236 Chapter 12
sheet to smoke in the high - voltage fi eld of an
electrostatic apparatus; in two or three
minutes, the sheet turns yellow or brown.
According to Ziemba (1969) and Ruiter
(1979) , a signifi cant contribution to the for-
mation of the color of smoked goods comes
from the reactions of carbonyl compounds,
mainly glycolaldehyde and methylglyoxal
present predominantly in the vapor phase of
the smoke, with the amino groups of proteins
and nonprotein nitrogen compounds. The
smoke phenols form stable colors in reac-
tions with proteins at weak alkaline
conditions.
The intensity J of the color of the smoked
products is primarily related to the optical
density of the smoke E 0 and the time of
smoking τ :
JkE= 0 τ
The value of k increases with the rise in
smoke temperature and velocity. High tem-
perature favors the development of dark
color, since it increases the concentration of
the components of the dispersing phase of
smoke and the rate of the carbonyl - amino
reactions and polymerization of various com-
ponents. The higher the temperature and
water activity of the surface of small - caliber
Br ü hwurst sausages, within limits set by
other technological requirements, the darker
is the color of the sausages. The kind of wood
used for smoke generation is also important.
Smoking with beech, maple, ash, sycamore,
or lime - tree smoke leads to gold - yellow
color; yellow - brownish tint comes from oak,
nut, and alder smoke, and lemon - like from
acacia smoke. Products treated with smoke
from coniferous wood have dark coloration.The Flavor and Taste
The smoke compounds are the dominant
factor directly responsible for the smoky
fl avor. Smouldering wood smoke generated
at 450 – 550 ° C is regarded as the most suitable
for imparting the smoky fl avor to smoked(1979). In laboratory experiments, the smoke
phenols have been shown to reduce signifi -
cantly the concentration of thiol and amino
groups in solutions of amino acids, peptides,
and proteins and in meat. Such interactions
may decrease the lysine availability some-
what. However, since the concentration of
smoke components is the highest on the
surface and in the thin outer parts of the
smoked meat products, no signifi cant
decrease in the nutritional value of the meat
proteins should be expected. Furthermore,
the phenolic constituents of smoke absorbed
by the sausage can be oxidized. The contents
of guaiacol and phenol in smoked sausages
stored 1 month may decrease by about 35%.
The Sensory Effects
Introduction
The desirable, sensory properties of smoked
products result from the concerted action of
salting or curing, seasoning, pre - drying,
smoking, and heating, and in some cases also
dyeing. The smoke compounds induce smoky
color and fl avor themselves and by interact-
ing with the meat components, which results
in the creation of other sensory - active sub-
stances. Interactions with the nitrogenous
meat constituents may lead to some texture
changes. The desirable intensity of sensory
changes induced by smoking depends on the
kind of meat products; some assortments are
expected to acquire only a slight smoky note,
while for others, mainly regional products,
very heavy smoking must be applied to suit
the typical consumer preferences.
The Color
The color developed on the surface of the
products is due to the presence of colored
smoke components and to the interactions of
reactive compounds with those in the meat or
sausage casings. The direct coloring role may
be easily shown by exposing a plate of tin