Topic 5: Part G Flashcards
Animal proteins
- meat
- milk and dairy
- eggs
Meat
Broadly defined, meat includes muscle tissue and organs of beef, veal, lamb, pork, poultry and fish.
Red meat has..
negligible carbohydrate content as the glycogen us used up in the continue metallic process after slaughter
Major component of red meat are..
water, fat and protein. some minerals/vitamins
Poultry tends to have ..
lower fat content and slightly higher protein content per weight than red meat
High water content and neutral pH makes meat..
susceptible to spoilage, this can be reduce by curing (salt addition) or drying
Other processing of meat includes..
grinding, canning or freezing
Meat usually has some ..
visible fat within the muscle (white streaks/drops is muscle) called marbling
Presence of fat increases..
juiciness and gives better eating quality
Due to health concerns some animals are bread to have ..
leaner meat
The toughness of meat is directly related to the ..
amount of collagen it contains. (older animals have accumulated high levels of collagen yield tougher than young meat)
The colour of meat is often used to ..
judge freshness and usually wrapped in material the is permeable to oxygen to preserve the red colour
Without oxygen beef is normally what color?
blueish-purple. when its not fresh it turns brown
Fish flesh is highly ..
perishable because of the high levels of unsaturated fatty acids which can be readily oxidized
Fish fat is rich in a chemical called…
trimethylamine oxide (TMAO)
After capturing fish, the TMAO is converted into..
trimethylamine (TMA) that is responsible for the ‘fishy’ odour.
Milk is a ..
near perfect food, it is an important source of high quality protein, mineral B vitamins and energy but low iron
Milk is composed of 2 protein fractions ..
1: casein (80% of total milk protein)
1: whey (20% of milk protein)
During manufacture of cheese..
acid or chymosin/rennin (enzymes) is added to coagulate most of the casein proteins while the whey proteins remain in solution.
Whey proteins are composed mostly of ..
beta-lactoglobulin and alpha-lactalbumin.
Homogenization is used to produce a..
whole milk product and involves a process that decreases the size of fat globules dispersed in milk so they are more optimally dispersed
Freezing destroys process of homogenization, hence the fact that when most milk products are frozen and then..
thawed there is some separation of fat and liquid
Evaporated milk
Over half of the water (~60%) is evaporated out of the milk prior to canning. In Canada, it is fortified with Vitamins D and C.
Sweetened condensed milk
a canned product where approximately half of the water content is evaporated out of the milk prior to canning and to which a high percentage of sugar is added.
Cultured/fermented milk
Bacterial cultures added to ferment the lactose into lactic acid, which thickens the consistency. Ex: Buttermilk, kefir, acidophilus milk, sour cream, yogurt
Skim milk powder
The water content of the milk is removed, first through the use of a vacuum and then by spray drying. This form of milk can be used in baked goods and can be added to water to reconstitute fluid milk.
Ultra high temp (UHT) milk
the milk is heated for approximately 2-6 seconds at 300F to remove all viable microorganisms. i.e., the product is sterile.
Eggs have..
2 major parts: white and yolk
Eggs contain ..
protein, fat, vitamins, minerals and a small amount of CHO, with the yolk containing the fat and cholesterol and most of the calories (75%), while the white is the more protein-rich portion
Major protein of the egg white is ..
ovalbumin. Also find conalbumin, ovomucoid, lysozyme and avidin.
Major proteins of the yolk are..
the lipoproteins: high density lipoproteins (HDL) and low density lipoproteins (LDL)
The shell of the egg is..
94% calcium carbonate and has small pores that allow carbon dioxide and water to escape, while allowing oxygen in.
Inside the shell of an egg there is a ..
shell membrane and an egg membrane both for protection. A space forms between the two membranes at the rounded end (ie. air cell) as the egg ages.
When the egg is freshly laid the ..
shell is completely filled. The air cell is formed by contraction of the contents during cooling and by the loss of moisture. A high-quality egg has only a small air cell.
Functional characteristics of eggs
- Emulsification
- Foaming
- Coagulation
Emulsification
lipoproteins and phospholipids present in the yolk help to keep fat dispersed in water. Used in mayo, salad dressings, sauces (like hollandaise), ice cream and some cakes.
Foaming
proteins in the white have a high capacity to form strong protein films that surrounds air bubbles to produce stable foams. The foams can become 6-8X the original volume. Used in soufflés, fluffy omelets, meringues and some cakes (e.g., angel food).
Coagulation
egg white proteins can set and form a gel during heating. They can help to bind food mixtures together, such as meat loaf, meat patties and manicotti.
Plant proteins can be divided into 4 broad groups based on solubility properties ..
a. Albumins- soluble in water.
b. Globulins- soluble in salt solutions but insoluble in water.
c. Gliadins- soluble in 70-90% alcohol.
d. Glutelins- insoluble in neutral aqueous solutions, saline solutions or alcohol. Can only be solubilized by dilute alkaline solution.
Plant protein crops
- cereals
- pulses, nuts and oilseed
Cereals
have protein contents no greater than 15-17% (wheat, corn, rye, rice)
In wheat the principal proteins are the ..
the gliadin and glutelin fractions, which represent about 80% of the endosperm protein.
Gluten is a complex formed from..
gliadins and glutelins following hydration and mixing of wheat flour.
The hydrated gluten complex forms a ..
a 3-dimensional viscoelastic network that gives wheat flour its valued dough and bread-making characteristics
Pulses are..
beans (e.g., Navy beans, kidney beans, black beans, etc.), peas (e.g., split peas, chickpeas) and lentils.
Contain higher protein contents ranging from …
18-45%. (e.g., peas, lentils, beans, soybean, canola, mustard).
Pulses, nuts, oilseeds contain
very little gliadin and glutelin. Majority of the proteins are albumins and globulins.
Most pulses offer protein of ..
good quality, while being low in fat
Legumes include ,,
pulses, soybeans, seeds and peanuts.
Nuts are grown on ..
various trees and ground plants. Provide protein, unsaturated fat, fibre, vitamins, minerals and phytochemicals
