Sensory
Testing

• 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.

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.

• 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

The following labo­ra­to­ries of the Tentamus Group offer senso­rial analysis: