Week8-Course1 Flashcards
T or F : sodium benzoate can be found in cranberries and it is a natural preservative
T
T or F : papayas contain papain and proteolytic enzyme
T
What are food additives?
constituents either isolated from food or synthesized that are added to food.
T or F : GRAS are exception to food additives regulation because they are not considered to be food additives
True
Why droplets of fat have the tendency to coagulate in a water mixture?
To reduce the interfacial tension
Complete : in an o/w emulsion, oil is the internal or ____ phase
and water is the external or ____ phase
(dispersed) phase
(continuous) phase
Which one will have a higher HBL : mono or diglycerides?
monoglycerides because there is two hydroxyl group so it is more hydrophile.
T or F : emulsifiers are used in such small amounts that their affect the lipid content of a food
False
What is HBL?
hydrophilic lipophilic balance and it is a calculation of the strength of an emulsifier.
What are the uses of acidulants (4)
- food preservation
- flavor
- gel formation
- prevent enzymatic browning by inhibiting polyphenol oxidase
Name two common acidulants
phosphoric acid (inorganic, les natural) organic acid (more natural)
What are the function of organic and inorganic acids in food?
- flavors
2. acidifying characteristics
Foods with a pH below 4.6 are ____ food and needs a ____ heat treatment
high acid food
non-agressive
Foods with a pH over 4.6 are____ food and needs a ____ heat treatment
low-acid
agressive or extensive (over 100C)
What is the name of the enzyme that is responsible of the browning in cut fruits and vegetables
polyphenol oxidase
T or F : when you cut fruits and veggies, there is some enzymatic and non-enzymatic browning happening
False, non-enzymatic browning is another name for the maillard reaction and has nothing to do with cutting fruits
T or F : canned meat products are high acidic food product
false, they are a low-acidic food product
Name 4 electron rich compounds
- Unsaturated fats and oils
- Vitamin C
- Chlorophyll
- Beta-carotene
What is oxidation?
a reaction in which an electron is removed from a
molecule by an oxidant.
What are antioxidants?
Antioxidant is a compound that prevents (or delays) reactions of food components with O2
Name three natural antioxidants
- Lecithin
- Ascorbic acid
- Tocopherols
Name 2 synthetic antioxidants
- Butylated hydroxyanisole (BHA)
2. butylated hydroxytoluene (BHT)
What are free radicals?
Free radicals are species that have a single unpaired electron: they
are extremely reactive
lipid autoxidation involves the formation of ____
peroxy radicals: LOO.
How does antioxidant function?
by scavenging free radicals and terminating
free-radical chain reactions.
Name all the groups of compounds that contribute to food color that we saw in class
- chlorophylls
- anthocyanins
- Carotenoids
- Meat proteins
- Tannins
What is the analogue of chlorophyll that doesn’t contain the Mg ion
pheophytin
What is particular with pheophytin
it is dimer in color than chlorophyll more brown green
Why is it that the colour of fresh green veggies are more vibrant
because processing results in the loss of the Mg ion of chlorophyll and converts it into pehophytin that is dimmer in color
What factors affects the chlorophyll pigment (3)
- pH
- Processing
- oxidation
What color are anthocyanins?
red/blue/violet
Describe the molecule of anthocyanins
three-rnig phenolic compounds, two aromatic rings fused together while the third is attached by a single bond.
Anthocyanins are part of the ____ large class
flavonoids
T or F : anthocyanins color intensity is sensible to pH
true
What are the possible R groups of anthocyanins that makes them sensible to pH
H, OH, or OCH3
T or F : anthocyanins can have a sugar molecule attached to a COOH group. It is called glycolysation
False, the glycosylation happens on a OH group
T or F : Color intensity of anthocyanins is sensitive to pH changes. This sensitivity is due to protonation and deprotonation of the aromatic rings.
False, it is because of the deprotonation of the R groups.
Carotenoids are saturated or unsaturated molecules?
highly unsaturated
Name two carotenoids seen in class
- lycopene
2. Lutein
What pigment is added to fish diets to turn their meat more pink
carotenoids
What pigment is added to hens diets to turn their egg yolks more organge
lutein
What pigment is added to cheddar cheese and margarine to give a orange-yellow color
Annatto (cotain bixin and norbixin)
What is the plant that carries saffron
crocus stamen
T or F : pigments and colors can function as antioxidants
T, they have delocalized electrons and are easily oxidized
T or F : The red color of fresh meat is due to the binding of oxygen (in the air)
to the heme group of hemoglobin
False, it is due to the binding of O2 by myoglobin
The color of fresh meat is very unstable over time: oxidation of the ____ on in myoglobin molecules to____ slowly occurs and causes the
color to shift from red toward ____
Fe2+
Fe3+
purple
What can added to meat package (in usa) to prevent the purple to develop in meat and how does it work?
Carbon monoxide because it binds the Fe2+ more strongly than oxygen and the binding produce a cherry-red color
T or F : the color change in cooked meat is due to the loss of the Fe ion
False, it is due to the denaturation of proteins
What is the color associated with tannins?
black brown yellow
Complete : tannins contribute to the ____ of foods
astringency
Name two food components responsible for brown/black/yellow color in food
maillard reaction
tannins
T or F : The appropriate color in food is required for a proper flavor response to be
obtained.
True
T or F : The human tongue can perceive 4 taste
False, 5, because of umami
T or F : monosodium glutamate (MSG) is a flavor potentiator and has the GRAS status
true :-(
Complete : _____ are major contributors to the aroma of
onions and garlic.
Sulfur-containing compounds
T or F : generally, flavors are effective compounds
T
What is the key compound of the banana flavor
isopentyl acetate
Complete : Essential oils are made up largely of _____, a class of volatile molecules that are _____ (lipo or hydrophobic)
terpenes
hydrophobic
limonene is the essential oil responsible for the flavor of _____
lime
citral is the essential oil responsible for the flavor of _____
lemon
beta-sinensal is the essential oil responsible for the flavor of _____
orange
nootkatone is the essential oil responsible for the flavor of _____
grapefruit
Name two categories of flavor compounds seen in class
essential oils reaction flavors (due to reaction like maillard or caramelization)
