234 Chapter 12
phase is more effective than that of the
particles and droplets. A rise in the tempera-
ture of the smoke also accelerates sorption
of these compounds by the meat being
smoked.
The quantity of different smoke compo-
nents accumulated in the meat depends on
the temperature, humidity, agitation, and
composition of the smoke; the properties of
the components, particularly their volatility
and solubility; the characteristics of the
surface of the product; and the duration of
smoking. Wet surfaces absorb about 20 times
more phenols than dry ones. The published
data on the total amount of smoke compo-
nents absorbed by meat products are incom-
plete and vary within a broad range. The
large range of values is caused both by the
properties of the products and the parameters
of smoking, as well as by differences in the
analytical procedures applied by various
investigators. The use of phenol as a standard
in colorimetric determination of total phenols
may lead to signifi cant underestimation,
since the amount of phenol in smoked meats
is rather low. The content of phenols in dif-
ferent smoked sausages, according to pub-
lished data, ranges from about 0.02 to
300 μ g/g. In smoked pork belly strips and
summer sausage, the total recovery of phenols
was, according to Lustre and Issenberg
(1970) , about 280 μ g/g and 60 μ g/g, respec-
tively. The composition of the absorbed
fraction depends more on the conditions
of smoking, especially the humidity of the
surface of the meats, than on the concentra-
tion of individual phenols in the smoke. The
quantity of formaldehyde in cold smoked
goods may be as high as 20 – 40 μ g/g. The
amount of formaldehyde in different assort-
ments of sausages may reach 2 to 50 μ g/g;
the surface layers of some products may
contain about fi ve times more than the inner
layer.
The rate of deposition of smoke compo-
nents can be greatly increased by applying
high - voltage electrostatic precipitation, as inhydrocarbons. In the fraction of about 20
aliphatic hydrocarbons, the compound
present in the highest concentration is
methane, known also as the product of dry
distillation of wood. Much larger is the
group of polycyclic aromatic hydrocarbons
(PAH) identifi ed in numerous investigations
(Obiedzi n ́ ski and Borys 1977 ). Some smoked
products contain up to 100 different PAH and
their alkylated derivatives, of molecular
weights from 116 (indene) to 302 (dibenzo-
pyrenes). They are generated at temperatures
above 420 ° C and, having high boiling tem-
perature, are present mainly in the dispersed
phase of smoke. Thus the contents of PAH
can be decreased by reducing the wood
smouldering temperature and fi ltering the
smoke.
Smoke fl avorings produced commercially
for the food industry contain only traces of
PAH. They are generally smoke extracts fi l-
tered and separated from the tars or distillates
of pyroligneous liquids. Various fl avorings
of different brands are available as aqueous
solutions or in free - fl owing, dry form on salt,
yeast, or other material.
Wood smoke also contains a number of
other chemicals, including NO, NO 2 , and
NO 3 , as well as various heterocyclic com-
pounds, including the N - heterocyclic pyrrole,
pyrazine, and carbazole.
Accumulation and Interactions of
Smoke Components in Meats
Deposition on Smoked Surfaces
Due to Brownian motion, the smoke particles
and droplets undergo coalescence and settle
on the smoked products under the effect of
gravitational and centrifugal forces. Their
natural, electrostatic charge and absorption
in the wet surface layer also contribute some-
what to deposition on the meat. Thus, the
high humidity of the smoke increases the rate
of smoking. On wet surfaces, the deposition
of components present in the dispersing