How is Descriptive Analysis Done?
The scope of any descriptive sensory analysis project depends upon your needs. Many factors affect the scope of a project, including:
- Number of different products to be tested/compared
- Number of product attributes to be tested
- Broadness of testing; Taste only? Taste and texture? Appearance?
- Complexity of product preparation
- Number of panelists involved
- Number of replicates each sample will be tested
- Physical factors which may affect the testing, such as strong tastes or aroma, and which may necessitate long 'rest' times between testing
- Your budget
Given all these variables, once the objective of the test is defined in consultation with the client, and the necessary products are received in our lab, the assigned Project Leader screens the samples, with the assistance of several additional panelists. This initial 'sampling' allows the leader to make plans for the actual panel testing and to confer with the Lab Manager as to what references may be needed in the testing.
This is a good point at which to explain 'references' or 'reference samples.' In descriptive analysis, the goal is to quantify our observations; that is, to assign intensity scores to the product attributes we are testing. Generally attributes are scored on a 15-point scale but even then it is not enough just to arbitrarily assign a '10' or a '7.5' to something. Who's to say we'd score it that way tomorrow? Or that another panelist would not assign a much different score?
The way we handle that is to use references particular foods, solutions, or other products that have been predetermined to have a intensity or value relative to other products on an external 'universal' scale. For example, the intensity of the grape flavor in Welch's grape juice is a '10.0' and the cooked apple flavor in Mott's apple sauce is a '5.0'. By having these and many other references available during analysis, panelists are calibrated like analytical instruments and are able to score product attributes intensities using the same 'ruler'. Data from our highly trained panelists will often demonstrate statistically significant differences between means of 0.2 to 0.4 on a 15 point scale. While these are generally not perceptible to the consumer, it demonstrates how highly calibrated the panelists are.
So back to the actual process. After the screening, the panelists meet and they do their own 'sampling.' This screening is when the panelists pool all of their observations about the products' characteristics. From their observations, a ballot is created and a precise lexicon is developed ensuring that all of the panelists 'file' their observations in a uniform manner.
An important part of this orientation phase is panel training. This may sound strange when one considers the hundreds if not thousands of hours of prior experience and training each of our panelists has accumulated. However, for each and every project, panelists explore and learn the nuances of the sample and references set. In this way, the panel's consistency and quality is maintained and assured.
In preparation for the testing, the product samples are coded and re-coded to eliminate any potential bias. When the actual testing takes place, the coded product samples are presented, generally in a random order which is different for each panelist. Each panelist compares the products to the references as necessary and gives the product scores for the attributes listed on the ballot. Each panelist also has at hand the lexicon prepared especially for that project, listing and defining all the attributes to be tested, along with the scores for the reference samples being utilized.
Clients are invariably amazed at the consistency of the scores between the various panelists. This is attributable to their thorough and uniform training and to the use of well-chosen references with which to compare the product being tested.
When the panelists are through with testing, their scores are statistically analyzed and data graphs are prepared to illustrate the products differences and similarities. Through this whole process the Project Leader has been in close touch with the client. The project leader and data analyst write a report that includes the findings, protocols, lexicons, data analysis and graphs.
Complex? Yes! Involved? Definitely! But at 21st Sensory we have refined this process under the direction of our expert staff to the point that, from the arrival of the product in our lab to the submission of the final report, a project can be completed in a surprisingly rapid manner. But at no time is quality ever compromised, and our clients' satisfaction is our ultimate goal. We do whatever it takes!