BLBS102-c17 BLBS102-Simpson March 21, 2012 11:52 Trim: 276mm X 219mm Printer Name: Yet to Come
322 Part 3: Meat, Poultry and Seafoodseliminating Hb’s heme group. From blood, natural red pigments
can be obtained without using coloring agents such as nitrous
acid salts; these pigments have zinc protoporphyrin as the metal-
loporphyrin moiety, and can be used in producing beef products,
whale meat products, and fish products (including fish pastes),
and a favorable color (Numata and Wakamatsu 2003).
There was wide variation in amounts of Hb extracted from
muscle tissue of bled and unbled fish, and the residual level
in the muscle of bled fish was substantial. Mb content was
minimal as compared to Hb content in mackerel light muscle
and trout whole muscle. Hb made up 65% and 56% of the total
heme protein by weight in dark muscle from unbled and bled
mackerel. That blood-mediated lipid oxidation in fish muscle
depends on various factors, including Hb concentration, Hb
type, plasma volume, and erythrocyte integrity (Richards and
Hultin 2002).
Alvarado et al. (2007) reported that the Hb content can vary
a lot among animal species and muscle types; it is clear that the
Hb levels present in muscle-based foods have the potential to
substantially contribute to lipid oxidation. Also, the presence of
blood, Mb, Fe^2 +,Fe^3 +,orCu^2 +can stimulate lipid oxidation in
the fillets of ice-fish (Rehbein and Orlick 1990).
The formation of ferryl and/or perferryl species upon re-
action with hydrogen peroxide or lipid hydroperoxides has
been reported to be either truly initiators or important cata-
lysts of lipid oxidation in raw muscle meat products (Baron and
Andersen 2002). Various factors such as the ability of the Hb
to auto-oxidize and release of hematin, the heme–iron moiety
nonbound to the protein, have also been reported to be crucial
in promoting lipid oxidation (Grunwald and Richards 2006).
As was mentioned in the preceding text, blood utilization by
the food industry is minimal, but many blood sausages are elab-
orated around the world (Diez et al. 2009). Problem associated
with blood uses is discoloration through the disruption of the
heme group of the Hb moiety. Several attempts are made to find
a possible solution to the color problems caused by blood addi-
tion, one of them is the Hb moiety conversion into the more stable
and sensorial accepted carboxyhaemoglobin (COHb) by satura-
tion with carbon monoxide (CO). This pigment is very stable
and can be visualized by the reflectance spectra (400–700 nm)
(Fontes et al. 2010).
Fontes et al. (2010) reported differences between the spectra
of blood CO-treated and its untreated counterpart. When CO was
bubbled into the blood samples, the spectra reflected the COHb
color properties in the red region, whose maximum reflectance
occurs at 700 nm. Greater color stability was also observed in
CO-treated sample as indicated by small differences between
reflectance curves.
In adipose tissues, residual Hb is associated with the pres-
ence of capillaries or with hemorrhage. Irie (2001) reported
that internal fat is whiter, with less Hb and with harder fat,
than subcutaneous fat. The Hb derivatives are MHb, OHb, and
deoxyhemoglobin (DHb). This Hb derivatives show different
reflectance and absorbance spectra in which each showed differ-
ent absorbance bands (AB); thus, MHb showed AB at 406, 500,
and 630 nm; OHb showed 418, 540–542, 516–578, 950 nm; and
DHb showed 430, 555, 760, and 910 nm.From technological point of view, COMb can be used in sev-
eral types of meat processing; thus, CO can be used in (i) mod-
ified atmosphere packaging of several type of meats (Raines
and Hunt 2010), (ii) pasteurized meat products (Fontes et al.
2004), (iii) dry blood (Fontes et al. 2010), and (iv) combination
with injection-enhancement ingredient (lactate) for beef color
stabilization (Suman et al. 2010). But several legal problems are
associated with its use; thus, the industry must avoid its use to
rejuvenate the color of spoiled meat.
Stiebing (1990) reported that during cooking, the oxygen par-
tial pressure in blood sausages decreases to a point where oxi-
dation occurs, instead of oxygenation. But the CO-treated blood
can increase shelf life (refrigerated storage, 4 days).FAT COLOR
From a technological point of view, fat fulfils several functions,
although as regards color, its principal role is in the brightness
of meat products. Processes such as “afinado” during the elabo-
ration of dry-cured ham involve temperatures at which fat melts,
so that it infiltrates the muscle mass and increases the brilliance
(Sayas 1997). When the fat is finely chopped, it “dilutes” the
red components of the color, thus decreasing the color intensity
of the finished product (P ́erez-Alvarez et al. 2000). However,
fats do not play such an important role in fine pastes because,
after emulsification, the fat is masked by the matrix effect of the
emulsion, so that it contributes very little to the final color.
The color of fat basically depends on the feed that the live ani-
mal received (Esteve 1994, Irie 2001). In the case of chicken and
ostrich, the fat has a “white” appearance (common in Europe)
when the animal has been fed with “white” cereals or other
ingredients not containing xanthophylls, since these are accu-
mulated in subcutaneous fat and other fatty deposits. However,
when the same species are fed on maize (rich in xanthophylls),
the fatty deposits take on a yellow color.
Beef or veal fat that is dark, hard (or soft), excessively bright
or shiny lowers the carcass and cut price. Fat with a yellowish
color in healthy animals reflects a diet containing beta-carotene
(Swatland 1988). While fat color evaluation has traditionally
been a subjective process, modern methods include such tech-
niques as optical fiber spectrophotometry (Irie 2001).
Another factor influencing fat color is the concentration of the
Hb retained in the capillaries of the adipose tissues (Swatland
1995). As in meat, the different states of Hb may influence the
color of the meat cut. OMb is responsible for the yellowish
appearance of fat, since it affects different color components
(yellow-blue and red-green).
The different states of Hb present in adipose tissue may react
in a similar way as in meat, so that fat color should be measured
as soon as possible to avoid possible color alterations.
When the Hb in the adipose tissue reacts with the nitrite
incorporated in the form of salt, nitrosohemoglobin (NOHb)
is generated, a pigment that imparts a pink color to the fat.
This phenomenon occurs principally in dry-cured meat products
with a degree of anatomical integrity, such as dry-cured ham or
shoulder (Sayas 1997).