Positive result for mucic acid test?
When galactose is oxidized by nitric acid, insoluble mucic acid is formed. A positive result is the formation of a precipitate. Lactose is a dimer of glucose and galactose. The nitric acid will hydrolyze the dimer and so lactose will also give a positive result.
Would sucrose test positive for glucose?
It wouldn't. That is what is used as artificial sweeteners and that is why people use those to substitute for monosaccharides, because your tongue, much like the glucose test strips, won't recognize the sucrose because it doesn't have the right enzyme to digest it, but the food or drink or whatever will still taste sweet.
Maltose is a dissacharide.what positive tests for maltoses? and what color could be observed?
maltose is actually a reducing sugar so a test for reducing sugar could be carried out. 1)Add 2cm3 of Benedict's solution to 2cm3 of maltose solution in a test tube and shake. 2)Leave the test tube in a beaker of boiling water for 5 minutes. Observations: 1)blue solution to green mixture- conclude that there are traces of reducing sugar 2)blue solution to yellow or orange precipitate- conclude that there are moderate amt of reducing sugar 3)blue solution to brick red precipitate- conclude that there are large amt of reducing sugar
Why is the result of Benedict's test for sucrose different then lactose?
Its because sucrose is a non-reducing sugar. each mono-saccharid has a reducing end (thats normally C1 in Aldoses and C2 in ketoses) sucrose is made by formation of a covalent bond between C1 of a Glucose and C2 of a fructose, that both are reducing ends of the sugars, so in sucrose there isn't any reducing end, so the benedict's test would be negative. but in lactose C1 of the Galactose will make a covalent bond with C4 of the glucose, so there is still one reducing end (C1 of glucose), so the Benedict's test would be positive. In benedict's test you will reduce the Cu2+ to Cu, so you need a reducing end to get a positive result.
Test for to show that lactose is a reducing sugar?
Describe how you would use a biochemical test to show that lactose is a reducing sugar. It's a 2-mark question. What are the key words/points? I don't know how to explain the answer. Help!
What is the cause of false positive phosphatase test for screening quality of milk?
The Alkaline Phosphatase (ALP) test is used to determine whether milk has been well pasteurized or not. There may be false positive results in the following cases;If the milk samples were held at above 4 degrees C from the time of collection until analysis.If the standard colour discs aren’t used or the reading was taken under non-approved sources of illumination.It’s also important to note that the ALP test is not to be carried out on sour milk or milk that’s preserved with chemicals.
What is the chemical test to distinguish between glucose and maltose?
Glucose and maltose are related. Glucose is a monosaccharide (one sugar unit) and maltose is a disaccharide (two sugar units) and is comprised of two glucose units. Both glucose and maltose are reducing sugars - reducing sugars meaning that they can reduce either Cu(II) or Ag(I) under certain conditions.There are a variety of chemical tests that can be used to identify if a sugar is a reducing sugar or if it is a mono vs disaccharide. To determine if a sugar is a reducing one, Fehling’s or Tollen’s test can be used. The Barfoed test can be used to determine if the sugar is a mono or disaccharide and gives a positive result (change for blue to red, Cu2O formation). Only monosaccharides give a positive test so this could be used to distinguish glucose from maltose.One other test that would be useful is Glucose Oxidase test, gives a brown color with glucose, no reaction with maltose.