Sensory Testing of Food (2024)

• Olfactory sense
  The sense of smell is a chemical sense, as the perception of smell is caused by soluble and volatile chemical substances. Smelling ability is influenced by gender, age and environment. For example, the ability to smell decreases with age. The sensory cells adapt to odors, i.e., one should not smell a sample for too long.
• Gustatory sense
  Taste is perceived via taste receptors on the tongue. A distinction is made between the basic tastes sweet, sour, salty, bitter and umami.
• Visual sense
  The food is first perceived visually, whereby characteristic properties such as color, shape, size and structure are determined.
• Tactile sense
  The stimulus is received here, for example, via the receptors in the skin. The characteristic properties of texture, consistency and temperature can be picked up via this sense.
• Auditory sense
  The sense of hearing is a mechanical sense, since pressure fluctuations are picked up by the movement of air or bones.

The purpose of a sensorial evaluation is to provide the research department of a product with scientific information about the sensory properties of the product. The researchers can use this information to further improve their product.

Furthermore, sensorial evaluation serves to control and maintain a specific and defined product quality.

Sensory testing is particularly recommended for:

• the assessment of the marketability of a product
• the exact description of product characteristics (e.g. profile testing)
• the examination of storage stability (examination of the best-before date, MHD)
• product comparison and product positioning
• the handling of complaints (complaint processing)
• changes to the product
• the development of new products

Food sensory testing involves the use of the human senses in the objective evaluation of food products. Characteristics such as appearance, texture, odor and taste are analyzed by trained testers to assess product quality or derive opportunities for improvement.

We help you bring products to market that will delight your customers with all their senses!

Who carries out sensory testing?

Sensory tests are carried out in the laboratories of the Tentamus Group by a sensory panel. According to DIN ISO 5492, a panel consists of a group of testers – these can be laymen or established testers. In ISO 8586, a distinction is also made here between test persons and sensor persons. Test persons are all persons who participate in a sensory test, i.e. laypersons or persons with experience. Sensory persons have been trained and have experience.

The test persons of a panel must fulfill various requirements:

• Availability
• Neutral attitude towards the product to be tested
• Linguistic competence
• No allergies or intolerances to test product
• Good senses (no olfactory, gustatory disorders, etc.)

To ensure the quality and neutrality of the tests, a sensory test group of Tentamus Laboratories consists of several test persons as well as trained and experienced sensory experts.

How do off-flavors occur?

Off-flavor is an undesirable taste, odor or mouthfeel. This can arise during storage or processing and often leads to a deterioration in the sensory quality of the product.

Off-flavor occurs,

• when a food is contaminated
• by undesirable compounds as a result of chemical changes or contamination during storage or production, or
• by the formation of bacteria in a product

Examples of off-flavors may include:

Off-flavor	Chemical Formula	Odor	Most frequent cause	Matrix
Geosmin		moldy, red beet	Microorganisms (Streptomyces)	Chocolate
2,4,6-Trichloranisole		Musty, cork note	Microbial transformation of chlorine-containing substances in the bark of the cork oak tree	Wine
3-Methyl-2-buten-1-thiol		Skunk	Sunlight	Beer
Various unsaturated Aldehydes		Greasy, metallic	Sunlight/PET-bottles	Mineral Water
4-Vinyl-2-methoxyphenol		Clove	Degradation of 4-Hydroxy-3-methoxycinnamic acid	Orange Juice
p-cresol		Like Cowshed	Malfermentation	White Pepper

As off-flavors can be produced by an immense variety of compounds, with concentrations in the ppb or ppt range often sufficient to spoil an originally delicious taste, they present a significant analytical challenge.

For consumers, off-flavors can lead to dissatisfaction or even reductions or lapses in purchasing behavior.

If your product has an off-flavor, we identify the cause in our sensory analysis lab. With our help, your customers will once again be able to enjoy their favorite food or drink in the usual high quality.

How are the samples being prepared for sensorial evaluation of food?

For successful sensory testing, sample selection, preparation, neutralization, coding and presentation are critical to provide an objective evaluation.

• Sample selection
  The differences between the samples should be as small as possible, i.e. all testers should receive the same samples as far as possible.
• Sample preparation
  Samples must all be at the same temperature, unprepared samples are tasted at room temperature (except e.g. ice cream).
• Sample neutralization
  In most cases it is undesirable that e.g. the manufacturer is known. Thus, the sample must be transferred to a neutral container.
• Sample coding
  The samples are neutrally coded before testing to make them anonymous.
• Sample presentation
  The samples are presented in neutral vessels, these must have the same shape and color for all testers.

What types of sensory testing do our laboratories offer?

Our laboratories perform food sensory testing of both already prepared and unprepared products. The raw products are sensory evaluated. According to the instructions on the packaging, the products are then prepared and sensory tested again by our staff.

• Sensory testing according to the DLG scheme
  The DLG scheme is a scoring system in which a descriptive sensory analysis of the visual, haptic (texture), olfactory (smell) and taste qualities of a product is carried out using an evaluation scheme. Our testers record all sensory descriptors (negative trait characteristics) that are included in the scoring. Points are awarded from 0-5, where 0 (zero) corresponds to unsatisfactory and 5 to very good. The awards that a product can achieve based on this test procedure are gold, silver and bronze awards. The manufacturer can advertise with the DLG quality seal on his product for a certain period of time.
• Hedonic sensory testing
  Hedonic sensory testing also belongs to the field of food sensory analysis. Here, the food and its properties are evaluated with the sensory organs. The special feature here is that these tests are carried out by untrained personnel or normal consumers. The food products to be tested are classified and finally evaluated on a so-called hedonic scale based on subjective criteria. In order to ensure representative results for our customers, the laboratories of the Tentamus Group take special care to include a diverse and large group of test persons in the test.

• Simple descriptive test
  This test is performed according to DIN 10964 and aims to describe the sensory criteria in terms of appearance, smell, taste and texture. The descriptions can be freely chosen by the tester or selected from a list. These descriptions should not be judgemental.
• Comparative sensory / rank order testing
  In rank order testing, different samples are compared with each other. These samples are then ranked based on variables such as taste, odor or texture. The evaluation is usually done using the Friedman test, which indicates whether there is a significant difference between the samples.
• Triangle Test
  The triangle test, is a scientific method in which three products are presented to a test panel. Two products of them are identical, and one is different from the others. The 3 products are tasted blind to see if the tester can detect a sensory difference. Significance tables from the DIN standard are used for evaluation, which allows a judgment on the distinctness of the samples. This sensory test is performed to optimize the product by checking whether, for example, the additional ingredient adds sensory value to the overall product.
• Paired Comparison Test
  This test is used to determine a perceptible sensory difference or similarity between two samples in one or more specified attributes. A distinction is made between a one-sided and a two-sided test. In the one-sided test, the test group leader knows the difference between the two products and knows which sample the tester would have to choose. In the two-sided test, the test group leader knows the difference but does not know how it will play out and how the tester will decide.
• Duo-Trio test
  In the Duo-Trio test, the tester is given a control sample and compares it to at least one pair of samples. One sample of this pair is identical to the control sample and it is tested whether this is recognized by the examiners. Based on table values, a statement can be made at the end as to whether a significance level has been reached and whether the samples are different.

On customer request, an evaluation based on the DLG can also be performed.

• Trained specialists comprehensively test and assess your products with regard to their sensory properties
• Sensory evaluation for standardization of product series, as well as assessment of marketability
• Customer training for sensorial evaluation