Soy ELISA Kit (Soybean Trypsin Inhibitors, STI)

Full Name: Soy ELISA Kit (Soybean Trypsin Inhibitors, STI)
Sample Type: Food (Instant Soups, Chocolate, Sausage, Ice Cream, Cereals, Cookies)
Sensitivity: 16.0 ppb


Soy (also called Glycine max) and more commonly known as soybean is a member of the legumes that are native to East Asia. These beans are rich in dietary minerals, B vitamins and phytic acid. Soy vegetable oil is often used in many industrial and food applications. The fraction of proteins in soy beans is relatively high (approx. 40%). It is these proteins which lead to allergic reactions (for example: Glycinin, Gly m1, Gly m4 and Kunitz-TrypsinInhibitor) in about 2% of the population. Approx. 40% of soy is protein, which contains a high concentration of allergenic proteins that might trigger allergy reactions in some people. Soy protein isolate may possibly be able to cause an allergic reaction if it’s cross-contaminated with the ground soy.

Majority of problems tend to be found in younger children and the initial diagnosis of soy allergy tends to be based on the symptoms that have been previously reported by parents, as a result blood test or skin test for the allergy. The diagnosis of soy allergy requires an elimination diet and then reintroduction of the food product in question with repeated blood tests and skin tests. Skin test is usually positive within hours of exposure to soy protein whereas blood test may take a few days to show positive results.


Soy ELISA kit is intended for measuring quantitative levels of soybean trypsin inhibitors (STI) present in soy residues in foods (such as chocolate, ice cream, cookies, cereals, sausage and instant soups). This assay has a minimum analytical sensitivity limit of 16.0 ppb.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • Microtiter Plate: Coated with anti-soy antibodies.
  • STI Standards 1-5: Concentration 0, 40, 100, 1000 ppb.
  • Conjugate.
  • Substrate Solution (TMB).
  • Stop Solution (0.5 M H2SO4).
  • Extraction and sample dilution buffer (Tris)(10x).
  • Washing Solution (PBS + Tween 20)(10x Concentrate).
  • Instruction Manual.


The minimum detection sensitivity level of soybean trypsin inhibitors (STI) using current soy ELISA kit was 16.0 ppb. The standard range for this assay is 40.0 – 1,000.0 ppb.


– Sensitivity: Limit of detection, LOD (16.2ppb), Limit of quantification, LOQ (40.0ppb)
– Intra-Assay Precision: 6 – 8%
– Inter-Assay Precision: 5 – 13%
– Inter-Lot Precision: 3 – 11%
– Linearity: 81 – 114%
– Specificity (Cross Reactivity): No cross reaction was detected for the following: Adzuki bean, Celery, Crab (cooked), Isinglass, Peanut, Sesame, Almond, Cherry, Crab (raw), Kidney bean, Pecan, Shrimp (cooked), Barley, Chervil, Cress, Kiwi, Pepper, Shrimp (raw), Bean (white), Chestnut, Cumin, Lamb, Pine seed, Sunflower seeds, Beef, Chia, Duck, Lentil, Pistachio, Tomato, Bovine gelatine, Chicken, Egg, Lupin, Plum, Turkey, Brazil nut, Chickpea, Ewe’s milk, Macadamia, Poppy seed, Walnut, Buckwheat, Chili, Fenugreek, Mustard, Pork, Wheat, Caraway, Cocoa, Fish gelatine, Nutmeg, Potato, Carob gum, Coconut, Gliadin, Oats, Pumpkin seed, Carrot, Cod, Goat’s milk, Onion, Rice, Cashew, Corn, Guar gum, Paprika, Rye, Cayenne, Cow’s milk, Hazelnut, Pea, Saccharose.
– Recovery: Cookies (106%), Cereals (100%), Sausage (96%), Instant soup (90%), Ice cream, Chocolate (77%).


  1. Soy provides modest benefits on endothelial function without affecting inflammatory biomarkers in adults at cardiometabolic risk. Mol Nutr Food Res. (2015) 59 (2): 323-33. Reverri E.J., et al.
  2. Allergenicity of major component proteins of soybean determined by enzyme-linked immunosorbent assay (ELISA) and immunoblotting in children with atopic dermatitis and positive soychallenges. J Allergy Clin Immunol. (1988) 81 (6): 1135-42. Burks A.W. Jr, et al.
  3. Determination of protein levels in soy and peanut oils by colorimetric assay and ELISA. J AOAC Int. (2010) 93 (1): 213-20. Jablonski J.E., et al.
  4. Immunoreactivity, sensory and physicochemical properties of fermented soy protein isolate. Food Chem. (2016) 205: 229-38. Meinlschmidt P., et al.
  5. ELISA analysis of soybean trypsin inhibitors in processed foods. Adv Exp Med Biol. (1991) 289: 321-37. Brandon D.L., et al.


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