Detailed Explanation of Liquid Fish Protein Feed Processing Methods
Liquid fish protein feed is made from waste or low-value fish from aquatic product processing. After being minced or ground, a certain amount of acid or microorganisms is added for fermentation, and the fish's own enzymes produce autolysis, liquefying it into a slurry product. Because this protein feed has good storage stability, some 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 sugarcane sugar-processing byproducts at a ratio of 15% of its weight, stir evenly, and place into a sealed container for natural anaerobic fermentation. As lactic acid bacteria multiply in large numbers, 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 drops to about 4.5. Due to the action of the acid, the raw fish liquefies, the protein partially decomposes, and the growth of spoilage bacteria is inhibited, so the liquid fish protein feed is storage-stable. 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 stabilizes at about 4.5, it can be fed. If well sealed, it can be stored at room temperature for 1 to 2 years.
The growth and reproduction of lactic acid bacteria require carbohydrates, with an addition amount of 10% to 30%. If there is no molasses, 15% to 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 many are undesirable strains, so the quality of liquid fish protein is sometimes unstable. To make lactic acid bacteria multiply 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 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 into a sealed container, culture and activate it for 24 hours under the condition of 300 degrees, 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 requires 7 to 8 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, a product pH of 2 can achieve a better storage effect; if formic acid is used, the storage effect is best when the product pH is 4 to 4.5. 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, in producing liquid fish protein feed, formic acid at a concentration of 85% is used, 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 the type of raw material, freshness, and season. If the raw material has begun to spoil or is mainly crustacean raw material (such as shrimp waste), the amount of acid used needs to be appropriately increased, and the required formic acid amount is 4% of the raw material weight. If the raw fish has a high fat content, the liquefied product is best degreased. The specific method is: heat the liquefied product to 60°C, use a centrifugal precipitator 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 to 2 years.