136 Chapter 6
The oxidation of nitrite to nitrate in meat
is also the primary reason why nitrate will be
found in considerable concentrations in meat
products to which only nitrite has been added
(see also footnotes to Table 6.3 ). In Figure
6.11 the nitrite concentrations of German
meat products are shown. The emulsion type
and cooked sausages and cooked hams are
manufactured with nitrite only, but they
contain a mean of 20 – 30 mg nitrate/kg, as is
also shown in a very recent survey outlined
in Table 6.8. Nitrite is in most cases lower
than nitrate in the fi nished product, with con-
centrations below 20 mg nitrite/kg in the
median value. Only a few samples of sau-
sages and hams contain above 60 mg nitrite/
kg (Fig. 6.11 ), and these also have higher
nitrate concentrations. Nitrate may have been
added to the raw meat products.
It can be assumed that the concentration
of nitrate, in a sausage to which only nitriteand that nitrate also forms. The nitrite con-
centration at day 0 (immediately after prepa-
ration) with pH 6.3 is twice the concentration
at pH 5.3; after twelve days in storage at pH
6.3, it is six times higher. The nitrate formed
from nitrite by sequestering oxygen is less
infl uenced by pH during manufacturing. It is
reduced during storage but rather indepen-
dently of pH. Immediately after heating, the
measured sum of nitrite and nitrate at pH 5.3
amounts to 48%; at pH 5.8 and pH 6.3 it is
75/76%. During storage for twelve days, the
amount of the sum is reduced to 14% at pH
5.3 and 41% at pH 6.3.
Table 6.6 shows that the disappearance
of nitrite continues with storage. Heating
reduces the nitrite to ca. 30% of its added
amount, while 0.5 mg nitrite/kg remain after
sixty days of chilled storage. When 75 mg
nitrite/kg was added to the batter, a similar
degree of breakdown was observed after the
addition of 200 mg nitrite/kg.
Table 6.7 shows nitrite ’ s possible reaction
partners. The wide range of percentages is
due to the various concentrations of nitrite,
heating and storage conditions, and pH.
Table 6.5. Nitrite breakdown and nitrate appearance after nitrite addition (100 mg/kg) to meat
batters of various pH values after heating and storage (adapted from Ð or d- evi c‘ et al. 1980 )
pH of batter days of storage nitrite (mg/kg) nitrate (mg/kg) sum of nitrite +
nitrate (mg/kg)
5.3 0 28 20 48
12 5 9 14
5.8 0 45 30 75
12 13 8 21
6.3 0 58 18 76
12 31 10 41Table 6.6. Nitrite remaining (mg/kg) during
chilled storage (2 ° C) after addition of 75 and
200 mg/kg after heating to 80 ° C (adapted from
Kudryashow 2003 )
time nitrite 75 mg/kg
addednitrite 200 mg/kg
added
after heating 22 (30%) 54 (27%)
20 days 75 15.4
60 days 0.5 5.8Table 6.7. Nitrite and metabolites in meat prod-
ucts (adapted and changed from Cassens et al.
1978 )
bound to/or form % of total assumption
Honikel
nitrite 5 – 20
nitrate 1 – 10 10 – 40 a
myoglobin 5 – 15
bound to – SH 1 – 15
bound to lipids 1 – 15
bound to proteins 20 – 30
gas 1 – 5
sum ∼ 70 90
a according to results presented in fi g. 6.11 and tables 6.5
and 6.6