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may be stored at room temperature for 6 months.
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Internal quality control samples
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sample, crude protein as nitrogen content × 6.25 and ash should be
determined to determine the nonprotein organic matter content of
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of the corn starch control sample is estimated as 100% minus
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100 mg of each sample with each batch of test samples. Glucose
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Determination of accuracy of volume additions for use of
summative volume approach
.—The method as described relies on
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water. Calculate the grams of water in each tube as:
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D. Preparation of Reagent Blanks, Standard Curves, and Test
Samples
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Reagent blank.
—For each assay, two reaction tubes
containing only the reagents added for each method are carried
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degree as samples (no dilution or diluted to the same degree as
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solutions prepared from test and control samples.
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Standard curves.
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solution,
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standard glucose solutions,
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against wall of tube, so it will mix well with the sample. Vortex
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determination run.
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Test samples.
—Feed and pet food amenable to drying
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then ground to pass the 0.5 or 1.0 mm screen of an abrasion mill
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E. Determination of Dietary Starch
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: Samples for Free Glucose Analysis
Test and Control Sample
Portions and Blanks
Add 30 mL Na
acetate buffer
Add 30 mL Na acetate
buffer and heat-stable,
alpha-amylase.
Vortex. Incubate 1 h
at 100°C. Vortex at
10, 30 and 50 min.
Cool on bench
0.5 h.
Add diluted
amyloglucosidase.
Vortex. Incubate 2
h at 50°C.
Vortex at 1 h.
Add 20 ml water, or
filter and bring to
100 mL volume in a
volumetric flask.
Invert tubes >4 x
to mix completely.
Test and Control Sample
Portions and Blanks
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: Samples for Enzymatically-Released +
Free Glucose Analysis
Invert tubes >4 x to
mix completely.
Vortex. Incubate
1 h at 100°C.
Vortex at 10, 30
and 50 min.
Test Solutions
In duplicate, pipette 0.1 mL working standards and test
solutions into 16 x 100 mm glass tubes, add 3.0 mL GOPOD.
Prepare dilutions as needed or
analyze test solutions directly.
Vortex. cover tubes with plastic film to seal.
Incubate in a 50°C waterbath for 20 min.
Read absorbance on a
spectrophotometer.
Solutions with
Developed
Chromogen
Add 20 ml water, or
filter and bring to
100 mL volume in a
volumetric flask.
Volume by Sum of Volume Additions
Centrifuge portion at 1000
x g
for 10 min (if
still cloudy, centrifuge 10 min at 10,000
x g
).
Volume Using Volumetric Flasks
Proceed to dilution step.
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