Sensory Evaluation CDE Preparation

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Sensory Evaluation CDE Preparation

• Jeffri Bohlscheid
• School of Food Science
• University of Idaho

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Objectives

• After this session the student will be able to
• Apply techniques of orthonasal evaluation of
  unknown aromas
• Apply multiple techniques to differentiate common
  food products

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Food Sensory Evaluation

• One does not necessarily have to have a special
  gift
• Most professional sensory evaluators are trained
• Specific techniques are used for different
  products

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FFA Sensory CDE

• Two parts
• Aroma Recognition
• Pool of samples from 31 possible common aromas
• Triangle test
• Choosing which one sample of the three presented
  is different

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Aroma Recognition Possibilities

• 1. Peanut Butter
• 2. Chocolate
• 3. Maple
• 4. Molasses
• 5. Vanilla
• 6. Almond
• 7. Oregano
• 8. Basil
• 9. Licorice (anise)
• 10. Clove
• 11. Nutmeg
• 12. Cinnamon

• 13. Ginger
• 14. Lemon
• 15. Lime
• 16. Orange
• 17. Banana
• 18. Coconut
• 19. Raspberry
• 20. Strawberry
• 21. Cherry
• 22. Grape

23. Onion 24. Garlic 25. Butter 26. Smoke
(liquid) 27. Lilac (Floral) 28. Wintergreen 29.
Peppermint 30. Menthol 31. Pine
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Aroma Recognition

• Training
• Group similar aromas
• What are the similarities and differences between
  groups?
• What are the similarities and differences within
  groups?
• Develop Sense Memory
• You want to try to link a visual memory with the
  aroma
• See aroma in your head
• Improved recognition

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How to Smell

• Dont wash for a month (just a joke)
• Remove interferences to what you are evaluating
• Dont chew gum
• Dont were perfume, cologne, strongly scented
  deodorant, hair products, or other personal care
  products
• Dont smoke or use smokeless tobacco products
• Stay away from strong bleach or other caustic
  fumes
• Wash your hands, and use a neutral smelling soap
• Close the windows and doors

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How to Smell

• Things to remember
• Our sense of smell habituates quickly.
• We get used to an aroma rapidly and lose the
  ability for fine discriminations.
• Caused by over sniffing.
• Need to take a 30-60 second break to allow
  receptors to recharge.
• Sniff water between samples to moisten nasal
  passages and flush aroma molecules out.

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How to smell

• When you have the sample (most likely in a
  bottle)
• Uncap and hold about ½ in. below your nose
• Close your eyes
• Take two short strong sniffs then one longer one
  where you can feel the air at the back of your
  throat
• Move the bottle away and visualize the smell
• Cap the bottle.
• If you re-sniff, sniff some water in between

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Set up for training

• A pitcher or bottle of neutral smelling water
• Small cups (wax Dixie)
• Labeled samples
• Usually small dark colored glass vials or
  medication bottles (2-4 oz).
• Small wad of cotton (increases surface area and
  allows for more volatilization of the aroma
  molecules)
• A few drops of the sample is generally sufficient
• Unlabeled samples
• Actually use a random 3 digit codes to
  differentiate
• Use a different code each time

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Aroma Training

• Start out with one aroma from each group with
  labeled bottles
• Sniff and visualize
• Mix up and try again with unlabeled bottles
• Evaluated until 100 correct
• Try with another set and repeat process

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Aroma Training -Continued

• Now try 3 or 4 from the same aroma group
• Developing finer discrimination skills
• Sniff and visualize
• Remember to take a break between each sample
• Now try with randomized, unlabeled bottles

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Aroma Training -Continued

• When you have reached a high level of accuracy
• Begin random selections of 12 unlabeled samples
• If you miss one, go back and try to figure out
  what you were missing do you have a strong
  mental picture of the smell?
• Repeat with different set of 12
• Continue until you have gone through all of the
  sample
• Keep randomizing and sniffing!

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Training Schedule

• Mastery of the aromas will take a number of
  sessions
• Sensory fatigue will generally occur after 30-45
  minutes
• Mix this activity up with other classroom
  activities
• The senses are generally most acute around 10 am
  and worst right after lunch or at the end of the
  day.
• Training in the morning and testing your skill
  later in the day

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Homework

• Get in the habit of evaluating all of the foods
  and smell you run across each day.
• You will be surprised how quickly you will begin
  to develop your skills
• Imagine only practicing a musical instrument or
  sport 30 minutes a day, once a week vs. 1-2 hours
  and everyday

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Sources of Aroma

• Many of the aroma manufacturers will provide
  sample free of charge. See the appendix at the
  end of the slides.
• You can also purchase a number of essences and
  extracts from grocery (see the spice aisle) and
  health food stores.
• You may need to dilute with water.
• Be aware that many of these products are
  sensitive to heat, light, and oxygen.
• They will start losing there strength after a few
  months.
• Store in a cool dark place.

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Triangle Test

• Sing with me!
• One of these things is not like the other one,
  one of these things is not the same
• The object of this activity is to differentiate
  between different food products. Examples
• Diet vs. Regular soda
• Different brands of corn flakes
• Different types of yogurt (low fat vs. fat free)

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Triangle Test

• You will be presented with three samples
• Use all of your sensory skills to determine which
  is different
• Vision
• Touch
• Smell
• Taste

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Visual Evaluation

• Look for differences in color, shape, size of
  product, texture, or components (chunks of fruit
  in yogurt)
• Different shades of brown in toasted oat cereal?
• For gels or thick products
• Do they break or smear the same
• Do they both stick or drip for a spoon the same
  way?

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Touch Evaluation

• For dry items
• Are they the same texture?
• Do they crumble the same way?
• Do they smoosh the same way between your
  fingers?
• Moist items
• Smooth vs. grainy
• Sticky, gummy, tacky or slimy

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Smell Evaluation

• Use the techniques we discussed earlier

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Taste evaluation

• Combination of four aspects
• Taste
• Sensation
• Aroma/Flavor
• Mouthfeel

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Taste evaluation

• Taste
• Sweet sugar, honey
• Salty table salt
• Bitter quinine, caffeine, strong cold coffee
• Sour vinegar, lemon juice, citric acid
• Umami meaty or brothy, bullion cubes

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Taste evaluation

• Sensation
• Drying astringency
• Strong cold black tea
• Cooling minty
• Breath mints
• Chewing gum with xylitol
• Hot spicy, piquant
• Jalapeño pepper, cayenne peppers, cinnamon
  candies
• Temperature how cold or hot

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Taste evaluation

• Aroma
• Retronasal evaluation
• Chew, inhale through your mouth, and exhale
  through your nose
• Use your smell evaluation skills

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Taste evaluation

• Mouthfeel
• How does the product feel in your mouth?
• Crunchy
• Sticky
• Slimy
• Hard
• Grainy
• Does the item dissolve quickly or coat your
  mouth?
• Rub the food with your tongue across the roof of
  your mouth

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Triangle test

• Try to find one aspect that stands out for
  different types of food products
• Look for obvious differences, but be aware of
  subtleties

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Triangle test

• When setting up samples always use the same
  sizes, shapes, and amount/volume.
• Also use the same plates or cups.
• Do not let the evaluator see or smell anything
  until the time for evaluation
• Limit the time to no more than 3 minutes per
  sample

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How do you improve your skills

• Practice, practice, practice!
• Concentration on task
• Find your weak points and work on them

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Aroma Standard Sources

• You may be able to obtain free samples of aromas
  from the following manufacturers
• http//www.ottensflavors.com/company.asp
• http//www.virginiadare.com/
• http//www.bellff.com/?idlngeng
• http//www.dmflavors.com/index.cfm/fuseaction/dmfl
  avors.home/index.cfm
• http//www.givaudan.com/givcom/
• http//www.firmenich.com/m/flavors/solutions/overv
  iew/index.lbl