Final: Meat, Poultry, Fish, Game, and Gelatin

Question 1

what the isoelectric point of protein is.

Answer 1

Effect of pH on meat quality
+ of acids like vinegar, lemon juice, etc. can inc WHC of lean tissue since the proteins are lower than the IP (isoelectric point) and thus protein solubility is increased
Result: inc juiciness and perceived tenderness of the meat.

Question 2

Understand the process of rigor mortis in meat

Answer 2

• Rigor mortis: Latin for “stiffness of death”
  :temp stiff state after death as muscles
  contract
• Aging - Ripening that occurs when carcasses are hung in ref for longer periods than that required for the reversal of rigor mortis
  -Proper level of glycogen prior to slaughter is necessary to get enough lactic acid production postmortem to get good
  pH drop (from 7.0 to 5.5)
  -Meat needs to go through rigor mortis and then relax to get tender meat, get cold shortening if chill too soon after
  slaughter
  -Meat tenderized due to cathepsins acting on Z lines, actin - myosin linkages

ATPase - found in sarcoplasm, may cause rigor mortis,
due to lactic acid formation
Pyrophosphatase – affect WHC of meat
Cathepsins - breakdown tissues as meat ages

]

Question 3

connective tissues in meats & understand how cooking affects them

Answer 3

Connective tissue proteins:
1. Collagen - most abundant, fibrous, found both within &btween muscles,
need to break down collagen to b > tender
collagen can be broken down with heat
white
2. Elastin - yellow, insoluble, has amino acids
elastin cannot be broken down
strong connective tissue
3. Ground substance - amorphous matrix of plasma proteins and glycoproteins, hold collagen and elastin
4. Reticulin - associated with myristic acid (fatty acid)

Question 4

connective tissues in fish & & understand how cooking affects them

Answer 4

Muscle Composition & Structure of Finfish

1. Collagen : Fish are only 3 %collagen.
2. AA Content:

Question 5

Understand meat tenderizers – and know what the ultimate form of tenderizing is.

Answer 5

Meat tenderizers: mechanical & enzyme
1. Mechanical: needles, blades, pounders or grinders
connective tissue is cut & muscle fibers can be broken up
Meat is more tender but can be drier due to loss of WHC
2. Enzymes - proteolytic enzymes; bromelein (fresh pineapple), ficin (fresh figs), papain (fresh papaya)(commercial blend has chymopapain, papain, peptidase),
-Act on surface and in to 2 mm
-Active from 55-80 ̊C
-Destroys sarcolemma surrounding myofibrils in muscle fibers, hydrolyzing actomyosin and other proteins in fiber, meat gets mushy, most action happens in cooking of meat
*factors play a part in natural tenderizing?
-particular cut of the meat
-Age at slaughter (connective tissue
concentration)
-Heredity and diet
-Marbling
-Slaughtering conditions
-Aging

Question 6

Know what dark cutting beef

Answer 6

Quality of Beef and Pork with insufficient glycogen
-Beef: pH drop will only go from 7.0 to 6.6
Meat will be blackish red, and slimy, sticky
=DARK CUTTING BEEF
-Pork - the pH can drop too much and go from 7.0 to 5.1

Question 7

Know the pigments found in meat

Answer 7

Meat Pigments
1. Myoglobin - one strand of protein (globin) - 80% of color in meat
-a heme structure with iron in middle
-purplish red in color
2. Hemoglobin - four strands of globin - 20% of color in meat
-heme structure with iron in middle




Question 8

Know the pigments found in meat & how they are affected by various factors including oxygen and heat.

Answer 8

-Generally the amount of myoglobin increases as the oxygen requirement of the muscle goes up.
= > the muscle is used for activities during the animal’s life, the higher the myoglobin content and the darker the meat.

(Veal is light because the animals are fed a diet which makes them anemic.)

Question 9

Know what PSE pork is.

Answer 9

Meat is pale, soft and exudative (loses liquid)

• PSE MEAT
• In both beef and pork this is due to stress in the animal prior to slaughter

Question 10

Rigor Mortis in Fish

Answer 10

:A stiff body is preferred when selecting a finfish bc it shows that it is still in rigor mortis, which occurs after slaughter.

• Flesh that is allowed to go through rigor mortis (stiff to relaxed muscles) has a better texture and flavor.
• water-holding capacity of the proteins is inc, which makes the flesh juicier than fish that have not undergone rigor mortis.

Question 11

main components of meat

Answer 11

Muscle tissue
Connective Tissue
Fat
Pigments

Question 12

Organization of connective tissue

Answer 12

1. Epimysium - encases bundles of bundles of fibers, thicker membrane covering entire muscle
2. Perimysium - encases a bundle of several muscle fibers, consists of ground substance and collagen
3. Endomysium - found between each muscle fiber (cell), consists of ground substance and collagen

Question 13

organization of muscles in fish

Answer 13

1. Myotomes: Layers of short fibers in fish muscle.

2. Myocommata: Large sheets of very thin connective tissue separating the myotomes.

Question 14

Pigments in pork, veal, chicken, fish and game

Answer 14

1. Light meat color in chicken, veal and pork - due to the presence of only hemoglobin.
2. In fish, the light meat contains only hemoglobin while the dark muscle contains myoglobin as well.
   - In salmon, the flesh also contains, astaxanthin, a carotenoid pigment, which gives it the orange color.
3. Game meats, which are dark, contain extensive myoglobin pigmentation.