FH II Lab 3

Question 1

Define meat

Answer 1

• Def. 1.: „The skeletal muscle and the closely attached edible tissues (fat, connective tissue, blood) of food producing animals”
• Def. 2.: „Every part of the animal’s body from which food can be produced”

Question 2

Organoleptic properties of meat

Answer 2

Colour, specific smell, glossy, inelastic

interwoven with CT and fat

Influenced by; maturation, species, breed, age, gender, body part, feed and slaughtering process

Question 3

Organoleptic properties of meat 2

Answer 3

Smell, taste, pH, rot, Colour, body condition, incomplete bleeding, stuffiness

Question 4

pH

Answer 4

glycogen @pH7.6 water + CO2

pH 5.5 lactic acid

Question 5

How to measure pH

Answer 5

Nitrazine yellow
bromothymol blue
electronic pH meter
indicator paper

Question 6

Colour, oXygen level of meat

Answer 6

high - oxymyoghobin (lightest)
low 1% - metmyoglobin
none - deoxymyoglobin (darkest)

Question 7

Yellow discolouration

Answer 7

lipochromatosis (carotenoids) dissolves in ether
lipofuscin like pigments (Unsaturated FA)
Icterus, jaundice - pathological - bilirubin dissolves in alcohol

Question 8

Black discoularation

Answer 8

Melanin, porphyrins
Fit / unfit for human consumption

eg. melanosis in the lungs , porphyria in ribs

Question 9

Taste and smell

Answer 9

Organoleptic judgment, boiling and roasting
abnormal smell
- alimentary (fish meal, mouldy feed)
- boar taint ( andrstenone, skatole)
- antemortem (disease, metabolic disorder - lab exam)
- postmortem (acquired from the environment)

Question 10

Body condition

Answer 10

Leaness: physiological
emanation, cachexia, pathological

Young age, runtiness

Question 11

Incomplete bleeding

Answer 11

Hemoglobin infiltration of meat 
reasons 
- slaughtering technology 
- disorder of the circulatory / nervous system 
- Toxicosis 
- infection 
- stress 

Determination with the Reder’s test (Loffler reagent, methylene blue)

Question 12

Rot

Answer 12

bacterial decomp of nitrogenous compounds

• ph increase
• protein –> biogenic amines, indole, skatole, H2S, NH3, CO2
• Fat - VFAs, Palmitic acid
• Detection: NH3 presence (Ebers test, Nessler test)

Question 13

Types of rot

Answer 13

Aerobic
- starts from the surface
Psuedomnoas, proteus, achrombacter, micrococcus, alcaligenes

Anaerobic

• deep in side large muscles
• Clostridial infections –> gas production

Question 14

Stuffiness

Answer 14

• enzymatic degradation of nitrogenous compounds
• acidic / neutral pH
• H2S production
• detection with lead acetate / lead nitrate test

Question 15

Physical Characteristics of Meat

Answer 15

Consistency : compressibility
- grau and Hamm: filter press method

Tenderness , texture

• sensory judgement
• enzymatic digestion
• Warner bratzler shear force test

Question 16

Liquid holding capacity

Answer 16

• Protiens: actin, myosin, sarcoplasma proteins
• dissolved salts
• pH
  Determination
• Grau and Hamm, .3g of meat and filter paper, press fr 5 mins
• Liquid leakage: measuring drip loss
• drying method

Question 17

Experiments

Answer 17

pH - indicator paper, electrical pH meter
Cooking test : Bunsen burner, pot
Reder;s Test; loffler reagent, (methylene blue) (haemoglobin infiltration of meat)
Ebers test: glass tube, NH3
Nessler reagent: NH3
Liquid holding capacity: Grau Hamm
Consistency: Grau Hamm filter paper pressmethod

Shear force test - Warner Bratzler