The superiority and inferiority of compound feed products largely depend on the formula and the level of manufacturing, but the importance of raw material quality for feed quality is self-evident. Therefore, when the feed factory purchases raw materials, it should conduct quality inspection according to national and industry standards. The chemical analysis of raw materials is a must, and it is also the most reliable. The result of the laboratory analysis is the best description of the quality of the raw materials. However, in the actual production process, sensory determination (including vision, taste, smell, touch, etc.) and simple detection (including screening method, bulk density method, washout elimination method, specific gravity method, microscopic examination method, and some simple chemical analysis methods, etc. ) is the preferred method of identification. It is the first step in the identification of raw material quality. Under normal circumstances, if the raw material does not pass the sensory comprehensive judgment and simple test, it will be regarded as unqualified and there is no need for chemical analysis. In addition, because chemical testing often takes a long time, sometimes due to production needs, raw materials that are considered qualified by sensory evaluation and simple testing will enter emergency release use procedures to address production needs (in addition to sample retention for chemical testing). The results of sensory judgments and simple tests are particularly important. This article presents a quick and easy identification method for the quality of commonly used feed ingredients.
1? Rapid identification of fish meal quality?
Fishmeal is the most commonly used high quality animal protein source for compound feeds. It contains relatively complete essential amino acids for fish and shrimps. It has good palatability and rich vitamin content. It is used in aquafeeds, especially in high-grade aquatic feeds. Big. Due to its large amount and high price, adulteration is particularly serious.
1.1? Sensory discrimination
1.1.1 Shape High-quality fishmeal is powdered, containing scales, fish bones, etc. Visible fish silk, should not have excessive heat particles and debris, should not have agglomeration and insect pests.
1.1.2? Color Momorton fishmeal is light yellow or light brown; sardine powder, fish meal is yellow-brown, it is also known as "yellow fish meal"; North Ocean fish meal, salmon meal, and salmon meal are pale yellow or white, also known as "White fishmeal"; high-quality fishmeal is shiny, such as overheating or high fat content, the color deepens.
1.1.3 Flavors High-quality fishmeal has a rich roasted fish flavor, sweet aroma and slightly fishy oily flavor, and should not have rancidity, ammonia odor and overheated burnt flavor. The salt content of high-quality fishmeal is about 2%. If the salt content is too high, the entrance will have a bitter and salty taste.
1.1.4? Lumps High-quality fishmeal has no lumps, and has a loose feel, no lumps, and no stickiness when squeezed by hand. It can be loosened after being released.
1.1.5 Other issues that should be highlighted: adulteration, mildew, insect pests, browning, coking (blackening, burning, no color), fatty degeneration (with ammonia), fat oxidation (greasy, deep) Brown, odor, and whether or not there is fever.
1.2? Physical discrimination?
1.2.1 volumetric weight method?
Any substance has a certain volume, and if it is doped, the volume will change. The volume of normal high quality fishmeal is 450-660g/l.
1.2.2? Heating method Using aluminum foil wrapped with a fire to burn, the taste produced by it to determine whether incorporation of leather powder, feather powder, tire powder, etc.; use pan, if ammonia smell, then doped with urea; The electric stove burns, and if there is aroma of dry fried grains, it is mixed with vegetable substances.
1.2.3 Gravity Gravity Method Standard gravity solution is used for the separation of specific gravity to separate organic matter and inorganic matter. If the content of inorganic matter is large, the quality is poor. In addition, the separated organic and inorganic materials can be microscopically examined.
1.2.4 Water Soluble Method Add a small amount of fishmeal and about 10 times of water to the beaker, and let stand for several minutes after stirring. After stirring gently, observe that there are no floating objects on the high-quality fishmeal, no precipitate underneath, and the water is more transparent; however, the inferior fishmeal is the opposite. Under normal circumstances, floating objects are feathers or plant matter, and sediments are sand and other minerals.
1.2.5? Experience Method Fresh fish meal is rich in viscoelasticity, and 75% fish meal + 25% a starch plus 1.5 times water is used to make the dough. The visco-elasticity is superior.
1.2.6? Screening Method A set of sieves with different meshes are used to screen and check the proportion, composition, inclusions, etc. of various (mesh) screen elements.
1.2.7 Mirror (magnifying glass, microscope) General method of microscopic examination of fishmeal: The fish muscles (blocks) are visible in high quality fishmeal, and the more the better, there are jade white fish bones, but not too much; visible concentric ring Thin and transparent scales; visible ball-shaped fish eyeballs. Microscopic examination of adulterants in fishmeal:
(1) Rice hulls (rice bran) may be mixed if there are rectangular lumps with regular grid patterns and rules.
(2) If there are small pieces of thick, multi-layer, concave shell, cottonseed cake may be added.
(3) If there is a remaining light yellow, curved surface feathers, plumes, feathers, it may be mixed with hydrolyzed feather powder.
(4) If you see red balls or bright red balls, you may have blood meal.
(5) If there is a mica flake shell, it may be mixed with shrimp shell powder.
(6) Shell powder may be incorporated if it is square or irregular, off-white, opaque or translucent.
(7) Crab shell powder may be added if there is a porous, orange-red, cloth honeycomb, or small cap-shaped crab shell.
(8) If white silk or sawdust is seen, leather powder may be mixed.
1.3? Chemical discrimination
1.3.1? Detection of adulterated plants
(1) Take 1 ~ 2g of fishmeal in a 50ml beaker, add 10ml of water, heat for 5min, cool, add 2 drops of iodine-potassium iodide solution. Observe that if the solution turns blue or dark blue immediately, it indicates that the mixture contains phytoplasma. .
(2) Take a sample 1g into a watch glass and soak it in a solution of phloroglucinol for 5 to 10 minutes. Add 2 to 3 drops of concentrated hydrochloric acid dropwise. Observe that the sample is dark red, indicating that it is adulterated with lignin.
1.3.2? Incorporation of urea detection Take 20g of sample in a flask, add 10g of raw soybeans and the appropriate amount of water, add and heat for 15-20min, remove, if smell the ammonia odor, there is urea.
1.3.3 Doping with calcium carbonate (limestone), shell powder, shrimp crab shell powder Add a small amount of fish meal in a beaker, add appropriate amount of diluted hydrochloric acid or white vinegar, if there are a lot of bubbles and produce a buzzing sound, prove that the above substances At least one of them (the order of the amount of generated bubbles is: calcium carbonate> shell powder> shrimp crab shell powder> meat bone meal> fish meal).
1.3.4 Difference between Plant Fiber and Fish Muscle Fiber Samples were placed in a beaker and an appropriate amount of zinc chloride solution was added, stirred, and allowed to stand for 10 minutes. Observe the change of color: the color of the plant fiber sample is deepened, while the color of the fish muscle fiber sample remains unchanged.
2. Quick identification of soybean meal quality Soybean meal is the most commonly used vegetable protein source for compound feeds, and its consumption is generally larger, so it has a greater impact on finished feed products.
2.1? Sensory discrimination
2.1.1 Shape Good quality pure pods are irregularly shaped or powdery and occasionally have a small amount of lumps. However, after incorporating zeolite powder, corn and other impurities, the color is light, the color is not uniform, and the agglomerates are numerous, and white powdery substances are seen. In addition, if the shell is too much, the quality is poor.
2.1.2 Color High quality pods are pale yellow-brown to light brown with uniform color. If there is a dopant, there is a significant color difference. If the color is whitish, the uremic enzyme is too high, and if the color is red, the uremic enzyme is low. The pale yellow soybean meal is due to insufficient heating. Dark brown or dark yellow soybean meal is due to overheating and poor quality.
2.1.3 Flavors High-quality pods have a roasted bean flavor and should not have spoilage, mildew or coke, raw bean curd, and bean odor (newly produced pods have pod flavor). The bean pods that had been incorporated with the sundries smelled slightly more beans, and those with the largest amount of beans had no beans. When the heating is excessive, there is a burning smell; if the heating is insufficient, the smell of raw soybeans is present in the mouth.
2.1.4? Empirical method The pods in the safe moisture are good when they are caught by hand, and the pods that have too much moisture have a lag.
2.2? Physical discrimination
2.2.1 Volumetric weight method The volume of normal pure soybean meal is 594-610g/l (flakes 490-640g/l, powder 300-370g/l). If the measured bulk density of the sample is compared with it, if it exceeds more, it indicates that the soybean meal is adulterated.
2.2.2? Water-soluble method Take a small amount of sample, add appropriate amount of water, stir and let stand for a few minutes. The mud makes the water cloudy, sand and other minerals sink to the bottom, and the wheat skin floats on the water.
2.2.3? Empirical Methods Most of the adulterants have the common characteristics of fine particle size, large specific gravity, and inexpensiveness. If adulterants are present in the soybean meal, the packaging volume will usually be smaller and the weight will increase. The package volume can be increased. The size of the raw material to determine whether the normal; smash, fake soybean meal large dust, into the glass, dust will adhere to the bottle wall, and pure soybean meal does not have this phenomenon.
2.2.4 Screening method Observe the composition and type of screened material in each layer after sieving.
2.2.5? Microscope microscopy The appearance of the inside and outside surfaces of the shell during the microscopic examination of the soybean pods is smooth, shiny, and has the impression of being needled.
When the soybean meal contains adulterants such as corn, wheat bran, cotton cakes, shell powder, peanut shells, etc.
(1) The corn kernels are smooth, translucent, and resemble nail lines and stripes. This is a distinctive feature of corn kernels that distinguish them from soybean kernels. In addition, the color of corn kernels is deeper than that of soybean kernels and is orange-red.
(2) There are fine wrinkles on the outer surface of the wheat bran cereal and some have wheat hair.
(3) The thickness of rapeseed hulls in cottonseed cakes is thicker, and the bands with brown or white cross-sections are ladder-shaped, with cotton threads on some surfaces.
(4) Shell powder granules are square or irregular and have a grayish-white color.
(5) Peanut shells are somewhat striated or streak-like protrusions and are also serrated.
(6) Refer to the microscopic examination of fish meal adulteration.
2.3? Chemical discrimination If soybean meal is mixed with urea, it can be detected by detecting urea in fish meal.
3. Rapid identification of corn quality Maize is the main plant energy source for compound feeds. It has a large amount of feed in the livestock feed and its starch structure is very good. Using it to produce extruded feed can achieve better results.
3.1? Sensory discrimination
The 3.1.1 shape high-quality corn grain is uniform and uniform, and the high-moisture corn grain shape has a large swelling and strong brilliance.
3.1.2? The color yellow corn is light yellow to golden yellow, and the concave corn is light in color.
3.1.3? The taste of corn is sweet, and when it is crushed, it has a raw grain taste but no sourness and musty taste.
3.1.4? Tactile discrimination?
The corn kernels were pressed, rubbed, and pinched by hand to feel their hardness and hardness. By biting teeth, the level of moisture was judged according to the degree of hardness, the degree of crushing, the feeling of teeth, and the level of sound produced. In the safe state of moisture, the umbilical portion of the corn is shrunk, conspicuously concave, wrinkled, and the teeth are crushed and have a crisp sound. To use the nail file is more laborious, holding the hand in a thorny hand.
3.2? Physical discrimination
3.2.1 volume weight method
The normal corn volume weight is: 690-750g/l.
3.2.2? Screening method The composition and type of the sieved material after screening were observed.
3.2.3? Experience method?
(1) Crushing method: Once the corn is broken, it loses its natural protective effect and it is extremely easy to degenerate.
(2) Aura of deterioration: The first sign of moldy corn is that the axis turns black, then the embryo changes color, and finally it becomes charred.
3.2.4 Microscopic examination Corn kernels are smooth, translucent, and resemble nail lines and stripes. This is a distinctive feature of corn kernels that distinguish them from soybean kernels. In addition, the color of kernels is deeper than that of soybean kernels. .
3.3? Chemical discrimination When suspected corn flour mixed with lime, you can use a small amount of dilute hydrochloric acid, such as the occurrence of foam is mixed with quicklime or shellfish and other minerals.
4) Peanut meal, rapeseed meal, cottonseed meal, sub-powder, wheat bran, rice bran quality discrimination Peanut meal, rapeseed meal, cottonseed meal, sub-powder, wheat bran, rice bran and other raw materials because of the price is not high, the general artificial doping There are fewer false phenomena, mainly paying attention to their own quality problems such as purity, freshness and moisture content.
> The feed value of peanut meal is second only to soybean meal. Protein and energy are high, but the composition and proportion of amino acids are not appropriate. Normal peanut pods are fresh yellow-brown or light brown, with the smell of cooked peanuts, good palatability. Water should be controlled below 12%.
Both rapeseed meal and cottonseed meal are cheaper, high-protein raw materials, but due to their inherent toxicity, the amount is controlled. The normal rapeseed meal is yellow-brown, reddish-brown, gray-black shards, crushed or coarse powder, and has round, reddish brown, grayish black or deep yellow rapeseed, crispy and fragile, dull, and vegetable Seed flavor, bitter taste. Generally the redder the appearance, the lower the protein content. Water should be controlled below 12%.
Cottonseed meal is usually light brown, dark brown or blackish, powdery or small, showing cottonseeds. Seen under the microscope are translucent, white shiny fibers on the cottonseed shell fragments. The main concern is the content of lint, and the more the content, the worse the quality.
Sub-powder is a by-product of wheat flour milling. It is light white to brown fine powder, and its moisture content should not exceed 13%. Some aquafeeds require secondary granules to have a certain degree of gluten, and additional gluten testing is required. ?
Wheat bran is rich in vitamins. The normal wheat bran should be light yellow to reddish gray. The color is fresh and consistent, finely crumb-like, and the bran should not be too large, otherwise the quality will decline. It has the unique odor of pulverized wheat, no fermentation, mildew, agglomerate, odor. Similar to rice bran, it has a loose structure, small bulk density, easy to absorb moisture, and poor fluidity. Crude fat is lower than rice bran, so the shelf life can be longer than rice bran, but should not exceed one month. Easy to heat, worms, metamorphism under high temperature and humidity, storage moisture should be controlled below 13%. ?
Rice bran is a light yellow or brown powder or coarse powder, slightly oily, containing a small amount of broken rice, coarse glutinous rice, and unique flavor of rice bran, which should not have a bad smell. No insects and agglomeration, rough can not be too much, or poor quality. The volume is 220-320g/l. Because of its high fat (12% to 15%), it is easily rancid, easy to oxidize, easy to heat and mildew, can not be stored for too long. And strong water absorption, it should pay attention to storage in a dry place, humidity can not be too large (70% to 80% is appropriate) place, the storage period is limited to 20d. Water should be controlled below 13%.
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