Browning

Question 1

Lipid oxidation

Answer 1

aret effected by light, oxygen, temp and water activity

Control of factors - reduces extent

Question 2

Malliard browning stages

Answer 2

1. Early MR - chemically defiend without browning
2. Advanced M - formation of volatile or soluble substances

3 Final MR - insoluble polymers created

Question 3

Maillard reaction

Answer 3

Occurs between reducign sugars and animes at high temps
results from condensation of an amino group and a reducing sugar

temp, high pH and low Aw = perfect combo

Question 4

Anti-nutritional effects of Mr

Answer 4

loss of subsrates

Vitamin destrcution

Question 5

Colour changes

Answer 5

deterioration of chlorophyll pigments

Question 6

Macro biological changes

Answer 6

Rodents

insect pests

Question 7

Browning reactions

Answer 7

Diverse collection of reactions which produce darkening colour
Flavour and aroma production

Question 8

Caramelisation

Answer 8

sugar heated to 160-200 to produce colour

Under acidic conditions temp is reduced to 110-130

Question 9

Enzymic browning

Answer 9

enzyme and substrate are generally separate in food
If disturbed they come togerther and catalystic effect occurs
Apple - catehol - browning occurs

Question 10

Denaturation of proteins

Answer 10

Large protein molecules = fragile
Fucntional properties lost
Mechanical agitation, acids, alkalis