food composition, sensory evaluation, fruits Flashcards
oligosaccharide ex?
raffinose and stachyose (dried beans digestion = gas)
fructo oligosaccharides (fruits and veg, prebiotics)
used as bulking agents and fat replacers
starch vs glycogen vs fiber
starch:
- amylose and amylopectin
- energy store for plants
- digestible by humans
glycogen:
- stored energy for animals
- digestible by humans
- fiber
- cellulose, hemicellulose, pectic substances
- undigestile by humans
- in plant originated food
where are cholesterols found?
only animal foods
purposes of food additives
mprove appeal
Extend storage life
Maximize performance
Protect nutrient value
influences of food selection
Sensory Nutritional Cultural Religious Psychological and sociological Budgetary
sensory aspects of food
appearance odor taste texture sound flavor
describe odor and smells in sensory evaluation
- detected first by olfactory epithelium (upper part of nasal cavity)
- need a volatile molecule to make contact with olfactory receptors = sends impulses to brain
what is anosmia
lack of ability to smell
groups of odors:
6 groups:spicy, flowery, fruity, resinous, burnt, foul
4 groups:fragrant, acid, burnt, caprylic
2 groups:inedible vs. edible
describe taste in sensory evaluation?
papillae
taste bud life?
- substance must be dissolved in liquid or saliva to seep into taste bud = nerve impulse to brain
- taste buds distributed in papillae on tongue, palate, esophagus, cheek, epiglottis
- papillae have microvillae
- taste buds are regenerated within 2 weeks
- humans: 10,000 taste buds
categories of taste?
sweet (tip) salty (tip of tongue) sour (sides of tongue) bitter (bck of tongue) umami oleogustus
what is the taste threshold
concentration necessary to elicit a taste respons
how is tactile character of food determined?
by shape = kinesthetic sensations = feeling of resistance to motion detected by nerves
assessed by mouth, tongue, jaws
what are factors affecting touch?
texture
consistency
astringency
chemsthesis
describe flavor in sensory evaluation
composed of aroma and mouthfeel
aroma: combination of odor and taste (independent of mouthfeel)
mouthfeel: sense of touch in mouth. influenced by: texture, consistency, astringency, chemsthesis
types of taste test
difference:
- trained evaluators or untrained consumed
- difference between protoypes of new product
- they choose most preferred
acceptability tests:
- consumer testing
- is the product positively perceived by consumed
types of flowers?
simple
aggregate
multiple
fruit classification?
- simple fruits: derived from ovary of one pistil (ie. drupes and pomeS)
- aggregate fruits: formed by single flower with many stamens and pistils
- multiple fruits: formed from many flowers and remain together as single mass
- berries:
- true berries: currants, tomatoes, cranberry, kiwi, banana, grapes, avocado
- pepo: melon, squash
- hesperidium: citrus. rind, juicy interior
diff b/w animal and plant cells
plant: 1. has primary cell wall. thin and contains: -cellulose -hemicellulose -pectic substances secondary cell wall: -thin -contains lignin (non carb material withbenzene derived structure)
- intercellular air: fills spaces between cell walls. gives volume, crispness, textural differences
composition of plastids?
storage organells
- lecuoplasts: starch and water. major digestile portion.
- chloroplast: green color. CHO synthesis -chromoplasts: cartoene or xanthophyll
describe skin of fruits
secretes waxy cutin ( protects surfaces. slows water loss)
additional wax is used commercially
macro compoisition of fruits
- 70-95% water
- less than % protein
- solid parts: mostly carbs
phytochemicals in blueberries, cranberries, rasp, straw, watermelon,
blueberries: flavanoids: anthocyanins and flavinols
cranberries: proanthocyanins
rasp and straw: ellagitannins
watermelon, grapefruit, tomatoes: lycopene
acidity of fruits?
pH below 5
least acidic fruits = more bland and sweet
veg are usually pH > 4.5
