Question 10. (8 points): a. Raffinose (below) is a sugar found in beans. It can

Question

Question 10. (8 points): a. Raffinose (below) is a sugar found in beans. It can be hydrolyzed in the presence of a-galactosidases. Humans do not produce a- galactosidases. Therefore gut bacteria metabolize raffinose, resulting in flatulence (gas). Is raffinose a reducing or non-reducing sugar? - b. The product Beano claims to contain. -galactosidase. Briefly describe how you would design a test to determine if Beano contains the enzyme -galactosidase. How would you set up the experiment and using which reagents/chemicals? What test could you use to determine if raffinose was hydrolyzed? What would you expect to observe during the test?

Explanation / Answer

Raffinose is a non reducing sugar(trisaccharide). A sugar is reducing only if it has a free anomeric carbon. In raffinose ask the anomeric carbon atoms as bonded, hence making it non reducing sugar.

Raffinose reacts with alpha galactosidase to produce gases like carbon dioxide, methane, hydrogen etc. The optimum conditions are a slightly acidic pH (5.5) and a temperature of 50 degree Celsius. Hence, you can set up a simple experimental setup by dissolving raffinose in slightly acidic solution and then adding beano until in excess.

The observation includes effervescence due to release of gases mentioned above.

Hydrolysis of raffinose yield D galactose and sucrose. Galactose being reducing sugar, will answer Fehling test or Tollen test. Raffinose doesn't answer these tests, but products will. Hence, just use products for Fehling or Tollen test and price that the products are reducing which in turn proves that raffinose has hydrolysed.

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