140 Chapter 6
venting their release on heating. By dissolv-
ing and swelling the meat protein structure,
salt also tenderizes meat and leads to
heat - stable structures in “ emulsion type ”
sausages.
The curing agents nitrite and nitrate react
with meat ingredients due to the easily
changeable oxidation status of nitrogen into
many derivatives. Nitrite gives the products
an esteemed and stable red color, acts as
an antioxidant by sequestering oxygen, pre-
vents or retards mircobial growth, and fi nally,
adds a pleasant fl avor. The positive effects
are overwhelming compared to the small
possibility of the formation of nitrosamines.
The intake of curing agents (nitrite plus
nitrate) through meat products is small (a few
percent) in comparison with other foods
(EFSA 2008 ).References
Adamsen , C. E. , J. K. S. M ø ller , K. Laursen , K. Olsen ,
and L. H. Skibsted. 2006. Zn - porphyrin formation in
cured meat products: Effect of added salt and nitrite.
Meat Science 72 : 672 – 679.
Andersen , H. J. , and L. H Skibsted. 1992. Kinetics and
mechanism of thermal oxidation and photooxidation
of nitrosylmyoglobin in aqueous solution. Journal of
Agricultural Food Chemicals 40 : 1741 – 1750.
Cassens , R. G. , L. Ito , M. Lee , and D. Buege. 1978. The
use of nitrite in meat. Bioscience 28 ( 10 ): 633 – 337.
Dahl , H. , L. Lotte , and C. A. Bunton. 1960. 42. Ü ber
die Oxydation von Ascorbins ä ure durch salpetrige
S ä ure. Teil VI: Ü bersicht und Diskussion der
Ergebnisse. 18. Mitteilung ü ber Reduktone und 1,2,3 -
Tricarbonylverbindungen. Helvetica Chimica Acta
53 : 320 – 333.
Dederer , I. 2006. Personal communication.
Deierling , H. , U. Hemmrich , N. Groth , and H.
Taschan. 1997. Nitrosamine in Lebensmitteln.
Lebensmittelchemie 51 : 53 – 61.
Directive 2006. Directive 2006/52/EC of the European
Parliament and of the Council of 5 July 2006 amend-
ing Directive 95/2/EC on food additives other than
colors and sweeteners and Directive 95/35/EC on
sweeteners for use in foodstuffs, O. J. L204 of
26.7.2006.
Ð or d- evi c ́ , V. , B. Vuksan , P. Radeti c ́ , H. Ð ur d- ica , and
M. Mitkovi c ́. 1980. Prilog ispitivanju uticaja poje-
dinih faktora na promene sadr ž aja nitrita u mesu.
Tehnologija mesa 21 ( 10 ): 287 – 290.
EFSA. 2003. Opinion of the Scientifi c Panel on
Biological Hazards on the Request from the
Commission related to the Effects of Nitrites/Nitratesif oxygen is used up, it turns brown (because
of the presence of metmyoglobin) or green
(indicating spoilage from microbial action).
Reducing enzymes, or chemical reactions
with a reducing agent like ascorbate, reduce
the Fe 3+ to Fe 2+. The NO formed from N 2 O 3
can bind to the myoglobin (Fe 2+ ) and form a
heat - stable NO - myoglobin. Oximyoglobin is
not heat stable and dissociates. The meat
turns grey or brown.
Oxygen, carbon monoxide (CO), and NO
are biatomic molecules. Like NO, CO binds
to myoglobin very tightly. In some countries,
MAP packaging of fresh meat with 1 – 2% CO
is permitted. CO and NO addition to fresh
meat are not permitted in the EU.
The CO - myoglobin and the NO - myoglobin
are heat stable. Heating denatures the protein
moiety, but the red NO - porphyrin ring system
(often called nitroso - hemochromogen) still
exists and is found in meat products heated
to 120 ° C. This heat - stable red color will
change after bacterial spoilage, and it fades
under UV light. The fi rst is advantageous,
since it allows the consumer to recognize
spoilage, as fresh meat also changes color
when it spoils. CO bound to myoglobin is
light resistant.
In the last two years the riddle of the red
color of cured raw hams, like Parma ham
produced without nitrite or nitrate, has been
solved. Various authors have proved that the
Fe 2+ in the porphyrin ring is exchanged with
Zn 2+ , which gives the hams a pleasant red
color. Nitrite addition prevents the exchange
(M ø ller et al. 2003 ; Parolari et al. 2003 ;
Wakamatsu et al. 2004a, b ; Adamsen et al.
2006 ).
Conclusions
Salt as the primary curing agent has several
effects on meat. It lowers the water activity
and retards or prevents microbial growth and
spoilage. Salt enhances water binding in
meat. Thus, it prevents the cookout of water
on heating and also covers fat particles, pre-