Structurally, an intact inulin has no reducing function. So the minimum DP for a non reducing inulin is 2: saccharose is a non reducing sugar, and inulin is build by adding fructoses on the fructose moiety of a saccharose, itself a dimer of fructose and glucose linked 2-1 i.e. the glycosidic bond involves both reducing functions.

However the fructan in inulin is VERY acid-labile, explaining why there  may be reducing functions after almost any heat-treatment.

Thank you for the information madam. The reason to ask for this question is I tried with two commercial, procured from two different companies and lab extracted inulin for inulinase assay. I found that substrate itself (inulin) is giving reducing sugar reading. I tried with 3 different buffers of pH 5.0, 7.0,  8.0. In all the cases the result was same. Reducing sugar reading in the substrate itself. 

Literature says that inulinase assay is carried with Sodium acetate buffer of pH5.0. But I am getting reducing sugar reading in the substrate itself with this buffer. So how can I proceed to check the inulinase activity.

Is there any method to dissolve inulin in the above said buffer of pH5.0?  For the assay purpose, I dissolved inulin hot buffer, as inulin not dissolved in cold buffer.

Whether dissolving inulin in the hot sodium acetate buffer, makes inulin to degrade to give reducing sugar reading? As sodium acetate is acidic buffer.

Please help me in finding solution to the above problem

Regards

Jayaram C

Hi,

I am not surprised that there is already some reducing functions, This may very easily happen during extraction, storage or indeed dissolution. If it is not too high, just go on with the hydrolysis and reducing sugar assay, substracting the blank. Or try dissolving in the cold overnight, inulin is acvtually one of the fairly soluble polysaccharides..

Once again thank you for the information madam. I will try with your suggested method and I will update the same.