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269 Cards in this Set
- Front
- Back
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Mechanical
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o Firmness
o Adhesiveness o Cohesiveness o Viscosity o Springiness |
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Geometrical
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o Size and shape related
o Flakiness, grittiness, beady, crystalline |
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Compositional
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o Moisture and fat content
o Juiciness |
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Meat Texture Characteristics
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Mechanical, Geometrical and Compositional
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Muscle Type
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determines how tender the meat will be
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support vs. locomotion
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size of muscle fibers affect tenderness of meat
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small fibers
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tender meat
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large, long fibers
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tough meat
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filet mignon vs. bottom round
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filet mignon is super tender, it comes from the short loin, the strip of muscle that does the least amount of work when the animal moves around, therefore making the boneless cut extremely tender.
bottom round is a lean cut and it is moderately tough. |
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Factors that influence tenderness and juiciness:
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animal's age at slaughter, amount of fat and collagen and brining
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animal's age at slaughter
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older animals have more collagen cross-linking
younger = tender, older = tougher |
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amount of connective tissue (collagen):
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more collagen = tougher
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Rigor Mortis:
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stiffness of death
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three phases of rigor mortis:
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Delay: muscle contains sufficient ATP, extensible
Onset: ATP no longer formed, muscle less extensible Completion: ATP depleted, muscle inextensible |
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Resolution of rigor:
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protein degradation
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Meat aging to improve meat tenderness:
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z-line degradation, cathepsin and calpain
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warner-bratzler shear
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measures meat tenderness
dull, v-shaped blade cuts perpendicularly to the fiber direction |
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cell wall polyssacharides
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cellulose
hemicellulose pectin |
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lignin
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-polymerized phenolic compounds
-makes vegetables firm and crunchy -at lower temperatures it decreases the hardening rates -enzymes involved: peroxidase and polyphenol oxidase |
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Turgor Pressure
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pressure exerted on a plant cell wall by water passing into the cell by osmosis (key driver of cell expansion)
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hypertonic
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water goes out of cell
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isotonic
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water pressure remains equal in and out of cell
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hypotonic
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water goes in cell (think hippo)
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Crispness
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Pressure on the tissue from the teeth --> increase hydrostatic pressure --> sudden fracturing of the plant structure --> crack propagation --> cell wall rupture, juice release
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Crispness and Turgor Pressure
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Moisture lost --> low turgidity --> rubbery
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Bread staling
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increase in crumb firmness, moisture independent
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viscosity
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resistance to flow due to internal friction
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viscosity =
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viscosity = shear stress/shear rate
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Newtonian Fluids
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dependent only on temp but not on shear rate and time, regardless of the forces acting on the fluid it continues to flow
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Newtonian fluid examples:
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water, honey, coke, milk, hfcs, sugar solutions and mineral oil
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explanation of newtonian fluids:
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it continues to display its fluid properties no matter how much it is stirred or mixed
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viscosity is independent to __________.
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shear rate
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Non-newtonian fluids:
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o Bingham plastic
o Pseudoplastic o Dilatant o Thixotropic o Rheopectic |
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Bingham plastic
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Initial resistance --> Newtonian
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Bingham plastic examples
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ketchup, chocolate, butter, cheese, icing, spread
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pseudoplastic
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shear thinning
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Pseudoplastic examples:
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gelled dessert, pudding
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dilatant
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shear thickening
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dilatant examples:
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concentrated cornstarch/water slurries (uncooked)
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Thixotropic
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Same as pseudoplastic (shear thinning), but the original viscosity is restored after a period of rest. This system is time-dependent.
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Thixotropic examples
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mayonnaise, sauces, and greases
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Rheopectic
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Same as dilatant (shear thickening), but the original viscosity is restored after a period of rest. This system is time-dependent.
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Rheopectic examples:
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egg whites and whipping cream
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Types of viscometers (used to measure viscosity)
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o Rotational viscometer
o Capillary viscometer o Falling ball viscometer o Consistometer |
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Botanical Vegetables
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a member of plant kingdom
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Culinary Vegetables
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an edible plant or part of a plant
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Botanical Fruits
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A part of flowering plant derives from ovary and/or accessory tissues of flower
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Culinary Fruits
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A fleshy structure of a plant that is sweet and edible in raw state
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Edible plant parts:
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leaves, stems, bulbs, roots, tuber, flower, fruits, seeds
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examples of leaves:
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cabbage, lettuce, spinach
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examples of stems:
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asparagus and celery
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examples of bulbs:
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garlic and onion
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examples of roots:
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beets, carrots, radishes and sweet potatoes
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example of a tuber:
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potato
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examples of a flower:
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broccoli and cauliflower
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examples of fruits:
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tomatoes, peppers and cucumber
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examples of seeds:
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beans and corn
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Falling ball viscometer formula
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μ = K (ρt-ρ)t
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major component of a cell wall:
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cellulose, hemicellulose, pectin and lignin
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vacuole
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organelle filled with water and various solutes
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plastids
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-Chloroplast
-Chromoplast -Leucoplast -Amyloplast -Elaioplast -Proteinoplast |
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Chemical composition of fruit and vegetable
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Water, carbohydrates, proteins, non-protein nitrogen, lipids, organic acids, pigments, minerals, vitamins
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water
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80-90% in fruits and vegetables
10-50% in cereals, nuts, pulses |
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Carbohydrates
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~75% cell dry mass
Polysaccharides: Cellulose, hemicellulose, pectin, starch Simple sugars: Sucrose, glucose, fructose, raffinose, stachyose |
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Proteins
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insignificant in leafy vegetables and fruits but high in legumes (storage proteins)
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cereal proteins
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Gliadin, glutenin, zein
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pulse storage proteins
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β-Conglycinin, glycinin, phaseolin
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Tuber proteins
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potatin
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Non-protein nitrogen compounds
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Amino acids, amines, purines, pyrimidines, nucleotides, betanins (taste, aroma and precursor colors)
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Lipids
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approx. 1% in fruits and vegetables; much higher in pulses and oil seeds
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organic acids
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Citric acid, malic acid, tartaric acid, oxalic acid, ascorbic acid, benzoic acid, shikimic acid
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pigments
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Chlorophylls, carotenoids, flavonoids
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minerals
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K, Ca, Mg, Fe, P, S, N
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Vitamins
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Vitamin C (fruits and vegetables), E (oil seeds), A (vegetables)
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Respiraton
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attempt to maintain life
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climacteric
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o Period of enhanced metabolic activity during growth senescence
o Increase in respiration rate during ripening o Changes in color, flavor, texture o Triggered by endogenous ethylene o Rate of respiration: Floral tissue and stems > fruits > root, tuber |
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rate of respiration
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Floral tissue and stems > fruits > root, tuber
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Q10
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o Change of the rate of a biological or chemical system as a consequence of increasing the temperature by 10 °C
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changes during ripening
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color, flavor and texture
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color change
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chloroplast --> chromoplast (degradation f chlorophyll)
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ethylene gas and abscisic acid
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plant hormone that accelerates ripening
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flavor
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tannins decrease on ripening, starches can degrade to sugars and acids generally decrease on ripening (except for citrus fruits)
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texture
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softening or hardening
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softening
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hydrolysis of pectin (polygalacturonase)
de-esterification of pectin (pectin methyl esterase) |
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hardening
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lignin formation (peroxidase, polyphenol oxidase)
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proctopectin
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underripe, hard and highly methylated
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pectinic acid
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ripe, less methylated group, optimum texture
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pectic acid
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overripe, little methyl groups and mushy
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controlled atmosphere storage to speed ripening:
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treat with ethylene
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controlled atmosphere storage to slow down ripening:
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Store in modified atmosphere (low in oxygen, high in carbon dioxide)
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pectin structure:
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Methyl ester of polygalactouronic acid [α 1-4 linked galacturonic acid]
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pectin location:
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present in plant middle lamella and primary cell wall
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pectin function:
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"cement” the cells together
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degree of polymerization (DP)
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o The number of D-galacturonic acid residues per molecule
o The higher the DP, the higher the molecular weight of the polymer |
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Degree of Esterification (DE)
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o The number of carboxyl groups esterified compared to total number of carboxyl group, expressed as percent (%)
o High methoxyl pectin (HMP): DE > 50 % o Low methoxyl pectin (LMP): DE < 50 %. |
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Protopectin
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approx. 100% -CH3
Immature plant material, insoluble in water more methyl groups, firmer |
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Pectin
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>75% -CH3
mature plant material |
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Pectinic acid
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0-75% -CH3
mature plant material |
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Pectic acid
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approx. 0% -CH3
overripe plant material less methyl groups mushy |
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pectin grade
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amount of sugar, by weight, required per unit weight of pectin to prepare normal jelly
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normal pectin gel conditions
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• pH: 2.8-3.4
• Sugar concentration: 65% (w/w) • Pectin concentration: ~1% (w/w) • Temperature: 104.5 ºC → cooling |
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Low methoxyl pectin gels
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pH: 3.2-4.0
No sugar, dietetic products In practice, a small amount of sugar is left in the dietetic products as a tenderizer, making jellies less brittle than they would be without sugar Gel setting: o DE > 70 or DE < 50: rapid o 70 > DE > 50: slow |
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How to modify Pectins?
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o De-esterification with a diluted acid or base
o Depolymerization with a diluted acid or at a high temperature |
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Hydrophobic amino acids
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o Non polar R groups
o aromatic and sulfur containing o G, A, V, L, I, P, F, W, Y, M, C o Mnemonic: George And Valerie Live in Poland; Friends Went Y? Montana is Cooler. o V, L, F, W, M and I are also essential A.A. o M and C are deficient in legumes |
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Hydrophilic amino acids
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o S, T, N, H, D, E, R, K, Q
o Mnemonic: STaN Hates DEReK. Questions? o T is also an essential A.A. o Amide containing A.A. N and Q o Acidic: D and E o Basic: K, R, H H is only essential for infants K is an essential A.A K is also deficient in cereals |
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Essential Amino Acids
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o V, L, I, W, H(infant), M, F, T, K
o Mnemonic: Vanessa Lives in Idaho With Her Mom, For The Kids |
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Helix Breakers
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PG
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Chiral carbon:
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tetrahedral carbon with 4 different groups attached
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AA with chiral centers:
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0 chiral center: glycine
1 chiral center: most amino acids 2 chiral centers: threonine & isoleucine |
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Natural A.A. are L- or D- Amino Acids?
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-Can’t be d-amino acids because our bodies can NOT utilize that conformation
-L-amino acids are most abundant in nature, D-amino acids are only found in some bacteria (e.g., E. coli) |
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AAs with no charged side chain:
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pI = (pKa1 + pKa2)/2
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AAs with acidic side chain:
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pI = (pKa1 + pKaR)/2
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AAs with basic side chain:
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pI = (pKa2 + pKaR)/2
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Albumin
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water soluble (ex. egg albumin)
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globulin
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salt soluble (ex. phaseolin)
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prolamin
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ethanol soluble (ex. zein)
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glutelin
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acid/alkali soluble (ex. glutenin)
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primary protein structure
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-Amino acid sequence
-Polypeptide chain linked by –CO-NH- -Peptide bond: a covalent link between the amino group of one amino acid and the carboxylic group of a second -Peptide bond has double bond character and displays trans and cis conformations -Trans conformation is favored for most amino acids -Exceptions: proline and glycine because they are HELIX BREAKERS |
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Secondary structure
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α-helix, β-sheet (antiparallel vs. parallel), turn, loop, coil
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α-Helix
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• Stabilized by H-bonding
• Helix formers: A, L, M, K, E • Helix breakers: G, P • Side chains project outward from α-helix • Amphiphilic: Hydrophilic on one side, hydrophobic on another |
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β-Sheet
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• Stabilized by H-bonding
• Parallel vs. antiparallel o Parallel is less stable than antiparallel • Generally more stable than alpha-helix |
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π-helix
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–NH– H-bonded to 5th preceding –CO–
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β-bend/β-turn
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o ≤ 5 amino acids
o Directional change |
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Loop/coil
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o > 5 amino acids
o Flexibility |
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Tertiary structure
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-Spatial arrangement or folding
-Result of energy minimization -Motifs (combination of secondary structures) -Domains (combination of linked motifs) |
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Quaternary structure
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Association of two or more subunits
• Myosin: 2 heavy chains and 4 light chains • Hemoglobin: complex of 4 myoglobin |
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Forces stabilizing protein structure (energy)
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Covalent bond, electrostatic interaction, H bond, hydrophobic interaction, Van der Waals interaction
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covalent bond
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Cys–SH + HS–Cys Cys–S–S–Cys
330-380 kJ/mol |
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electrostatic interaction
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Lys–NH3+ … -OOC–Asp
42-84 kJ/mol |
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hydrogen bonding
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Ser–OH … NH3+–Lys
8-40 kJ/mol |
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hydrophobic interaction
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Leu–CH2–CH–(CH3)2
CH3–CH2–(CH3)CH–Ile 4-12 kJ/mol |
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van der waals interaction
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Ser–CH2–OH … H–CH2–Ala
δ+ δ- δ+ δ- 1-9 kJ/mol |
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protein denaturation
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disrupting the native conformation of a protein by environmental changes or chemical agents
-changes secondary, tertiary and quarternary structures -improves digestibility of enzymes -destroys toxins -improves functionalities |
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physical factors affecting denaturation
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temperature, pressure, stress or shear
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chemical factors affecting denaturation
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pH (most stable at pI)
salts (calcium cross-link carboxyl groups) denaturants (urea) surfactants (SDS) |
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protein renaturation
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restoring the native conformation of a protein when environmental agents are removed
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enzymes in food processing
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Polypeptide that catalyzes a reaction with a certain degree of specificity
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enzymes found in plants
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pectinases
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enzymes found in animals
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rennet
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enzymes found in microbes
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recombinant chymosin
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major types of enzymes
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carbohydrases, proteases, lipases, oxidoreductases, isomerases
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carbohydrases ex.
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amylase
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proteases x.
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bromelain
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lipases ex.
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lipase in rennet
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oxidoreductase ex.
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lipoxygenase
-polyphenol oxidase -desirable for enzymatic browning in: cocoa, coffee, prune and teas undesirable for E.B. in: apple, pear, banana and potato |
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isomerases ex.
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glucocose isomerase
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pectic enzymes desirable for:
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fruit juice clarification and canning
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fruit juice clarification
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cleavage of pectin-protein complex
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canning
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blanching --> activates pectin methyl esterase
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pectic enzymes:
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pectin methyl esterase, pectin lyase and polygalacturonase
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brewing
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starch --> glucose --> ethanol
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amylases in brewing
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alpha-amylase and beta-amylase
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alpha amylase
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endoamylase
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α-Amylase source
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plant (barley malt)
fungi bacteria animals |
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β-Amylase
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exoamylase
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β-Amylase source
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plant
fungi bacteria |
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brewing process
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malting
mashing boiling with hopes cooling fermentation |
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malting
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germination of barley
amylase increase starch releases |
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mashing
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hydrolysis of starch
wort = sugar rich liquid |
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confectionery
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increasing sweetness: invertase, glucose isomerase, beet sugar refining, corn syrup
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Invertase
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• From yeast, bee
• Sucrose (1) --> glucose (0.5-0.8) + fructose (1.2-1.5) |
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Glucose isomerase
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• Glucose (0.5-0.8) --> fructose (1.2-1.5)
• Used in the manufacture of high fructose corn syrup |
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Beet sugar refining
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• α-Galactosidase
• Raffinose --> sucrose + galactose • Raffinose interferes with crystallization of sucrose and causes flatulence |
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Corn Syrup
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• Acid hydrolysis or α-amylase
• Produces corn syrups with different dextrose equivalents (DE, amount of reducing sugars in a sugar product) • Corn starch: ~0 DE; corn syrup: > 20 DE; dextrose (glucose): 100 DE; sucrose: 0 DE |
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Milk Clotting
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Cheese making
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Rennet =
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• Rennet = Rennin (chymosin) + pepsin + lipase
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Cheese ripening
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• Due to rennet and proteases and lipases from starter cultures
• Texture and flavor changes during aging (mild 1 month --> medium 3 months --> sharp 6-9 months) o Hard cheese: 25-35% insoluble protein soluble o Soft cheese: > 80% insoluble protein soluble |
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Lactase
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• Lactose --> glucose + galactose
• For lactose intolerant people |
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Enzymes in Meat
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Calpain, transglutaminase and endogenous transglutaminase
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calpain
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tenderizes meat
breaks down structural proteins |
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transglutaminase
|
meat glue
cross-links gln and lys |
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endogenous transglutaminase
|
• Surimi --> suwari --> kamaboko
• increase Setting: 40 °C 40 min or 15 °C 16 h |
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enzymes in egg processing
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Desugarization
-Sugar in eggs: glucose -Cause Maillard browning in dehydrated egg products -Glucose oxidase: Glucose --> gluconic acid + H2O2 -Catalase: 2 H2O2 --> 2 H2O + O2 |
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Glucose oxidase:
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Glucose --> gluconic acid + H2O2
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Catalase:
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2 H2O2 --> 2 H2O + O2
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Enzymes in Bakery
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lipoxygenase and amylases
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lipoxygenase
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• Rich in soy flour
• C18:2, C18:3 LOO• • Bleach carotenoids in dough and oxidize sulfhydryl groups to improve dough rheology |
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amylases
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• Convert starch to maltose for yeast fermentation and retard staling
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egg membrane
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double membrane and air cell
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air cell
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indicates egg freshness (egg candling)
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egg white
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albumen
60% of whole egg weight 88% water 10% protein |
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egg white composition
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ovalbumin
conalbumin ovomucoid lysozyme ovomucin avidin ovoglobulin |
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Ovalbumin
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• Major albumen protein
• Phosphoglycoprotein, contain S • Susceptible to surface denaturation (whipping) • heat resistant |
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Conalbumin
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• No P or S
• Susceptible to surface denaturation (whipping) • Heat resistant • Binds Fe3+, defends microbial attack |
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Ovomucoid
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• Glycoprotein
• Heat resistant in acid, heat labile in base |
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Lysozyme
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• Lyses bacteria
• High pI (10.7) |
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Ovomucin
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• Glycoprotein
• Responsible for viscosity • Heat resistant |
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Avidin
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• Binds biotin
• Toxic but heat labile |
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Ovoglobulin
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• Foaming agent
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egg yolk proteins
|
Phosvitin, lipovitellin, livetin, LDL
|
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phosvitin
|
10% P
binds FE |
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Lipovitellin
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HDL
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livetin
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globular protein
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proteins in granular fraction
|
phosvitin and lipovitellin
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proteins in plasma fraction
|
livetin and LDL
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Factors affecting coagulation:
|
• Temperature (promotes coagulation)
• Dilution (increase temperature for coagulation) • Sugar (increase temperature for coagulation) • pH (pI of ovalbumin: 4.6-4.8) • Salts (usually promotes coagulation except for Fe3+, dependent on valence of cation) |
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Factors affecting foaming:
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• Beating (foaming capacity and stability ↑→↓ due to Ostwald ripening and bubble coalescence)
• pH (at pI, thicker protein film, FC↓, FS↑) • Sugar (↑viscosity, FC↓, FS↑, when to add?) • Lipid (FC&FS↓, more surface active, compete protein at surface and form less cohesive, elastic film) |
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Emulsification
|
Mayonnaise
Mainly due to yolk • Lipoproteins • Lecithin Albumen • Ovalbumin (weak emulsifier) |
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milk proteins
|
casein and whey proteins
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cow milk:
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o A colloid suspension of casein, globular proteins, and lipids (an oil-in-water emulsion)
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Casein micelles:
|
• Structure: diameter 30-300nm but the average is 150nm
• Stabilized by complexing • Calcium phosphate dissolves at pH 4.6 • Micelles are stabilized by complexing: casein-phosphate-Ca-phosphate-casein |
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• How to precipitate casein?
|
Acidify to pH 4.6 or add rennin
o Micelles are stabilized by κ-casein: o C-termini on surface create steric stabilization o Charged surface keep micelles suspended |
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whey protein
|
o Byproduct of cheese industry
o Gluten = gliadin + glutenin + H2O + work o Because of their high nutritional values and functionalities, whey proteins are now widely used in various food preparations, e.g., meat products, bakery, beverage, etc. |
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gliadins
|
prolamin
30-40% wheat protein Fluidity & extensibility |
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glutenins
|
glutelin
30-40% wheat protein Cohesiveness, elasticity, firmness, sponginess |
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β-Lactoglobulin
|
-Contains 2 disulfide bonds, 1 free sulfhydryl
-Excellent functionality (gelling, emulsifying) -Interacts with κ-casein to stabilize casein micelles and promotes milk gelation (e.g., yogurt) |
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Soy proteins
|
2S, 7S, 11S, 15S
|
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2S proteins
|
Trypsin inhibitors
|
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7S proteins
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β-conglycinin (85%)
-Glycoprotein -4 subunits (α’, α, β, γ) in heterogeneous trimers (α’β2, αβ2, α’αβ, α2β, α2α’, α3, β3) -Good emulsifier (hydrophobic) Hemagglutinin, lipoxygenase, β-amylase |
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11S proteins
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Glycinin
-12 subunits (6 acidic, 6 basic) in hexamers (A-S-S-B)6 -Good gelling agent (up to 12 Cys residues) |
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Meat proteins
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Myofibrillar, sarcoplasmic, stromal
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myofibrillar proteins
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myosin, actin, tropomyosin and troponin
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myosin
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makes thick filament
myosin head has ATPase activity - regulates muscle contraction and relaxation |
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actin
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major constituent of thin filament
6 actin strands surround a thick filament |
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contractile myofibrillar proteins
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myosin and actin
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regulatory myofibrillar proteins
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tropomyosin and troponin
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tropomyosin
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double stranded alpha helix that binds and stabilizes f-actin
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troponin
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complex of three proteins Tn-C binds Calcium and Tn-I binds Actin, Tn-T binds tropomyosin
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stromal proteins
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collagen
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collagen
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most abundant protein in animal (20-25%) but less than 10% in muscle
hydrolysis of collagen --> gelatin AA --> polypeptide chain --> helix --> tripohelix (tropocollagen) --> collagen fiber |
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sarcoplasmic proteins
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water soluble
myoglobin enzymes - lactate dehydrogenase and calpain |
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myoglobin
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oxymyoglobin, deoxymyoglobin, metmyoglobin
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oxymyoglobin
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red
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deoxymyoglobin
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blue/purple
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metmyoglobin
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brown
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muscle contraction and relaxation
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Sarcomere: basic unit of muscle (Z-line to Z-line)
Nerve impulse → Cell membrane depolarization → Release of Ca2+ from sarcoplasmic reticulum → Ca2+ binds Tn-C causing conformational change → Expose actin binding sites to myosin heads → Myosin binds actin, hydrolyzes ATP → Power stroke causes relative movement of thin filament |
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resolution of rigor
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Breakage of links between myosin and actin
Proteolysis by cathepsins released from lysosomes Proteolysis by calpain |
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breakage of links between myosin and actin
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• e.g., inject pyrophosphate
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proteolysis by cathepsins released from lysosomes
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(active at pH 5.5)
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proteloysis by calpain
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Break down structural proteins (e.g., α-actinin in Z-line)
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Development of rigor:
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O2 supply shut off, metabolism → anaerobic
Glycolysis converts glycogen → lactic acid pH ~7.0 → ~5.5 (glycolytic enzymes inhibited) Creatine phosphate (CP) depleted CP + ADP → creatine + ATP (regenerated via glycolysis) ATP depleted Permanent myosin-actin complex |
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meat curing
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o Application of salt, nitrite or nitrate, seasonings and other additives to meat to develop unique color and flavor and resistance to rapid deterioration
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why is meat cured?
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Flavor and color
Variety of diet Convenience Preservation |
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curing ingredients?
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salt, sugar, nitrate, nitrite, ascorbate, erythorbate, polyphosphate
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salt
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• Typically 2-3%
• Flavor • Dehydrating • Solubilize protein (luncheon meat) vs. coagulate protein (ham) |
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sugar
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• Flavor (off-set saltiness)
• Color (Maillard reaction, caramelization) |
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Nitrite/nitrate
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• Nitrite (NO2-): direct curing agent
• Nitrate (NO3-): must be converted to nitrite • NO3- → NO2- → NO → curing • Color: bright red • Cured flavor • Bacteriostatic: Clostridium botulinum |
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Ascorbate/Erythorbate
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• Erythorbate: isomer of L-ascrobate, cheaper
• Color development • Antioxidant |
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polyphosphate
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• Pyro-, tripoly- and hexametaphosphate
• ↑ Water holding capacity • ↓ Rancidity (chelator) • Cured flavor |
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toxicity
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• Nitrite itself is poisonous (lethal dose to human: 0.01 oz)
• Nitrosamine (carcinogen) |
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enzymatic treatments to tenderize meat:
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papain, bromelin, ficin, actinidin, zingibain
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papain
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found in papaya
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bromelin
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found in pineapple
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ficin
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found in fig
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actinidin
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found in kiwi
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zingibain
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ginger extract
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1. Which of the following compounds has the highest degree of esterification?
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D. Protopectin
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2. What is the degree of polymerization and degree of esterification of the pectin showing below?
2 COOCH3 and 2 COO- |
DP: 4
DE: 50% |
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3. Which of the following pairs of enzymes catalyze a similar reaction during fruit ripening?
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Protopectinase and pectin methyl esterase
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How much sugar is required for 30 oz of 90 grade pectin to from gel? What is the yield of the jelly?
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Sugar: 2700 oz
Jelly: 4153 oz |
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5. Which of the following compounds will NOT affect the gelling of low methoxyl pectins?
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sugar
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1. Which of the following letters is NOT an abbreviation for 20 common amino acids?
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B
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Overall, is the polypeptide “FAWLIRVHYM” hydrophobic or hydrophilic? How many basic amino acids does it have?
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hydrophobic
2 |
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4. What is the pI of lysine and glutamic acid if their pKR is 10.5 and 4.3, respectively?
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9.75
3.15 |
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5. Which of the following secondary structure is the most stable?
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Antiparallel β-sheet
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1. Which of the following enzymes is an oxidoreductase?
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Polyphenol oxidase
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2. Which pectic enzyme is involved in firming up the canned vegetables?
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Pectin methyl esterase
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3. Which of the following enzymes is endogenous in meat?
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calpain
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After adding an enzyme to a starch solution, numerous maltoses are formed. Which is likely the enzyme?
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β-Amylase
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5. Which of the following statement is wrong for an enzyme?
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B. Enzymes are converted to products after reaction
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1. Which of the following proteins is the most abundant in egg albumen?
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Ovalbumin
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2. Which of the following proteins is responsible for the thickness of egg albumen?
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Ovomucin
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3. Which of the following compounds is a good protein emulsifier?
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Lipovitellin
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4. Which of the following proteins is the most hydrophilic?
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κ-Casein
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5. Which of the following structures of a casein micelle is susceptible to rennin?
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C-terminus of κ-casein
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1. Which of the following proteins is the most abundant in muscle?
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myosin
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3. Which of the following proteins has ATPase activity?
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myosin
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4. Which of the following proteins in troponin complex binds actin?
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Troponin-I
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5. Which of the following structures remains the same length during muscle contraction?
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A band
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