The gluten content of multipurpose flour can be analyzed using a number of different methods, including both instrumental and non-instrumental techniques. One non-instrumental method for determining gluten content is the "Farinograph" test. This test measures the water absorption, mixing time, and stability of the dough to give an indication of the gluten content of the flour.
Another method for gluten analysis in multipurpose flour is the "Elisa" (Enzyme-Linked Immunosorbent Assay) test. This test is a quick, sensitive, and specific method for gluten detection in food products. However, this method required an ELISA kit, an instrument, and specially trained personnel to perform the test.
Here is an example of a test method for gluten analysis in multipurpose flour using the "Zeleny" test, which is a non-instrumental method:
Materials:
Multipurpose flour sample
Distilled water
Graduated cylinder
Stirring rod
Centrifuge
Graduated cylinder
- Glass test tube
Pipette
Procedure:
Take 10 g of multipurpose flour sample and mix it with 90 ml of distilled water in a graduated cylinder using a stirring rod.
Allow the mixture to stand for 2 hours at room temperature.
Centrifuge the mixture at 3000 rpm for 15 minutes.
Carefully decant the supernatant liquid from the centrifuged mixture into a graduated cylinder.
Measure the volume of the supernatant liquid and record it as "V1."
Add 90 ml of distilled water to the centrifuged sediment, mix thoroughly, and centrifuge again at 3000 rpm for 15 minutes.
Decant the supernatant liquid from the centrifuged mixture into a graduated cylinder and measure the volume. Record it as "V2."
Add 90 ml of distilled water to the centrifuged sediment again, mix thoroughly, and centrifuge for the last time at 3000 rpm for 15 minutes.
Decant the supernatant liquid from the centrifuged mixture into a graduated cylinder and measure the volume. Record it as "V3."
Calculate the gluten content of the flour sample using the following formula:
- Gluten content (%) = (V1 + V2 + V3) / 10 x 100
Interpretation of Results:
The gluten content of the multipurpose flour sample is expressed as a percentage of the original 10 g sample. According to the Codex Alimentarius, gluten-free food should contain less than 20mg/kg of gluten. Therefore, if the gluten content of the multipurpose flour sample is less than 2% it can be considered gluten-free.
It's important to note that this test is for the gluten content, for the gluten-free claim, the gluten-free food must be tested for gluten protein by R5 ELISA method.
It's also important to note that this test method may not be suitable for all types of multipurpose flour and the results may vary depending on the specific type of flour and the specific brand.
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