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ER 3

Spectrophotometric measurement does work well and is easy, quick, and reliable. Quantitative of

sugars by HPLC is also simple (a bit more expensive though) but will allow tracking of sucrose to assure

its digestion did not occur. The method's steps do prevent sucrose digestion by relying on high-purity

enzymes. Since these enzymes are more expensive, laboratories using lower cost enzymes would be at

risk of reporting less accurate, higher values.

ER 4

Lack of sophisticated instrumentation will be unappealing to those inclined to high level tech methods.

ER 5

Quadratic fit may be difficult for some users to use, and automation of the whole quantitation process

is somewhat difficult to achieve. Scaling up is somewhat limited because of the need to measure

absorbency within 30 min of GOPOD reaction. High content of anti-oxidant will prevent accurate

determination of glucose, forcing other glucose detection methods into consideration.

ER 6

- potential interference of substances with anti-oxidant activity (if this is unknown it needs to be

assessed somehow, or an alternative glucose assay should be used) - although it is mentioned that

glucose assays other than GOPOD can be used, it does not appear to have been tested or validated. - it

is mentioned that leaving the sample (taking a break) after dilution of fully digested samples has an

impact on recovery - but why should that be the case?

ER 7

none

ER 8

This is a good method, but would appear not to be an improvement over AOAC

Supporting Data Comments

ER 1 Impressive data package

ER 2

15 labs. collaboratively studied the method and analyzed 10 homogenous test materials (animal feeds

and pet foods) using the described method for dietary starch (ranging starch contents of 1-70%). The

average within lab. Repeatability as sr for % Dietary starch was 0.49 with a range of 0.03 to 1.56, and

among –laboratory repeatability of standard deviation sR averaged 0.96 with a range of 0.09 to 2.69.

HORRAT averaged 2.0 for all test samples and 1.9 for samples containing dietary starch more than 2%.

ER 3

Excellent study

ER 4

Excellent data package. Well done study.

ER 5

Well-organized summary tables about statistics of all matrix results Good study on the glucose

standard responses across different batches

ER 6

This looks to be a straight forward assay which did not appear to be problematic for most of the labs

involved in the MLT. The authors have mentioned that alternative assays for glucose could be used

instead of GOPOD (and may be essential for samples with high anti-oxidant contents). It would be

interesting to know if this has been tested in any of the labs because although it is mentioned it does

not appear to have been verified.

ER 7

good

ER 8

Method should be accepted with some changes to text

Method Optimization

ER 1 Done

ER 2

The method has been optimized for its efficiency and better recovery of starch.

ER 3

Keep as written (see comment in Cons/Weaknesses for optional digestion)

ER 4

No further work needed.

ERP PROFILE SUMMARIES

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