I want to estimate total sugars in carrot and products developed from it. I have been using lane and eynon method. I could get the values for reducing sugars but not for total sugars. What is the procedure for total sugars..please explain
Normally people claim to measure total sugars using reducing sugar methods after "inversion" of sucrose. Inversion simply means hydrolysis of sucrose to release glucose + fructose. You need to make the measurement before and after inversion, and you need to account for the extra mass when you make the hydrolysis (1 mole sucrose = 342g, after hydrolysis it gives 1 mole of glucose = 180 g + 1 mole of fructose = 180 g)
However, reducing sugars methods are not really appropriate for analysing total sugars and I would not recommend using such an approach. There will always be some error (either through underestimation of some sugars (for example maltose) or overestimation as is the case of the presence of oligosaccharides, and in particular in the presence of inulin or fructooligosaccharides - which will also be hydrolysed when you make the inversion and release more fructose + glucose). Far better to use a chromatographic approach, there are many published options.
Thanks a lot for the answer. for the total sugars the hidrolisis with fenol, does not looks good idea ?
are you thinking about the phenol-sulphuric acid method of Dubois et al (1956) ??? This method will measure total carbohydrate (not only sugars).
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