1. Food Quality Sensory attributes Nutritive content Food safety
Food Quality: complex concept…..indicates degree of excellence of food…affects food acceptability

2. Sensory Evaluation Human senses to evaluate palatability
“humans” as panelist or judges as measurement instrument
Value depends on objectivity & precision of judgments
Even though its subjective must use objectivity. Must evaluate food characteristics, not biased by food preferences

3. Primary sensory attributes
Appearance
Flavor
Texture
Perceived by senses individually and processed by brain into total impression of quality
Each has more than one contributor & there are overlapping zones
Classified according to the major human senses
Appearance: eye 1St. Impressions, “eat with our eyes” sense of sight more developed than other senses (dogs
have developed sense of smell) EX. Lack of acceptance of blue foods.. Yellow perceived as lemon
Flavor: taste & olfactory
Texture: muscle endings of tongue & hand

4. Appearance Shape & size Color or hue
Gloss/luster/sheen & other surface characteristics
Volume
Interior appearance
Size & shape: associated with quality(standards in food industry) balance, symmetry, contour,etc.
Color: “characteristic” of typical product or high quality product…sometimes influences other perceptions
cake baked vs. microwave
Light is either 1. Absorbed, 2. Reflected, or 3. Transmitted through
We don’s see absorbed colors, only reflected ones (why leaves are green)
Opacity: translucent or opaque, clear or cloudy (milk vs water)
Interior: cell size, lumps

5. Factors Affecting the Perception of Appearance
Nature of the light source
Nature of the object
Nature of the surroundings
Light source: fluorescent (blue), incandescent (yellow), halogen
Object: same cake baked at different times or temp will look different
Surroundings: optical illusions due to plate color, white cake on a dark plate will appear different than same cake on a white plate

6. Texture: chemical & physical
Hardness/tenderness
Brittleness
Chewiness
gumminess
Cohesiveness
Viscosity
Elasticity
Adhesiveness
In a panel need to list specific qualities to be evaluated
Mouthfeel: related to moisture & fat (oiliness, greasiness)
Tenderness: not too soft or too hard “number of chews” use similar bites of food chewed to same end point
Cohesiveness: strength of internal bonds making up the body of product
Viscosity: rate of flow
Elasticity: rate at which deformed material goes back to original shape
Adhesiveness: work necessary to overcome attractive forces between surface & other (tongue, teeth)
Also evaluate texture by visual (gritty or lumpy) or sound (chips are crunchy)
Have students list describe adjectives to define texture

7. Flavor Olfactory (smell) Taste Nose Nasal cavity from mouth
Salt (front sides)
Bitter (back)
Sweet (front tip)
Sour (sides)
Umami (taste enhancers such as MSG that are savory)
Combination of taste & smell…ind.variations in abilities & sensitivities
Aroma: foods more volitale at higher temp, judging should be at serving temp & avoid competing aromas
Taste: taste buds are stimulated on tongue, compounds need to be in a solution to react with taste buds
Sour: sides, instant, makes mouth water (pickles or yogurt)
Bitter: back, lingering aftertaste, (strong coffee or unsweetened choc)
Astringent: drying sensation (tannins bind protein in saliva) strong black tea

10. 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
Bullet 1: pulls flavor molecules up to the olfactory cells
Bullet 2: flavor molecules pulled up the back of the throat
Pungency of ginger, burn of cinnamon, cool of mint, tingle of carbon dioxide, sting of alcohol

11. Factors affecting taste sensitivity
Time
Concentration
Temperature
Taste interactions
Taste fatigue
Age (?)
Time: salt detected sooner than bitter, bitter lingers
Concentration: depends on tasters taste threshold (tasters, non-tasters, supertasters)
Temp.: taste sensations less intense as temp of food goes below 68, and inc above 86. Volatiles inc with temp
as temp inc. salt dec (BP biscuits will taste more salty at room temp) evaluate products at serving temp
as temp inc. Sweetness inc
as temp inc, Aroma inc
Taste interactions: sugar & salt, etc
inc acid, dec sweetness
inc sugar, dec sourness
flavors dissolve in fat, low fat dec rate of release of flavor molecules (perceived as less flavorful)
Odor fatigue more a problem quicker than taste fatigue

12. Experiment on your tongue
Let’s taste test!
Materials Needed:
cotton swabs
water
small cups or glasses
unsweetened baking cocoa
lemon juice
salt
honey
pens and paper for charting

13. Instructions for Tongue Mapping
Ask a friend to help. One of you will be the taster and the other will be the tester. When the first person is done tasting, you can switch so both of you will get a chance to taste.
Put a little bit of each substance in a cup. Mix the non-liquids with some water so that all the substances have about the same consistency.
Draw a chart for recording your results. Along the left side of the paper write each of the foods you will test in a separate row. Use unsweetened baking cocoa and water to test bitter, lemon juice to test sour, honey to test sweet, and saltwater to test salty. Across the top draw three columns for each taster. Label each with the taster's name and "front," "back," and "side."
Make some predictions. Do you think different places on your tongue will taste different flavors more intensely? Where on your tongue do you think each flavor will taste strongest? Will some flavors be easier or harder to taste than others?
Have the tester dip a cotton swab into one of the liquids and dab it either on the front, back or side of the taster's tongue.
The taster tastes the liquid, then takes a sip of water. This helps clear your tongue of the taste so it doesn't interfere with the next part of the experiment.
The tester then dips a new cotton swab in the same liquid and dabs it on a different part of the taster's tongue. The taster tastes the liquid again and sips some water. Now, try it again on the third part of the taster's tongue.
Once all the parts of the tongue have tasted the liquid, the taster says which part of his tongue tasted the liquid the strongest. The tester records the taster's answer on the chart.
Follow the same process for each of the different liquids. Then switch who tastes and who tests and do the whole taste test again with the new taster.
When all tasters have finished testing, talk about your results. Were your predictions correct? Did some of your results surprise you? Did both tasters taste the same things on the same parts of your tongues?