What do you decipher when you come across the word ‘sensory evaluation’? When you separate the two, what you are left with is a thought- testing something about hearing, smelling or eating. Beyond this, there is hardly anyone aware of the intricate technicalities. This is why we give you a quick guide on Sensory Evaluation.
Sensory Evaluation is the composition of scientific measuring techniques to test the food attributes, especially quality, by means of the five senses, namely sight, smell, sound, touch and taste. The age old technique of our ancestors to assess the food quality is now revamped, with standardized and set parameters put forth.
Before we get to the bottom of the topic, let’s see what the types of sensory evaluation test are:
1 Discriminative sensory tests: These tests help understand the basic difference between the given samples. Two types of discriminative testing methods are the Triangle test and the 2 or 3 Alternative Forced Choice test. The panelist size is around 30 in both the tests.
In Triangle test, panelists are provided with three samples; two identical and one different and the odd one is to be chosen from them.
In 2 or 3 AFC, the panelists are asked to indicate the highest in the specified dimension, eg sweetness.
2 Descriptive sensory tests: These have an underlined agenda of understanding, inclusive but not limited to, the taste, texture and smell of the food sample. Quantitative Descriptive Test (QDA) is the most common and prolifically used test under the mentioned method. It consists of three steps:
The first step consists of product familiarization and development of a word which accurately describes the same.
The second step involves training the panelists to standardize the sensory attributes of the given food sample.
The third step is scoring the food sample based on its description on an intensity scale.
3 Hedonic sensory tests: This method aims at understanding the customers directly. A large group of untrained people are selected to understand the product qualities like formulation, the preferences of people in general, whether an ingredient can go undetected, or there is any difference detected if an ingredient is missing. The 9-point hedonic scale is widely used for evaluation.
Not just any but a group of highly trained people are chosen for tests. However these panelists vary according to the type of test. While the two previously mentioned tests emphasis the need on training, consumer validation on a large scale based on hedonic tests utilize untrained panelists.
Some important considerations for sensory tests:
While necessary training can be provided to the people chosen, equally important factor of environment needs to be brought under control during the conduction of the evaluation:
1 Particular products need to be tested at apt timings; for eg, while chocolate can be tested during the morning time, one cannot test alcoholic products at wee hours of the morning. Hence, the timing differs according to the sample to be tested.
2 Ambient air quality, appropriate, stable temperature need to be maintained during the testing process. Proper ventilation needs to be facilitated with odor detectors. Any kind of pollutant in the air needs to be brought into light.
3 Lux value needs to be around 400 at table area and 700 around the entire testing place. Shadow free area should be maintained. Kind of lighting chosen needs to be specified with the reason and apt measures should be taken for cooling of the bulbs.
4 Palate cleansers need to be facilitated for avoiding the influence of one food sample over the next.
Though the gestation period for developing the sensory tests was long, it has emerged as a direct and one of the most effective methods of checking consumer acceptance. No doubt chemical and microbial testing authenticates the purity and quality of the product from a health perspective; it is, however, the acceptance or presentation of the food which compels a person to buy the food product in the first place.