What's it all about?
- Sensory basics, Do’s, and Don'ts
- Assessment methods: Analytical tests, hedonic rating, In-Out test, DfC
- Tips for product testers, requirements
Is this powder snow white? Creamy white? Or rather greyish white? Not so easy to judge, looking at the substance in the test tube. Comparing it to the other nine tubes filled with corn starch makes it easier: the lighter contents can be distinguished from the darker ones – which is precisely the task the participants of this sensory workshop are facing.
One of several practical exercises in the seminar organized by METRO’s Global Quality Assurance team and led by Christoph Sippel, state certified food chemist and sensory expert at Eurofins. Sensory analysis is crucial when it comes to food. Be it the development of new products or regular quality maintenance of existing products, for example for METRO's own brands, their quality assurance, or also the creation of menus in gastronomy. That's why there are dedicated standards for evaluation with human sensory organs. Put simply, the senses of taste, smell, touch and hearing as well as sight are used as measuring instruments, because, last but not least, the tasty presentation is also important.
Sensory analysis and product evaluation: dos and don'ts
Professional tasting starts with the selection of a suitable room and its preparation. Things to consider, for example:
👉🏼 Ventilation: Sufficient exchange of air
👉🏼 Ambient noise: Quiet atmosphere
👉🏼 Smell: The tasting room must be odourless, no odour-intensive cleaning agents or other substances should be used
👉🏼 Presentation of samples: Daylight (if necessary by daylight lamps), neutral tableware
Why does loudness matter for a food tasting? ‘Product testers should feel comfortable and there should be no distractions,’ advises sensory expert Sippel. After all, judgements should be as unbiased as possible.
There are various methods for professional tastings to ensure reliability and validity. Basically, a distinction is made between
analytical and hedonic methods. The former aim to achieve objective results by having specially trained panel members describe and evaluate products analytically using selected technical terms – for example, aromas or texture characteristics. Hedonic sensory tests are more subjective: Here, testers without special sensory training give their verdict on how well they like a product.
Triangular Test: Is there a perceptible difference?
To find out whether a difference between two products can be perceived, the so-called triangular test is suitable.
Example: a soft drink. The tasters are given two samples. One of them contains a different sweetener or a slightly different recipe. The tasters are now asked to indicate whether they can tell the difference: Do the samples match (in) or is a difference perceptible (out)?
Here it is important that the entire tongue is covered by the test product. ‘We don't just taste with the tongue, but also with the palate and throat area,’ Sippel explains. In his practice seminar, the participants are given ten different glasses of water for training purposes. Sweet, sour, salty, bitter and umami (savoury-spicy) are the five basic directions for taste. The question: Which water tastes like what? During the practice tasting, the lay testers came up with quite different results. No surprise, says Sippel: ‘The saltier someone eats in general, the less sensitive he is – and it’s generally more difficult than for them then to recognize salt.’ It’s the same with sugar.
The sensory expert's tip: ideally, testers should avoid highly spiced food the day before – and not eat anything for at least half an hour, preferably an hour, before the tasting. Also one hour in advance: ‘No coffee, no tea, no more smoking.’ This of course does not help in the visual assessment of the different corn starch powder mixtures in the test tubes. At the end of the workshop, however, almost all participants mastered the task. And have thus passed a test themselves: the sight test.
Customer feedback as a benchmark
When evaluating own-brand products, METRO relies on feedback from those who need to know: Restaurateurs. Like the team from the San Rocco Hotel and Restaurant on the Croatian peninsula of Istria. The crew collaborates on the development of new food products. Watch the video here: "Hotel und Restaurant San Rocco: Ambassador of the Croatian way of life"