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Sensory Evaluation

Sensory Evaluation

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Sensory Evaluation

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  1. Sensory Evaluation FCS 3120

  2. Food Quality • Sensory attributes • Nutritive content • Food safety

  3. Sensory Evaluation • Human senses to evaluate palatability • “humans” as panelist or judges as measurement instrument • Value depends on objectivity & precision of judgments

  4. Types of panelists • Consumer (untrained) • Semi-trained (experienced) • Trained (highly trained) • Responses recorded on ballots (scorecards)

  5. Primary sensory attributes • Appearance • Flavor • Texture • Perceived by senses individually and processed by brain into total impression of quality

  6. Appearance • Shape & size • Color or hue • Gloss/luster/sheen & other surface characteristics • Opacity • Volume • Interior appearance

  7. Factors Affecting the Perception of Appearance • Nature of the light source • Nature of the object • Nature of the surroundings

  8. Flavor • Olfactory (smell) • Nose • Nasal cavity from mouth • Taste • Salt (front sides) • Bitter (back) • Sweet (front tip) • Sour (sides) • Umami (taste enhancers such as MSG that are savory)

  9. Tips for evaluating smell • Take several small “bunny sniffs” • Block nose & briefly chew food then release nose & breathe in deeply • Breathe fresh air between to avoid fatigue

  10. Terms • Aftertaste • Exhaling vigorously after swallowing, forcing volitals up to olfactory receptors • Threshold level • Level at which taste is detected • Subthreshold levels • Compounds not tasted but influence perception

  11. Texture: chemical & physical • Hardness/tenderness • Brittleness • Chewiness • gumminess • Cohesiveness • Viscosity • Elasticity • Adhesiveness

  12. Factors affecting taste sensitivity • Time • Concentration • Temperature • Taste interactions • Taste fatigue • Age (?)

  13. Types of sensory testing • Descriptive • Affective/Preference • Sensitivity/Difference

  14. Difference tests • Paired comparison • Duo-trio • Triangle • Rank order

  15. Descriptive Tests • Scoring/scaling • Structured: specific intervals on scale labeled with numbers or descriptive terms • Unstructured: verbal descriptions at ends but not all along the scale Descriptive Flavor Analysis Panel

  16. Affective/Preference Tests • Preference • Paired-preference • Ranking for preference • Acceptance

  17. Sample Preparation & Presentation • Experimental Control • Expectation Error • Stimulus/logical error • Halo effect • Suggestive error • Degree of motivation • Contrast effect • Positional bias • Fatigue

  18. Ballots/Scorecards • Developed for specific experiment, date, name of judge • Listed in order of evaluation • Descriptive characteristics need careful descriptions & way to score numerically • Acceptability