Triangular test

One way of conducting a statistical test is the triangular test. In this test, tasters are presented with three samples each. Two of the samples are the same, one is different. 

Assessment of taste is achieved by sensory analysis, from very simple experiments such as triangular tests aiming at determining detection thresholds to complex descriptive analysis approaches. A method referred to as time-intensity that consists in recording continuously the intensity of a given sensation over time under standardized conditions has been applied to study flavonoid bitterness and astringency properties. 

Now significant has two meanings one ordinary and one statistical. The statistical meaning is related to confidence levels, and a type of statistical test that is used is the triangular test. Here, tasters are given three examples of the product under test two are the same, one is not. Tasters are asked to identify which two samples are the same and which is different. There is always a chance that tasters will guess correctly, purely by chance. This probability can be calculated and is compared with the real result. The size of the difference can be related to the chance... 

Consult a text book on statistics and set up a triangular test using two different variants of one of the recipes. Carry out the test and analyse the results. Repeat the exercise using two different batches of the same product which are identical except for the random variations that normally occur in cooking. Are they significantly different statistically ... 

Orthonasal detection fivesholds were determined in water (Vittel) with seven panelists. Eight samples were presented in order of decreasing concentrations (factor 10 between samples) to estimate the range of threshold concentration. Threshold values were determined by triangular test using a series of four concentrations (factor 2.S between samples). Threshold values correspond to >70% of correct answers. 

Triangular test. A common form of the boundary approach to analysing sequential trials. 

Perception threshold. This is the minimum concentration at which the presence of an odoriferous substance is detected by 50% of tasters in a triangular test, although they are not necessarily capable of identifying the smell. 

Amon and coworkers (1986, 1989) analyzed 37 wines affected by cork taint, using gas-phase chromatography, equipped with an olfactometry system and coupled with a mass spectrometer. They analyzed the compounds most frequently found, both in corked wine and their respective corks. Their findings are shown in Figure 8.13. These same authors ran triangular tests with a panel of twelve tasters and found that the perception thresholds for these compounds in a non-aromatic, dry white wine were particularly low (Table 8.11). 

In general, the olfactory threshold of a compound is several orders lower than the taste threshold (Table 23.4). This may represent the probability of a compound taken into the mouth reaching the olfactory epithelium. In the ASBC triangular test (see later) the assessors are required to distinguish the similar beers first on the basis of odour. Similarly, with one brewery taste panel it was found that most members differentiated between two beers on the basis of aroma rather than taste 90-95% of the tiine [30]. The olfactory threshold (OT) can be calculated from the simplified equation ... 

Triangular test Difference test no. of Quality or preference test... 

When the intended aim is to change a formula, reduce costs or duplicate a formula, an evaluation is sought. Holistic tests (with same-different or triangular tests) can be used in the context of a similarity-based approach (beta risk). In practice, these tests can certainly be implemented, but at project team level they are impossible to manage because of insufficient participants. Rework of products is also difficult, because these tests do not provide any information on how products differ. We have therefore formalized an approach that can evaluate proximity between tests and a reference product. 

Discrimination tests, such as pair comparison or triangular tests, have been widely used in order to evaluate the sensory abilities of children. Discrimination tests in the olfactory domain have indicated a lower ability to discriminate odours in 2- to 4-year-old children compared to children over 5 years (Richman et al., 1995). Discrimination... 

Having outlined the general procedure in the problem of applying triangular tests as they are more often encountered, given a specified... 

Number of Successes Needed in Triangular Tests for Significance at Certain Probabilities of Type I Elrror n — Number of independent trials... 

The flavour of the bread from dough mixed in partial vacuum has also been compared with that of bread from doughs mixed in an oxygen-enriched atmosphere using two taste panels of 40 people. In the triangular test conducted, less than one-third of the panellists were able to select the odd sample correctly this result is not statistically significant. As a further check, the results from the two panels were compared and it was found that only two panellists had made the correct selection on both occasions. 

The first test was with PSL dispersed In distilled water. The PSL was measured in triangular test cells at the various desired light collection angles between 20 and 70 degrees. The PSL was dispersed and kept in motion via a magnetic stirrer. 

Proof height (h) Bread volume (rapeseed displacement) Triangular test (j) Bowl-life test Foam (head retention) test (1) AOM... 

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