Sensor technology (food testing)
The sensor technology in food technology or food analysis , also food sensor technology , deals with the evaluation of properties with the sensory organs . It is used in industrial and craft product development, production, quality control, quality assurance, marketing and research; Food can also be judged by the authorities, for example by the trade inspectorate .
Instruments
Humans and their sensory organs are the most important measuring instrument for assessing the sensory value of food .
Be used when considering the sense of sight , the sense of touch , the smell , the taste and the sense of hearing .
For the characteristics and differentiations of perceptions, see Sense Organ and Perception .
Methods
The sensory examination or test or analysis is methodologically an independent examination within the food examination, which corresponds in its meaning to other analytical examination methods and is equivalent in its value.
The design of tests depends on the product. The implementation is subject to DIN and ISO standards. DIN EN ISO 5492: 2009 regulates the terminology used in sensor technology, while DIN 10950 gives a general overview of the basics of the methodology of sensor testing.
Difference tests (discriminatory test)
The aim of the difference check is the objective determination of product differences that can be detected by sensors for similar products.
Duo trio test
In the duo-trio test, the test person receives three samples. The first sample is control sample K. This control sample is presented to the test person so that it is clear to him whether the control sample is product A or B. The other two samples are once product A and once product B, the order being chosen at random. There are therefore only two possible combinations, KAB and KBA. The test person should now choose the sample that corresponds to the control sample. Guessing gives you a 50% hit rate.
“A” - “Not A” test
The following two tests are performed by sensory-trained individuals. In the “A” - “Not A” test, the tester first receives sample A and has to memorize the sensory properties well, because back-tasting is undesirable. Then the examiner is given a few samples, each of which is to determine whether it is sample A or not.
"2 out of 5" test
A total of five samples are set up. Of these, two samples belong to product A and three to product B or vice versa. Regardless of the order, there are a total of 10 different combinations to arrange the five samples of the two products. The examiner should now find the sample pair that only appears twice in total. The probability of finding the correct allocation for non-gourmets is just 10%. However, the large number of samples can cause sensory fatigue, which can adversely affect the motivation and performance of the examiner.
Descriptive examination (descriptive examination)
A product or sample is assessed by sensors and simply described. The aim of the descriptive test is the neutral description of sensory product properties and impressions. Regular test procedures are based on the "simple descriptive test", which is defined as a DIN standard and contained in the LFGB according to Section 64. This test includes a description of the external condition for later identification and a description of the odor. A description of the taste is also given for almost all samples.
The result of this examination is usually decisive for whether a more extensive sensory examination must follow, the type and scope of which depends on the nature of the sample material and the question. It is co-determinative for the definition of the examination spectrum to be carried out.
Affective testing (hedonic)
Better known as popularity tests or acceptance tests, is an integral part of preference mapping .
Threshold check
During the threshold test, the stimulus, recognition, difference and saturation thresholds are determined. The tests are carried out with the ranking test or the triangle test.
Detection test
During the tests, the basic flavors are tested in an aqueous solution. In these tests, the test person should recognize the type of sensation (salty, sweet, etc.). Is considered a test to assess the test person's (sensory) sensitivity to taste. In a modification, it is also used to detect odorous substances.
Ranking check
A number of patterns must be sorted in ascending order. The taste to be recognized is recognized and sorted in different concentrations diluted in aqueous solution. Depending on the product, a ranking check for colors and smells is also possible. This test is also held to identify the daily form. You have to consider that an emerging cold, which the test person has not yet physically noticed, has a negative impact on his sensory properties. The ranking check is also common for other sensory assessments (odor).
2-AFC test
The abbreviation AFC stands for "Alternative Forced Choice". The test person has a certain number of alternatives and there is a compulsion to choose. In the 2-AFC test, only two samples are built up, one A and one B. Both samples differ in their sensory characteristics. The test person should taste the sample with the sensory stronger or weaker intensity of a certain taste characteristic. There are only two possible arrangements AB and BA in the experimental setup. Non-discriminators have a 50% chance to hit.
3-AFC test
The 3-AFC test is carried out in the same way as the 2-AFC test. In contrast to the previous test, the subjects now have the choice between three different products A, B and C and are asked to determine the product with the strongest or weakest sensory intensity. There are already 3 here! = 6 different ways to arrange the three samples: ABC, ACB, BAC, CAB, BCA and CBA. In the 3-AFC test, non-tasters only have a hit probability of 33.3%.
Triangle check
Also called the triangle test , it is a difference test. The triangular test is used for sensory testing of three samples to determine slight differences between individual or complex sensory impressions. With this method, two different test samples are compared using sensors.
Is considered a difficult and safe placement test, is also used for training and classifying examiners (threshold value determination). A triangular test can secure a ranking test. Three samples are set up at random, whereby two samples are identical and you are asked for the most strongly deviating sample (due to the inhomogeneity of the test material, there may be a difference even with supposedly identical samples). The samples are set up in the shape of a triangle.
See also
literature
- Maynard A. Amerine, Rose Marie Pangborn, Edward B. Roessler: Principles of Sensory Evaluation of Food. Academic Press, New York 1965, ISBN 978-1-4832-0018-7
- ASTM International. 2009. Standard Terminology Relating to Sensory Evaluations of Materials and Products, E253-09a. ASTM International, West Conshohocken, PA. E253-09a
- Sensory analysis: method overview and areas of application - Part 2: Difference tests . In: DLG (Ed.): DLG worksheets sensor technology . No. 1 , 2010 ( PDF ).
Web links
- Expert knowledge of sensor technology at the DLG - website with free online literature