Scientific issues

LAB EQUIPMENT Analysis equipment, peripheral equipment and consumables
LAB FURNITURE Laboratory furniture of Köttermann, Waldner, Flores Valles and others
CONTAINER LAB Mobile or semi stationary laboratories in a container or on a trailer
SENSORY LAB Special equipment for the sensory product control
TRAINING Training of the users as well as preparation for certification
INSTALLATION Installation of laboratory furniture

Implementation of sensory tests under controlled conditions in the sensory lab

People are slightly deflected and suggestible in their perceptions. In compare to the functional superior senses of hearing and seeing, the chemical senses smell and taste are providing fewer clearly structured, unreliable sensations and it is difficult to observe the substances in a differentiated way, which are included for example in food and beverage. It is of enormous importance to eliminate all potential disturbing variables within the scope of sensory tests. From experience, it will only succeed during test applications under strictly standardized lab conditions

To carry out sensory tests professionally, it is not enough, to have suitable testing methods and volunteers. Only if the premises and the equipment are performing the corresponding criteria (constructional and technical), it is possible to obtain the data of scientific significance.

For example, it requires a bit of featured equipment, „normal“ labs do not posses of, to eliminate sense interference factors. This includes single test stations, a special lighting technology, sound-reducing building materials, a partitioned preparation room if necessary with kitchen and direct hatch to the single test stations and much more. The standardization of the tests will be ensured by identically equipped test stations, the individually controlled lighting situation, independent of time and arrangement of the test stations and the appropriate climate adjustments.

Aims

Scientific aims Measures
Meaningful and valid results Suitable volunteers and methods, elimination of disturbance variables
Statistisch auswertbare Ergebnisse Standardization of test conditions, elimination of disturbance variables
Independent objective results Open question options, elimination of disturbance variables

During testing, the volunteers should:

  • Feel at ease – ergonomic sitting position, comfortable chairs, pleasant climate
  • Find single, standardized test conditions
  • Absence of psychological influence
  • Not be distracted or interrupted, that means absence of disturbance variables

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Framework conditions

Elimination of disturbance variables

The disturbances are comprising all factors, which influences the perception of the volunteers or diverting the attention generally.

In this reason, measures to the avoidance resp. minimization are to take of:

  • Ambient noises
    • Test stations not be in the immediate vicinity of air condition or manufacturing plants
    • Avoid internal noise pollution
    • Test room not directly towards street side – avoid external noise
    • Noise abatement floor covering
  • Foreign odors
    • Exhausting/ ventilation system with an adequate air exchange per hour
    • Pressure difference between preparation room and test room: the test room ideally suggests of a higher air pressure
    • Use of smell inert materials for floors, wallpapers and cabins – For example, no carpet floor covering
  • Visual stimulation like reflections, shadows, irritating colors
    • Exclusion of daylight
    • Neutral color selection (white, light grey) for furnishings, ceilings and walls
    • Red light resp. green light for masking of different product colors
    • White light with an illumination level of 1000-1500 Lux
    • Regular glare-free illumination
  • Climatic influences
    • Constant conditions of temperature (air condition)
    • Constant humidity
  • Exertion of influence/distraction by test-neighbours at individual tests
    • Single cabins resp. partitions between test stations
  • Exertion of influence by contact with personal or insight into preparation room
    • Strictly separated preparation room without direct access from the test room
    • Hatches with minimal insight into preparation room

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Standardized test conditions

To achieve results of a high quality and to operate time- and cost-efficiently, tests under standard conditions are assisting. Some test conditions are to standardize product-dependently. At tasting, beer should have another standard temperature (+6°C) than red wine (+16°C). Below are the standardized areas.

  • Personal ergonomics
  • Test environment
  • Prearrangement/preparation
  • Specimen coding
  • Test procedures
  • Timetable
  • Evaluation

Examples:

  • Tasting with always constant product temperature
  • Identical test station equipment
  • Identical light situation at any test station
  • Testdurchführung laut einem vorher definierten Zeit- und Ablaufplan
Appropriate test personal

Depending on the question, the tests will be conducted by sensory experienced internal and external panels, own personal or untrained consumers.

Panels with inexperienced laymen (consumers or employees) will be used for affective testing. It is about questions of the popularity – preference – or acceptance of products. The product evaluation of the individuals is to be determined.

Analytical tests will be carried out by experienced assessors. They provide objective results within the framework of identification and quantification of sensory product characteristics and the balance declaration to other products.

The volunteers can be sensory experienced employees or extern panels. These, for example, passed a basic training, according to DIN 10961:

  • Detecting the types of the basic aromas
  • Balance tests
  • Aroma perception
  • Threshold testing

It is important to train and to check the sensory abilities at regular intervals. Some tests require panels with so called expert examiners. These have additional product-specific knowledge.

Suitable testing methods

Essentially, there are 3 existing types of testing methods. It is to ask the “right” questions and to clarify them by help of suitable methods.

  • Hedonic test procedures
  • Discriminative methods
  • Descriptive methods

Balance tests and descriptive testing will be combined to the analytic methods.

Hedonic or also affective test procedures deal with the subjectiven product evaluation. These include:

  • Acceptance measures
  • Preference tests
  • Aversion tests
  • Boredom tests
  • Permanent preference tests

Analytic test methods are calculating the product awareness. There is a distinction:

  • Discriminative methods – balance tests: Several products will be compared. The method is used, for example, at the exchange of raw materials, change of the production method or in cases of complaint. Examples for balance tests:
    • Ranking test DIN 10963
    • Triangle test ISO 4120
    • 2 of 5 testing
    • Paired balance test
  • Descriptive methods: These serve to describe the sensory properties and to quantify the intensity of this feature. They are an important component of the product development. Examples:
    • Simply descriptive testing DIN 10964
    • Descriptive testing with subsequent quality evaluation DIN 10969
    • Check of profile DIN 10967

Benefit

  • The volunteers can focus themselves on the specimens and the product variations – obtaining valid, reproducible and statistically analysed test results
  • Capacities will be used efficiently
  • Prevention of costly/unnecessary repeat tests

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