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Summary of Method
ER 1 Acceptable
ER 2
It consists of incubation of an aliquot of the sample with thermostable alpha-amylase in pH 5.0 acetate
buffer for 1 hr at 100°C with periodic mixing to gelatinize and partially hydrolyze alpha-glucan.
Amyloglucosidase is added and mixture is incubated at 50°C for 2 h and mixed. After subsequent
addition of water, mixing, clarification, and dilution as needed, free + ezymetically released glucose are
measured using a colorimetric glucose oxidase-peroxidase method. Values from a separate
determination of free glucose are subtracted to give values of enzymatically-released glucose. Dietary
starch = Enzymatically- released glucose multiplied by (162/180) or 0.9 and divided by the as received
sample weight (g) used in the assay.
ER 3
Dietary starch is digested to glucose and the increase in glucose level is used to calculate %dietary
starch. Potential interferences are either accounted for (inherent glucose) or excluded (deter inherent
sucrose digestion and deter maltulose formation).
ER 4
Starch is digested by traditional amylase/amyloglucosidase using gelatinization conditions. Glucose
released is measured colorimetrically with adjustment for free glucose in the sample.
ER 5
Ground or homogenized samples are digested with α-amylase and amyloglucosidate in acetate buffer
to release glucose from dietary starch. The digestate, after optional dilution, is analyzed for its glucose
content. A second sample portion is also assessed for free glucose by treatment with all reagents but
the enzymes. The difference of the two glucose result is used to calculate dietary starch content in the
sample.
ER 6
Sample (containing up to 100mg of starch) is weighed in duplicate. sodium acetate buffer (pH 5.0) is
added to both tubes. Then to one tube alpha-amylase and amylglucosidase are added to hydrolyse the
starch. To the other tube no enzymes are added. Samples are then clarified (centrifugation or
filtration) and diluted. Aliquots from each tube are then taken for analysis of glucose using the glucose
oxidase peroxidase (GOPOD) method, or other suitable validated method for glucose determination.
Glucose determined in the untreated sample is subtracted from the glucose determined in the enzyme-
treated sample. The result is then multiplied by 0.9 to correct for water uptake during hydrolysis to
calculate starch content.
ER 7
good
ER 8
A well performed study. However, the advantages over AOAC Method 996.11 need to be more clearly
identified. A
significant contribution is the application to samples more relevant to the particular study, but some of
the stated
general advantages are not substantiated.
Method Scope/Applicability
ER 1 Animal Feeds and pet foods. 1%-70% starch
ER 2
Animal feedstuffs and pet foods. Limitation in application: The method underestimates dietary starch
in feeds and foods whose antioxidant content is known to exceed 10-20 micromol of hydrophilic
antioxidant (as ascorbic acid) per 0.1 g of test dry matter. The method in the current format may not be
easily applicable to foods/feeds high in phenolic compounds (e.g. beets, red sorghum grain).
ER 3
A wide range of animal and pet feeds were covered in the study. Dry and wet products were included
along with a variety of grains as the base material.
Appendix 1
ERP PROFILE SUMMARIES
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