Sensory Evaluation of Food

Arnav Bhattacharya1MS10CH005

Introduction Sensory Evaluation is

defined as “A scientific discipline used to evoke, measure, analyze, and interpret those responses to products that are perceived by the senses of sight, smell, touch, taste, and hearing.”

Sensory science is the study of the reactions of the five senses - sight, hearing, smell, taste and touch - to the characteristics of physical matter.

The discipline does not just deal with "likes and dislikes," but scientifically evokes, measures, analyses and interprets psychological responses to physical stimuli, and thus belongs to the specialized field of psychophysics.

"Sensory science," adopts a unique approach to identification of the attributes that matter most to the end-consumer.

It employs “trained panellists," and where possible sensitive instruments, to provide the right guidance to the food manufacturers on what perceived attributes need to be incorporated into their products for their marketing success.

Sensation of some Basic Foods

Sensation of Taste Taste or gestation: This is a

"chemical" sense. There are four main types of tastes that receptors(buds) in the tongue can distinguish:

Sweet Salt Sour Bitter

Sense of Smell Smell or olfaction: This is a ““chemical" sense. Unlike taste, there are hundreds of olfactory

receptors in our olfactory epithelium (where the receptor are located).

Odour molecules have a variety of features and can combine with many or few receptors.

It is known that there isn’t one receptor for specific kinds of smells, our sense of smell works with ‘‘patter recognition’’

Why Use Sensory Analysis to Evaluate Food Products?

To evaluate quality (quality control) or improve quality.

To provide input for decision making (product development).

To determine the market value of a product.

To determine shelf--life of a product.

Why Use Sensory Analysis to Evaluate Food Products?

Ingredient substitution in product formulation.

To compare a product(s) with the competitor’s product(s).

To determine storage conditions.

Market Involved Today's consumers are

discerning, demanding & more knowledgeable about food and expect products which are safe, good value and of high sensory quality.

Therefore, knowing consumers' preferences and perceptions of the sensory characteristics of food products is very important to food manufacturers & retailers alike.

Statistical Techniques A person's sense of taste, smell,

touch, sound and sight form his perception of food. In a taste panel, these senses can be measured scientifically to obtain information about particular aspects of a food.

When conducting a taste panel, food is uniformly prepared and presented to panellists in isolated booths.

Judges record evaluations of the product on a sensory evaluation sheet that is decoded and analyzed by statistical procedures.

Comparison of various Parameters used to consider a Snickers bar

Comparison of various samples of Pillsbury Flour, depending on Wheat Content

Comparison of various values associated with a sample of Japanese green tea

Uses To improve sensory quality of a

product, or to ensure inter-batch consistency.

To understand the sensory characteristics of products, & how they influence customer selection.

To understand how their product fares with respect to that of competitors.

To understand how consumers differentiate between similar products.

Requirements for Sensory Evaluation

Sophisticated sensory booths that conform to American Society for Testing and Materials (ASTM) standards (Separate air-conditioning maintained at 20±2°C and RH 40±5%)

Glassware/containers for sensory evaluation of varieties of foods

Specialized software for statistical evaluation of sensory data

Laboratory for chemical/physical analysis of raw materials and processed foods

Model Sensory Evaluation Centre

Expectations from Panellists To produce reliable and valid data, the

sensory panel must be treated as a scientific instrument

It is therefore, necessary that panellists are free from any psychological features and physical conditions which might affect human judgments

Panellists must have an ability to perform the task and to repeat their judgments

Sensory Ability of Panellists It is necessary that each

panellist must be free from the following defects:

Taste perception disorders Odour perception disorders Colour blindness Denture defects

Health Requirements It is necessary that each panellist must

be free from the following defects: Allergies Use of those medications that effect

the ability to taste. Prone to minor infections of nose &

throat.

Discriminative Tests All panellists will be assessed for the

following 2 types of discriminative tests:

Difference Tests: Tests to find a difference between the control and other products.

Sensitivity Tests: To test the ability of panellists to detect sensory characteristics.

Descriptive Tests Descriptive tests to be carried out

among the panellists to measure their ability to evaluate qualitative and quantitative characteristics of the product

Possible Errors in Analysis Expectation Error Stimulus Error Suggestion Error Halo Effect Lack of Motivation Central Tendency Error Order Effect

Sensory Team Composition Based of the individual

performance of each trainee panellist, 5 should finally be chosen for the sensory evaluation work and 2 should be kept as reserved panellists

Separate sensory teams to be selected for different types of products based on the individual abilities of the panellists

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