Reference sample is critical for defining a sensory attribute
We all know there are qualification and quantification concepts for every chemical compound as we discuss chemical analysis. The concepts will be the same for sensory analysis on product. In terms of sensory analysis, qualification will refer to sensory attributes (characters) while quantification will refer to the sensory intensity (human perception) of certain sensory attribute. The qualification and quantification jobs done by panelists will rely on reference samples.
The reference samples can be employed as the communication tool or so called a bridge with the panelists
Why can it communicate with panelist and what do you want to communicate on? For example, if you got 10 panelists find grassy odor in a green tea drink, then how can you confirm that whether they are referring to the same odor or not? In this situation, you can have a reference sample for grassy odor prepared by the panel staff for the panelists. The reference can be a fresh grass or a dried green tea. All panelists can confirm whether the odor of the reference sample is the one they picked up in the green tea drink. If it is not the one, then the staff should prepare another reference later.
The reference samples, however, should meet 4 basic principles, not easy ones
- It needs to be representative
This means it can get the consensus agreement among all the panelists and state that the perceived sensory attribute of the reference is the one I perceived in the sample.
- It needs to be stable
This means that you can get the same reference sample today, tomorrow and next week. The same means that it will be recognized by the panelists that they are the same.
- It needs to be producible
Of course, the production/preparation for a reference sample should be as easy as possible. If it is hard to prepare it, then your sensory test will be a hard work to conduct in the future.
- It needs to be storable
Usually, it can be easier if the reference can be stored for certain time which you can employ it in some replications.