Electrophoretic identification of garlic and garlic products

We developed a rapid and simple method for identifying garlic and garlic products using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with silver staining. Samples were homogenized with 1% SDS or 6M urea and centrifuged. Supernatant containing garlic proteins was mixed with the same volume of loading buffer containing SDS and mercaptoethanol, heated in boiling water for 2 min, and applied to the wells of a ready-to-use polyacrylamide gradient gel (4-20%). Electrophoresis was performed 20 mA constant current for 2 h. The gel was stained with a silver staining kit and dried. Protein patterns of garlic and garlic products are different from those of other Allium plants such as onion, rakkyo, and caucas. The method was used to analyze samples of spice and garlic clove products. Absence of protein bands in garlic extract products suggests the products may contain less proteins and/or denatured proteins.