| Seed
Count |
| |
Seed
count is also offered as a component of
the Tofu and Soymilk Process
Test.
Seed
count is a measure of soybean seed size.
Some soybean processors have strong preferences
for particular seed sizes. For instance,
tofu manufacturers often prefer very large
beans. Natto beans are very small.
The
test is performed by randomly selecting
100 representative intact seeds. The seeds
are weighed and reported as seeds per pound.
Possible Values
1200-4600 seeds per lb.;
Typical Results 2400-3200 seeds per lb.
|
|
|
| Foreign
Material and Splits |
| |
Foreign
material and splits are part of the GIPSA
Official United States Standards for Grain
grading criteria. Foreign material in soybeans
is defined as all matter that passes through
an 8/64 round-hole sieve and all matter other
than soybeans remaining in the sieved sample
after sieving according to procedures prescribed
in FGIS instructions. Splits are defined as
soybeans with more than one-fourth of the
bean removed and that are not damaged. |
|
|
| Damage
|
| |
Damage
is part of the GIPSA Official United States
Standards for Grain grading criteria for soybeans.
A damaged soybean is defined as one that is
materially damaged by weather, insects, fungus,
disease, etc. Low amounts of damage are desired,
particularly in food uses. |
|
|
| Moisture
Content (Motomco Meter) |
| |
Moisture
Content from the Motomco 919 Moisture Meter
is also offered as a component of the Tofu
and Soymilk Process Test and Seed
Count.
Moisture
content is a critical factor for the long-term
storability of soybeans. Soybeans should
be dried in the field or artificially to
13% moisture for storage up to 6 months,
12% for storage up to one year, and 11%
for over one year. Over-drying of soybeans
wastes energy, money, and time. Overdrying
soybeans will also lead to an increase in
splits.
The
test involves filling the moisture meter
with 250 grams of soybeans. A reading is
obtained from the meter which correlates
to a specific moisture content at the testing
temperature. The moisture content is reported
as an “as is”, or “wet
basis”, percentage.
The
ideal Moisture Content for further soybean
testing is between 10 and 13%.
Possible Values
5-35%; Typical Results 8-15%
|
|
|
| NIR
Proximate Analysis – Soybean |
| |
NIR
Proximate Analysis is also offered as a
component of the Tofu and
Soymilk Process Test, NIR
Complete Analysis – Soybean, and
NIR Complete
Analysis plus Isoflavones – Soybeans.
Proximates
are the major components of the grain. For
soybeans, the NIR Proximate Analysis includes
Oil Content, Protein Content, Fiber Content,
and Moisture Content. The test does not
include Ash Content. This procedure is nondestructive
to the soybeans. Proximate Analysis is also
available using wet chemistry methods for
protein
content, oil
content, and moisture
content but the sample must be ground.
Various
end users have different demands for soybean
composition. A tofu manufacturer will usually
want very high protein levels. Operators
of a large soybean crushing plant may want
to balance the protein and oil content to
fit processing needs.
Results
(other than Moisture Content) are reported
on a dry basis
percentage (percent of non-water material).
Moisture Content is reported
“as is” (percent of total
sample weight).
| |
Possible
Values |
Typical
Results |
| Oil Content |
16-25%
|
18-23% |
| Protein
Content |
36-50% |
38-45% |
| Fiber
Content |
3.5-6% |
4.0-5.0% |
| Moisture
Content |
5-35% |
8-15% |
|
|
|
| NIR
Amino Acid Profile – Soybean |
| |
NIR
Amino Acid Profile is also offered as a component
of the NIR Complete
Analysis – Soybean and NIR
Complete Analysis plus Isoflavones tests.
The NIR
Amino Acid Profile provides an analysis of
the amino acid content of a soybean sample.
Amino acids are the “building blocks”
of protein. The proper blend of amino acids
(a measure of protein quality) is necessary
for a proper feed ration. Amino acids must
be supplemented if the diet is insufficient
or negative productivity or health consequences
will develop.
In this
test, a ground sample of soybeans is analyzed
using a NIR spectrophotometer. The instrument
uses a calibration to evaluate the level of
18 individual amino acids:
- Cystine
- Methionine
- Lysine
- Threonine
- Tryptophan
- Arginine
|
- Alanine
- Isoleucine
- Proline
- Leucine
- Glutamic Acid
- Aspartic Acid
|
- Valine
- Serine
- Glycine
- Histidine
- Phenylalanine
- Proline
|
Of
these, five – cystine, methionine, lysine,
threonine, and tryptophan – are usually
considered the most critical in balancing
a feed ration. Amino acids are reported on
a dry basis
percentage. Desired levels are dependent on
the end user. The Amino Acid Profile is also
available using wet chemistry (HPLC)
methods. |
|
|
| NIR
Fatty Acid Profile – Soybean |
| |
NIR
Amino Acid Profile is also offered as a component
of the NIR Complete
Analysis – Soybean and NIR
Complete Analysis plus Isoflavones tests.
The NIR
Fatty Acid Profile provides an analysis of
the fatty acid content of a soybean sample.
Fatty acids are components of lipids (fats
and oils). Levels of various fatty acids in
livestock rations have been shown to affect
animal nutrition and meat quality.
In this
test, a ground sample of soybeans is analyzed
using a NIR spectrophotometer. The instrument
uses a calibration to evaluate the level of
5 individual fatty acids:
- Oleic Acid
- Linoleic Acid
- Linolenic Acid
- Palmitic Acid
- Stearic Acid
|
Fatty
acids are reported on a dry
basis percentage. Desired levels are dependent
on the end user.
The Fatty
Acid Profile is also available using wet chemistry
(Gas Chromatography) methods. |
|
|
| NIR
Total Isoflavones – Soybean |
| |
NIR
Amino Acid Profile is also offered as a
component of the NIR
Complete Analysis plus Isoflavones tests.
Isoflavones
are a series of chemicals that have been
reported to be beneficial in fighting heart
disease, cancer, osteoporosis, menopausal
symptoms, and other ailments. Soybeans and
soyfoods are some of the best sources of
these compounds. However, levels of isoflavones
can vary with genetic and environmental
differences.
In this
test, a ground sample of soybeans is analyzed
using a NIR spectrophotometer. The instrument
uses a calibration to evaluate the level
of isoflavones. While individual isoflavone
compounds can be quantified, the result
from this test is only the total amount
of these constituents. The result is given
in parts per million on a dry
basis.
It is
important to note that there is no standard
approved method for measurement of isoflavones
in soybeans. The reference lab used for
the development of this calibration has
outstanding experience in the isoflavone
area. However, results from this reference
lab, and hence calibration, may not agree
with results from another lab. It has been
shown that the “high” results
from one lab correlate well to “highs”
from another; the same has been seen for
low values. Therefore, it is recommended
that the test be used primarily as a screening
tool for relative performance as opposed
to individual values. Comparisons of results
from other labs to IPG lab results may be
invalid.
Possible Values 400-4500 ppm; Typical Results
1000-3000 ppm; Average Result 2100 ppm
|
|
|
| NIR
Complete Analysis – Soybean |
| |
NIR
Complete Analysis for soybeans includes proximate
analysis, amino
acid profile, and
fatty acid profile by NIR. |
|
|
| NIR
Complete Analysis plus Isoflavones –
Soybean |
| |
NIR
Complete Analysis for soybeans includes proximate
analysis, amino
acid profile, fatty
acid profile and total
isoflavones by NIR. |
|
|
| Protein
Content – Combustion Method |
| |
The
Combustion (Dumas) Method can be used to measure
the protein or nitrogen content in a wide
range of substances. It has replaced the slow,
dangerous, and environmentally unfriendly
Kjeldahl procedure for most applications.
The combustion method is an approved method
and has become the most common reference (“wet
chemistry”) method for NIR
calibrations for protein content. The combustion
method is typically employed for samples for
which no NIR calibration exists. The IPG lab
does offer protein content
for soybean using NIR. There are situations
in which the combustion method may not be
suitable.
In this
test, a 50-300 mg representative sample (liquid
or ground solid) is burned at high temperature
in a sealed system. The nitrogen in the sample
is converted to nitrogen gas, separated from
the other chemical components, and measured
by thermal conductivity. The nitrogen content
can be converted to protein content by using
a conversion factor (typically 6.25 x nitrogen)
to obtain the “as
is” protein percentage. This test
is performed in duplicate, and the moisture
content in the original sample is determined
by the air oven
method to convert the protein content
to dry basis.
Protein
contents measured by the combustion method
can range from very low (0.1% to 90+%). |
|
|
| Oil
Content – Ether Extraction |
| |
Ether
extraction can be used to quantify the amount
of fat or oil in a sample. The ether extraction
method is an approved method and is a common
reference (“wet chemistry”) method
for NIR calibrations
for oil content. The ether extraction method
is typically employed for samples for which
no NIR calibration exists. The IPG lab does
offer oil content
for soybeans using NIR. There are situations
in which ether extraction may not be a suitable
method for oil measurement.
In this
test, a representative sample is ground and
extracted in refluxing petroleum ether. Extracted
oil is captured in the boiling flask. The
oil is separated from the ether and weighed
to determine the percentage of the original
sample weight collected as oil to obtain the
“as is”
oil percentage. This test is performed in
duplicate, and the moisture content in the
original sample is determined by the air
oven method to convert the protein content
to dry basis.
Oil contents
measured by the ether extraction method can
range from very low (0.2% to 50+%). |
|
|
| Moisture
Content – Air Oven |
| |
The
Air Oven method can be used to quantify
the amount of water in a sample. The air
oven method is an approved method and is
a common reference (“wet chemistry”)
method for NIR
calibrations for moisture content. The air
oven method is typically employed for samples
for which no NIR calibration or other reliable
rapid method (NIR or
Moisture Meter)
exists. There are situations in which the
air oven method may not be a suitable method
for moisture measurement.
In this
test, a representative sample (liquid or
ground solid) is weighed into a tared cup
and placed in an oven. Oven temperatures
and residence times vary by substance. The
dried sample is cooled in a dessicator and
the weight of the remaining material is
recorded. The weights may be used to determine
the amount of water removed in the oven.
Moisture content is reported as the amount
of water removed from the original sample.
Solids content is the weight of material
remaining after drying divided by the original
sample weight. Moisture content and solids
content are reported as an “as
is”, or wet
basis percentage. They are related by
the equation:
Moisture Content ("as
is") + Solids Content ("as is")
= 100%
|
|
|
| Sugar
Profile – High Performance Liquid Chromatography |
| |
The
sugar profile measures the quantities of
seven sugars in a sample. While applicable
for a number of products, soybeans are the
most common request for the IPG lab. For
soybeans, sugar contents are expressed on
dry basis:
| |
Possible
Values |
Typical
Results |
| Sucrose |
3.0-9.0%
|
4.0-7.0% |
| Glucose
(dextrose) |
0.0-0.5% |
0.0-0.1% |
| Maltose |
0.0-0.5% |
0.0-0.3% |
| Lactose |
0.0% |
0.0% |
| Fructose |
0.0-0.1% |
0.0–trace% |
| Raffinose |
0.2-1.6% |
0.5-1.2% |
| Stachyose |
2.0-6.5% |
3.5-5.5% |
High
levels of sucrose (“table” sugar)
are often desired to mask the beany flavor
in soyfoods. Low amounts of the oligosaccharides
raffinose and stachyose are wanted. These
sugars are not digested in the upper digestive
system and are fermented in the intestine.
The gases produced in fermentation can cause
the discomfort and flatulence associated
with some foods from soybeans.
|
|
|
| Amino
Acid Profile – High Performance Liquid
Chromatography |
| |
The
High Performance Liquid Chromatography (HPLC)
method can be used to quantify the amount
of various amino acids in a sample. The HPLC
method is an approved method and is a common
reference (“wet chemistry”) method
for NIR calibrations
for amino acid contents. The HPLC method is
typically employed for samples for which no
NIR calibration exists. The IPG lab does offer
amino acid profile
for soybeans using NIR.
Various
procedures must be employed depending on the
amino acids of interest. The moisture content
in the original sample is determined by the
air oven method
to convert the amino acid contents to dry
basis. |
|
|
| Fatty
Acid Profile – Gas Chromatography |
| |
The
Gas Chromatography (GC) method can be used
to quantify the amount of various fatty acids
in a sample. The GC method is an approved
method and is a common reference (“wet
chemistry”) method for NIR
calibrations for fatty acid contents. The
GC method is typically employed for samples
for which no NIR calibration exists. The IPG
lab does offer
fatty acid profile for soybeans using NIR.
Various
procedures may be employed depending on the
fatty acids of interest. The moisture content
in the original sample is determined by the
air oven method
to convert the fatty acid contents to dry
basis. |
|
|
| Lipoxygenase
Activity |
| |
Lipoxygenase
enzymes are responsible for much of the “beany”
or “grassy” flavor associated with
soybeans. The three primary lipoxygenase enzymes
(L1, L2, and L3) catalyze the reaction of
soybean lipids (oils) to the offensive flavor
compounds when the ground bean is exposed
to air and water, as when making soymilk and
tofu.
The production
of the enzymes in the plant is controlled
by specific genes (Lx1, Lx2, and Lx3). Types
of soybeans have been found which are “null”
(not genetically able to produce the enzyme)
for one or more of the lipoxygenases. A “triple
null” seed contains none of the three
enzymes. Soybean breeders are using these
null genotypes to develop new, high-yielding
varieties with improved flavor characteristics.
The lipoxygenase
test is performed seed-by-seed and for each
specific enzyme. Clients can choose to check
for one, two, or all three enzymes and specify
the number of seeds to check. A yes/no (wildtype/null)
result is obtained for each seed tested. The
final report lists total wildtype seeds and
total null seeds tested.
|
|
|
| Tofu
and Soymilk Process Test |
| |
 |
 |
The Tofu and Soymilk Process Test
gives a soybean processor information
on the yield and quality of the products
they could expect from a particular variety
or sample of beans. Data is collected from
the raw soybeans, the soymilk made from
those beans, and the silken (non-pressed)
tofu product made from that soymilk.
The
whole soybeans are evaluated using the NIR
Proximate Analysis and Seed
Count tests. A sample of the beans are
ground into a powder and blended with hot
water. The resulting slurry is steam-cooked
and put through a juice extractor. Insoluble
solids (okara) are removed by filtration
through a series of cloths and refrigerated.
The total volumetric yield is determined
after the sample has sat overnight and warmed
to room temperature. The solids content
of the soymilk is also measured using the
Air Oven Method
and reported.
A portion
of the soymilk is mixed with a coagulant
and cooked in a hot water bath to make the
tofu product. Glucono-delta-lactone (GDL)
is the standard coagulant, although the
traditional nigari (magnesium chloride)
is available as an option. The finished
tofu is weighed to measure product yield
and the moisture content is determined using
the Air Oven
Method.
The
color of the soymilk and tofu are measured
using the Hunter Lab color scale:
L – measure of lightness (0 = black
to 100 = white)
a – measure of greenness (larger negative
number) to redness (higher positive value)
b – measure of blueness (larger negative
number) to yellowness (higher positive value)
The protein
content of the soymilk and tofu are measured
using the
combustion method.
| |
Possible
Values |
Typical
Results |
Soymilk
Yield (liters
per kg of
dry soybeans) |
4.7-6.0 |
5.0-5.5 |
| Soymilk
Protein (d.b) |
38.0-57.0% |
41.0-51.0% |
| Soymilk
Solids |
10.0-11.5% |
10.5-11.3% |
| Soymilk
Color L |
70-85 |
77-82 |
| Soymilk
Color a |
(-2.0)-(-0.3) |
(-1.7)-(-0.75) |
| Soymilk
Color b |
10.0-15.5 |
12.0-15.0 |
Tofu
Yield (kg per kg of
dry soybeans) |
5.0-7.0 |
5.5-6.5 |
| Tofu
Protein (d.b) |
36.0-58.0% |
41.0-52.0% |
| Tofu
Moisture |
87.0-89.5% |
87.5-89.0% |
| Tofu
Color L |
77.0-81.5 |
78-81 |
| Tofu
Color a |
(-1.5)-0.7 |
(-1.0)-0.4 |
| Tofu
Color b |
11.0-15.0 |
12.0-14.0 |
|
|
|
| Nitrogen
Solubility Index (NSI) |
| |
The
Nitrogen Solubility Index, or NSI, is a
measure of the solubility of soybean protein
in water. High solubility is very important
to manufacturers of soymilk and tofu, as
their job is to extract as much protein
from the soybean as possible.
 For
this test, a sample of soybeans is ground,
mixed in a specific ratio with water, and
stirred at a set speed (120 rpm) in a constant-temperature
(30°C) water bath for a specific time
(2 hours). The nitrogen content of the ground
soybeans and of the extract are determined
using the combustion method. The NSI value
is the quotient of the nitrogen content
of the extract divided by the nitrogen content
of the original bean.
Possible Values 50-95; Typical Results
70-90
|
|
|
| Protein
Dispersibility Index (PDI) |
| |
The
Protein Dispersibility Index, or PDI, is
another measure of the solubility of soybean
protein in water. High solubility is very
important to manufacturers of soymilk and
tofu, as their job is to extract as much
protein from the soybean as possible.
For
this test, a sample of soybeans is ground,
mixed in a specific ratio with water, and
blended at a set speed (7500 rpm) for a
specific time (10 minutes). The nitrogen
content of the ground soybeans and of the
extract are determined using the combustion
method. The PDI value is the quotient of
the nitrogen content of the extract divided
by the nitrogen content of the original
bean.
Possible Values 50-95; Typical Results
70-90
|
|
|
