sensory analysis

1. Sensory evaluation

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 by :

• Taste panel evaluation

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, and paired comparison.

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
It determines the specific differences and how extreme are those differences. It requires trained panels example – Linear scorecard.

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.