ASTM E1885-04
(Test Method)Standard Test Method for Sensory Analysis—Triangle Test
Standard Test Method for Sensory Analysis—Triangle Test
SIGNIFICANCE AND USE
This test method is effective for the following test objectives:
5.1.1 To determine whether a perceivable difference results or a perceivable difference does not result, for example, when a change is made in ingredients, processing, packaging, handling or storage; or
5.1.2 To select, train and monitor assessors.
This test method itself does not change whether the purpose of the triangle test is to determine that two products are perceivably different versus that the products are not perceivably different. Only the selected values of pd, α, and β change. If the objective of the test is to determine if there is a perceivable difference between two products, then the value selected for α is typically smaller than the value selected for β. If the objective is to determine if the two products are sufficiently similar to be used interchangeably, then the value selected for β is typically smaller than the value selected for α and the value of pd is selected to define “sufficiently similar.”
SCOPE
1.1 This test method covers a procedure for determining whether a perceptible sensory difference exists between samples of two products.
1.2 This test method applies whether a difference may exist in a single sensory attribute or in several.
1.3 This test method is applicable when the nature of the difference between the samples is unknown. It does not determine the size or the direction of the difference. The attribute(s) responsible for the difference are not identified.
1.4 Compared to the duo-trio test, the triangle test can achieve an equivalent level of statistical significance with fewer assessors. For details on how the triangle test compares to other three-sample tests, see Refs (1), (2), (3) and (4).
1.5 This test method is applicable only if the products are homogeneous. If two samples of the same product can often be distinguished, then another method, for example, descriptive analysis, may be more appropriate.
1.6 This test method is applicable only when the products do not cause excessive sensory fatigue, carryover or adaptation.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: E1885 – 04
Standard Test Method for
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Sensory Analysis—Triangle Test
This standard is issued under the fixed designation E1885; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope of Foods and Beverages
2.2 ISO Standard:
1.1 This test method covers a procedure for determining
ISO 4120 Sensory Analysis – Methodology – Triangular
whether a perceptible sensory difference exists between
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Test
samples of two products.
1.2 This test method applies whether a difference may exist
3. Terminology
in a single sensory attribute or in several.
3.1 Definitions–For definition of terms relating to sensory
1.3 This test method is applicable when the nature of the
analysis, see Terminology E253, and for terms relating to
difference between the samples is unknown. It does not
statistics, see Terminology E456.
determine the size or the direction of the difference. The
3.2 Definitions of Terms Specific to This Standard:
attribute(s) responsible for the difference are not identified.
3.2.1 a (alpha) risk—probability of concluding that a per-
1.4 Compared to the duo-trio test, the triangle test can
ceptible difference exists when, in reality, one does not. (Also
achieve an equivalent level of statistical significance with
known as Type I Error or significance level.)
fewer assessors. For details on how the triangle test compares
2 3.2.2 b (beta) risk—probability of concluding that no per-
to other three-sample tests, see Refs (1), (2), (3) and (4).
ceptible difference exists when, in reality, one does. (Also
1.5 This test method is applicable only if the products are
known as Type II Error.)
homogeneous. If two samples of the same product can often be
3.2.3 p —probability of a correct response.
c
distinguished, then another method, for example, descriptive
3.2.4 p (proportion of discriminators)—proportion of the
d
analysis, may be more appropriate.
population represented by the assessors that can distinguish
1.6 This test method is applicable only when the products
between the two products.
do not cause excessive sensory fatigue, carryover or adapta-
3.2.5 product—material to be evaluated.
tion.
3.2.6 sample—unit of product prepared, presented, and
1.7 This standard does not purport to address all of the
evaluated in the test.
safety concerns, if any, associated with its use. It is the
3.2.7 sensitivity—general term used to summarize the per-
responsibility of the user of this standard to establish appro-
formance characteristics of the test. The sensitivity of the test
priate safety and health practices and determine the applica-
is rigorously defined, in statistical terms, by the values selected
bility of regulatory limitations prior to use.
for a, b, and p .
d
2. Referenced Documents 3.3 triad—three uniquely coded samples given to an asses-
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sor in the triangle test; two samples are alike (that is, of one
2.1 ASTM Standards:
product) and one is different (that is, of the other product).
E253 Terminology Relating to Sensory Evaluation of Ma-
terials and Products
4. Summary of Test Method
E456 Terminology Relating to Quality and Statistics
4.1 Clearly define the test objective in writing.
E1871 Guide for Serving Protocol for Sensory Evaluation
4.2 Choose the number of assessors based on the level of
sensitivity desired for the test. The sensitivity of the test is, in
part, a function of two competing risks: the risk of declaring
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This test method is under the jurisdiction ofASTM Committee E18 on Sensory
the samples different when they are not (that is, a-risk) and the
Evaluation of Materials and Products and is the direct responsibility of Subcom-
mittee E18.04 on Fundamentals of Sensory.
risk of not declaring the samples different when they are (that
Current edition approved Oct. 1, 2004. Published October 2004. Originally
is, b-risk).Acceptablevaluesof aand bvarydependingonthe
approved in 1997. Last previous edition approved in 2003 as E1885 – 97 (2003).
test objective and should be determined before the test (see
DOI: 10.1520/E1885-04.
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Appendix X3).
The boldface numbers given in parentheses refer to a list of references at the
end of the text.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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