2009_Book_FoodChemistry

516 10 Milk and Dairy Products
Table 10.22. Mineral composition of milk
Constituent mg/l Constituent µg/l
Potassium 1500 Zinc 4000
Calcium 1200 Aluminum 500
Sodium 500 Iron 400
Magnesium 120 Copper 120
Phosphate 3000 Molybdenum 60
Chloride 1000 Manganese 30
Sulfate 100 Nickel 25
Silicon 1500
Bromine 1000
Boron 200
Fluorine 150
Iodine 60
Table 10.23. Vitamin content of milk
Vitamin mg/l Vitamin mg/l
A (Retinol) 0.4 Nicotinamide 1
D (Calciferol) 0.001 Pantothenic acid 3.5
E (Tocopherol) 1.0 C (Ascorbic acid) 20
B 1 (Thiamine) 0.4 Biotin 0.03
B 2 (Riboflavin) 1.7 Folic acid 0.05
B 6 (Pyridoxine) 0.6
B 12 (Cyanocobalamine)
0.005
10.1.2.7 Enzymes
Milk contains a great number of enzymes which
are not only of analytical importance for the detecton
of heat-treated milk, but can also influence
the processing properties. The rate of heat inactivation
of the enzymes indicates the type and extent
of heating (cf. 2.5.4).
Hydrolases identified include: amylases, lipases,
esterases, proteinases and phosphatases. Proteinase
inhibitors have also been found. Important
oxidoreductases in milk are aldehyde dehydrogenase
(xanthine oxidase), lactoperoxidase and
catalase. A general idea of the occurrence and localization
of enzymes in boving milk is given in
Table 10.24
10.1.2.7.1 Plasmin
The serine endopeptidase plasmin is of special interest
in milk technology.
Table 10.24. Enzymes in bovine milk
EC Name Localization a
Number
1.1.1.27 L-Lactate dehydrogenase P
1.1.1.37 Malate dehydrogenase
1.1.3.22 Xanthine oxidase F
1.4.3.6 Amine oxidase
(copper-containing)
1.6.99.3 NADH dehydrogenase F
1.8 Sulfhydryl oxidase b S
1.8.1.4 Dihydrolipoamide F
dehydrogenase
1.11.1.6 Catalase L
1.11.1.7 Lactoperoxidase S
1.15.1.1 Superoxide dismutase
2.3.2.2 γ-Glutamyltransferase F
2.4.1.22 Lactose synthase S
2.4.99.1 β-Galactoside-α-2,6-
sialytransfersase
2.6.1.1 Aspartate aminotransferase P
2.6.1.2 Alanine aminotransferase
2.7.1.26 Riboflavin kinase
2.7.1.30 Glycerol kinase
2.7.7.2 FMN adenyl transferase
2.8.1.1 Thiosulfate sulfurtransferase
3.1.1.1 Carboxylesterase S
3.1.1.2 Arylesterase
3.1.1.7 Acetylcholine esterase F
3.1.1.8 Choline esterase S
3.1.1.34 Lipoproteinlipase C
3.1.3.1 Alkaline phosphatase F
3.1.3.2 Acid phosphatase F
3.1.3.5 5 ′ -Nucleotidase F
3.1.3.9 Glucose-6-phosphatase F
3.1.3.16 Phosphoprotein phosphatase P
3.1.4.1 Phosphodiesterase I F
3.1.27.5 Pancreatic ribonuclease S
3.2.1.1 α-Amylase S
3.2.1.2 β-Amylase
3.2.1.17 Lysozyme S
3.2.1.24 α-Mannosidase
3.2.1.31 β-Glucuronidase
3.2.1.52 β-N-Acetylglucosaminidase
3.4 Acid peptidases
3.4.21.7 Plasmin C
3.6.1.3 Adenosinetriphosphatase F
3.6.1.9 Nucleotide pyrophosphatase
4.1.2.13 Fructosebiphosphate
aldolase
5.3.1.9 Glucose-6-phosphate
isomerase
a C: casein micelle, F: fat-globule membrane, L: leucocytes,
P: plasma, S: serum.
b Not thiol oxidase EC 1.8.3.2.