1. Protease inhibitor (Trypsin inhibitor)
①. The two types are Kunitz (accounting for 60%, large molecular substances, mainly inhibiting trypsin), and Bowman-Birk (accounting for 40%, small molecular substances, simultaneously inhibiting trypsin and chymotrypsin).
② Kunitz inhibitor is sensitive to heat, but Bowman-Birk inhibitor is stable to heat and needs to be heated at 150°C to be inactivated.
③ The level of protease inhibitors contained in common soybean meal is 2-6mg/g.
④ Mammals have stronger tolerance to soybean protease inhibitor than fish, and the level of soybean protease inhibitor that fish can tolerate is 5mg/g.
① Definition of soybean antigenic protein: some macromolecular proteins or glycoproteins in soybean and its products that can cause allergic reactions in humans or livestock.
② Types of soybean antigenic protein:
At present, there are 32 kinds of soybean antigenic proteins confirmed, glycinin (glycinin), β-conglycinin (β-conglycinin), soybean vacuolar protein, soybean hydrophobin, soybean shell protein, soybean inhibitor protein, trypsin inhibitor wait.
Glycinin is 11S globulin, which is the main storage protein in soybean, accounting for 19.5%-23.1% of the total protein of soybean seeds and 40% of the total globulin. β-conglycinin is 7S globulin, which is also one of the main storage proteins of soybean, accounting for 10.0%-12.7% of the total protein of soybean seeds and 30% of the total globulin. β-conglycinin is more stable to proteolytic enzymes, so β-conglycinin activity can be used to evaluate the quality of soybean meal. Piglets eating soybean meal containing antigens can lead to villi atrophy, decreased protein digestion and absorption rate, immune dysfunction, and reduced growth performance, etc. Phenomenon. Enzyme treatment and fermentation can degrade and inactivate the antigenic protein.
①, such as stachyose (stachyose), raffinose (raffinose), etc., accounting for 4%-6% of soybean meal dry matter, soluble in water.
② There is no galactosidase (α-1,6-galactosidase) in animals, so stachyose and raffinose cannot be digested.
③. The non-digestible oligosaccharides are fermented and utilized by anaerobic microorganisms in the back part of the intestinal tract, resulting in accelerated reproduction and disruption of the intestinal microbial balance, which can eventually lead to diarrhea in piglets. However, pigs with a body weight greater than 20kg have no such negative effects, and they can use the fatty acids produced by fermentation for energy.
④. It is soluble in ethanol, and the concentrated soy bean white produced by the alcohol-soluble method hardly contains oligosaccharides.
① Pigs cannot synthesize plant enzymes by themselves, so they cannot use phosphorus in phytic acid.
② The utilization rate of phosphorus in soybean meal by pigs is about 40%, and the utilization rate can be increased to 50-70% after adding exogenous phytase.
③ Heat treatment and fermentation can reduce the level of phytic acid.
①, as a glycoprotein, can lead to red blood cell agglutination.
② Heat treatment can inactivate lectins.
6. Goitrogens: cause thyroid enlargement
①, glycosides, bitter taste, can lead to lysis of red blood cells.
②. It can be completely dissolved in water, and any aqueous solvent can remove saponin.
8 Estrogens (Soy Isoflavones, Isoflavonids): Enlarge reproductive tract
9 Cyanogens: Poisoning
10 Urease (urease): It can decompose nitrogen-containing compounds into ammonia, reduce the utilization rate of protein and non-protein nitrogen, and produce a large amount of ammonia gas at the same time, which can cause poisoning.