Sensory evaluation
1.It is defined as a scientific discipline used to measure, analyze and interpret reactions to those
characteristics of materials as they are perceived by the senses of sight, smell, taste, touch and hearing.

2.The objectives of sensory evaluation are

• To study the sensory evaluation of meat in its use for research
• To demonstrate the methods of meat cookery used for sensory evaluation.
• To describe the correct procedures for temperature control, coring, shearing and serving samples to panels.

3.The evaluation of meat products can be divided to into two categories

• Taste panel evaluation
• Measurement of sensory attributes by help of machine s like instron and Warner - Bratzler shear force .

i)Sensory evaluation by taste panels
The taste panel is selected based on the following considerations
a)Function of a panel within the total sensory evaluation system
b)The types of the panels and there functions — under this it should be understood that how panel work fit into
overall sensory evaluation program , choosing qualified and motivated persons, thorough training in terminology by
using a broad and comprehensive frame of references for each product , introducing a scaling method which can
be taught effectively and which can be treated statistically and using the panel data effectively to study products
in depth and provide detailed product analysis to management.

Various methods used for sensory evaluations by taste panels
a) Discrimination
It determines how products perceived and and significance of difference. it requires trained panel example – triangle
test, paired comparison
b)Descriptive
It determines the specific differences and how extreme are those differences. It requires trained panels
example – Linear scorecard.
c)Affective
It measures preferences for products or magnitude of like/dislike for a product. It can be used for consumers
or trained panelists example Hedonic test.

a)Discrimination
i)Triangle test – panelists receive three coded samples. They are told that two of the samples are the same
and that one is different. Panelists are asked to identify the odd sample. This discriminatory testing method is
often used as a tool in quality assurance programs to insure that samples from different production lots are
against yours. Triangle tests are also used in product development studies to determine if various ingredient
substitutions or changes in processes will rresult in adverse product effects.

ii)Duo- Trio test – in this test, three samples are presented : one sample is labeled "R"( reference) and the other
two are coded. One of the coded samples is identical to "R" and the other coded sample is "R" . Panelists
are asked to identify the correct sample by choice is always 50%. Both Triangle and Duo-Trio may be used to
screen panelists for their ability to repeatably select a specific trait when tasting products for flavor, the
Duo-Trio test is often used instead of the Triangle test because the former method requires less tasting.

iii) Paired - comparison test — A pair of coded samples is presented for comparison on the basis of some
specified characteristic (saltiness, sweetness etc.) This method is similar to the triangle tests, however fewer
samples are required and there is less tatting. The statistical efficiency is not, however , as great with the
paired- comparison as it is with triangle test.

iv)Ranking test — this test is an extension of Paired- comparison test. panelists receive three or more
coded samples are asked to rank samples for intensity of some specific characteristic. ranking tests are often
used to screen one or two "best samples' from a group of samples rather than to thoroughly test all samples.
However , no indication of the magnitude of difference between samples is obtained because samples are only
evaluated in relationship to each other.

b)Descriptive methods
It involves discrimination of qualitative and quantitative traits of a sample by use of a small ( 5- 10 0 member trained
panel. Such techniques as flavor profile, textural profile and QDA ( quantitative descriptive analysis are used.
Descriptive analysis requires at least three evaluative processes. First, discrimination of the trait ; second,
description of the trait; and third, quantifying the trait. The steps of discrimination and description of traits are
qualitative. The language used is developed through careful training an d practice with the panel. This requires
panelists to develop a common vocabulary which catalogues various sensory stimuli with appropriate language.
Descriptive analysis is a complex cognitive process which requires more mental acuity than sharp taste or olfactory
senses. Discrimination among stimuli is only part of the qualitative process. The third step in descriptive analysis is
to quantify the traits as to how strong they are. Two products may be quite similar in their qualitative components
but differ overall because of the relative intensities of these characteristics. Descriptive analysis is the only sensory
method that deals with the total picture or profile of a food product. it may be used to suggest or interpret
instrumental methods or other sensory test information or be used as a research guideline tool, or as
a method of quality assurance or quality control.

Scale tests – Many types of scales or scoring systems are used for preference evaluations. These may include
structured word scales or graphics. In structured scales a scale of 7 to 10 points is recommended because
panelists tend to avoid using the end points on the scale. To use fewer than 7 point scale may not allow the
panelists to show the degree of variation observed. More of a word- descriptive scale becomes the most critical
feature. It may be appropriate to involve the panel n defining word descriptions and numerical scores to be assigned
to these words. Remember , the panel results must be interpretable and accurately reflect what was objectively
measured.

Hedonic scale – The word " hedonic" is of Greek origin and relates to degree or magnitudes of like or dislike.

Rank preference – when more than 4 or 5 samples are served in a ranking test, the difficulty for the panelists
to rank products is increased. More re-testing is generally done in order to assure the correct positioning
of the rankings.

Paired preference test – This is the most simple and oldest method for to the panel. The panel is asked to
indicate which sample they preferred and why they chose the preferred sample. In all preference testing at
least one sample ( control) with a known hedonic value ( scale of like or dislike ) should be included. Samples
may be ranked from most to least desirable even when all samples are considered to be of questionable desirability.
A known sample provides a reference point upon which to base results.