Singh_Shresh_2014_CABE

ENGG371-13C Engineering Work Placement 1
2013
Fishmeal Palletisation
Shresh Singh
Summer Placement Student
Dr. Mark Lay
Waikato District Council based at The University of Waikato
Dr. Mark Lay

Executive Summary
The University Of Waikato Bachelor Of Engineering (Honours) offers its students the
opportunity to gain industry experience at an undergraduate level by providing work
centred placements. Industry experience grants a useful insight and a general
understanding of how operations are carried out in work place settings. The opportunity
is a great way to recognise your own interests, to gain confidence in the workplace,
develop independence, leadership and initiative. I was fortunate enough to be offered a
summer placement through Waikato District Council based at The University of Waikato.
Under the supervision of Dr. Mark Lay, I was able to reinforce and apply previously
learned theories and concepts in a practical setting.
The aim of the summer research project was to create a floating aquaculture feed from
composted Koi carp, which is commonly referred to as fishmeal. In order to carry out the
project successfully, I familiarised myself with concepts by researching numerous journal
articles where concepts and processes on extrusion methods, fish feed formulas, amongst
others were explained in detail. The journal articles were beneficial in helping me to
understand fishmeals importance and why Koi carp is mainly used.
The results of the experiment showed that changing the amount of wheat flour in the
aquaculture feed had significant impact in the extrudate properties. The differences
observed were the changes in the expansion ratio, moisture content and durability. It was
also found that when the screw speeds of the twin-screw extruder were increased, the
extrudates decreased in bulk density and water absorption Index (WAI). For example, the
bulk density decreased as much as 37.64%, for extrudate containing 50 g wheat flour and
without any whey protein present. Overall, the results suggest that an aquaculture feed
from fishmeal can be created successfully with a balance between the correct formulation
and ideal conditions.
Further experimentation could be carried out to enhance aquaculture feeds. Improvements
could be made by the addition of vitamins and minerals. It also is essential to carry out
feeding trails to identify if the fish can consume the fishmeal as a primary source of food.
These two methods could greatly contribute to improving the outcomes of the aquaculture
feed.

Acknowledgments
Firstly, I would like to express my gratitude to Waikato District Council and a special
thanks to Dr. Mark Lay for offering me the opportunity to do a summer work placement
at The University of Waikato. Dr. Mark Lay provided me with continual support,
direction, and feedback with my research.
Secondly, I would like to thank all the laboratory technicians Chris Wang, Indar Singh,
Lisa Li and Yuanji Zhang for helping me throughout the experiments and for letting me
use the facilities.
Many thanks for your contribution to the skills and work place knowledge I have acquired
over the work placement.

Table of Contents
List of Figures................................................................................................................ i
1. Introduction ........................................................................................................... 1
2. Background............................................................................................................ 2
2.1. Feed Formulation ........................................................................................... 2
2.2. Extrusion process ........................................................................................... 4
3. Aims ...................................................................................................................... 5
4. Methods ................................................................................................................. 5
4.1. Aquaculture Feed Formulation....................................................................... 5
4.2. Experimental Design and Extrusion Processing ............................................ 5
4.3. Measurement of Physical Properties.............................................................. 5
5. Results and Discussion.......................................................................................... 7
5.1. Expansion Ratio ............................................................................................. 8
5.2. Moisture Content............................................................................................ 9
5.3. Durability ..................................................................................................... 10
5.4. Bulk density.................................................................................................. 11
5.5. Water Absorption Index (WAI) ................................................................... 12
5.6. Water Solubility Index (WSI) ...................................................................... 13
6. Conclusion/ Recommendations........................................................................... 16
7. References ........................................................................................................... 17
Appendices.................................................................................................................... 1

i
List of Figures
Figure 1: Lake Waikare Facility....................................................................................... 1
Figure 2: Koi carp, Cyprinus carpio (Environmental Research Institute, 2014) ............. 2
Figure 3: Starch Polymers, retrieved from
http://polymerinnovationblog.com/thermoplastic-starch-a-renewable-biodegradable-
bioplastic/ on 15 February 2014....................................................................................... 3
Figure 4: Twin-Screw Extruder........................................................................................ 4
Figure 5: Expansion Ratio for extrudates with and without whey protein at 350 rpm and
420 rpm............................................................................................................................. 8
Figure 6: Moisture Content for extrudates at 350 and 420 rpm, with and without whey
protein............................................................................................................................... 9
Figure 7: Durability for extrudates at 350 and 420 rpm, with and without whey protein
........................................................................................................................................ 10
Figure 8: Bulk Density for extrudates at 350 and 420 rpm, with and without whey protein
........................................................................................................................................ 11
Figure 9: WAI for extrudates at 350 and 420 rpm, with and without whey protein ...... 12
Figure 10: WSI for 0.1M Phosphate Buffer 0.1M, pH7................................................. 14
Figure 11: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Sulphite.................. 14
Figure 12: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Dodecyl Sulphate .. 15
Figure 13: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Sulphite + Sodium
Dodecyl Sulphate............................................................................................................ 15

1
1. Introduction
The Bachelor of Engineering degree at The University of Waikato provides work
placements to better understand the industry and to gain experience at an undergraduate
level. The placement provides insight and a general idea of how engineering industries
operate. The opportunity is a great way to recognise your own interests and also, to gain
confidence in the workplace, develop independence, leadership and initiative. I was
fortunate enough to be offered a summer placement through Waikato District Council
based at The University of Waikato.
The placement was involved in research aspects of engineering, my particular work
placement project was in the Polymer and Composite Group as an undergraduate summer
research student. The main supervisors in the group were Dr. Johan Verbeek who is the
Bio-Plastics Leader, Prof. Kim Pickering who is the Composites Leader and Dr. Mark
Lay.
The project objectives were to use composted Koi carp (Cyprinus carpio) referred to as
fishmeal, for the purpose of creating a floating aquaculture feed. Although the concept of
fishmeal and aquaculture feeds were unknown to me at first, after reading numerous
journal articles I had a clear and concise idea. The Koi carp was provided from Waikato
District Council from their Lake Waikare facility (Figure 1). Koi carp are pests and pose
a dangerous threat to many freshwater ecosystems (Tempero, Ling, Hicks, & Osborne,
2006). Therefore, using Koi carp is a viable choice as an aquaculture feed.
Figure 1: Lake Waikare Facility

2
2. Background
Koi carp, Cyprinus carpio (Figure 2) are believed to be an ornamental strain of common
carp that were taken to Japan from China and bred for coloration and scale patterns.
(Tempero et al., 2006). The species is thought to have been imported into New Zealand
by accident in the 1960s as part of a goldfish consignment (Conservation, 2014b).
Figure 2: Koi carp, Cyprinus carpio (Environmental Research Institute, 2014)
2.1. Feed Formulation
Five ingredients were used in the formulation of the floating pellets. These were fishmeal
from Koi carp, wholemeal flour, corn flour, bovine whey protein, and distilled water.
Fishmeal was provided from Waikato District Council, wholemeal and corn flour was by
Edmonds and Pam’s, and bovine whey protein from The University of Waikato.
2.1.1. Fishmeal
Fishmeal, from composted Koi carp can make a very viable option for aquaculture feeds.
This is mainly because Koi carp are currently thought to be one of the most ecologically
detrimental freshwater species (Tempero et al., 2006). The fish was recognised as a threat
to New Zealand’s ecosystem in the 1970s, after self-sustaining populations were found
in the Waikato River in 1983 (Tempero et al., 2006). Koi carp have the ability to reach
large biomasses and have unique feeding habits, which are dangerous to the environment
and causes major destruction in many freshwater ecosystems such as lakes and rivers
(Conservation, 2014a; Tempero et al., 2006).
Koi carp, like most other fish species contains a high level of proteins, fats and low
amounts of carbohydrate. This feature is useful as fish feed requires high amounts of
protein depending on the fish size.

3
A smaller fish would require large amounts of protein for growth to occur and the demand
for protein decreases as the fish gets larger (Craig & Helfrich, 2009), as the fish does not
require as much protein for growth.
When the protein conversion efficiency of fish is compared to land-based animals, more
levels of protein are found in fish (N. Chevanan, Muthukumarappan, & Rosentrater,
2009). Another contributing factor as to why Koi carp are a viable option for aquaculture
feeds.
2.1.2. Wholemeal and Corn Flour
Wholemeal flour is composed of a high amounts of starches. Starches are a complex
carbohydrates which are a class of polysaccharides. Starch is an essential ingredient for
the extrusion process that was carried out during the experimentation process. It’s
primarily responsible for the expansion of extruded products that were produced. Starch
is a biopolymer, this means it is made up of two types of macro molecules, amylose and
amylopectin (Kannadhason, Rosentrater, Muthukumarappan, & Brown, 2010).
Corn has high proportion of starch and has an even higher proportion of amylopectin
content (76%) compared to amylose content (24%). The amount of amylopectin and
amylose play a big role in the outcome of extrudates produced. Amylopectin is
responsible for the expansion of starch during extrusion, this results in a smooth and
sticky external structure. Whereas, amylose results in harder and less expanded extrudate
(Kannadhason et al., 2010). The expansion volume of starch is dependent on the
gelatinization amount within the extruder. The degree of gelatinization is the amount of
pressure and shear developed during extrusion (Kannadhason et al., 2010).
Figure 3: Starch Polymers, retrieved from http://polymerinnovationblog.com/thermoplastic-starch-a-
renewable-biodegradable-bioplastic/ on 15 February 2014

4
2.1.3. Whey protein
Whey protein is added as a binding agent, it can be used as a binder in aquaculture feeds
to keep fish feed pallets together (N. Chevanan et al., 2009). The mechanisms of how
whey protein helps in binding are not yet known, nonetheless its presence in binding the
pellet is useful for it to remain consolidated.
2.1.4. Distilled Water
Distilled water acts a plasticizer which increases plasticity or fluidity of a material.
Distilled water is an efficient plasticizer for protein but has the distinct disadvantage is
evaporation from material over time (Bier, Verbeek, & Lay, 2014).
2.2. Extrusion process
Experimental extrusion was performed using a bench-top 16 mm co-rotating twin screw
extruder. It has a segmented barrel (TSE 16 TC), constant torque with proportional
integral derivative (PID) temperature control. The maximum screw speed it could reach
was 500 rpm with 1.25 kW motor. The extruder had a length-to-diameter ratio of 25:1
(Figure 3).
There are many advantages using a twin-screw extruder in comparison to a single screw
extruder. Twin-Screw extruders can handle viscous, oily, sticky and wet ingredients with
different levels of protein, starch, fats and fibre over a wide range of particle sizes and
can achieve an array of extrudates properties (Nehru Chevanan, Rosentrater, &
Muthukumarappan, 2007).
Figure 4: Twin-Screw Extruder

5
3. Aims
The aim of the summer research project was to create floating aquaculture feeds from
composted Koi carp (fishmeal) as the main ingredient in the feed. Furthermore, it was
required the pellet also had to be consolidated and not break down in water for an
extended period of time. On top of that, the project endeavoured to test different
properties within the aquaculture feeds. Properties such as expansion ratio, moisture
content, durability, bulk density, Water Absorption Index shortened to WAI and Water
solubility index (WSI).
4. Methods
4.1. Aquaculture Feed Formulation
Initially, first set of formulations contained different levels of fishmeal, wheat and corn
flour, distilled water and whey protein. The ingredients were mixed and blended in a
Kenwood Multipro FP950 food processor (Table 1 in Appendices).
Lastly, the second set of formulations consisted of successful feed formulation from the
first set of conducted experiments (Table 2 in Appendices).
4.2. Experimental Design and Extrusion Processing
Experimental extrusion was performed on a bench-top 16 mm co-rotating twin screw
extruder with segmented barrel (TSE 16 TC), constant torque with proportional integral
derivative (PID) temperature control. It had a maximum screw speed of 500 rpm with
1.25 kW motor and a length-to-diameter ratio of 25:1, with a feed hopper. The feed
hopper was set to 50 Hertz. The extruder speeds were at 150, 320 and 420 rpm.
The barrel had five temperature zones from the feeding section to the die section, which
were set at 60, 80, 80, 100 and 110 o
C throughout the experiments.
4.3. Measurement of Physical Properties
4.3.1. Expansion Ratio, radial expansion ratio was measured as the ratio of diameter of
the extrudates to the diameter of the die (Nehru Chevanan et al., 2007). The diameter of
all the extrudates were measured using a digital callipers and an average of five readings
were taken and calculated.

6
4.3.2. Moisture Content of the extrudates was measured using an oven at 70 o
C
overnight. This was measured by weighing a known mass of extrudates before and after
and calculating the ratio moisture loss.
4.3.3. Durability of Extrudates was measured by the standard method of S269.4 (ASAE
2004). Extrudates (approximately 100 pellets of similar length) were tumbled inside a
pellet durability tester for 10 minutes at 50 rpm. The difference in mass was then recorded
and analysed.
4.3.4. Bulk Density of the extrudates was determined by measuring mass, density and
volume of sodium chloride and also, measuring the mass of pellets. The pellets were
mixed into a known volume and mass of sodium chloride and the total volume was
measured. Bulk Density was calculated as
Volume (cm3
) = Mass /Density, Volume Pellet (cm3
) = Total Volume – Volume Sodium
Chloride, Bulk Density Pellet (g/cm3
) = Mass Pellet/Volume Pellet
4.3.5. Water Absorption Index (WAI) was determined by the method of Chevanan et al
(2007). WAI is expressed as the mass of gel (g) attained per mass of solid (g). To measure
WAI, 2.5 g of finely ground sample was suspended in 30 mL of distilled water at room
temperature in a 50 mL tarred centrifuge tube. The samples were mixed intermittently
over a period of 30 minutes and then centrifuges at 4000 rpm for 10 minutes. The
supernatant water was transferred into a beaker and the remaining gel was weighed and
WAI was calculated as the ratio of the mass of gel to the mass of sample.
4.3.6. Water Solubility Index (WSI) was determined by the water soluble fraction in the
supernatant. Half a gram of sample was measured in to test tubes, four solvents were
separately used. These solvents were 0.1M phosphate buffer at pH 7, 0.1M phosphate
buffer and sodium dodecyl Sulphate, 0.1M phosphate buffer and sodium sulphite and
0.1M phosphate buffer and sodium sulphite and sodium dodecyl sulphate. Each sample
had different chemicals added at 10 mL, boiled at 100 o
C for 120 minutes, transferred to
a centrifuge tube and centrifuged at 4000 rpm for 10 minutes. The supernatant was
collected. Supernatant was collected in to containers and put in the oven overnight at 70
o
C. The mass of the supernatant was recorded and analysed.

7
5. Results and Discussion
This experiment initially had three differing amounts of wheat flour, corn flour and
distilled water along with fishmeal and whey protein which was kept constant (Table 1 in
appendices). It was found that corn flour and distilled water samples did not float and
were difficult to extrude at screw speeds of 150 and 350 rpm. Furthermore, wheat flour
samples all floated and further experiments could be conducted. The second part of
experiments was done using different levels of wheat flour, with whey protein or without
whey protein, fishmeal, corn flour, distilled water (Table 2 in Appendices). These samples
were then extruded at different screw speeds of 350 and 420rpm.
Finally, a floating test was conducted to determine the amount of time a pellet could float
for. The majority of pellets that did float, floated for at least eight hours. However, the
pellets that were unsuccessful at floating were those samples that contained 40g of wheat
flour.
The aquaculture feed underwent changes when the levels of ingredients were altered. The
most observable change occurred when the amount of distilled water was increased, it
resulted in the feed not extruding as desired, as it became fixed while extruding even
when the speed of the feed hopper was decreased. Also, as the amount of corn flour was
increased, the bulk density of the pellets increased. During the initial floating test the
pellets did not float. As the amount of wheat flour increased, after being extruded at screw
speeds of 350 and 420 rpm, all the samples floated. Overall, the screw speed was
increased from 150 to 350 and 420rpm the pellets density decreased and majority of the
pellets at 350 and 420rpm floated.

8
5.1. Expansion Ratio
The amount of expansion is an important factor in aquaculture feeds, as it directly impacts
floatability, unit density, bulk density, fragility and hardness of the extruded products.
(Nehru Chevanan et al., 2007; Rosentrater, Muthukumarappan, & Kannadhason, 2009).
A decrease of 13.93% in expansion ratio occurred as the amount of wheat flour was
increased with in samples with no whey protein and extruded at a screw speed of 350 rpm.
The samples without whey protein and extruded at a screw speed of 420 rpm had a
decrease of 35.98% as the amount of wheat flour increased. Samples with whey protein
and was extruded at a screw speed of 350 rpm had an increase of 9.39% as the amount of
wheat flour increased. It became apparent that the same trend was observed with an
increase of 29.14% as wheat flour was increased. These results are shown in Table 3 in
appendices.
The overall trend suggests that samples with whey protein had an increase in expansion
ratio whereas, samples without whey protein had a decrease as wheat flour was increased.
There was no noticeable trend for the change of screw speed.
Figure 5: Expansion Ratio for extrudates with and without whey protein at 350 rpm and 420 rpm
0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
70.0%
80.0%
90.0%
100.0%
350/No Whey 420/No Whey 350/Whey 420/Whey
ExpansionRatio(%)
Screw Speed (rpm)/Whey Present
40g Wheat Flour
50g Wheat Flour
60g Wheat flour

9
5.2. Moisture Content
Moisture Content is a very important parameter as this affects the extrudates properties
such as durability, WAI and WSI (Nehru Chevanan et al., 2007).
The observed results indicated that as the amount of wheat flour that is present increases,
the moisture content decreases. Samples without whey protein that were extruded at screw
speeds of 350rpm overall, tended to decrease by 5.88%. Those samples without whey
protein that were extruded at screw speeds of 420rpm had an overall decrease of 15.94%.
The presence of whey protein in sampled being extruded at screw speeds of 350rpm
overall decreased by 10.88%. Samples with whey protein that were extruded at screw
speeds of 420rpm overall decreased by 33.84% as the wheat flour was increased. As
screw speeds were increased and whey protein was added to samples with 40g of wheat
flour, an overall increase of 20.04% was observed. As screw speed was increased with
samples without whey protein in samples with 50g of wheat flour, a decrease was
observed of 4.86%. Samples with whey protein had an increase of 3.64%. As screw
speeds were increased and whey protein was added to samples with 60g of wheat flour,
an overall decrease of 12.09% occurred. The results are shown in Table 4 in appendices.
Figure 6: Moisture Content for extrudates at 350 and 420 rpm, with and without whey protein
0
5
10
15
20
25
30
35
40
45
MoistureContent(%)
40g Wheat Flour
50g Wheat Flour
60g Wheat flour

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5.3. Durability
This is important quality parameter of feed materials and can indirectly measure the
mechanical strength of extrudates. (N. Chevanan, Muthukumarappan, Rosentrater, &
Julson, 2007). The overall durability for all of the extrudates is very high at 96.44 –
99.18 %. Samples that were extruded with screw speed of 350 rpm, without whey protein
and 40 g wheat flour had a decrease of 2.37% when the amount of wheat flour in the
sample was increased to 50 g. An increase of 2.68% in durability occurred as the amount
of wheat flour present in the sample increased from 50 to 60 g. Samples extruded with
screw speed of 420 rpm and without whey protein present had an increase of 1.24% as
the amount of wheat flour was increased.
Samples with screw speed of 350 rpm, with whey protein and 40 g wheat flour had an
increase of 0.004% as wheat flour was increased to 50 g, and a decrease occurred as wheat
flour increased from 50 to 60 g of 0.003%. Samples extruded with screw speeds of 420
rpm and had whey protein present increased by 0.01% as wheat flour was increased. No
such obvious trend occurred with all the samples. These results are shown in Table 5 in
appendices.
Figure 7: Durability for extrudates at 350 and 420 rpm, with and without whey protein
93
94
95
96
97
98
99
100
101
Durability(%)
40g Wheat Flour
50g Wheat Flour
60g Wheat flour

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5.4. Bulk density
Bulk density of the extrudates is affected by the volume of pores inside the extrudates as
expansion occurs during extrusion processing, as well as void spaces formed during
filling of the irregular shaped extrudates into containers of a specific size during testing
(Nehru Chevanan et al., 2007). Bulk density is very important because it determines the
space required to store the extruded feed materials (Nehru Chevanan et al., 2007).
Samples that were extruded at screw speeds of 350 and 420 rpm, which had no presence
of whey protein, decreased in bulk density by 41.49% and 39.62% respectively as wheat
flour was increased. Samples with screw speeds of 350 rpm, with whey protein and 40 g
wheat flour decreased by 10.48% as wheat flour was increased to 50 g.
Furthermore, samples with 50 to 60 g of wheat flour increased in bulk density by 28.68%.
Samples with screw speed of 420 rpm, without whey protein had an increase of 25.98%
as wheat flour was increased. The biggest reduction in bulk density was 37.64% in a
sample of 50 g wheat flour and without any whey protein present.
The overall trend that was observed was an increase in screw speed led to decreased bulk
density. These results are shown in Table 6 in appendices.
Figure 8: Bulk Density for extrudates at 350 and 420 rpm, with and without whey protein
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
BulkDensity(g/cm3)
Screw Speed (rpm)/whey Present
40g Wheat Flour
50g Wheat Flour
60g Wheat flour

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5.5. Water Absorption Index (WAI)
WAI is the measure of volume occupied by the starch that maintained integrity during
the extrusion process (Nehru Chevanan et al., 2007). Also, WAI is indirectly related to
the water holding capacity and results in the storage properties of the pellets.
Samples with screw speeds of 350 and 420 rpm, without whey protein had an increase of
8.22% and 9.20% respectively as wheat flour was increased from 40 to 60 g. Samples
with extruded screw speeds of 350 and 420 rpm, with whey protein followed similar
trends by decreasing WAI from 40 to 50 g wheat flour and increasing WAI from 50 to 60
g wheat flour, these values are as follows 1.32% decrease, 8.07% increase at 350 rpm and
1.67% decrease, 9.48% increase at 420 rpm.
The overall trend that was observed was as screw speed was increased the WAI decreased
in all samples. These results are shown in Table 7 in appendices.
Figure 9: WAI for extrudates at 350 and 420 rpm, with and without whey protein
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
WAI(-)
40g Wheat Flour
50g Wheat Flour
60g Wheat flour

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5.6. Water Solubility Index (WSI)
WSI is the measure of the degree of starch conversion occurring during the extrusion
process. It is an indicator of the degradation of molecular components. (Nehru Chevanan
et al., 2007). Usually, WSI increased as the temperature was increased, as a result of
starch depolymerisation, which leads to a reduced length of amylose and amylopectin
chains (N. Chevanan et al., 2007). Buffers were used in the experiment, Phosphate buffer
at pH 7 only changes pH slightly when a small amount of strong base or acid is added
and so it is used to prevent changes in pH of a solution; Sodium Sulphite (SS) is the
sodium salt of sulphuric acid and Sodium Dodecyl Sulphate (SDS) is an amphiphile
which has both hydrophilic and lipophilic properties.
Changing the amount of ingredients and the screw speeds of extrudates did not result in
a significant change in WSI. There are many factors that depend on WSI. For example,
different sources of starch results in different levels of WSI depending on the amount of
amylose and amylopectin present in the starch.(Kannadhason et al., 2010; Nehru,
Muthukumarappan, Rosentrater, & Julson, 2007) Furthermore, the dextrination amount
in extrudates results from a high shear and high temperature which affect WSI. Moreover,
the interactions between protein and starch also affect WSI. (Nehru et al., 2007).
The most significant change in a single solution was 1.06% from 50 g to 60 g wheat flour
at screw speed of 350 rpm and in Phosphate buffer solution (Figure 9). WSI increased as
SS, SDS and SS with SDS was added to Phosphate buffer. The highest solubility
percentage was 5.18% associated with sample at 60 g wheat flour, screw speed of 350
rpm, whey protein present and in solution of phosphate buffer with SS and SDS (Figure
12). As different levels of chemicals are added the WSI changes, SS with SDS has both
acid and base properties and this results in a higher chance of changing WSI. When both
are present in solution of phosphate buffer a higher change of WSI is observed. These
results are shown in Table 8, 9, 10, and 11 in appendices.
The results for 40 g wheat flour with whey protein are not present in the graphs below as
the data was inconclusive.

14
Figure 10: WSI for 0.1M Phosphate Buffer 0.1M, pH7
Figure 11: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Sulphite
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
3.00%
3.50%
4.00%
Solubilty%
40g Wheat Flour
50g Wheat Flour
60g Wheat flour
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
3.00%
3.50%
4.00%
4.50%
Solubilty%
40g Wheat Flour
50g Wheat Flour
60g Wheat flour

15
Figure 12: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Dodecyl Sulphate
Figure 13: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Sulphite + Sodium Dodecyl Sulphate
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
3.00%
3.50%
4.00%
4.50%
5.00%
Solubilty%
40g Wheat Flour
50g Wheat Flour
60g Wheat flour
0.00%
0.50%
1.00%
1.50%
2.00%
2.50%
3.00%
3.50%
4.00%
4.50%
5.00%
5.50%
6.00%
Solubilty%
40g Wheat Flour
50g Wheat Flour
60g Wheat flour

16
6. Conclusion/ Recommendations
The aim of the work placement was to create a floating aquaculture feed from composted
Koi carp (fishmeal). This was done through numerous research and literature search of
general aquaculture feeds, Koi carp, feed formulation, processing of feeds, properties of
feeds and how to conduct experiments.
This experiment initially had a formulation of fishmeal (100 g), wheat flour (40, 50, 60
g), corn flour (30, 40, 50 g), whey protein (5 g) and distilled water (60, 70, 80 g). Corn
flour and distilled water extrudates did not produce a floatable pellet and were difficult to
extrude at both screw speeds of 150 and 350 rpm. Furthermore, wheat flour samples all
floated and further experiments were conducted. The second sets formulations consisted
of fishmeal (100g), wheat flour (40, 50, 60 g), corn flour (20 g), whey protein (0, 5 g) and
distilled water (50 g) also at different screw speeds of 350 and 420rpm. All the pellets
apart from the extrudates consisting of 40 g wheat flour were floating.
Changing the amount of wheat flour had significant changes in the extrudates properties
such as expansion ratio, moisture content and durability. When the screw speeds were
increased the extrudates had a decrease in bulk density and WAI. Also, as sodium sulphite
and sodium dodecyl sulphate were added to phosphate buffer the WSI increased but no
significant changes were observed as screw speed and amounts of ingredients were
changed.
The results obtained from this experiment on the twin-screw extruder, suggests that a
successful floating aquaculture feed can be produced from the ingredients and conditions
that were tested.
This was the only known trail that fishmeal has being used as a major ingredient in an
aquaculture feed, further studies and experiments has to be conducted in order to create
an effective and efficient aquaculture feed with all the essential vitamins and minerals for
the fish. Also, feeding trails can be conducted in order to determine if the feed created is
an effective source of food for the fish.

17
7. References
Bier, J. M., Verbeek, C. J. R., & Lay, M. C. (2014). Thermal and Mechanical Properties
of Bloodmeal-Based Thermoplastics Plasticized with Tri(ethylene glycol).
Macromolecular Materials and Engineering, 299(1), 85-95. doi:
10.1002/mame.201200460
Chevanan, N., Muthukumarappan, K., & Rosentrater, K. A. (2009). Extrusion Studies of
Aquaculture Feed Using Distillers Dried Grains with Solubles and Whey. Food
and Bioprocess Technology, 2(2), 177-185.
Chevanan, N., Muthukumarappan, K., Rosentrater, K. A., & Julson, J. L. (2007). Effect
of die dimensions on extrusion processing parameters and properties of DDGS-
based aquaculture feeds. Cereal Chemistry, 84(4), 389-398. doi: 10.1094/cchem-
84-4-0389
Chevanan, N., Rosentrater, K. A., & Muthukumarappan, K. (2007). Twin-Screw
Extrusion Processing of Feed Blends Containing Distillers Dried Grains with
Solubles (DDGS). Cereal Chemistry, 84(5), 428-436.
Conservation, D. o. (2014a). Freshwater Ecosystems of New Zealand. Retrieved 09
February, 2014, from http://www.doc.govt.nz/conservation/land-and-
freshwater/freshwater/freshwater-ecosystems-of-new-zealand/
Conservation, D. O. (2014b). Koi Carp. Retrieved 03 February 2014
Craig, S., & Helfrich, L. A. (2009). Understanding Fish Nutrition, Feeds, and Feeding.
Environmental Research Institute, W. U. (2014). Killing koi could be the key to saving
the lakes - Environmental Research Institute : University of Waikato. Retrieved
08 February 2014, from http://www.waikato.ac.nz/eri/research/case-
studies/killing-koi-could-be-the-key-to-saving-the-lakes
Kannadhason, S., Rosentrater, K. A., Muthukumarappan, K., & Brown, M. L. (2010).
Twin Screw Extrusion of DDGS-Based Aquaculture Feeds1. Journal of the World
Aquaculture Society, 41, 1-15. doi: 10.1111/j.1749-7345.2009.00328.x
Nehru, C., Muthukumarappan, K., Rosentrater, K. A., & Julson, J. L. (2007). Effect of
Die Dimensions on Extrusion Processing Parameters and Properties of DDGS-
Based Aquaculture Feeds. Cereal Chemistry, 84(4), 389-398.
Rosentrater, K. A., Muthukumarappan, K., & Kannadhason, S. (2009). Effects of
ingredients and extrusion parameters on aquafeeds containing DDGS and potato
starch. Journal of Aquaculture Feed Science and Nutrition, 1(1), 22-38.
Tempero, G. W., Ling, N., Hicks, B. J., & Osborne, M. W. (2006). Age composition,
growth, and reproduction of koi carp (Cyprinus carpio) in the lower Waikato
region, New Zealand. New Zealand Journal of Marine and Freshwater Research,
40(4), 571-583. doi: 10.1080/00288330.2006.9517446

1
Appendices
First set of samples extruded at 150 and 350 rpm
Table 1: First set of formulations
Weight of Ingredients FMpph
Feed Ingredients Blend 1 Blend 2 Blend 3
Fishmeal 100 100 100
Wheat Flour 40 50 60
Corn Flour 20 20 20
Whey Protein 5 5 5
Distilled Water 50 50 50
Corn Flour 30 40 50
Whey Protein 5 5 5
Corn Flour 20 20 20
Whey Protein 5 5 5

2
Second set of samples extruded at 350 and 420 rpm
Table 2: Second set of formulations
Corn Flour 40 40 40
Whey Protein 10 10 10
Corn Flour 20 20 20
Whey Protein 0 0 0

3
Conducted Experiments
Table 3: Expansion ratio of samples
Expansion Ratio (%)
Standard Formulation containing
40 g Wheat Flour 50 g Wheat Flour 60 g Wheat flour
Screw Speed
(rpm)/ Whey
Present
350/No Whey 71.80 62.80 61.2
420/No Whey 69.20 64.80 44.3
350/Whey 73.30 75.30 80.9
420/Whey 59.10 71.80 83.4
Table 4: Moisture Content of samples
Moisture Content (%)
Standard formulation containing
Screw Speed
(rpm)/ Whey
Present
350/No Whey 29.22 28.41 27.51
420/No Whey 29.64 27.03 24.91
350/Whey 31.16 26.92 24.79
420/Whey 36.55 27.94 24.18

4
Table 5: Durability of Samples
Durability (%)
40 g Wheat Flour 50 g Wheat Flour 60 g Wheat Flour
Screw Speed
(rpm)/Whey
Present
350/No Whey 98.78 96.44 99.09
420/No Whey 97.32 98.54 98.55
350/Whey 98.75 99.18 98.92
420/Whey 98.13 98.68 99.08
Table 6: Bulk Density of samples
Bulk Density (g/cm3)
Screw Speed
(rpm)/ Whey
Present
350/No Whey 0.76 0.71 0.44
420/No Whey 0.57 0.44 0.34
350/Whey 0.61 0.55 0.77
420/Whey 0.43 0.53 0.58

5
Table 7: WAI of samples
WAI (-)
Standard formulation containing
Screw Speed
(rpm)/ Whey
Present
350/No Whey 3.328 3.580 3.626
420/No Whey 3.002 3.174 3.306
350/Whey 3.164 3.122 3.396
420/Whey 3.084 3.032 3.198
Table 8: WSI for 0.1M Phosphate Buffer 0.1M, pH7
WSI for 0.1M Phosphate Buffer 0.1M, pH7 (%)
Screw Speed (rpm)/
Whey Present
350/No Whey 2.45 2.41 3.47
420/No Whey 2.40 2.64 2.98
350/Whey 0.00 2.82 3.00
420/Whey 0.00 2.86 2.90

6
Table 9: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Sulphite
WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Sulphite (%)
Screw Speed
(rpm)/ Whey
Present
350/No Whey 3.46 3.37 3.62
420/No Whey 3.37 3.83 3.78
350/Whey 0.00 3.66 3.94
420/Whey 0.00 3.66 3.94
Table 10: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Dodecyl Sulphate
WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Dodecyl Sulphate (%)
Standard Formulation Containing
Screw Speed
(rpm)/ Whey
Present
350/No Whey 3.75 4.11 4.02
420/No Whey 3.84 3.97 3.98
350/Whey 0.00 4.33 4.27
420/Whey 0.00 4.23 4.25

7
Table 11: WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Sulphite + Sodium Dodecyl Sulphate
WSI for 0.1M Phosphate Buffer 0.1M, pH7 + Sodium Sulphite + Sodium Dodecyl
Sulphate (%)
Screw Speed
(rpm)/ Whey
Present
350/No Whey 4.70 4.94 4.87
420/No Whey 4.68 5.23 5.05
350/Whey 0.00 5.06 5.18
420/Whey 0.00 4.98 5.14

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