Walnut, BioAssay(TM) ELISA Kit (Juglans regia)

Walnut (Juglans regia) belongs to the walnut plant family (Juglandaceae). With 15% the fraction of proteins in walnuts is high. Some of these proteins are known for being allergenic, such as rJug r 1 and rJug r 4. Many of them are heat resistant making them stable to different production processes. For this reason walnut represents an important food allergen. For walnut allergic persons hidden walnut allergens in food are a critical problem. Already very low amounts of walnut can cause allergic reactions, which may lead to anaphylactic shock in severe cases. Because of this, walnut allergic persons must strictly avoid the consumption of walnuts or walnut containing food. Cross-contamination, mostly in consequence of the production process, is often noticed. The chocolate production process is a representative example. This explains why in many cases the existence of walnut residues in food cannot be excluded. For this reason sensitive detection systems for walnut residues in foodstuffs are required. The United States Biological Walnut ELISA represents a highly sensitive detection system and is particularly cap-able of the quantification of walnut residues in cookies, cereals, ice cream and chocolate.\n\nIntended Use:\nFor the quantitative determination of walnut in food.\n\nSensitivity: \n0.35ppm\n\nRecovery (spiked samples): ~75-106%\n\nIncubation Time: 60 min\n\nTest Principle:\nThe United States Biological Walnut quantitative test is based on the principle of the enzyme linked immunosorbent assay. An antibody directed against walnut proteins is bound on the surface of a microtiter plate. Walnut containing samples or standards are given into the wells of the microtiter plate. After 20 minutes incubation at room temperature, the wells are washed with diluted washing solution to remove unbound material. A peroxidase conjugated second antibody directed against walnut proteins is given into the wells and after 20 minutes of incubation the plate is washed again. A substrate solution is added and incubated for 20 minutes, resulting in the development of a blue color. The color development is inhibited by the addition of a stop solution, and the color turns yellow. The yellow color is measured photometrically at 450nm. The concentration of walnut is directly proportional to the color intensity of the test sample.\n\nKit Components:\n1. Microtiter plate 1x96 wells each, coated with anti-walnut antibodies.\n2. Standard 0ng/ml 1x1ml, ready to use.\n3. Standard 2ng/ml 1x1ml, ready to use.\n4. Standard 6ng/ml 1x1ml, ready to use.\n5. Standard 20ng/ml 1x1ml, ready to use.\n6. Standard 60ng/ml 1x1ml, ready to use.\n7. Conjugate (anti-walnut-peroxidase): 1x15ml, ready to use.\n8. Substrate Solution (TMB): 1x15ml, ready to use.\n9. Stop Solution (0.5M H2SO4): 1x15ml, ready to use.\n10. Extraction and sample dilution buffer 10x (Tris): 2x120ml. \n11. Washing Solution 10x (PBS + Tween 20): 1x60ml. \nDilute 1+9 with distilled water. If during the cold storage crystals precipitate, the concentrate should be warmed up to 37 degrees C for 15 minutes.\n\nStorage and Stability:\nStore components at 4 degrees C. Stable for 6 months. For maximum recovery of product, centrifuge the original vial prior to removing the cap.

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SPECIFICATIONS

Catalog Number

W0755-01

Size

1Kit

Applications

ELISA

References

1. Doi H, et al. (2008) - Reliable enzyme-linked immunosorbent assay for the determination of walnut proteins in processed foods. J Agric Food Chem, 56(17):7625-30. 2. Wallowitz M, et al. (2006) - Jug r 4, a legumin group food allergen from walnut (Juglans regia Cv. Chandler). J Agric Food Chem, 54(21):8369-15. 3. Niemann L, et al. (2009) - Detection of walnut residues in foods using an enzyme-linked immunosorbent assay. J Food Sci, Published Online 10 Jun 2009. 4. Goetz DW, et al. (2005) - Cross-reactivity among edible nuts: double immunodiffusion, crossed immunoelectrophoresis and human specific IgE serologic surveys. Ann All Asthma Immunol, 95(1):45-52. 5. Roux KH, et al. (2003) - Tree nut allergens. Int Arch Allergy Immunol, 131(4):234-44.