1. Unit 3: Sensory Evaluations | The Human Factor
CH. 3

2. Introduction - Food Opinions
Your mouth waters as the smell of fresh baked cookies surrounds you. You feel warmer just seeing the steam rising from a cup of coffee.
How would you feel about eating grubs? Drinking rattlesnakes blood? Or chewing fish eyes?  other areas of the world consider these delicacies.
We are going to explore why people have differing opinions on what tastes good and how food scientists overcome these opinions to create new foods.

3. Sensory Evaluation
Definition: the human analysis of the taste, smell, sound, feel and appearance of food.
Ex) Sammy may like his apple pie sweet, but John may like his apple pie crisp and tart even though they grew up in the same house.

4. Influences on Food Likes & Dislikes
Physical
Psychological
Cultural
Environmental

5. 1) Physical Influences
Your body’s genetic makeup will affect what you can taste and how well you can identify flavors.
Flavor detection affected by
Number of taste buds
Gender
health
*give thiourea taste strips to show that people inherit slightly different body chemistries.

6. 1) Physical Influences Continued…
People are classified based on how well they can taste individual flavors
Supertasters: identify subtle differences in flavor and aroma.
Medium Tasters
Nontasters: “taste blind” unable to distinguish between different tastes
*differences in tasters are mainly because of the amount of taste buds. Supertasters have as many as 1,100 taste buds per square centimeter on their tongues. Nontasters have been found to have as few as 40 taste buds per square centimeters.
*women’s hormone changes also influence tastes causing changes in food preferences and cravings during pregnancy

7. 2) Psychological Influences
Believed to be a protective mechanism of the brain
Taste bias: when positive/negative experiences cause a person to like/dislike a food, respectively.
Trained taste testers have to put taste testing biases aside when evaluating food products.
*negative food experience examples: being ill and eating a certain food. Getting ill after eating a certain food.
*bias’ examples: preferring chocolate to vanilla. Label terms and brand names.

9. 3) Cultural Influences
Culture: beliefs and behavior followed by a group of people passed from one generation to another
Ex) Grits – regional food more likely served in the south.
French lifestyle: daily shopping for fresh ingredients.
Jewish religion traditionally does not eat pork, and Hindu followers do not eat beef.

10. 4) Environmental Influences
People are more likely to eat what is available and economical
Environmental factors: climate, geography, and fuel availability affect food costs and obtainability.
*Jamaicans eat a lot of fresh fruit bc it is grown abundantly
*Alaskans eat less fruit due to the climate
*Coastal regions eat more seafood.

11. Sensory Characteristics of Food Products
To evaluate a food product, you have to identify the desirable characteristics of that product
3 main sensory characteristics:
1) Appearance
2) Flavor
3) Texture
* Desire changes from one product to the next. You want cake to be moist but the crackers to be crunchy etc

12. 1) Appearance
Definition: refers to the shape, size, condition and color of a product.
Evaluated on the interior and exterior.

13. 1) Appearance Continued…
Color – can influence a person’s perception. Can be measured with exactly with a colorimeter.
To avoid color influencing a taste test panel, researchers will use colored lights or blindfolds.
*Colorimeter measures hue (basic color- red, blue, green), value (light or dark), chroma (how intense a color is).
*Ex) Chocolate bar that is darker brown might give the idea that it has a richer flavor.

14. 2) Flavor Definition: the combined effect of taste and aroma.
5 basic tastes:
Salty
Bitter
Sour
Sweet
Savory (umami)

15. 2) Flavor Continued…
Each region of the tongue is designed to respond to one type of taste. The more taste buds a food stimulates, the more intense the flavor is perceived to be.

16. 2) Flavor Continued…
Sour foods are evaluated by their astringency – the ability of a substance to draw up the muscles in the mouth

17. 2) Flavor Continued…
Flavors of some foods become more intense depending on the temperature.
Ex) Europeans serve cheese at room temperature rather than chilled to bring out the flavor of the cheese.

18. 2) Flavor Continued… Aroma – the odor of food.
Through training most people can improve their ability to distinguish flavors. As your ability improves, so will the ability to distinguish flavors.

19. 2) Flavor Continued…
Aromas stimulate the olfactory bulb (“smell memory” nerves) located at the base of the brain behind the bridge of the nose.
2 pathways to reach the olfactory bulb
Through the nostrils
Through the back of the mouth
Smelling and chewing food longer allows more information to the olfactory bulb, which makes flavors more intense.
*nostrils- this is why you can almost taste a food your are smelling.

20. 3) Texture
Definition: how a food product feels to the fingers, tongue, teeth, and palate (roof of mouth).
Evaluated based on
Chewiness
Graininess: size of the food particles in a product
Brittleness: how easily a food breaks apart
Firmness: food’s resistance to pressure
Consistency: thinness or thickness
*Chewiness: taffy high in chewy, pudding low.
*Graininess: grits highly grainy, cream low.
*Brittleness: crackers very brittle, cake low.
*Firmness: beef jerky very firm.
*Consistency: measured in terms of pourability.

21. Measuring Sensory Characteristics Objectively
Different instruments are used to measure how much force is needed to compress, tear, or juice a food to measure texture.
Scientists can also measure the amount of sugar, salt, acid content, as well as color, size and shape.
This is needed to keep products uniform in quality and packaging.
*Although there are measuring standards available, this does not determine what the consumer wants. Taste testing panels determine the public’s interest by using these panels.

22. Taste Test Panels
Definition: a group of people who evaluate the flavor, texture, appearance, and aroma of food products.
Can be trained professionals or untrained consumers
Taste testers must be able to distinguish why they like or dislike certain qualities of food. Ex) You make like the flavor, but not the texture
*must be able to recognize biases. If there is a bias, (you may not like chocoalate flavor) you can still feel if the food is smooth, creamy or gritty.
*professional taste testers – used more during a products development. Can tell the differences between subtle differences to make the product sucessful.
*untrained consumers – used more to evaluate products already in the market place. Sometimes they evaluate whether they would buy a totally new type of product.

23. Setting up Taste Testing Panels
Researchers must remove any factors that could sway testers such as
Influences from other testers
Environment of the testing room
Psychological biases
*body language of other panelists can affect the outcome. Either tested individually or not allowed to make comments or sounds.
*Blindfolds or color lights can be used in the testing room to control environmental influences. Taking a sip of warm water in-between testing will rinse any residue from the mouth. All samples must be at the same temperature.
*people prefer low number samples (1 or A) to higher numbers (C or 3) so it is best to use a 3 digit code. Only 4 to 5 samples can be judged at one time to get accurate results.

24. Creating an Evaluation Form
Number scale is usually with odd numbers to provide a neutral point. Occasionally each number has a meaning
Ex: Number : definitely like, 2: mildly like, 3: neither like nor dislike, 4: mildly dislike, : definitely dislike

25. Creating an Evaluation Form Continued…
Sometimes testers are asked to verbally describe their sample as well.
Ex: product too brittle, creamy, chewy or salty, sour, strong/weak