2009_Book_FoodChemistry

602 12 Meat
Table 12.21. Chemical composition of beef extract
Organic matter 56–64
Amino acids, peptides 15–20
Other N-compounds 10–15
Total creatinine 5.4–8.2
Ammonia 0.2–0.4
Urea 0.1–0.3
N-free compounds 10–15
Total lipids >1.5
Pigments 10–20
Minerals 18–24
Sodium chloride 2.5–5
Moisture 15–23
pH-value of a 10% aqueous solution approx. 5.5
The composition of the extract is given in
Table 12.21. For addition to soup powders and
sauce powders, the thick pasty meat extract is
blended with a carrier substance and vacuumor
spray-dried.
%
Yeast cells (Saccharomyces and Torula spp.) are
forced to undergo shrinking of protoplasm by
addition of salt, which causes loss of cell water
and solutes (plasmolysis), or the cells are steamed
or subjected to autolysis. Cells treated in this
way are extracted with water and the extract is
concentrated to yield a brown paste. Yeast extract
is rich in the B-vitamins. The concentrations
of thiamine and thiamine diphosphate are
above their taste threshold values and may contribute
to the product’s unpleasant flavor. On the
other hand, the spicy flavor of the paste is essentially
due to 5 ′ -nucleotides freed during hydrolysis
and to amino acids, particularly glutamic
acid.
12.7.3.5 Hydrolyzed Vegetable Proteins
The production of this protein hydrolysate is
schematically presented in Fig. 12.35. According
to the given formulation, the different plant
protein-containing raw materials, such as wheat
and rice gluten and roughly ground soybeans,
palm kernels or peanuts, are automatically
delivered from raw material silos, weighed,
and fed to a hydrolysis boiler (double-walled,
12.7.3.2 Whale Meat Extract
This product is obtained from meat of various
whales (blue, finback, sei, humpback and sperm)
in a process similar to that used for beef extract.
12.7.3.3 Poultry Meat Extract
Chicken extract is obtained by evaporation of
chicken broth or by extraction of chicken halves
with water at 80 ◦ C, followed by a concentration
step under vacuum to an end-product of 70–80%
solids.
12.7.3.4 Yeast Extract
Fig. 12.35. Production of hydrolyzed vegetable protein