Detailed Explanation of the Processing Method for Liquid Fish Protein Feed
Liquid fish protein feed is made from waste or low-value fish from aquatic product processing, which is minced or ground, then mixed with a certain amount of acid or fermented with microorganisms; through the autolysis produced by the fish's own enzymes, it is liquefied into a slurry product. Because this protein feed has good storage resistance, some people also call it acid-preserved feed.
Lactic acid bacteria fermentation method (molasses fermentation)
Natural lactic acid bacteria fermentation: mince raw fish with no pollution source or disease, add molasses or by-products from sugarcane sugar processing at 15% of their weight, stir evenly, and place into a sealed container for natural anaerobic fermentation. With the massive reproduction of lactic acid bacteria, anaerobic fermentation produces a large amount of lactic acid. Under normal conditions, after 3 days the acidity of the mixture rises rapidly, and the pH value drops to about 4.5. Due to the effect of the acid, the raw fish is liquefied and the protein is partially decomposed, and the growth of spoilage bacteria is inhibited, so the liquid fish protein feed is storage-resistant. The length of fermentation time is related to the ambient temperature. Generally, after 30 days, when the raw fish is completely liquefied and the pH value stabilizes at about 4.5, it can be fed. If sealed well, it can be stored at room temperature for 1 year to 2 years.
The growth and reproduction of lactic acid bacteria require carbohydrate substances, and the added amount is 10%-30%. If there is no molasses, 15%-25% corn flour, @#@245@#@ flour, cassava flour, or 12.5% cassava flour plus 12% papaya flour can be used instead.
Adding lactic acid bacteria preparation for fermentation: Under natural conditions, the number of lactic acid bacteria in raw fish, molasses, air, utensils, and containers is limited, and there are often undesirable strains, so the quality of liquid fish protein is sometimes unstable. To make lactic acid bacteria reproduce as quickly as possible, each gram of raw material must contain more than 100,000 lactic acid bacteria. To produce high-quality liquid fish protein feed (especially when starch raw materials are used instead of molasses), lactic acid bacteria need to be added.
Method of using the lactic acid bacteria preparation: take lactic acid bacteria preparation, molasses or sucrose, glucose, etc. at 0.02% of the total amount of the raw fish and molasses mixture, dilute each 100 times, prepare a mixed diluted solution of lactic acid and molasses, place it in a sealed container, culture and activate it at 30°C for 24 hours, then sprinkle it into the fermentation mixture, stir evenly, and carry out sealed anaerobic fermentation.
Acid addition method
Grind fish and fish waste with a hammer mill, add an appropriate amount of acid, stir evenly, place into an acid-resistant container for liquefaction and storage, and stir regularly. The liquefaction time needs seven to eight days. The acid added can be an inorganic acid, such as sulfuric acid or hydrochloric acid; or an organic acid, such as formic acid or propionic acid; or a mixture of organic acid and inorganic acid. If sulfuric acid or hydrochloric acid is used and the product pH is 2, a good storage effect can be obtained; if formic acid is used and the product pH is 4-4.5, the storage effect is best. In addition to accelerating liquefaction, formic acid also has a bactericidal effect, is less corrosive to containers, and is convenient to use; it does not need to be neutralized before feeding animals. Therefore, the production of liquid fish protein feed all uses formic acid at a concentration of 85%, with an amount of 3.5% of the weight of the raw fish. In addition, the amount of acid used can be determined according to differences in the type of raw material, freshness, and season. If the raw material has begun to deteriorate or is mainly crustacean raw material (such as shrimp waste), the amount of acid used needs to be appropriately increased, and the required amount of formic acid is 4% of the weight of the raw material. If the fat content in the raw fish is relatively high, the liquefied product is best degreased again. The specific method is: heat the liquefied product to 60°C, use a centrifugal sedimentation machine to centrifuge off the oil, and then degreased liquid fish protein feed can be obtained. Store the finished product in an acid-resistant covered container, and it can be stored at room temperature for 1 year to 2 years.