Meat and Egg Cooking Science

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Questions and Answers

What is the primary factor that influences meat tenderness?

The cooking temperature

The method of slaughter

The species of the animal (correct)

The age of the animal (correct)

Which cooking method is most likely to tenderize meat with high connective tissue content?

Moist heat cooking (correct)

Grilling

Deep frying

Baking

What chemical change contributes to the brown color observed in cooked meat?

Protein coagulation

Denaturation of myoglobin (correct)

Formation of nitrogenous molecules

Loss of water content

What percentage range of B vitamin loss occurs in meat cooked at high temperatures?

20% to 40% Signup and view all the answers

How does cooking meat with minimal water impact vitamin retention?

It reduces vitamin loss significantly. Signup and view all the answers

What is one consequence of excessive water loss during meat cooking?

Dried out texture Signup and view all the answers

Which of the following is a potential health risk associated with cooking meat at very high temperatures?

Nitrosamines formation Signup and view all the answers

What type of meat tends to be less flavorful according to the factors affecting meat flavor?

Milk-fed lamb Signup and view all the answers

Which of the following combinations results in high-quality protein?

Bulgur Pilaf and Kidney Beans Signup and view all the answers

What happens to proteins during denaturation?

Their functions diminish Signup and view all the answers

What is an indicator of a fresh egg?

An intact and centered yolk Signup and view all the answers

At what temperature does the egg white begin to solidify during cooking?

60°C Signup and view all the answers

How does the cooking time of an egg affect its protein structure?

Longer cooking times lead to irreversible denaturation Signup and view all the answers

Which of the following proteins is considered low-quality?

Legumes Signup and view all the answers

What compounds are formed when the iron in egg yolk reacts with hydrogen sulfide in egg white?

Iron sulfide Signup and view all the answers

What is indicated by the observation that eggs float in saltwater?

They are stale Signup and view all the answers

What is the maximum proportion of eggs from one weight class lower than specified in inspections involving 180 or more eggs?

5% Signup and view all the answers

In inspections involving fewer than 180 eggs, how do the tolerances for weight control compare to those involving 180 or more eggs?

They are double the limits specified for 180 or more eggs. Signup and view all the answers

Why are egg proteins referred to as reference proteins?

100% of them are converted into body proteins. Signup and view all the answers

What is the composition percentage of saturated fats in egg fat?

33% Signup and view all the answers

What is the recommended frequency for healthy individuals to consume eggs?

3-4 times a week Signup and view all the answers

What is a crucial nutritional benefit of consuming eggs for individuals with restricted dietary protein intake?

They provide high-quality protein. Signup and view all the answers

What is the health risk associated with consuming raw (uncooked) eggs?

Difficulty in digestion. Signup and view all the answers

How do eggs consumed with vegetables and grains affect blood cholesterol levels?

They minimize negative impacts on cholesterol levels. Signup and view all the answers

What is the primary benefit of combining legumes with vitamin C-rich foods?

To enhance the bioavailability of minerals Signup and view all the answers

Which legume has the highest biological value of protein?

Soybeans Signup and view all the answers

What is the primary reason for the low protein quality in legumes?

Limited essential sulfur-containing amino acids Signup and view all the answers

Which combination can increase the biological value of legume proteins up to 70%?

Mixing legumes with grains Signup and view all the answers

Which nutrient does phytate negatively affect the bioavailability of?

Iron Signup and view all the answers

What is the main impact of heat treatment on soybeans?

Improves iron bioavailability Signup and view all the answers

Based on TBSA 2010 study data, what percentage of adults consumed legumes daily or 5-6 times a week?

4.4% Signup and view all the answers

What are legumes notably low in among dietary components?

Quality protein Signup and view all the answers

What potential health risk is associated with excessive protein consumption?

Increased risk of cardiovascular diseases Signup and view all the answers

Excessive protein intake can lead to which of the following kidney-related issues?

Excessive kidney strain Signup and view all the answers

How does high protein consumption affect calcium levels in the body?

Increases calcium excretion in urine Signup and view all the answers

What is a potential consequence of excessive protein intake related to gout?

Accumulation of urate crystals in joints Signup and view all the answers

Is there evidence supporting the need for high protein consumption for muscle growth?

No, beyond required amounts is unnecessary Signup and view all the answers

What happens to excess protein consumed by the body?

It is stored as fat Signup and view all the answers

What is the average annual consumption of legumes per person?

31 kg Signup and view all the answers

Which organ systems are stressed by excessive protein intake?

Kidneys and liver Signup and view all the answers

What is a primary use of soybeans in food production?

Vegetable oil production Signup and view all the answers

Which legume does not require soaking before cooking?

Lentils Signup and view all the answers

What nutritional benefit is enhanced by cooking legumes with grains?

Protein bioavailability Signup and view all the answers

What should be done with the soaking water of legumes?

Discard it Signup and view all the answers

What is a disadvantage of cooking legumes at dry heat above 100°C?

It causes protein loss Signup and view all the answers

Which legume is commonly processed into roasted chickpeas?

Chickpeas Signup and view all the answers

What happens to legumes during the soaking process?

They absorb water equivalent to their weight Signup and view all the answers

When might the outer skins of legumes be removed?

When preparing for children or to improve digestibility Signup and view all the answers

Study Notes

Meat and Meat Products, Eggs and Legumes, Nuts and Oilseeds

Meat contains protein, fat, minerals, and vitamins
It is one of the most important protein sources due to its high-quality protein content and high protein ratio
The proportion of protein and fat in meat varies depending on whether the meat is lean or fatty
Fatty meats have a higher saturated fatty acid and cholesterol content
Fish, especially, are a significant source of omega-3 fatty acids
Meat should be included in the diet during periods of increased protein requirements, such as infancy and childhood
Meats are lean in vitamin C, vitamin E, and calcium. However, they are rich in vitamin B12, iron, and zinc
The iron found in meat is highly bioavailable, making it significant in preventing iron deficiency anemia
Individuals with certain conditions, such as coronary artery disease, diabetes, or hypertension should prefer lean red meat, skinless white meat (chicken, turkey), fish under the supervision of a dietitian.
Fish meat contains proteins equivalent to red meat and poultry, such as chicken and turkey
Marine fish are a good source of iodine
Fatty fish, especially, are rich in n-3 (omega-3) fatty acids, and it is recommended to consume fish at least twice a week for a healthy diet
Adequate dietary intake of n-3 fatty acids is crucial for the prevention of cardiovascular diseases and for brain development in children
Various meat products are made through different processes
Chemicals like nitrites and nitrates are used in the production of salami and sausages to prevent color changes and inhibit microbial growth
Harmful substances produced by these chemicals can be neutralized or eliminated with antioxidants such as vitamins C and E
When consuming such products, include fruits and vegetables rich in vitamins C and E in the diet
Consumption of processed products should be limited due to their high saturated fat content

Meat Consumption (Red Meat, Poultry, Fish, and Seafood)

United States: 82 kg/year
In our country, it's 19 kg (52 g/day)
Denmark: 60 kg/year
% of individuals who do not consume red meat: 20%
% of individuals who consume chicken once or twice a week: 42.9%
% of individuals who do not consume fish: 39%
In the 2010 TBSA study, 6.4% of adults consumed red meat every day or more than once a day in the past month
56.9% of adults consumed red meat only 1-2 times per month or never.

Structure of Meat

As connective tissue increases, meat toughness increases
The connective tissue is higher in parts of the animal that are highly active
Muscle tissue, connective tissue—Collagen, Elastin
Collagen hydrolyzes into gelatin at 60-80°C
Elastin does not hydrolyze

Meat - Protein

Actin, Myosin
Actomyosin is important for muscle movement
During Muscle Movement: Actomyosin + ATP
During Muscle Relaxation: Kreatin-P → ATP + Kreatin
Myogen (play a role in muscle contraction and structure)
Albumin (maintaining osmotic pressure)
Myoglobin: Gives red meat its characteristic red color

Rigor Mortis

After slaughter, muscle movements continue, but oxygen intake is cut off
This leads to the formation of lactic acid, causing the muscle to harden
As the meat rests, the acids formed through metabolism increase the meat's ability to retain water
With the action of enzymes, the hardness disappears
Depending on the type of animal and the temperature at which the meat is stored
In poultry, rigor mortis disappears within 1 hour
In large animals (cattle, sheep), rigor mortis resolves in 10 days at 0°C and in 3 days at 15°C
Animals with less fat lose rigidity faster

Meat- Composition

Saturated fats (palmitic, stearic fatty acids)
Minerals and some organic components
Small molecules containing creatine and amino acid nitrogen
Freshly slaughtered animal meat → Glycogen → Ç

Factors Affecting the Flavor of Meat

Meat tenderness depends on species, age, fat content, diet, connective tissue, and nutritional condition
Meat from poorly fed and/or highly active animals tends to be tough
As fat content increases, tenderness increases
Milk-fed lamb has a higher water content and is not as flavorful as meat from animals slaughtered at the optimal age
Cooking method is applied depending on the type of meat and its connective tissue content
Raw meat proteins → Proteins denature → Meat solidifies → Water loss
If water loss is excessive, the meat becomes dry, negatively affecting its flavor
Increased connective tissue makes meat tough when cooked with dry heat
Collagen is hydrolyzed, making the meat tender when cooked as ground meat with moist heat

Changes in Meat During Cooking

Proteins coagulate, and water is lost
In moist heat, the connective tissue protein collagen is hydrolyzed, which helps tenderize the meat
Myoglobin → Metmyoglobin (denaturation), resulting in a brown color
Nitrogenous molecules (amines, hydrogen sulfate, and organic acids) are formed, enhancing flavor
Melted fats + gelatin = forms a fatty gel when cooled
Some vitamin loss occurs in meat cooked at high temperatures
Heat and water loss result in a reduction of folic acid, B1, and B12 vitamins
In baking, grilling, and frying, the loss of B vitamins depends on temperature and duration, ranging from 0% to 40% (average: 20%)
In moist cooking, if the cooking water is not used, the loss can reach 70% (Thiamine is lost the most)
Cooking with minimal water and retaining the cooking liquid prevents any loss
Nitrosamines are formed in partially charred meat cooked at very high temperatures (deep frying in hot oil) or in close contact with fire (grilling), exhibiting carcinogenic activity

Meat Cooking Methods

Dry Heat Cooking: Grilling, oven roasting, cooking in oil-free or lightly oiled heavy-bottomed pans
Moist Heat Cooking: Kebabs, steaks, and chops cooked over low heat; water can be added. Examples include tray-baked chops, oven kebabs, and meatball dishes
Frying in Oil: Meatballs. If the oil is too hot, the outer surface solidifies, making it difficult for heat to penetrate the interior.

Foods Made from Meat

Sausage and Sucuk (Dry Fermented Sausage): Meat → Minced → Salt + Spices added → Stuffed into animal intestines, gelatin, or cellulose casings
Salami and Pastrami: After partial drying, the meat is seasoned with spices
Cold Cuts: Meat is boiled and cooked, then pressed together with gelatin under pressure to form cold cuts
Kavurma (Braised Meat): Meat is braised as ground meat or in small pieces. It is preserved by sealing it with a layer of fat on top.

Health Standards for Meat

Meat must come from healthy animals
Diseases transmitted from animals to humans: intestinal parasites (such as tapeworms), bacterial diseases (anthrax, glanders, tuberculosis, salmonella), cattle plague, foot-and-mouth disease, smallpox, mad cow disease (Bovine spongiform encephalopathy)

Meat Storage

Minced meat should not be kept in the refrigerator for more than 1 day
Whole cuts of meat can be stored for 2-3 days in the refrigerator
Meats should be divided into portions suitable for cooking and wrapped in parchment paper before freezing
Frozen meat should be thawed in the refrigerator
Thawed meat should not be refrozen

Meat Inspection Marks

Edible Meats - Circle Shape
Edible Low-Quality Meats - Circle shape
Edible Meats After Proper Cooking - Square shape
Meats to Be Discarded - Triangle shape

Poultry Meats

Domestic Fowl (Poultry)- Fat↓, Energy↓, Saturated Fat and Cholesterol↓, Protein ↑, Iron ↑, Riboflavin, Niacin, B6, B12
Red Meats- Fat ↑, Energy ↑, Saturated Fat and Cholesterol ↑, Protein ↓, Iron ↑

Seafood

Consumption: Annual per capita consumption is 3 kg, comprising 65% fresh and 35% dried, salted, or canned products.
Nutritional Value: High-quality protein, rich in vitamins A, K, and B; contains iodine, phosphorus, and zinc
Energy: Fatty fish have higher energy content
Unsaturated Fatty Acids: Contains high levels of omega-3 (n-3) fatty acids
Calcium Intake: Consuming fish with bones increases calcium intake
Health Benefits: Increased fish consumption reduces the risk of coronary heart disease

Fish

Eyes: Bright and clear, free of blemishes
Gills: Reddish-pink in color
Scales and Fins: Firm, intact, and in good condition
Odor: No unpleasant or fishy smell
Press Test: When pressed, the indentation from a finger quickly bounces back

Fish Storage

Short-Term Storage: Store in ice or at temperatures below 0°C (32°F)
Long-Term Storage Methods: Freezing (fresh fish frozen at -32°C (-25.6°F) and stored at -18°C (0°F) for 3-6 months), Salting (Preserves fish by curing it with salt), Canning (Processed and sealed in airtight containers for extended shelf life), and Drying (Fish is dried to remove moisture for preservation)
Shelf Life of Salted and Dried Fish: Varies between 6-12 months depending on storage temperature and humidity conditions

Fish Meal

Fish meal is flour made from fish, processed into meal form in factories, used to enrich low-quality protein sources, and commonly utilized as animal feed

Fish Cooking Techniques

Low connective tissue in fish: Causes it to break apart easily during cooking
Fatty Fish: Best suited for grilling or steaming in its own juices (e.g., poaching or en papillote)
Lean Fish: Ideal for frying. To prevent the fish from falling apart, coat it in flour before placing it in hot oil

Egg

11% Shell
58% Egg White
31% Egg Yolk
Egg White Proteins: 63% Albumin, Remainder consists of mucin, mucoid, and avidin
Egg Yolk Proteins: Mainly vitellin and phosvitin

Egg - Composition

In Our Country: Average per capita egg consumption is 4 kg per year. The percentage of people who consume eggs daily is 30%.

Turkish Food Codex Egg Regulation

Class A Eggs: Obtained from Gallus gallus var. domesticus, intended for direct human consumption or food industry use.
Eggshell: Clean, intact, with normal shape, slightly rough texture
Air Cell: For “extra fresh” eggs, ≤4mm; for others, ≤6mm
Egg White: Should be clear, transparent, jelly-like
Egg Yolk: Round shadow in the center, not visibly separate from the center, and should not contain foreign matter
Embryo: No visible embryo
Odor: No foreign or unpleasant smells
Weight tolerance for Class A Eggs: For 180+ eggs: ≤5% eggs below specified; for <180 eggs: double the above tolerances.

Egg Composition and Nutritional Value

Energy (kcal): 140, (kJ): 584
Water (g): 76.11
Ash (g): 0.93
Protein (g): 13.13
Nitrogen (g): 2.10
Fat, Total (g): 9.69
Carbohydrates (g): 0.00

Egg - Protein

Eggs contain high-quality protein
Studies on lab animals show 100% of egg proteins convert into body proteins
For this reason, egg proteins are referred to as reference proteins

Importance of Egg Consumption

Egg fat is composed of 33% saturated fats, 16% polyunsaturated fats, and the remainder are monounsaturated fats • The fat is concentrated in the egg yolk, which has a high cholesterol content. However, it also contains a significant amount of unsaturated fatty acids and lecithin, which reduces its cholesterol-raising effect compared to fatty meats and dairy products • Egg yolk is rich in iron, Vitamin A, and B-group vitamins • Consuming one egg daily is beneficial for infants and children • In cases where dietary protein intake is restricted (such as kidney and liver failure), eggs are a crucial source of nutrition as they contain exemplary protein

Importance of Egg Consumption (raw eggs)

From a food safety perspective, consuming raw eggs is not recommended as they are difficult to digest and the beneficial effects of biotin (a B-group vitamin) cannot be fully utilized by the body

Importance of Egg Consumption(General)

One egg is equivalent to half a portion of meat and meat products
Consuming eggs together with vegetables and grains minimizes their negative impact on blood cholesterol levels
The lecithin in eggs helps regulate brain functions and supports the protection of the liver • When purchasing eggs, choose those that are clean, with no cracks or breaks, and store them unwashed in the refrigerator • If the egg is old or cooked for too long, a green sulfur (iron-sulfur) ring may form around the yolk

Egg Yolk Color ~ Chicken's Diet

The color of the egg yolk is influenced by the diet of the chicken

Changes in Stored Eggs

Viscosity of the egg white decreases
Water moves from the egg white to the yolk
The air cell enlarges
Overall, the egg becomes lighter due to water loss

Protein Quality

Amino acid profile in foods
Digestibility refers to the ability of food proteins to be converted into body proteins
Processing methods and storage conditions applied to foods can lead to the breakdown of amino acids in their composition, affecting their digestibility
Reference protein: Human Milk and Eggs
High-quality Proteins- Meat, Fish, Milk, and Dairy Products
Low-Quality Proteins- Plant-Based Foods

Food Digestibility

Eggs, meat, milk, and animal-based foods 91-100%
Cereal proteins 79-90%
Legumes 69-90%

Ways to Improve Protein Quality

Bulgur Pilaf + Kidney Beans → Balances the amino acid profile
Cereals + Legumes → High-quality protein
Rice + Milk → Rice Pudding: Balances the amino acid profile

Denaturation of Proteins

Enzymes lose their activity
Proteins' solubility decreases
Proteins' functions diminish
Digestibility increases
The solidification and whitening of an egg due to heat is irreversible
Many other denaturation processes are reversible

Which Eggs Are Healthy?

Different levels of cooking times (1 minute, 3 minutes, 5 minutes, 7 minutes, 9 minutes, 11 minutes, 13 minutes, 15 minutes) correlate with different degrees of egg firmness, resulting in varying nutrient bioavailability and potential health outcomes

How Long Should Eggs Be Cooked?

The iron (Fe) in the egg yolk reacts with hydrogen sulfide (H2S) present in the egg white, forming iron sulfide (FeS)

Determining the Freshness of an Egg

Size of the Air Cell: Fresh eggs have a small air cell, while older eggs have a larger one.
Floating in Salt Water: Eggs that float in saltwater are considered stale
Appearance When Cracked: When carefully cracked, the yolk should remain intact and centered, surrounded by thick egg white that holds its shape

Changes in Cooked Eggs

Egg Proteins Coagulate: Egg white solidifies at 60°C, and the yolk solidifies at 70°C
Digestibility: Normally cooked eggs are easy to digest
Green Color Formation: Eggs cooked at high temperatures for extended periods or stale eggs may develop a green color
High Heat + pH → Hydrogen Sulfide + Iron
Effect on Avidin in Egg White: Avidin + Heat → Avidin loses its properties

Cooking Methods for Eggs

Boiling in the Shell: depends on water temperature, cooking time, and amount of water used
Frying in an Oiled Pan: Eggs are cracked directly into the pan and cooked
Mixing with Other Foods: Eggs as a coagulating, leavening, or emulsifying agent, enhancing flavor, color, and aroma, ensuring proper firmness
Tempering: Beaten egg + lemon juice/yogurt is slowly added while the dish is removed from the heat to prevent curdling

Leavening Property of Eggs

Denaturation During Whipping: When eggs are whipped, the proteins in the egg denature
Incorporation of Air: Air bubbles are introduced into the whipped eggs
Leavening Effect in Baking: When well-whipped eggs are mixed with flour and baked (e.g., in cakes), the trapped air expands, causing the dough to rise
Egg Yolk as an Emulsifier: Egg yolk → Lecithin (phospholipid) → Acts as an emulsifier
Emulsion Formation: Lecithin reduces the surface tension between water and oil, allowing oil to disperse into water, forming an emulsion. This property is crucial in making rich pastries and mayonnaise

Data

Additional information about specific foods, regions, figures, and percentages are included for each respective topic.

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Description

Test your knowledge on the science of cooking meat and eggs. Explore factors that influence meat tenderness, cooking methods, vitamin retention, and protein quality. This quiz will challenge your understanding of how cooking techniques affect food characteristics.