeal production technology to further improve and enhance, but at the same time, we must crack down on fake fake fish behavior.