Download Essential amino acids - Feed-to-Food

EFFECT OF DIFFERENT THICKNESS OF DIE ON THE
STABILITY OF AMINO ACIDS IN PELLETING PIG FEED
Nedeljka Spasevski, Bojana Kokić, Saulius Bliznikas, Gintautas Švirmickas,
Đuro Vukmirović, Radmilo Čolović, Jovanka Lević
Institute for Food Technology, University of Novi Sad, Serbia
Corresponding author [email protected]
MATERIAL AND METHODS
INTRODUCTION
•Complete mixture for pigs II (from 15 to 25 kg) was conditioned in double-shaft pedal mixer - steam
• Pelleting is a process of pressing conditioned material trough die with specific
conditioner, Muyang SLHSJ0.2A, China, up to moisture content of about 16 % until material reached
dimensions of openings and thickness.
temperature of 80°C. Batch size was 25 kg. Steam was injected in the conditioner under pressure of 2 bars.
• Conditioning in animal feed production is process of converting mixed mash with use
• Conditioned material was pelleted on flat die pellet press 14-175, AMANDUS KAHL GmbH & Co. KG,
of heat, water, pressure and time, to a physical state which is more suitable for
Germany. Diameter of openings of pellet die was 6 mm, and die thickness was 18 mm (1:3) and 48 mm
compaction of feed mash.
(1:8), respectively.
• Conditioning increases production capacity and, in the same time, affects physical,
• Temperatures of the dies 1:3 and 1:8 were 57,6°C and 64°C, respectively. Pellets were stored for 24 hours
nutritional, and hygienic quality of produced feed
under room conditions in order to achieve stabile temperature.
• During condensation of the steam, a thin film of water is created around the particles,
• Moisture content was determined with moisture analyzer (OHAUS MB 45, Switzerland), in conditioned
which, together with the temperature increase, facilitates binding between particles.
material. Samples were milled to pass 1 mm sieve.
• When steam is used, the temperature of pellets after leaving the die is generally higher
• Amino acids were determined with HPLC using the AccQTag method. This method is based on a
in comparison with that of the conditioned meal due to the frictional heat in the die
derivatizing reagent developed specifically for amino acid analysis.
• With pelleting, increasing die hole length increases pellet residence time in the die,
• Waters AccQ·Fluor Reagent (6-aminoquinolyl-N-hydroxysuccinimidyl carbamate, or AQC) is an Nresulting in improved pellet durability although it may affect lysine reactivity.
hydroxy-succinimide-activated heterocyclic carbamate.
• Addition of heat and water leads to changes of components, such as starch and protein,
• Separating the derivatives was obtained on reversed-phase HPLC, column Nova Pak C-18 (150×3.9mm,
in a way that binding property comes into effect
5μm). The detection was obtained using the Waters 470 Scanning Fluorescence Detector.
• In this paper, it was investigated how different thickness of die at pellet press affects
stability of amino acids in pelleting process.
RESULTS AND DISCUSSION
Table 1 shows the content of non essential and essential amino acids expressed in g/kg
DM, for unprocessed sample and pelleted samples with dies 1:3 and 1:8, which had
temperatures 57,6°C and 64°C, respectively. As seen from the presented result, there is a
reduction in the level of amino acid content in relation to unprocessed sample for all
examined amino acids. For die 1:3 and 1:8 total amino acid content decreased 2,21% and
3,85%, respectively.
Table 1. Amino Acids Content
Amino acids in
g/kg DM
Aspartic Acid
Serine
Glicine
Alanine
Threonine
Valine
Methionine
Isoleucine
Leucine
Tyrosine
Phenylalanine
Histidine
Lysine
Arginine
Total content of
amino acids
unprocessed
Die 1:3
w=15.97%
Non Essential amino acids
14,57
14,25
9,35
9,17
11,59
11,47
12,95
12,58
Essential amino acids
6,56
6,48
8,53
8,51
7,42
7,04
7,31
7,17
19,06
18,79
5,90
5,45
9,07
8,99
6,93
6,80
9,97
9,62
10,56
10,36
139,77
136,68
Fig. 1. Decrease of non essential amino acids content after thermal
treatment
Figure 1. shows % of reduction of
non essential amino acid content
after
thermal
treatment
(conditioning and pelleting). In
comparison to unprocessed sample,
for both dies there is a decrease of
content of all non essential amino
acids. For aspartic acid, serine and
glicine, decrease of content is
higher when using die 1:8, while for
alanine the decrease of content
remains the same.
Die 1:8
w=16%
14,03
9,07
11,34
12,62
6,38
8,23
7,20
7,05
18,41
4,96
8,78
6,70
9,56
10,06
Amino acids in g/kg DM
For die 1:3 amino acid content it decreased in %
For die 1:8 amino acid content it decreased in %
99.01
98.16
97.83
97.79
97.45
96.28
Aspartic Acid
Fig.2. Decrease of essential amino acids content
after thermal treatment (part 1)
Glicine
Alanine
Fig. 3. Decrease of essential amino acids content after thermal
treatment (part 2)
Amino acids in g/kg DM
For die 1:3 amino acid content it decreased in %
For die 1:8 amino acid content it decreased in %
Amino acids g/kg DM
For die 1:3 amino acid content it decreased in %
For die 1:8 amino acid content it decreased in %
99.69
99.16
For die 1:3 total amino acid content decreased by 2,21% and
with die 1:8 it decreased by 3,85% because of higher
temperature in the pelleting process. As shown in the results
and discussion, increased temperature in the process of
pelleting pig feed undoubtedly lead to the reduction of
amino acids especially essential amino acids. Considering
that the essential amino acids human and animal body can
not synthesize, in the future more attention should be paid to
the choice of die and thermal treatment in the process of
pelleting.
Serine
Figure 2. and 3. show % of reduction of essential amino acid content after thermal treatment. As for non essential
amino acids, reduction of content of essential amino acids is higher when using die 1:8, while methionine is the only
exception and that result can be explained by error of method. When using die 1:3 and temperature 57,6°C, valine
showed to be the most thermostable and tyrosine the most thermolabile. When using die 1:8 and temperature 64°C,
glicine showed to be the most thermostable and again tyrosine the most thermolabile. It can be seen that pellet die
thickness has negative effect on amino acid stability, because die 1:8 cause higher friction between mash material and
thus higher temperature of the die.
134,39
CONCLUSION
97.14
96.98
96.78
98.07
96.70
96.48 95,84
98.10
98.75
98.08
95.26
97.26
92.35
97.06
96.49
96.40
96.59
94.87
84.20
Tyrosine
98.58
Phenylalanine
Histidine
Lysine
Arginine
Threonine
Valine
Methionine
Isoleucine
Leucine