Chapter 3 Flashcards
What chemical elements proteins may have
Carbon, N,O, S, fe, Cu, P, zn
what is the name of the central atom
alpha-carbon
What groups serves as an acid and as a base in AAs
carboxyl group-acid
amino-base
General formula for AAs
H2NCHRCOOH
What side chains are more soluble in water
Polar
what AAs will form hydrogen bonds with other molecules
Polar-neutral
What AAs can act as buffers
Positively and negatively charged
How many different proteins in the body ( estimate)
50000
How many AAs can be linked in a chain
20-33000
Essential AAs
Histidine Isoleucine Leuicine methionine Phenylalanine threonine tryptophan Valine Lysine
Non essential AAs
Alanine Asparagine Aspartic acid Glutamic acid Serine
Conditionally essential AAs
Arginine Cysteine Glutamine Glycine Proline Tyrosine
Complete protein
Animal protein: eggs, milk, meat
How can you get complete protein from plant sources
Combining incomplete proteins, such as beans and rice
What is the component in food that is responsible for aallergies
Proteins
Role of proteins in food
- Structure and physiochemical properties
- an ingredient in terms of functional properties and nutritional value
Protein responsible for milk allergies
Beta-lactoglobulin
2 types of secondary structures
Alpha-helix
Beta-pleated sheet
secondary structure of proteins are held together by
Hydrogen bonds
Proteins are folded in alpha and beta-pleated sheets , but other parts can be ___
Unordered or random
Beta-lactoglobulin acts as
A dimer
what can result in protein denaturation ( loss of secondary and/or tertiary structure)
pH, temperature, mechanical actions,sound waves and irradation, mineral salts (sodium or k salts)
How protein denaturation is used in food industry
Denaturation of protein-> denaturation of enzymes that are responsible for deterioration
How can you denature egg proteins
Solidification/opaqueness -. when heated , egg white turns white
Production of foam when egg white is whipped is due to encapsulation of air bubbles by surface-denatured protein molecules
What is coagulation
Permanent denaturation results when liquid or semi-liquid proteins form solid or semisoft clots
the coagulation of a protein (what happens to chemical properties)
Changes in physical characteristics
Alters the ability to bind with water
Interferes with biological interactions of enzymes
Colder temperature can cause what in proteins
Curdle
What is the purpose if kneadling
to strengthen gluten by mechanical actions
What products are the result of acid denaturation
Sour cream
Buttermilk
Yougurt
Why proteins can solubilize in water
NH
C=O
What are hydrogen-bonding or ionized functional groups in protein
- Hydroxyl
- sylfhydryl
- amide
- carboxyl
- amino
3 broad classes of proteins
- Globulae-soluble in water
- Fibrous-insoluble (concentrated in collagen)
- membrane- insoluble
Protein denaturation can result in protein ____, the same effect has ___
Aggregation mis-folded proteins aggregate (i.e., accumulate and clump together) either intra- or extracellularly-> forming a curd or a gel
Changes in pH
Major source of the gases emissions are
Cattle breeding and related meat consumption
How much protein we consume is animal-based
40%
Trend on meat consumption
Is going to rise
How much grain in the world is used for animal feed
2-15 kg of grain for 1 kg of animal product
40-50% of the global grain harvest is going ot cattle
What should people do in order to reduce area and energy
people should eat less
beef and more pork or chicken, reduce their portions, or change
the meat portion in the diet by meat substitutes, such as legumes
or eggs
What are novel protein sources
insects, algae, duckweed, and rapeseed)
What can be the issues with new types of protein
Food safety
The presence of contaminants,
antinutritional factors (ANFs), allergens, and accumulation
and modification of substances in protein matrices during processing
can have effects on public health.
Plant protein sources that are widely consumed
Soy,wheat,vegetables and potatoes
Another group of protein sources that is currently used for feed and biofuel products includes ___
rapseed,algae,grass,duckweed and by-product
Insect protein is now used for
Petfood and fish feed
What is the food for insects
chicken feed, vegetables, and waste streams
Problem of getting insects
need to eat specific duet
Not sure about the palce where they originated (maybe polluted)
Have presence of allergens
Some of them need special capture, storage, transportation
They maybe with harmful pathogens
What substances found in insects can be toxic
hydrocyanic
acid, heavy metals (lead, mercury, and cadmium), arsenic, benzoic
acid, and sorbic acid.
2 ways how insects can get toxic chemicals
Autonomous(defense chemicals)
Phytochemicals from food
What are algae
belong to a large and diverse group of organisms using
photosynthesis, which do not belong to the group of terrestrial
plants, photosynthetic eukoryotes
Two types of algae
Microalgae
Seaweed
2% of Algae is responsible for ___
can form neurotoxins and
hepatotoxins that can accumulate in shellfish, crustaceans, and
fish.
This may result in diseases such as paralytic shellfish poisoning
(PSP) due to saxitoxin, diarrhetic shelfish poisoning (DSP),
neurotoxic shellfish poisoning (NSP) due to brevetoxins, ciguatera
fish poisoning (CFP) due to ciguatoxin/maitotoxin, amnesic
shellfish poisoning (ASP), and microcystin
Use of microalgae
terrestrial and aquatic animals feed
Spirulina,chlorella,
gold algae,cyanobacteria ( all used msotly as a food supplement and as anumal feed additives)
safety hazards related to algae
Allergens, toxins, pathogens, heavy metals, and pesticides
Seaweed can be harvested from ___
the sea and cultivated
Seaweed is mainly used for
food supplement ( no research was done on extracting proteins form seaweed)
Can be sued as feed additives to fish diets
Safety hazards for seaweed
Iodine, ANFs (low levels
of lectins, tannins, and phytic acid, and high levels of trypsin
inhibitors and amylase inhibitors), heavy metals, radioactive isotopes, ammonium, dioxins, pesticides
What are duckweed
small floating aquatic plants, higher plants
Duckweed is found
Practically everywhere in the world except waterless deserts and those permanently frozen
Use of duckweed
supplemented to feed, especially to complement
diets and to increase animal growth. Duckweed is used
as feed for fish and domestic animals, including poultry,ducks and pigs
Duckweed can be a very good source of
a mineral
(particularly P) and N source.
Do humans eat duckweed
a human food resource in traditional/small farmer systems
in South Asia
Safety hazards for duckweed
the presence of heavy
metals, phenols, pesticides, dioxins, and pathogens.
Rapseed is
Rapeseed (Brassica napus) is a bright yellow flowering member
of the Brassicaceae.(canola)
Rapseed or canola proteins have been used as feed ingredients for
poultry, pig, cattle, and fish
Why we have limited canola protein products
due to technological limitations in relation to organoleptic
properties and ANFs
What are the potentials canola hazards
ANFs, heavy metals, and allergens. Rapeseeds contain several
ANFs, such as erucic acid, glucosinolates, phytic acid, phenolics
Limiting factor for the application of canola
the content of phenolic acids in canola meals is up
to 5 times higher than in soybean meals, and in rapeseed/canola
flours 10 to 30 times higher than in flours from other oleaginous
seeds such as flaxseed
If food and feed business operators want to include animal component, they should
Be approved before start of operations
What measures FBOs are required to do in primary production
to use potable or clean water whenever necessary to
prevent contamination, to use biocides, plant protection products,
veterinary medicinal products, and feed additives correctly, and to
keep records of measures taken to control hazards + the nature and the origin of feed fed to
animals
How novel good products are assessed
The assessment aims to establish whether the novel food, or
novel food ingredient, is safe for the consumer, does not mislead
the consumer, or when it replaces another ingredient, is not nutritionally
disadvantageous for the consumer
Besides administrative information, extensive data on composition,
nutritional value and metabolism, intended use, and intake of
and levels of hazardous substances in the novel food are essential.
Furthermore, microbiological and toxicological (including allergenicity)
information on the novel food should be provided by the
applicant.
what are difficulties for applicants of novel sources
Main uncertainties concern definitions and data requirements.
For new products like insect proteins, the data requirements
on composition, like analyses of a number of representative
batches regarding nutrients, micronutrients, and known and potential
contaminants, might be problematic if only pilot studies
have been performed with breeding and harvesting of insects.
To determine how effectively proteins will work in a food product,
food scientists analyze a protein s
degree of water absorption solubility viscosity stability in acids and alkalis
What do thickening agents do
increase viscosity because of their water binding
capacity and size
what kind of solutions is formed with protein and water
colloidal solutions, not true as CHO
If the same amount of positive and negative charges in protein, then in water it will ____
Precipitate
How pH influence protein structure
Change of the charge on R group, but they do not hydrolyze peptidic bonds
pH can change secondary structure
Do carboxylic and amino groups have charges
They never do
What component is responsible for juiciness of the steak
Proteins
Gelling agents examples
gelatin (hydrolyzed collagen), β lactoglobulin
What proteins are suspected to curd forming in food industry
e.g., milk proteins (specifically, caseins), soy proteins
production of tofu
What protein is used as meat analog
Soy
Example of protein property viscoelasticity
gluten in wheat
Example of protein that are responsible for color and flavor
e. g., myoglobin (muscle
protein) binding to oxygen is responsible for red color of fresh meat
Different colors of myoglobin
is bright red when oxygen molecule is attached
is purplish if oxygen molecule is not attached
is brown after prolonged exposure to oxygen
What amino acids participate in Maillard reaction
Amino acids that have side chains containing NH 2 (e.g., lysine)
participate in the Maillard reaction; and that have primary amine acids
What happens to lysine after Maillard reaction
It becomes unavailable for digestion
When proteins cannot participate in maillard reaction
Note: Peptide bond formation converts the amino groups of amino
acids to amide groups (except for the last amino acid in the
polypeptide) so they do not participate in the Maillard reaction
Examples of application enzymes in food industry
Production of high fructose sweeteners: amylases, glucose isomerase
Meat tenderization: papain (protein present in the papaya plant)
Removal of headspace oxygen from foods (to prevent oxidation of food
components): glucose oxidase
Curd formation in cheese manufacture: rennet
Nutritional contribution of proteins
Support growth and repair
Fight disease
Maintain fluid and mineral balance (transport proteins)
Maintain pH balance (Proteins in the blood are buffers that pick up or release acids and bases)
Control bodily functions (hormones)
Provide energy
Food scientists are developing affordable proteins to meet future
demands worldwide by
developing grains such as triticale and amaranth
using biotechnology
What is an enzyme
is a specialized protein that speeds up or starts a chemical reaction without
being changed by the reaction
allows chemical reactions in the cells to happen fast enough to meet the
body s needs
A catalyst
What is the better name for enzyme work than lock-key model
The induced fir model
The active site temporarily changes the shape of the enzyme to allow the
reaction to occur, then returns to its original configuration after the reaction
Coenzymes work by
attaching to the enzyme and changing its shape so the substrate can fit in
the active site
attaching to the substrate and changing its shape so it will fit the active site
of the enzyme
acting as a transfer agent in accepting an atom or molecular group that is
broken off and transferring it to another compound
Vitamins and minerals that are very important as coenzymes
the B vitamins, calcium, magnesium, and zinc
Nomenclature of enzymes
enzymes are named for the types of reactions or substances for which they
are the catalyst
the root name for the enzyme and the substrate are the same
enzymes end in ase
Other name for sucrase
Invertase
What is putrefaction
Proteolytic enzymes (proteases and peptidases)
degrade proteins to amino acids, which then undergo deamination
(loss of the amino group as ammonia gas) and decarboxylation (loss
of the carboxyl group as carbon dioxide gas) by the action of
deaminase and decarboxylase enzymes.
The result of putrefaction are
The products of these reactions have very distasteful flavors/odors.
Lipolytic rancidity refers to
Lipolytic rancidity refers to off flavors produced by lipolysis of
triglycerides that contain short chain fatty acyl groups. Only short
chain fatty acids such as butyric acid are associated with off flavors.
What are lipoxygenases
are enzymes that catalyze lipid oxidation, resulting in
rancidity.
Why water is important for enzymatic activity and what happens if there is not enough
The lack of water slows or stops enzymatic activity
Enzymatic reactions will not occur in dry products
Water must be a reactant in the breakdown of carbohydrates, lipids, and
proteins
The rate of enzymatic reaction increases with ___
The rate of enzymatic reaction increases as the concentration increases, up
to the saturation point
Heat ___ enzymatic activity
stops
Electrolytes can do what with enzymes
can prevent enzymes from reacting with a substrate
Enzyme inhibitors can
change the shape of the enzyme or the substrate
help protect foods from bacteria and mold by stopping the digestive
enzymes they release from working
Enzymes are used by the food industry to develop food products by
converting one food product into another, such as with milk into cheese
extracting food components from food systems such as the separation of
juice from insoluble residues
playing a key role in developing ingredients
Positive effects if enzymes in food
make food easier to eat preserve food improve flavor, quality, or appearance plays a role in fermentation
Negative effects of enzymes in food
break down the structure of fruits and vegetables unpleasant flavor and odor changes undesirable changes in texture and color
Carbohydrases react with sugars and starches for commercial uses
such as to
make corn syrup and high fructose corn syrup ferment wine and beers stabilize chocolate syrup clarify fruit juices
Lipases are used to (in food production)
extract unwanted egg yolk from egg white to improve the whipping
properties of egg white
improve flavor and texture of various products including cheese, ice cream,
margarine, butter, and many baked goods
Proteases are used to ( in food production)
tenderize meat by breaking long protein fibers, as in solutions for marinated meat reduce the size of proteins extracted from malt and grains during beer and ale production reduce mixing time increase pliability of dough change food into a different product, such as milk into cheese
To prevent browning of cut fruit,
the food industry
uses acids as enzyme inhibitors develops compounds from other sources, such as soy
Antinutritonal Factors are
are substances that when present in food reduce the availability of one or more nutrients and they are one of the concerns that must be addressed regarding novel proteins.
What you need to look at as a scientist when suggesting new food products
ANFs
Allergens
Contaminants
What insects are suggested as food (latin)
Gryllodus sigillatus
Acheta domesticus(crickets)
,Alphitobius diaperi
Tenebrio molito
Insects can be a good option of protein because ___
Do not need much resources (place, feed)
Multiply fast
They are already consumed by some cultures, so it is not completely allian for human diet
1,4-quinones are an example of …… that are considered toxic chemicals found in edible insects.
Defensive secretions
Seaweeds are subcategory of algae.. True/false?
True
Why seaweeds are considered as the alternative protein source
do not need extra land for production, can use oceans
a microalgae genus that is suggested for human consumption
Arthrospira(spirulina, namely, cyanobacteria
Safety hazards in algae include ……
Allergens
Heavy metals
Toxins
is the only identified secondary metabolites produced by duckweed that is toxic to animals at high levels (answer two words)
Oxalic acid
(22:1ω9) is an antinutritional factor in rapeseed that hinders its use as a novel protein for humans. (answer two words)
Erucic acid
Major export of Canada and why
Canola oil
Because they created breeds that do not have erucic acid
Where protein is found in rapseed
Cake after extracting oil
____is the maximum amount of pesticide residue that is expected to remain on food products when a pesticide is used according to label directions, that will not be a concern to human health
The maximum residue limit
To legislate the consumption of novel food product, extensive data on composition, nutritional value and metabolism, intended use, and intake of and levels of hazardous substances in the novel food are essential.
True /false?
True
Animal protein production is considered inefficient because
Cattle breeding is a major emitter of green house gases B. 40%- 50 % of global grain production is used as feed
What are lipids? Class features
Organic compounds (C,H,O) that are insoluble in water and have a greasy feel. They cannot be as straight-forward classified as proteins or CHO
3 types of lipids found in food and in the human body are
TGs,phospholipids,sterols
Ester bond is the result of
Reaction of glycerol and fatty acid that result in molecule of water
The smallest fatty acid is
Butyric acid
Fats and oils are predominately composed of
TGs (95%)
Glycerol is a polar molecule, fatty acids are polar, so how the combination of those are not polar
When the positive carboxyl group on a fatty acid joins with the
negative hydroxyl group on a glycerol, the polar ends combine ,
resulting in a nonpolar lipid
What type of glycerides are partially soluble in water
Mono and diglycerides
When we say fat we mean___, and oil___
Fat- solid at room temperature
Oil-liquid
The arrangement of TGs in the solid and liquid states depends on
A balance between the organizing influence of the attractive interactions between the molecules and the disorganizing influence of the thermal energy
Omega counting starts at
at carbon which is the most far from glycerol
Trans isomer of oleic acid is
elaidic acid 18 trans
