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|Definitions of words used in Sensory Science|
A glossary of words associated with Sensory Science.
Absolute threshold: See stimulus threshold.
Acceptance measurement: Consumer test to determine the acceptance of (new) products. Generally involves a comparison of new products with those already on the market.
Acquired preferences: Preferences which are acquired during life as a result of learning or conditioning processes.
Adaptation: Ability of a sense to show a change in perception as a result of the continuing effect of a constant stimulus; the stimulus threshold of the affected sense becomes adapted to the stimulus intensity level.
Adaptive response: An appropriate action in which the individual responds successfully to some environmental demand. Adaptive responses require good sensory integration, and they also further the sensory integrative process.
Additivity: Addition effect of sensory impressions in a mixture so that the perceived overall intensity is equal to the sum of the intensity of the single components.
Affective tests: Tests to evaluate the popularity of an aroma and/or taste impression (also called hedonic tests).
Aftertaste: Sensory impression that lasts longest after swallowing.
Analysis of variance: Multivariate statistical method. An independent variable Y, one or more independent variables X. Are there X differences between the products for term Y?
Analytical testing: See objective testing.
nosmia: Olfactory disorder resulting in temporary or permanent loss of smell.
Appearance: Characteristics that encompass all visually perceptible sensory impressions of a food. Examples include shape, surface, structure, colour, lustre, clarity, cloudiness, opalescence.
Aroma: Total (positive) olfactory impression gained from breathing through the nose and from expiratory olfaction.
Astringency: Ability of substances to cause the surface of the mouth cavity to contract.
Attribute: Single perceptible impression of a characteristic feature, e.g. red for colour, sweet for taste, firmness for consistency.
Authenticity tests: These are carried out to determine whether a product tastes as the consumer expects and whether it is considered “genuine” by the consumers.
Aversion tests: Tests to determine whether and by how much a taste is rejected.
Balancing: Products are placed in systematically changing order so as to neutralize external effects such as product positioning and product sequence.
Basic taste qualities: These comprise sweet, sour, salty and bitter. In Japan a fifth taste quality is also included known as umami (monosodium glutamate).
Blind test: Test products are presented without any distinguishing features relating to brand or manufacturer.
Boredom tests: Tests which can be used to determine whether a food is regarded as boring by the consumer, or whether a competing product is perceived as tasting more interesting.
Branded test: Test products are presented with brand and origin details. The (taste) evaluation differences between blind tests and branded tests give an indication of the brand influence.
Bulbus Olfactorius: Nerve cells of the brain in which the aroma stimuli transmitted through the receptor cells are further processed.
CASA: Abbreviation for Computer-Aided Sensory Analysis.
Category scale: Products are placed in categories according to particular attributes, which can be verbally or numerically subdivided.
Characteristic: Properties that are evaluated equally in a sensory-physiological sense, e.g. appearance, smell, taste.
Characteristic group: A combination of particular characteristics, e.g. appearance/phenotype, flavour, aroma, consistency, mouth feel, texture.
Cluster analysis: Multivariate statistical analysis method with several variables X. Example: can products be combined into uniform groups on the basis of similar characteristics using the terms X?
Coding: Products are given a code and tested with their identity unknown in order to eliminate the influences of product marking and manufacturer. The code can take the form of a 3-digit random number or a letter.
Comparison sample: See reference sample.
Conditioning: Influences which can lead to the emergence of preferences and aversions.
Conjoint analysis: Analytical methods which measure the contribution of single product components to perception or preference formation on the basis of integral consumer judgments.
Consensus profiling: Quantitative and qualitative description of all product-relevant attributes, with the final evaluation taking place in a group discussion.
Consistency: Density, firmness or viscosity of a sample; perceived by haptic sensation through pressing, feeling, chewing or swallowing.
Contextual influences: Influences arising as a result of the experimental conditions, e.g. the sequence of products to be tested; factors such as tiredness or alcohol can also have an effect.
Control sample: Sample from the same test batch with which all other samples are compared.
Correlation: A connection between 2 variables in statistics.
Crispiness: Haptic and acoustic impressions obtained from chewing a sample.
Cutaneous modalities: Sensations transmitted using specific sensors in the skin, the mucous membranes and deeper connective tissue layers (also tendons, muscular coats, periosteum) and which encompass the 3 sensory modalities, touch, heat and pain.
Deadaptation: Restoration of original sensitivity.
Descriptive process: Method of sensory assessment which describes the important product characteristics for the consumer.
Descriptive testing: Test method involving verbal description of characteristics or attributes of one or more products.
Descriptor culling: Reducing the number of descriptive terms used in descriptive analyses to a practical number, with which the panel can effectively work.
Detection threshold: See stimulus threshold.
Difference testing: Tests that compare at least 2 samples with each other. They can be differentiated into the paired comparison, triangle and duo-trio test.
Difference ranking test: panelists are asked to rank in order an attribute the sample possesses (or lack of).
Difference threshold (successive): The increase in stimulus intensity that a barely perceptible difference causes.
Dilution (profile) testing: Evaluation and description of the intensity of a sample following stepwise dilution with a suitable solvent.
Discriminance analysis: Multivariate statistical analysis method. A dependent variable Y and several independent X. Can the combination of several X terms explain product differences Y ?
Duo-trio test: Three samples are presented to the taster. One is labeled "R"(reference) and the other two are coded. One coded sample is identical with "R" and the other is different. The panelist is asked to identify the odd sample.
Error probability: Probability of arriving at the right results just by guessing.
Evaluation test: Test to evaluate product characteristics or characteristic attributes according to an assessment plan.
Excitation: Activated state of a cell or cell complex in response to a stimulus.
Expert: Formally qualified assessor who possesses specialist technical knowledge and experience and who is responsible for testing particular products/product groups.
External sensory panels: Groups of assessors not employed by the company.
Extrinsic factors: External influences on product acceptance, i.e. factors relating to marketing, packaging, brand, price, and so on.
Factor analysis: Multivariate statistical analysis method: several variables X; can certain X terms be combined to give a higher dimension?:
Flavor/flavour: The sum of olfactory, gustatory, thermal and haptic impressions.
Flavor-profile method: The flavor-profile method consists of a small laboratory panel of 6 or 8 people trained in the method measure of the flavor profile of food products. Descriptive words and numbers, with identifiable meaning to each panel member, are used to show the relative strength of each note on suitable scale.
Free choice profiling (FCP): Quantitative descriptive process, in which each panelist evaluates products using their own list of descriptors and scale. Training to coordinate panel performance is not necessarily required. Evaluation is by multivariate methods.
Generalized Procrustes Analysis: Multivariate statistical analysis method used to classify and analyse sensory data from consumers or descriptive panels.
Gustatory impression: See taste impression.
Gustatory perception: Sensory impressions arising from the action of water-soluble substances on receptors in the mucous membrane of the tongue, oral cavity and pharynx.
Habituation: Lowering of reaction intensity as a result of a constant stimulus.
Haptic impression: Sum of tactile and kinaesthetic perceptions such as temperature, pain, touch and strength.
Hedonic testing: Assessment of sensory perceptions according to like/dislike. Samples are presented in succession and the subject is told to decide how much he likes or dislikes the product and to mark the scales accordingly. The nature of this test is its relative simplicity. The instructions to the panelist are restricted to procedures, and no attempt is made at direct response. The subject is allowed, however to make their own inferences about the meaning of the scale categories and determine for themselves how they will apply them to the samples. A separate scale is provided for each sample in a test session.
Indicative consumer panel: Consumer panel, whose test results give an indication of the preference level and in principle remain available for repeat, comparative tests.
Innate preferences: Preferences existing from birth and not acquired through learning or conditioning processes.
Instrumental analysis: Measurement of (odour- and taste-determining) components of foods using technical equipment.
Integrated impressions: Sensory impressions resulting from the combined effect of different aroma and taste components and which can lead to effects such as suppression, additivity and synergy.
Intensity: Expression of attributes.
Intensity measurement: Determination of the expression of individual attributes.
Intrinsic factors: Inner factors of product acceptance, i.e., essentially the sensory characteristics.
Kinaesthetic impression: Sensory impression arising from deformation or comminution of the sample using the hands or teeth.
Layperson: Untrained assessor who gives a subjective statement on the sensory impression of a sample.
Limbic system: Phylogenetically old part of the diencephalon, responsible for the processing of olfactory impressions.
Line scale: Unstructured scale usually drawn as a line for marking a decision.
Long-term preference test: Test process which enables the preference profile, e.g. of new products, to be observed once initial effects such as curiosity have subsided.
Masking: Certain product properties can be suppressed by others and therefore not perceived. Sometimes this masking effect is carried out deliberately in order to better assess other properties, e.g. by using red light to mask colour.
Momentary preference: Current preference for a product which is not necessarily lasting.
Monadic tests: Evaluation of a sample without direct comparison to other samples.
Mouth feel: Sum of haptic ( tactile and kinaesthetic), thermal and nociceptive perceptions in the oral cavity, e.g. hardness and elasticity.
Multiple Paired Comparison Tests: Panelists are asked to taste two samples and rate attributes such as saltiness. The panelists may be asked to mark the sample that is the most or least salty. This test involves a number sample pairs.
Multivariate processes: Statistical analyses which can help explain large amounts of data, such as cluster analysis and factor analysis.
Neutralization aid: Item, such as water or bread, used to level out the flavour effects from preceding foods during sensory testing.
Numerical scale: Numbered sensory scale.
Objective testing: Methods that do not involve making a personal judgment. Also called analytical testing.
Off-flavour: Undesired aroma or taste impression, generally regarded as unpleasant and leading to product rejection or irritating sensations.
Off-odour: Olfactory impression that is not characteristic of the test material.
Off-taste: Gustatory impression that is not characteristic of the test material.
Olfactometry: Instrumental determination of olfactory impressions (concentration and duration of olfactory stimulus).
Olfactory impression: The sum of impressions that arise as a result of the action of volatile compounds on receptors present in the olfactory mucosa.
Olfactory memory: Memory of aromas can be learnt and maintained through regular use.
Olfactory perception: Impressions obtained from the action of volatile substances on receptors present in the nasal mucosa.
Organoleptic: Subjective impressions obtained using the human senses.
Organoleptic testing: Subjective product examination using the human senses.
Overall sensory impression: Assessment based on a combination of all characteristic attributes contributing to sensory quality.
Paired comparison: Pair of coded samples that represent the standard or control and an experimental treatment is presented to the panelist, who is asked to indicate which sample has the greater or lesser degree of intensity of a specified characteristic, such as sweetness and hardness. If more than two treatments are being considered, each treatment is compared with every other in the series.
Panel: Group of assessors selected to take part in a sensory test.
Panelist: Those participating in the sensory test.
Partial least squares (PLS): Multivariate statistical analysis method, enabling product sensory data from consumers or descriptive panels to be classified and analysed.
Perception: Information conveyed by the sensory organs without any recognition features, but having quality and intensity characteristics.
Perception threshold: See stimulus threshold.
Point scale: Numerical form of a category scale, which has established intervals and a starting and end point, e.g. a 5-point scale.
Popularity testing: See subjective testing.
Positional bias: A type of contextual influence. The preceding test product influences the evaluation of following products, with the tester unconsciously making comparisons, and therefore no longer providing an independent evaluation.
Preference measurement: Process to determine the popularity and/or preference of one product compared to another.
Preference tests: Preference or acceptance tests determine representative population preferences and these tests inherently require many people on the panel.
Principal component analysis: A special type of factor analysis. The dimensions consist of a linear combination of variables.
Product profile: Combination of the intensity of various characteristic attributes of a sample.
Profiling: See quantitative descriptive analysis.
Qualification: Proven abilities and skills gained through education and experience of selected test procedures and materials.
Quantitative descriptive analysis (QDA): Description of the intensity of the attributes of a sample.
Ranking: Simultaneous presentation of at least 3 products in random order, which then have to be arranged according to specified criteria (e.g. product properties, like/dislike).
Receptor: Nerve cell that is excited by stimuli. Receptors of relevance to food analysis include those for optical, acoustic, chemical, thermal, mechanical and pain-releasing stimuli.
Receptor cell: See sensor.
Recognition threshold (value): Minimum stimulus intensity that evokes a qualitative clearly describable sensation.
Reference sample: Sample from another batch which is used as a yardstick/standard for a given product attribute or intensity.
Regression analysis: Multivariate statistical method, e.g. can the term Y be explained using 1 or more of the terms X?
Reliability: Dependability of statistical results.
Replication: Test repetition.
Retronasal perception: Olfactorily perceptible attributes of the mouth contents obtained via the retro oral-nasal pathway (choanae). These aromas combined with the basic taste qualities provide the overall flavour sensation.
Sample rotation: Systematic changing of sample processing in order to offset sequential effects on flavour impressions.
Sampling: Procurement of test samples under defined conditions.
Saturation threshold: Stimulus intensity which results in the maximum sensitivity extent that can be described qualitatively; increasing the stimulus intensity does not affect the sensitivity extent, but can lead to discomfort.
Scoring: Coded samples are evaluated by the panelist who records his reactions on a descriptive graduated scale. These scores are given numerical values by the person who analyzes the results.
Selection methods: Procedures to find appropriate candidates for carrying out specific sensory analyses; they should possess a suitable memory for taste and good expression skills.
Selection tests: Aptitude tests for potential members of trained sensory panels.
Sense of hearing: Sound impressions are conveyed via hair cells (mechanosensors) in the cochlea. Different noises occur when chewing or biting and can be used to describe terms such as "crackly" or "crispy".
Sense of pain (nociception): Generally unpleasant sensations transmitted via free nerve endings in skin and tissue, e.g. stinging, burning, prickling, scratching, astringency; itching as a submodality of pain (tickling, tingling sensations).
Sense of sight: Sensory impressions gained using the eyes. Rods and cones act as sensors, whose perceptions (colours, shapes and contrasts) are conveyed to the optic track.
Sense of smell: Olfactory sensations conveyed via the olfactory cells (chemosensors in the olfactory mucosa). An olfactory sensation can also be obtained from the mouth contents via the retro oral-nasal pathway (choanae), known as retronasal or choanal olfaction.
Sense of taste: Gustatory impressions conveyed via taste cells (chemosensors) present in the mucous membrane of the mouth and also in the pharynx and upper oesophagus.
Sense of temperature: Temperature dependent sensitivity to the qualities of warmth and coldness as transmitted via thermosensors (heat and cold sensors) in the skin and subcutaneous tissue.
Sense of touch: Impressions obtained from feeling with the hands, lips and tongue, and also from movement in the mouth and throat which are transmitted by touch receptors.
Sense organ: Organ that receives sensory stimuli and transforms them into a state of excitation. Sensory sensations and perceptions occur in the central nervous system (CNS) as a result.
Sense system: Combination of sensory organ, associated neural pathways and processing centres in the central nervous system.
Sensibility: Physiological ability to perceive different stimuli using the sense organs. (General description for sensitivity/susceptibility to stimuli).
Sensitivity: In contrast to sensibility, the particular sensitivity or receptibility towards stimuli at low intensity.
Sensor: Cell or major cell component that receives and responds to particular stimuli (photo-, mechano-, thermo-, noci- and chemosensors).
Sensory analysis: Planning, preparation, carrying out and evaluation of sensory tests, plus interpretation of results as required. Human senses are used as the measuring instrument.
Sensory analyst: Formally qualified assessor who is competent in the theory and practice of sensory analysis.
Sensory cell: See sensor.
Sensory characteristics: Impressions of a product gained using the human senses.
Sensory impression: Reflection of a particular stimulus quality in the central nervous system. These can be differentiated into olfactory, gustatory, haptic, acoustic and optic sensory impressions.
Sensory input: The streams of neural impulses flowing from the sense receptors in the body to the spinal cord and brain.
Sensory leader: Experienced individual responsible for selecting and training the panel and for planning, implementing and evaluating the panel tests.
Sensory memory: Ability to remember chemosensory sensations, i.e. taste and smell; differentiations are made between ultra-short, short and long-term memories.
Sensory modality: Group of similar sensations that are transmitted by a particular sensory system, such as hearing, sight, taste and smell, as well as mechano-, thermo- and nociception (the 3 cutaneous modalities in the skin and mucous membrane), and the sense of balance.
Sensory quality: Those food quality attributes that can be perceived by the human senses.
Sensory quality assurance: Sensory quality of raw material, intermediate and final products, established by comparison with a standard.
Sensory science: The science of using human senses for testing and analytical purposes. Product characteristics are received, registered and analysed using the sense of sight (eyes), smell (nose), taste (mouth), and hearing (ears).
Shape: Visual impression evoked by external shape of the sample.
Simple descriptive analysis: Verbal characterization of characteristics or attributes of samples.
Smell: Total sensory impression gained from volatile compounds using the sense of smell. Characteristic for describing and evaluating sensory quality.
Somatosensory modalities: See cutaneous modalities.
Somatosensory perception: Also called mouth feel. Impressions that occur in the mouth during eating and drinking, but which are evoked by texture perception and thermoception rather than by gustatory or olfactory sensation.
Spatial summation: The more receptors that are stimulated upon sampling, the more intense the sensory sensation.
Spider-web diagram: Diagram representing a product's sensory profile. Measured intensities are plotted on radial lines, emanating from a central point.
Standard deviation: Deviation of individual values from the total mean value (mean error).
Standard sample: See control sample.
Stimulus: Something that elicits a reaction (response), resulting in a sensory sensation.
Stimulus threshold: Minimum stimulus intensity that provokes a response, which due to the low intensity can not be described qualitatively. Synonym for detection threshold.
Subjective testing: Tests requiring a personal opinion.
Symbolic scale: Scale that uses pictures/symbols instead of words.
Synergy: In sensory analysis describes the total taste impression, arising from the combined effect of several taste-producing substances.
Taste: Comprises the taste qualities, sweet, sour, salty and bitter. In principal this means all gustatory, olfactory and haptic impressions that occur as a result of taking food into the mouth.
Taste impression: Attributes perceived using the taste cells (gustatory sensors).
Test batch: Defined subset of the test material (e.g. by type, shipment, origin, treatment).
Test criteria: Criteria for sensory testing specified by the sensory leader.
Test material: The food that is the subject of the sensory analyses.
Test requirements: Defined conditions for conducting a sensory test, from sampling, through testing to evaluation.
Test sample: Item from the test batch to be sampled by the panelists.
Tester: Assessor who has undergone specific training and demonstrated an aptitude for sensory analyses.
Texture: Structural-conformational quality of food that can be assessed by haptic, rheological, optical and acoustic methods.
Texture Profile Analysis: Physical test using TA-XT2 texture analyzer to mimic taste panel scoring of food.
Thermoception: See sense of temperature.
Threshold testing: Presentation of products in order of increasing intensity in order to establish threshold values.
Time intensity tests: Quantitative measurement of changes in intensity with time, e.g. the taste changes that occur between intake of food into the mouth and swallowing.
Trained consumers: Members of the public with particular sensory abilities, who are trained in order to participate in a test group.
Triangle test: Sensory analysis of samples in order to determine slight differences in single or complex sensory impressions. Samples are arranged in the shape of a triangle; the aim is to tell which sample differs from the other two identical samples.
Trigeminal perception: The Trigeminus optical nerve which transmits the tactile sensations of the sight region is involved in aroma perception.
Two-out-of-Five test: Similar to the Triangle Test; panelists are asked to pick two out of the five that are similar in characteristics.
Umami: In Japan it is known as a fifth taste quality (monosodium glutamate).
Unstructured scale: A line with start and end points which is used for measuring the intensity of a product characteristic.
Validity: Preciseness and exactitude of statistical results.
Visual impression: Product attributes that are perceptible using the eyes (dark/light, colours and shapes).
Visual texture components: Inner quality (structure, make up) of the test material that can be perceived using the eyes.
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