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 oC 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 oC

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 oC 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

oC. 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

Exp

an

sio

n R

ati

o (

%)

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


Mo

istu

re C

on

ten

t (%

)


40g Wheat Flour

50g Wheat Flour

60g Wheat flour

10

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


Du

rab

ilit

y (

%)


40g Wheat Flour

50g Wheat Flour

60g Wheat flour

11

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


Bu

lk D

ensi

ty (

g/c

m3)

Screw Speed (rpm)/whey Present

40g Wheat Flour

50g Wheat Flour

60g Wheat flour

12

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


WA

I (-

)


40g Wheat Flour

50g Wheat Flour

60g Wheat flour

13

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%


So

lub

ilty

%


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%


So

lub

ilty

%


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%


So

lub

ilty

%


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%


So

lub

ilty

%


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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