Factors Affecting Sensory Evaluation

i) Health of Evaluator: The evaluator should be physically and mentally in good health. The sensitivity for evaluator in respect of sense of smell and taste should be normal. He/she should not be suffering from anosmia and ageusia.

ii) Age: Evaluators should preferably be in the age group of 18-50 years. Personsm of younger age are unable to properly interpret and communicate the sensory results, whereas at older age the memory decreases. Sharp memory of evaluator is considered highly useful in judging of dairy products, particularly for quality control applications.

iii) Interest and Motivation: Sensory evaluation work is very time consuming and sometimes fatigue also. The evaluator should, therefore, have interest and be motivated.

iv) Adaptation: Continuous exposure of evaluator to a particular stimulus, particularly at high concentration for long time, leads to decrease in his sensitivity(also called as fatigue). It is therefore desirable either to give sufficient time between the samples or use taste sanitizers, such as brine solutions, fruits and mild acids. The taste sanitizers improve the taste sensitivity or bring it back to normal level.

v) Sampling: The sample should be representative of the lot. Care shall be taken that no loss of flavour occurs and no foreign tastes or odours are imparted during the sample presentation. The sample should be drawn from a bulk lot in such a way that body and texture characteristics are not changed.

vi) Sample Numbers and Quantity: For economic efficiency of sensory testing, larger the number of samples per session, the better it will be. However, the size and quantity of sample for each judging session vary from product to product. Normally 5-8 samples with average intensity of flavour for each sitting are optimum. Number of samples may be increased in case of odorous material of low intensity. The amount of each sample should be about 25-50 ml or gm, which is sufficient for one full sip or bite.

vii) Score Card: The evaluation card should be simple, brief, easy to follow and all important sensory attributes included in it. It should be clearly printed and the matter should be arranged in logical sequence. Terminology used shall be clear and understandable.

viii) Miscellaneous Factors: The temperature of serving should be close to that recommended for each product (Unit 3). The test should be carried out preferably one hour before or after lunch. Use of materials, which are likely to vitiate results, such as smoking, chewing pan and taking intoxicants by the evaluator should have a time lapse of atleast 30 minutes before the test. Use of strong odoriferous substances such as cosmetics, flavours, hair oil should be avoided by the evaluator as well as in the testing area.