Exam 2 Flashcards
macronutrients
nutrients needed in the largest amounts (lipids, proteins, carbs)
how many essential nutrients are there/how do we get them?
50; from the diet (can’t be absorbed)
3 functions of nutrients
regulatory, structural, energetic
malnutrition
imbalance, too much or too little intake
calorie
the amount of energy needed to raise the temp of 1 kg of water 1 degree Celsius
absorption
digest nutrients enter the bloodstream through microvilli
3 ways that nutrients pass through membranes
facilitated diffusion, active transport, simple diffusion
simple diffusion
small lipids and water freely cross
facilitated diffusion
water soluble vitamins use a carrier
active transport
AA are absorbed with energy input
5 major functions of water in the body
regulates body temp lubricates reaction medium hydrolysis carrier
carbohydrates purpose & what they’re made of
our fuel; C, H, O
types of carbs
simple (sugars)
complex (starches)
simple carbohydrates
C, H, O bond in a ring shape molecule; mono or disaccharides
complex carbohydrates
long chain of sugar units (starch, cellulose, fibers, glycogen); polysaccharides
fiber is a ____ and what are the 2 types of dietary fiber?
polysaccharide; insoluble (swells in water) and soluble (dissolves and forms gel-like substance)
glycemic effect
the ability of a food to increase blood glucose
lipid classes
fats, oils, sterols, waxes, phospholipids
2 components of a lipid
glycerol & fatty acid
glycerol is a backbone that binds up to …?
3 fatty acids; mono, di, and triglycerides
are lipids water soluble or insoluble?
insoluble
how are lipids digested?
with emulsification from bile
healthiest kind of fatty acid
poly unsaturated
are trans fats healthy or unhealthy? why?
unhealthy, because of linear shape
hydrogenation
adding H atoms to oils to harden them and increase shelf life
proteins function & how are they made?
essential body builders; AA joined by peptide bond
protein quality
the presence of all EAA in a food in the amounts required to support protein synthesis
nitrogen is only provided by
proteins
vitamins
small organic compounds that must be supplied in the diet to maintain health
vitamins functions
antioxidants, coenzymes, disease prevention
minerals
inorganic substances, based on amount present in body (major or trace)
minerals functions
bone growth, vision, blood clotting, electrolyte balance, nerve function
sweeteners
substances alternative to sucrose
types of sweeteners
nutritive (provides some calories) non-nutritive (no calories, metabolized differently)
carb-based fat replacers
plant polysaccharides, thicken food & add bulk
protein-based fat replacers
proteins blended with gums form gel-structure similar to fat
fat-based fat replacers
same fatty acids, different length; flavor, baking & frying stability, shelf-life
energy metabolism & types
how the body uses energy nutrients; anabolic (synthesis) and catabolic (energy release)
hydrogen bond
large molecules like O and N attract the electron from H smaller nucleus, forming a weak intermolecular bond
types of chemical reactions in food
composition & decomposition OR enzymatic & nonenzymatic
enzymatic reactions in food
cause desirable or undesirable quality changes
if water in a food is free, that means
it can be easily pressed from food; it acts as dispersing and solvent agent
absorbed water in food
exists in layers around food molecules via H bond
bound water in foods
exists in tight chemically bound systems
water activity
measure of the availability of water molecules for reactions
what is a buffer?
solution of a weak acid and its salt that has the ability to maintain pH in a food
maillard browning
reducing sugars + AA = brown pigment; can be positive (color and aroma of bread, chocolate, cooked meats) or negative (browning during storage)
caramelization
formation of brown caramel pigments due to heat, resulting in flavor
humectancy
high affinity for moisture
oxidation of aldehyde in sugars results in
loss of sweetness
reduction of carbonyl in reducing sugars produces
sugar alcohols (moderately sweet) = alternative sweeteners
retrogradation
polymers reassociate into their structure after heating
lipid reactions
fractionation
hydrolysis
interesterification
polymerization
fat functionalities
melting point temp aeration in baked goods carry flavors creamy texture tenderizes food
protein reactions & functionalities
denaturation, buffering, hydrolysis, enzymes, fat reduction, stabilizers, foams
key factors that drive consumer acceptance of foods
color, flavor, texture
color
perception of food arising from a collection of sensations
flavor
combination of what you smell and taste
flavoring
substance that has a flavor of its own at the level at which it is used in food
flavor enhancer
does not have flavor, but intensifies natural or added flavors (MSG)
types of rancidity of lipids
hydrolytic rancidity (liberation of short chain FA by enzyme) oxidative rancidity
texture
perception of food structure when it is held by fingers, pushed by tongue against palate chewed by teeth and sensed within the cavity
texture is determined by ___ and influenced by ___
microstructure of food; texturizing ingredients
proper nutrition
adequate & balanced consumption of essential nutrients
