Which statement is true. If for an certain food both the AOAC and Englyst NSP method are used to determine fibre, in general

Title of page

The AOAC will give higher values than the Englyst method

The Englyst method will give higher values than the AOAC method

There will be almost no difference between fibre values provided by both methods.

Right. Lignin, resistant starch and non specific polysaccharides (waxes, muculages etc) are included in the AOAC fibre fraction but not in Englyst fibre. To understand this, remember that:

1. lignin is not a polysaccharide, thus acid hydrolysis of lignin does not result in elevated monosaccharide values.

2. resistant starch is largely resistant to hydrolysis thus acid hydrolysis of resistant starch does not result in elevated monosaccharide values.

3. non polysaccharides compounds that are monomers (waxes, muculages etc) are present in the final AOAC residue that is weighed, whereas the Englyst method only measures polysaccharides.

Therefore the AOAC method will give higher values than the Englyst method. Here you see some examples:

--------------------------------------------------------------------------------------------

Product AOAC fibre (%) Englyst fibre (%)

--------------------------------------------------------------------------------------------

Coleslaw 1.6 1.2

Salmon quiche 1.3 0.9

Wholemeal bread 8.3 6.8

Pasta Bolognese 1.8 1.1

--------------------------------------------------------------------------------------------

Source: Nutrition and food science 30 (5); 221-226 (2000)

Not right. In the AOAC method, fibre is defined as the residue after starch hydrolysis (minus protein and ash). However, in the Englyst method this residue is hydrolyzed by acid. As a results all non starch polysaccharides (NSP) are hydrolyzed and measured as monosaccharide equivalents. Therefore, lignin, resistant starch and non specific polysaccharides (waxes, muculages etc) are not included in the fibre fraction determined with the Englyst method.

Not right. In the AOAC method fibre is defined as the residue after starch hydrolysis (minus protein and ash). However, in the Englyst method this residue is hydrolysed by acid. This will result in different fibre values compared to the AOAC method.

a
b
c

So far you studied the AOAC method. Now you will study the second approach of fibre analysis.

In this approach dietary fibre is defined as plant cell wall materials of food. The methods based on this definition measure plant cell wall polysaccharides not being starch (Englyst NSP method). This approach can be most easily understood considering the method as a modification of the last part of the AOAC approach. The scheme below shows the Englyst approach, the AOAC methods is showed in gray.