Food Science and Protein Metabolism Lecture Review

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Flashcards to help review key concepts related to food consumption trends, food safety and quality, historical aspects of meat packing, the role and properties of water, proteins (structure, function, analysis), and lipids (types, properties) in food and muscle growth.

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40 Terms

1
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What percentage of their income do U.S. consumers spend on food?

12.9%, an increase of 6.9% from 2022.

2
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Which types of food account for over 30% of U.S. consumer expenditures?

Meats, poultry, fish, eggs, dairy, and some fats.

3
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What is the correlation between lack of meat consumption and physical development?

Lack of meat consumption is directly correlated with stunted growth.

4
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Name one factor that has driven increased demand for poultry products in recent years.

Increased demand for convenience, flexibility, consistency, nutrition, or lower price.

5
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Which region is projected to have massive growth in poultry consumption?

Asia, particularly China and India.

6
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Which country leads global beef exports?

Brazil.

7
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According to the USDA, what is food safety?

Conditions and practices that preserve the quality of food and keep it safe for consumption.

8
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What are the four main characteristics that define food quality?

Palatability, nutritive value, appearance, and preservation.

9
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Who is recognized as the first meat packer in the U.S. colonial period?

William Pynchon from Massachusetts.

10
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What major innovation by Swift enabled mass transport of meat?

The development of the refrigerated rail car.

11
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What famous novel by Upton Sinclair exposed conditions in the meatpacking industry?

The Jungle.

12
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What percentage of meat, eggs, and milk is composed of water, respectively?

Meat is 75%, eggs are 78%, and milk is 88% water.

13
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What is a 'hydrate' in the context of food science?

Any compound containing water in the form of H2O that is partially immobilized and does not separate from solids easily.

14
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Describe 'bound water' in food matrices.

Bound water directly interacts with protein molecules, is a very small amount, has a very low freezing point (-40 C), no solvent capacity, and greatly reduced mobility.

15
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What is 'water activity' (aw) and its significance?

Water activity is the amount of 'free water' available in food for microbial growth, useful in predicting spoilage and safety.

16
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What approximate range of water activity is typically found in fresh meat, eggs, and milk?

0.96-0.99.

17
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Name two methods to reduce water activity in food.

Adding salt, drying meat, freezing, or changing the matrix.

18
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What type of bond connects amino acids to form a protein chain?

A peptide bond.

19
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Name three functional properties of proteins in food.

Water binding, gelation, emulsification, viscosity, fat absorption, flavor binding, foaming, or color.

20
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What is the 'biological value' of a protein?

The measure of the proportion of protein retained in the body for growth and/or maintenance, based on a proper balance of essential amino acids.

21
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What is the 'isoelectric point' (pI) of a protein?

The pH at which a protein has no net charge.

22
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What is 'denaturation' of a protein?

The unfolding of a protein's primary structure, often caused by cooking, freezing and thawing, salt, aging, or fermenting.

23
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What is the 'Kjehldahl method' used for in protein analysis?

It is the gold standard method for determining protein content by measuring the amount of nitrogen.

24
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What is the primary function of lipids in the body?

Efficient long-term energy storage.

25
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What are the three main types of lipids?

Triglycerides, phospholipids, and sterols (cholesterol).

26
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What distinguishes a 'saturated' fatty acid from an 'unsaturated' fatty acid?

Saturated fatty acids contain only single bonds between carbon atoms, while unsaturated fatty acids contain one or more double bonds.

27
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How does the length of a carbon chain and the degree of saturation affect a fatty acid's melting point?

The longer the carbon chain and the more saturated the fatty acid, the higher the melting point.

28
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What is the difference between 'cis' and 'trans' configurations of double bonds in fatty acids?

In 'cis,' both carbons are on the same side of the double bond, making it 'kinky' with a lower melting point. In 'trans,' carbons are on opposite sides, allowing tighter packing and a higher melting point.

29
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What is 'hyperplasia' in muscle growth?

The growth and division of mononucleated muscle cells during the embryonic stage.

30
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What is 'hypertrophy' in muscle growth?

The postnatal growth of muscle where the number of cells does not change, but their size increases due to the accretion of protein.

31
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What is the main characteristic differentiating muscle fiber types?

The speed of contraction (e.g., slow-twitch red fibers vs. fast-twitch white fibers).

32
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Compare the key metabolic characteristic of 'red' (Type I) muscle fibers versus 'white' (Type IIb) muscle fibers.

Red (Type I) fibers primarily use aerobic (oxidative) metabolism for endurance, while white (Type IIb) fibers use anaerobic (glycolytic) metabolism for bursts of energy.

33
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What are the repeating structural units of myofibrils responsible for muscle contraction?

Sarcomeres.

34
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What two primary myofilaments make up sarcomeres?

Actin (thin filaments) and myosin (thick filaments).

35
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What are the three main types of proteins found in meat?

Myofibrillar, sarcoplasmic, and stromal proteins.

36
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Which type of meat protein primarily dictates texture and water holding capacity?

Myofibrillar proteins.

37
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What sarcoplasmic protein is responsible for meat color?

Myoglobin.

38
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How does age affect collagen in meat and its tenderness?

Meat from older animals tends to have tougher, more insoluble collagen, making the meat less tender.

39
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What is the fate of glycogen in meat after an animal's death, and what does it influence?

Glycogen (immediate energy) is converted to lactic acid, which influences pH, color, water-holding capacity, texture, and tenderness of the meat.

40
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Name three functions of fats in meat.

Flavor, juiciness, and texture.