Transcript Protein: Amino Acids - Resource Sites

Protein: Amino Acids
Objectives
• After reading Chapter 5, class discussion and
activities you will be able to:
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Identify food sources of protein
List nutrient found in high protein foods
Discuss amino acids and protein structure
Discuss digestion and metabolism of proteins
Describe the functions of proteins
Distinguish between complete and incomplete
proteins
– Identify sources of quality protein
Objectives
• Identify adult RDA for
protein, protein needs
• Discuss healthy protein
preparation options/ideas
• Define a protein allergy and
food service strategies for
consumers
Food Protein Sources
(grams)
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3 oz meat = 21
1 oz meat = 7
1 cup milk = 8
1 cup yogurt = 8
2 T. peanut butter = 7
1 egg white = 7
½ oz. nuts/seeds = 7
½ c. legumes/soy = 7
½ cup grain = 3
1 slice bread = 3
½ cup vegetables = 2
• 1 cup soy milk = 8
• ¼-½ cup meat substitute = 714
• Veggie Burger = 14
• ½ oz. tofu = 18
• Scoop of protein powder = 24
• Protein Bars- 7-14
• MyPlate- 76 grams
Protein Sources are also
sources of…..
• Iron
• B-vitamins (thiamin, niacin,
riboflavin, B-6, B-12)
• Zinc
• Magnesium and vitamin E
(nuts/seeds)
• Fiber (legumes)
• Omega 3 fats (fish, eggs)
Amino Acid
• Organic molecule
made of carbon,
hydrogen,
oxygen, nitrogen
• 20
p. 163
Fig 5-1
Amino Acids
• Essential amino acids
–Body cannot synthesize
–9
• Nonessential amino acids
–Body can synthesize
–11
Amino Acids
Essential
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Histidine
Isoleucine+
Leucine+
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine+
*- semi-essential
+- branched chain
Non-Essential
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Alanine
Arginine*
Asparagine
Aspartic acid
Cysteine
Glutamic acid
Glutamine*
Glycine
Proline
Serine
Tyrosine*
Protein Structure
• Long chains of amino
acids (sequence
unique to protein)
• Amino acids repel or
attract each other
• Fold and twist
• Two are more chains
loop
Pg. 176-168
Protein Denaturation
• Uncoiling & loss of shape and function
• Caused by
– Heat
• Egg white → cooked egg whites
• Curdled milk or egg based sauce
– Acid
• Vinegar, citrus, wine
• Meat marinades
– Mechanical
• Beating eggwhites to make a meringue
– Maillard Reaction
• Browning when sugar combines with protein
p. 176
Protein Digestion
• Peptide bonds join amino acids
together to make a protein
• Bonds break apart
– Polypeptide
– Tripeptide
– Dipeptide
– Single amino acids
Protein Digestion
• Mouth
– Mixing, moisturizing
• Stomach
–HCl
–Pepsinogen (proenzyme) 
pepsin (enzyme)
–Splits peptide bonds, short
proteins
Protein Digestion
• Small intestine
–Proteases, peptidases
–Tripeptides, dipeptides
• Intestinal cells
– Single amino acids
– Absorption into bloodstream
Protein Synthesis
• Delivering the instructions
–DNA
•mRNA- attaches to ribosome
–Protein-making machine
Protein Synthesis
• Sequencing errors
Protein Metabolism
• Protein turnover
–Amino acid pool: supply of AA
from food/body; collect in cells &
blood; ready for use
• “Recycling” affect
Functions of Proteins
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Structural component
Build, maintain tissues
Enzymes, hormones
Antibodies
Transporters
Fluid balance
Blood clotting
Energy
– 4 calories/gram
p. 164-168
Visuals For…
• Transport Proteins
• Fluid Regulation
– Protein albumin
– Edema
Nitrogen Balance
• Protein intake and protein use
• Follow nitrogen
• Nitrogen in = Nitrogen out =
Protein balance
–Positive nitrogen balance
–Negative nitrogen balance
Protein Quality
• Complete Proteins
– High-quality proteins
– 9 essential amino acids
– Animal proteins - beef, chicken,
turkey, fish/shellfish, eggs, dairy
– Soy, quinoa
• Incomplete Proteins
– Missing amino acids
– Plant proteins- grains, vegetables,
legumes, nuts, seeds
– “Limiting amino acids”
Complementary Proteins
• Two incomplete
plant based proteins
make a complete
protein when
consumed together
Protein Quality
• Digestibility
• PDCAAS
– Protein
digestibilitycorrected
amino acid
score
– Body’s use
Recommended Intake
• RDA
–0.8 g/kg/day (.36 gram/pound)
–10% - 35% of energy intake
Protein Needs Ranges
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7-12 months
1-3 years
4-13 years
14-18 years
Pregnancy/Breastfeeding
Older adults
Athletes
Stress/Trauma/Malnourish
1.5 gram/kg
1.1 grams/kg
.95 grams/kg
.85 grams/kg
1.1 grams/kg
1.2 grams/kg
1.2-2.0 grams/kg
1.5-3.0 grams/kg
Page 173
Food Labels
• Quantity of protein
• Daily Value
– 50 g protein
– 10% of a 2000 kcal
diet
Label Terms….
• Lean- Less than 10 grams fat, 4.5
grams saturated and trans
combined per 100 grams
• Extra Lean- Less than 5 grams fat,
2 grams saturated fat per 100
grams
• Wild caught- not farm raised
• Grass fed- not grain fed
Healthy Meat Prep…
• Dietary Guidelines- Lean or low fat meats
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80% lean vs 90% lean
Eye of round, top round, bottom round
“loin”
Trim visible fats
White, skinless poultry
Check ground meats...??
• Cook in using moist methods/grill/broil
– Sauteing, poaching, braising
• Add flavor by….
• Using rubs
• Marinades
Other Protein Prep Ideas
• Egg substitutes or egg whites
• Substitute beans/legumes
• Use meatless protein products
• Other ideas….
Protein Allergies
• 90% of reactions to:
– Milk, eggs, fish, shellfish, peanuts, tree
nuts, wheat, soy
• Immune- antibody response to protein
• Symptoms- Anaphylaxis (minutes –
hours)
– Skin, GI, respiratory, cardiovascular
• Eliminate allergen from diet
Food Allergies Video’s
• http://www.youtube.com/watch?v=dhycMN
Hf1DQ – food allergens, labeling
• http://www.youtube.com/watch?v=31hptH
YscX4 – peanut allergy guy
• http://www.youtube.com/watch?v=Fz5aoivFts - FAAN
• http://www.youtube.com/watch?v=Oa74l_o
gZac – food allergies, chef