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NUTR 211 exam 1
Sensory acceptability |
number one reason for food choice |
palatability |
please to the taste; provides sensory reward |
appetite |
a desire (craving) for food in general or for a specific food |
Evaluation |
to determine the significance, worth, or condition of something, usually by careful appraisal and study |
sensory evaluation |
-using all of our senses
-how we evaluate whether we enjoy a food or not |
Aesthetics |
-a pleasing appearance
-eye appeal |
Color indicators |
-ripeness
-degree of doneness
-freshness
-improve taste perceptions |
visual descriptors |
dull, transparent, glossy, turbid (cloudy), carbonated |
consistency |
-texture |
defects |
loaf of bread or cheese with mold |
Aromas/Odors |
result of volatile compounds that stimulate the olfactory center of the nervous system |
volatile compounds |
gaseous substances of low molecular weight |
retronasal olfaction |
affects perception of aroma |
orthonasal |
through the nose |
Aroma/odor impact |
-flavor
-stimulation of appetite
-detection of wholesomeness (spoiled or not) |
anorexia |
-loss of appetite
-negatively affected by odor |
ansomia |
-inability to smell
-use of flavor enhancers may increase intake associated with perceptual loss |
Gustatory |
what happens on our tongue |
taste |
recognition of volatile and nonvolatile compounds by taste buds on the tongue, palate and pharynx |
taste requires |
compound to be dissolved in liquid medium |
primary tastes |
sweet, sour, salty, bitter, savory/umami |
sweet |
sugars, glycols, alcohols, aldehydes
-everyone has same gene |
sour |
acids in food, H+ ions |
salty |
Na+ ions |
bitter |
caffeine, theobromine, phenolic compounds, alkaloids
-many genes related to bitterness |
savory/umami |
amino acids
-rich flavors
-ex. parmesan cheese, soy sauce, anchovies, mushrooms |
Concentration |
-the least amount of a substance that must be present to stimulate a response=threshold level
-taste fatigue-->cannot differentiate between higher level of flavor (extremely sweet) |
temperature |
most intense taste @ room temp |
warmer= |
sweeter |
increase temp= |
increase sweetness |
lower temp= |
increase saltiness |
Affect of aging on taste |
tastebuds lose abilities; less intense taste |
Tactile descriptors of food |
Consistency (chewiness, thick or thin), geometric properties (sandy, gritty), astringency (puckery mouthfeel) |
chemesthesis |
sensation of heating or cooling from food(hot peppers, cool mints) |
responsible compounds for chemesthesis |
-eugenol, piperine, capsaicin, gingerol, menthol |
flavor |
the combined sensory perception of aromas, taste, and mouthfeel. |
75% |
Percent that aromas plays in flavor |
consistency of food |
texture/viscosity |
fat content of food |
lingers longer than a lower fat food |
health status of individual |
foods don't taste as intense when sick |
auditory characteristics of food |
-no carbonation in soda=not fresh
-expectation |
Supplemental reading |
-Non-tasters ate more of the bitter vegetables (broccoli and more vegetables overall) |
Separation technique for supplemental reading |
taster or nontaster based on ability to taste .56 mmol/L soln of PROP |
bitter vegetables of supplemental reading |
black olives, raw broccoli, cucumbers |
sweet vegetables in supplemental reading |
carrots, red bell peppers |
Top notes |
-first impressions
-don't perceive for long, but big impact (citrus, herbs, spices) |
mid-notes |
-more subtle than top-notes, but longer perception on palate
-savory: umami, dairy, meat, salty |
low notes |
-primary tastes most predominant |
Finish (aftertaste) |
-what remains after swallowing
-bitterness, pungent aromas |
palate |
-"the complex of smell, taste and touch receptors that contribute to a person's ability to recognize and appreciate flavors"
-"the range of an individual's recognition and appreciation of flavors" |
flavor balance |
Western cuisines and eastern cuisines |
Western Cuisine |
salt, sweet and sour |
Eastern Cuisine |
hot, sour, salty, sweet |
salt |
salty foods such as anchovies, cheese, bacon, soy sauce & olives |
sweet |
honey, molasses, maple syrup, carmelized onions, balsamic vinegar |
sour |
lemon/lime juice, vinegar |
sodium reduction |
Dietary guidelines recommend ____ ____ by all americans |
tips for reducing sodium intake |
-create depth in food flavors by adding more spices
-avoid processed foods/reduce
-taste foods at table before adding salt
-adding a little acid (lemon juice/vinegar) can amplify salt taste in foods |
Sensory evaluation |
a science based discipline used to measure, analyze, and interpret reactions to those characteristics of food as they are perceived by our senses |
Subjective food evaluation |
use of people's responses to foods based on sensory experience |
objective food evaluation |
use lab instruments to measure sensory characteristics |
analytical tests |
subject evaluates differences between products |
Trained panelists |
very sensitive to flavors and odors |
Discrimination testing |
ask panelist if products are different from each other?
-forced choice or paired comparison test
-triangle test, duo-trio test
-ranking--rank intensity |
descriptive analysis |
how are food products different?
-describe flavor profile and identify perceived differences in intensity |
Affective Tests |
evaluate individual preferences
– Use panels:
– Hedonic scales:
– Ranking tests: |
Best facility characteristics |
-no odors, uniform lighting, low noise, lighting |
Panelists |
- no colds
- no gum
- no food 1 hour prior to testing
- non-smokers |
sample characteristics |
-same size
-same portion
-same freshness
-same temp
-same container
-random coding |
Quantitative food evaluation |
-measurement of food quality that seeks to mimic five senses
-reduces subjectivity (bias)
-less costly
-can compare to subjective tests |
physical tests |
measure certain observable aspects of food including size, shape, weight, volume, density, moisture, texture, and viscosity |
Warner-bratzler shear press |
Measures meat and baked products to determine tenderness.Less force= more tender |
refractometer |
measures concentration of organic compounds by passing light through solution |
Chemical Tests |
Can measure nutrient and non-nutrients components in food
pH meter for acidity or alkalinity
Chromatography can identify flavor components, fatty acid profiles
Fehling Tests to measure the presence of sugars
responsible for browning reactions |
USDA |
US dept. of agriculture
-Agricultural Research Service (ARS)
-chemical analysis of foods
-collects information about food composition from manufacturers
-online data base |
impact of processing |
highly processed bears little resemblance to original ingredients and loses more nutritional value w/added processing |
water content by weight |
Human body: 50-75%
Food:
-fruits/vegetables-70-95%
-meats-70%
-low moisture foods-2-4%
|
importance of water in food preparation |
-heat induction medium
-extracting flavor compounds
-cleaning food
-maintaining sensory acceptability
-removing water extends shelf life
-changes sensory experience
|
Polar substances dissolved by water |
carbohydrates and proteins |
specific heat of water |
heat required to raise 1 g of water, 1 degree C |
freezing point of water |
32 degrees F |
sublimation |
water vaper w/out ice melting |
sumblimation consequence on food |
-freezer burn |
boiling point of water |
212 degrees F |
boiling point |
when vapor pressure of steam just exceeds atmospheric pressure |
vapor pressure |
measure of liquids readiness to vaporize or evaporate into a gas |
factors that affect rate of evaporation |
-temp
-humidity
-surface area |
Effect of elevation on BP |
Increase elevation, decrease BP
-500 ft, decrease BP by 1 degree C |
Free water |
-can be separated from foods
-can act as a solvent
-acts as pure water |
bound water |
-part of structure of large molecules
-difficult to remove
-doesn't easily freeze
-reduced water activity in foods without more bound water |
water activity |
a measure of the amount of free water in a food; ranges from 0-1. |
Water activity in relation to perishability |
Increase water activity, increase microbial growth |
Ways to reduce water activity |
Drying, adding solutes to bind water, freezing |
water quality |
determined by presence of mineral salts |