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Sensory vs. organoleptic analysis

Sensory vs. organoleptic analysis. Sensory analysis = organoleptic analysis Sensory analysis ≠organoleptic analysis. Sensory Evaluation.

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Sensory vs. organoleptic analysis

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  1. Sensory vs. organoleptic analysis • Sensory analysis = organoleptic analysis • Sensory analysis ≠organoleptic analysis

  2. Sensory Evaluation A scientific discipline used to evoke, measure, analyze and interpret reactions to those characteristics of food and materials as they are perceived by senses of sight, smell, taste, touch and hearing. IFT; USA

  3. DEFINITIONS: • A group of similar sensory impressions mediated by a given organ is referred to as sense (modality). • Factors from the environment or from body biochemistry that elicit sensory impression are referred to as sensory stimuli • A combination of sensory impressions is called a sensation.

  4. DEFINITIONS: • An interpretation of sensation with reference to what has been experienced and learned by individual and the resultant overall impression is called sensory perception. • The least stimulus energy capable of producing a sensation is called an absolute threshold

  5. DEFINITIONS: • Detection threshold - the magnitude of stimulus at which a transition occurs from no perceived sensation to a perceived sensation (similar to absolute threshold). • Difference threshold - the least amount of change of a given stimulus necessary to produce a change in sensation.

  6. DEFINITIONS: • Recognition threshold - the minimum concentration at which a substance is correctly identified. • Terminal threshold - the magnitude of a stimulus above which there is no increase in perceived intensity of appropriate quality for stimulus.

  7. FOOD PRODUCTS ARE MULTIDI- MENSIONAL: • Visual: package appearance, product appearance, color. • Olfactory: product aroma/fragrance. • Kinesthetic/Tactile: product feel. • Gustatory: product taste, texture. • Auditory: sound from use.

  8. CAN WE DISCRIMINATE TWO STIMULI: • The sensitivity of human senses is limited • There are limits to the physical magnitude of stimulus - absolute sensitivity. • There are limits to the magnitude of physical difference between two stimuli which can be perceived - differential sensitivity.

  9. Principles of sensory response behavior: • The same stimuli may evoke a variety of sensory responses on different occasions. • Two physically different stimuli can evoke two identical responses.

  10. EXPERIMENTAL MEASURES USED TO OVERCOME THIS PARADOXICAL SITUATION ARE AS FOLLOWS: • Panelists are required to make a choice • Reliance is placed on repeated measurements

  11. SENSORY METHODS • ANALYTICAL TESTS • Discriminatory tests • Sensitivity tests • AFFECTIVE TESTS

  12. SENSORY METHODS • DISCRIMINATORY • Simple Difference - “which sample is different?” • Triangle test • Duo-trio test • Directional Difference - “which sample is sweeter?” • Paired comparison test • Ranking test • Scoring or Scaling - “how hard is the sample?”

  13. QUESTIONAIRE FOR SIMPLE PAIRED COMPARISON TEST Name: Date: Product: Taste the sample on the left first. Indicate which sample more sweet. Samples Check sweeter sample 234 _______ 345 _______ Comments:

  14. QUESTIONAIRE FOR DUO-TRIO TEST Name: Date: Product: On your tray you have marked control sample (R) and two coded samples. One sample is identical with R and the other is different. Which of the coded samples is different from R? Samples Check odd sample 435 ____________ 674 ____________ Comments:

  15. QUESTIONAIRE FOR TRIANGLE TEST Name: Date: Product: Two of these three samples are identical, the third is different. 1. Taste the samples in the order indicated and identify the odd sample. Samples Check odd sample 276 ______________ 398 ______________ 567 ______________

  16. Triangle test continued 2. Indicate the degree of difference between the duplicate samples and the odd sample. Slight _________ Moderate _________ Much _________ Extreme _________ 3. Acceptability Odd sample more acceptable _________ Duplicates more acceptable _________ Comments:

  17. Situation exercises • You used simple paired comparison test evaluated two samples of grapefruit drink for preferences. 14 of 24 judges selected sample a. Determine whether there is a statistically significant difference between samples A and B? • You used a simple paired comparison test to evaluate the sweetness of two muffin samples. 16 of 21 judges selected sample B to be sweeter. Determine whether there is a statistically significant difference in the sweetness between sample A and B. • You used duo-trio test to evaluate two sample of cottage cheese for prefence. 14 judges of 19 judges selected sample A over B. Determine whether there is a statistically significant difference in preference between sample A and B. • You used triangle test to evaluate two sample of citrus juice for bitterness. 16 of 22 judges selected sample A to be more bitter than sample B. Determine whether there is a statistically significant difference in bitterness between sample A and B. Next you further evaluated the correct responses to determine how great was the difference between sample A and B. You found that 10 judges said that the difference was moderate, 4 judges said that the difference was slight and two judges said that the difference was extreme. How great was the difference in bitterness.

  18. PSYCHOLOGICAL ERRORS AND PHYSICAL CONDITIONS: • Error of central tendency. • Time-order error. • Error of expectation. • Stimulus error. • Logical and leniency error. • Contrast and convergence errors. • Proximity error. • Suggestion effects. • Motivation.

  19. SENSORY EVALUATION IS USED TO: • Monitor formulation changes. • Monitor processing changes. • Monitor shelf-life changes. • Guide product promotion. • Determine consumer acceptance.

  20. INDUSTRY INTEREST IN SENSORY ANALYSIS IS OFTEN FOCUSED ON: • How to connect consumer acceptance data to sensory and analytical data. • How to determine the sensory strength and weakness of product. • How to monitor panelists and evaluate panel training. • How to understand cultural and other sources of differences in the use of rating scales. • How to manage the vast amounts of sensory and consumer data typically generated.

  21. IN SENSORY EVALUATION: • The aim is to discover something. • It is best to have a repeated measuring design. • A number of samples presented to judge is important. • Judge should work individually. • The rating may be influenced by a preceding stimuli. • The rating of stimuli depends on the context. • It may be difficult to produce physically identical samples.

  22. QUESTIONS ANSWERED BY SENSORY WORK: • Is there a difference? • Is the difference significant? • How great is the difference? • Is the product preferred? • How acceptable is the product? • What is the sensory description of the product?

  23. CONTROLS: • Temperature. • Lighting. • Atmosphere -smell. • Individual booths. • Sample selection (identical code dates). • Coding samples (3 digits codes). • Sample preparation. • Sample presentation. • Subject selection.

  24. CODING AND PRESENTATION OF SAMPLES • Blind testing. • Three-digit codes. • Balanced order of presentation. • Random order of presentation

  25. SENSORY EVALUATION STEPS: • Define overall project objective • Define test objective. • Screening the samples. • Designing the test (method and judges). • Conducting the test. • Analyzing the data • Reporting the results.

  26. SENSITIVITY TESTS: • Thresholds Methods are designed to measure the detection and difference thresholds. • method of constant stimulus differences • method of limits • Dilution Tests are application of threshold measurement for practical problems.

  27. Table of results

  28. Diagram showing the proportion as a function of stimulus values

  29. Guidelines to help to improve your sensory evaluations: • Please read instructions carefully. • Take as much time you need to arrive at your decision. • Note a flavor sensations when judging - initial, overall, and aftertaste. • Evaluate samples from left to right, as they face you on the tray. • Rinsing your mouth with water between each tasting helps remove the flavors and “standardizes” your mouth for the next test. • When testing between products with strong aftertaste, give yourself 1-2 minutes between tasting to avoid flavor carryover.

  30. Guidelines to help to improve your sensory evaluations: • Making sounds like groaning, laughing, or talking during the evaluation may influence others. Please use the form for recording all your sensations. • If you avoid eating, drinking, chewing gum and smoking 1/2 hour before tasting, it will sharpen your ability to taste and smell. • Check your results as they leave to see how you did but please remember to talk softly so others in the booths can’t hear. • It’s a great temptation to share your “taste experience” with others. Please wait until everyone has tasted, so you can’t bias their judgement.

  31. SENSORY JUDGES • Expert judges • Trained judges (3-10) • Semi-trained judges (8-25) • Consumers (80+)

  32. Factors affecting judge sensitivity: • Health • Smoking • Memory • Motivation

  33. Before selection of panelists we should know that: • Sensory skills vary from person to person. • Most individuals do not know what their ability is to taste and smell the product. • All individuals should learn how to take a test. • Not all individuals qualify for all tests • Judges are rewarded for participation not for correct scores. • Skills one acquired are forgotten if not used on a regular basis. • Skills can be overworked or fatigued.

  34. Before selection of panelists we should know that: • A judge performance can be influenced by numerous factors unrelated to the test or product. • All judges information should be treated in a confidential manner. • Judges should not be paid to participate in a sensory test. • Test participation should be always on volunteer basis.

  35. Training judges: • Use as test material the same products that will be tested. • Prepare the test to obtain variations in product similar to those which will be met in the actual experiment. • Adjust the difficulties of the test so the group as whole will discriminate between samples but some individuals will fail. • Use test forms similar to those to be employed later. • Start with a large group of candidates as feasible and a selection test that is operationally simple.

  36. Training judges: • Screen on the basis of relative achievement continuing until a top ranking group of reliable size can be selected. • At each step rejected those who are obviously inadequate, but retain more people than will be required for panel.

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