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Measuring Flavours in foods - Static and dynamic sensory methods for flavour assessment

43 important questions on Measuring Flavours in foods - Static and dynamic sensory methods for flavour assessment

Sensory methods can be classified into 3 classes, what are these and what are their differences?

Discriminative sensory methods --> difference between products
Descriptive sensory methods --> quantify the sensory properties in which products differ
Affective sensory methods, hedonic testing --> acceptance and/or liking of the product

How can sensory methods be classified in time?

Static --> one moment in time
Dynamic --> changes in perception over time during consumption

What kind of panel does descriptive sensory methods use?

Trained or untrained

When should discrimination tests be used?

When you want to determine whether 2 samples are perceptibly different.

When should a discrimination test not be used?

When the perception differences are too large or obvious (e.g. Large sugar reduction and you measure sweetness).

How many samples can be compared in a discrimination test?

2 samples

What is the maximum of series of discrimination tests you can do?

6-7 samples, so 3 series approximately

Which are the 2 most commonly used discriminative tests?

Paired comparison test or 2-Alternative Forced Choice test (2-AFC)
Triangle test

What happens in a paired comparison test (2-AFC)?

Two samples are compared using a directional question (which samples is sweeter, thicker, creamier, etc.).

Which chance level is used in 2-AFC tests?

P = 0.5

How many attributes can be used in 2-AFC testing?

1 attribute

Which chance level is used in triangle test?

P = 0.33

What is reduction by stealth?

To reduce the sugar or fat content in food very slowly, so that it is not perceived as different.

How many products can be used in a descriptive sensory analysis?

More than 10

Mention different approaches that can be used for descriptive sensory testing

Quantitative Descriptive Analysis (QDA)
Spectrum method
Check-All-That-Apply (CATA)
Rate-All-That-Apply (RATA)

What is the goal of QDA?

To provide a full description of all the sensory properties of a set foods/samples.

How is a wine wheel build up?

Center --> categories of typically occurring wine flavours
Next ring --> discrimination of different flavours within a category is presented
Outer ring --> descriptors: attributes that can be used to describe the flavour of wine

How big is the trained panel in QDA?

10-12 subjects

How many attributes can be tested in QDA?

Up to 30

Is perceptual dumping avoided in QDA? And if yes, how?

Yes, by offering > 15 attributes.

How can you visualise the data of QDA?

With a spider web.

QDA results in absolute values. T/F

False, it results in comparisons between samples or relatively to a reference sample.

Which statistical analysis can be performed on QDA data?

ANOVA, followed by Posthoc testing.

What happens in time intensity (TI) methodology?

The intensity of a single attribute (taste, aroma, texture, etc.) is measured over time.

TI uses a line scale. T/F

True

With which technique can TI be combined?

Nose-PTRMS.

What does nose-PTRMS measure?

The release of the aroma compound over time (in vivo) into the nasal cavity during consumption.

Does TI have a low or high risk of dumping effects?

High, as it only uses 1 attribute.

What are 2 disadvantages of TI?

Higher risk of dumping effect, due to use of only 1 attribute
Time consuming method

What does the increasing slope in a TI graph tell you?

How fast the flavour builds up.

What does the decreasing slope in a TI graph tell you?

Prolonging of the flavour perception during consumption.

How are sweeteners different from sucrose in giving taste?

Many sweeteners have a prolonged sweetness, so a lingering taste in contrast to sucrose.

What is the difference between TDS (Temporal Dominance of Sensations) and TI?

TI: 1 attribute
TDS: multiple (10) attributes

TDS is not a measure of intensity of an attribute. T/F

True

Which 3 time points are measured in TDS?

Attack, evolution, finish

What does the subject select during TDS?

The subject selects 1 attribute at the time, that is perceived as the dominant sensation, the sensation that attracts the most, during consumption.

What kind of panel does TDS use?

Before trained, now mostly untrained, naive subjects.

What is the dominant rate?

The sum of the amount of subjects that have selected that specific attribute as the dominant sensation at a moment in time.

Is the discrimination test an analytic or hedonic test?

Analytic

Is the descriptive test an analytic or hedonic test?

Analytic

Is the affective test an analytic or hedonic test?

Hedonic

How are gel hardness and aroma perception related?

A harder gel, gives a lower aroma perception.

How are gel hardness and aroma release related?

They are not related, there is not difference in aroma release at different hardness (measured with MS-nose).

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Food Flavour Design

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