M
ETHOD
For quantitative work, the sugars can be extracted from the homogenized foodstuffs either by treatment with80% v/v ethanol in a Soxhlet extraction apparatus for three hours or by boiling with 80% v/v ethanol for 20minutes. The free sugars in the extracts are examined by two reducing sugar methods or by HPLC to givethe glucose and fructose concentration. (We look at these in detail later in this module). Sucrose in theextract can be measured by inversion. The residue remaining after extraction of the free sugars is examinedfor starch and dextrin content.
Methods of Quantitative Determination:
1.Reducing Sugars
Sugars with a structure containing free aldehyde and ketone groups react as weak reducing agents and arecalled reducing sugars.