I'm planning to use Benidict solution to do research on the amount of glucose in candy, but I'm not sure how to calculate the specific amount of sugar from the Benedict solution. Is there a way to do it? Or is there a better way to calculate the amount of glucose in candies?
Lydia, as you will obtain a precipitate, it's hard to do quantitative measurements with Benedict's solution. Plus, the test is not specific for glucose, you'll also have it react with saccharose (common sugar) and other reducing components.
The easiest and possibly cheapest way might be extracting the candies with PBS buffer, clearing the solution by centrifugation or simply letting it sit for some time and determine glucose concentration using a glucometer and disposable test strips, as they are used for blood sugar measurements by diabetes patients. Prepare a standard curve of glucose in buffer for calibration. Measurement range is in the range of 0.5 to 4g/L.
Wolfgang Schechinger thank you! I'm not sure about the 'extracting candies with PBS buffer' and the 'preparing a standard curve' part. Can you explain it more? Thank you!
Hi Lydia,
Extracting means adding some buffer (e.g. 10ml buffer per gram of candy) and stir/mix/agitate to get the material crushed and, if possible, dissolved. Basically, water would do, but the glucose test strips later require defined pH conditions (physiological), therefore the buffer. PBS (Phosphate Buffered Saline) is suitable and should be quite easy to obtain (ask e.g. in a pharmacy or any biomedical research lab). Depending on the meter's reading, you might need less buffer or dilute further to be in the range, so some preliminary experiments might be required.
Standard curve means you'll have to prepare glucose solutions of known content (e.g. 0, 500, 1000, 1500, 2000, 3000, 4000, 5000 mg/L, at least 3 of them) so you may draw a curve that relates the meter's readings to the real content of the solution. As you don't use human blood (which is the designated sample material for the test strips), you should do this at least once, in order to validate your test, as you're operating outside the specs of the glucometer (e.g. if you intend to publish the results). If it's rather a demo experiment in a classroom, you might skip that step, as you then might be rather interested in approximate values and relative content.
For in depth discussion, please send me a personal message.
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