BS ISO 6658:2017 pdf free download – Sensory analysis一Methodology – – General guidance.
According to the case
— the leader of the panel mayshall be used to guide training,
— the leader of the panel mayshall be used to control a discussion and to establish a consensus.
5.4.3.4 Procedure
A preliminary set of trials (or training) is carried out with the range of products to be tested, so as to establish the organolepticsensory properties important in characterizing and distinguishing them. The results of these trials are used to develop a glossary of descriptive terms to be used, and to establish the experimental procedure for presenting and examining the samples. A panel is then trained in the methodology and particularly in the use of the glossary. It is useful at this stage to have a set of reference materials, pure compounds or natural products that elicit particular odour or flavour scores or have particular textural or visual properties.
In the test sessions, the assessors check the samples against the glossary of terms, scoring each attribute present on an intensity scale.
It is usual to note the order in which the factors are perceived, including the presence of an after-taste, and to score for the overall impressionintensity of aroma and flavour.
5.4.3.5 Interpretation of results
Results shall consist of intensity scores for each attribute. There are two basic approaches to the handling of data.
In consensus profile methods, immediately after the assessors have completed their assessments the leader of the panel tabulates the results and initiates a discussion to resolve differences. In the light of the discussion and, if necessary after re-examination of the samples, the panel arrives at a group decision on the profile.
In the other descriptive analysisprofile methods, there is no discussion and the profile obtained is a series of averages of the scores assigned to each descriptor by each assessor.
The averages can be compared statistically, for example by using analysis of variance. There are also, for all descriptive analysis methods, techniques of multivariate analysis.
5.4.4 Free-choice profilingConsensus profile
The assessors individually evaluate one sample ata time and they record the attributes, the intensities of attributes and their order of appearance. At the end of the evaluation of a product by the group the results are collected. Panel leader leads a general discussion to arrive at a consensus profile on the attributes, intensities, and any other aspects (such as the order of the attributes). Reference samples can be provided to enrich the discussion. Once the panel has reached consensus, a final sensory descriptive “profile” is created. When there is no agreement, the panel leader may decide to present the product in a new session or to record the differences among assessors. This process is repeated until all products have been evaluated.