Food Analysis - Determination of Sucrose & Monosaccharide Content Cereal

Question 1

Dialysis principles

Answer 1

The process of separating molecules in solution by the difference in their rates of diffusion through a semipermeable membrane, such as dialysis tubing

Due to the pore size of the membrane, large molecules in the sample cannot pass through the membrane, thereby restricting their diffusion from the sample chamber. By contrast, small molecules will freely diffuse across the membrane and obtain equilibrium across the entire solution volume, thereby changing the overall concentration of these molecules in the sample and dialysate

Question 2

empirical formula carbohydrates

Answer 2

Cm(H2O)n

Question 3

Acid hydrolysis breakfdown into reducing sugars

Answer 3

D+Sucrose + H2O -> D+Glucose + D-Fructose

Question 4

In the first step;

Answer 4

cereals are dialysed against distilled water to give samples containing low molecular weight sugars - free from starch and other polysaccharides

Question 5

How many aliquots of dialysed cereal solution?

Answer 5

four

Question 6

How many are acid hydrolysed?

Answer 6

2

Question 7

Acid hydrolysis

Answer 7

which a protic acid is used to catalyze the cleavage of a chemical bond via a nucleophilic substitution reaction, with the addition of the elements of water (H2O)

Question 8

Protic Acids

Answer 8

those acids that are able to donate one proton per molecule during the process of dissociation (sometimes called ionization)

Question 9

How is the total amount of reducing sugars in the unhydrolysed and hydrolysed samples determined?

Answer 9

By the reaction with 3,5 dinitrosalicylic acid.

Question 10

How is the absorbance intensity of the compound determined?

Answer 10

via UV/VIS spectroscopy