Practical 4 - Meat quality and growth

Question 1

factors that influence the eating aspect of meat quality include

Answer 1

Appearance (colour, fatness, marbling)
Flavour
Odour
Tenderness
Juiciness

Question 2

what is intramuscular fat

Answer 2

marbling - fat located inside the muscle. Marbling will have positive influence on meat tenderness, juiciness, and flavour

Question 3

what causes ‘boat taint’

Answer 3

The two major compounds responsible for causing taint are skatole, a metabolite of tryptophan, and 5→ androstenone, a C19-steroid. Androstenone is synthesised in the testes, thus its production is affected by the sexual maturity of the animal. Skatole is produced in the intestine.

Question 4

what are the two most abundant myofibrillar proteins

Answer 4

myosin and actin

Question 5

what makes red meat red

Answer 5

• ## contains more fast oxidative muscle fibres

Question 6

what makes white meat white

Answer 6

• contains more fast glycolytic muscle fibres that are designed to work in short fast bursts

Question 7

what is the general pH range of meat

Answer 7

5.4 to 5.6

Question 8

what is PSE meat

Answer 8

Pale, soft, exudative meat.
- losst of water holding capacity - makes meat dry when cooked
- caused by excessive glycolysis and build-up of lactic acid in muscle
- low pH

Question 9

what is DFD meat

Answer 9

Dark, firm, and dry
- for beef, ultimate pH is between 5.8 and 6.2 is associated with tough meat
- ultimate pH over 6.2 results in dark cutting meat

Question 10

what are some factors that influence glyocogen levels and meat pH

Answer 10

• age at slaughter - younger animals have a higher pH, while older animals have a lower pH. Younger animals have more glycogen stored in their muscles, which is converted to lactic acid after slaughter, increasing the pH
• animal nutrition - feeding animals a high-carbohydrate diet increases the amount of glycogen stored in their muscles, resulting in a higher pH after slaughter
• stress prior to slaughter - when animals are stressed before slaughter, they release adrenaline, which increases glycolysis and depletes glycogen stores in their muscles due to muscle contraction. Ultimately degrades the meat quality