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COLLEGE OF NATURAL SCIENCES DEPARTMENT OF CHEMISTRY FIELD ATTACHMENT REPORT AT UGANDA INDUSTRIAL RESEARCH INSTITUTE (UIRI) BY NIWEMUHWEZI ANSELM 12/U/946 UNIVERSITY SUPERVISOR: Assoc. Prof. Dr. STEVEN NYANZI ORGANISATION SUPERVISOR: Mrs. NABAGGALA RITAH A training report in partial fulfillment of the requirements for the award of the degree of Bachelor of Science in Industrial Chemistry of Makerere University August 2014
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COLLEGE OF NATURAL SCIENCES

DEPARTMENT OF CHEMISTRY

FIELD ATTACHMENT REPORT

AT

UGANDA INDUSTRIAL RESEARCH INSTITUTE (UIRI)

BY

NIWEMUHWEZI ANSELM

12/U/946

UNIVERSITY SUPERVISOR: Assoc. Prof. Dr. STEVEN NYANZI

ORGANISATION SUPERVISOR: Mrs. NABAGGALA RITAH

A training report in partial fulfillment of the requirements for the award of the

degree of Bachelor of Science in Industrial Chemistry of Makerere University

August 2014

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DECLARATION

I NIWEMUHWEZI ANSELM declare that the work produced in this report is from my research

and the information given by the instructors during practical sessions.

………………………………….

Signature

……………………………………

Date

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APPROVAL

This is to certify that this report contains a true record of what was done by NIWEMUHWEZI

ANSELM during the eight weeks of training at UIRI from 09th/06to 1st/08/2014.

Signature…………………………..

Date ……………………………….

Organization Supervisor: Mrs. Nabaggala Ritah

Signature…………………………..

Date ……………………………….

University Supervisor: Assoc. Prof. Dr. Steven Nyanzi

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ACKNOWLEDGEMENT

Thanks go to the almighty GOD for the gift of knowledge which has enabled me to accomplish

all these activities.

Am pleased with UIRI administration for granting me this opportunity to train from here it was a

very good experience and I managed to learn a lot of things as pertains my career.

Am so grateful and humbled by my Organization supervisor Mrs. NABAGGALA RITAH and

the staff in the chemistry laboratory for the information and knowledge they provided and other

individuals who shared their knowledge with me during this training period.

It would not be appropriate to forget my university supervisor Assoc. Prof. Dr. Steven Nyanzi for

sacrificing his time to come and supervise me and the knowledge which he shared with me

especially in report writing and project.

And finally to those who have in any way helped me either financially, academically or

otherwise to make this publication a success.

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PREFACE

This report covers the work which was done in industrial training from 09 th/06/2014 to

08th/08/2014 (9 weeks). It includes various food analysis tests, fruit juice tests, water analysis

tests and soap analysis tests. All the experiments were carried out using standard operating

procedures (SOPs). All the results were treated to obtain the parameter being analyzed and

recommendations given appropriately. It further includes general recommendations to the

organization and the university.

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TABLE OFCONTENTS

DECLARATION ..............................................................................................................................i

APPROVAL .................................................................................................................................... ii

ACKNOWLEDGEMENT .............................................................................................................. iii

PREFACE ....................................................................................................................................... iv

LIST OF FIGURES ....................................................................................................................... vii

ACRONYMS ................................................................................................................................ viii

CHAPTER ONE: INTRODUCTION ............................................................................................. 1

1.1. UGANDA INDUSTRIAL RESEARCH INSTITUTE (UIRI) BACKGROUND AND

LOCATION ................................................................................................................................ 1

1.2. THE CHEMISITRY LABORATORY ............................................................................ 4

CHAPTER TWO: INSTRUMENTATION .................................................................................... 6

2.0. SOXTEC SYSTEM.............................................................................................................. 6

2.1. pH METER .......................................................................................................................... 6

2.2. MUFFLE FURNACE .......................................................................................................... 8

2.3. ATOMIC ABSORPTION SPECTROMETER (AAS) ........................................................ 8

2.4. UV/VIS SPECTROPHOTOMETER ................................................................................. 10

2.5. OVEN ................................................................................................................................. 11

2.6. WATER BATH .................................................................................................................. 12

2.7. MAJI-METER.................................................................................................................... 13

2.8. ANALYTICAL BALANCE .............................................................................................. 14

2.9. KJELTEC SYSTEM .......................................................................................................... 15

CHAPTER THREE: ANALYSIS................................................................................................. 16

3.1. FOOD ANALYSIS ............................................................................................................ 16

EXP 1: DETERMINATION OF ASH CONTENT ............................................................... 16

EXP 2: DETERMINATION OF FAT CONTENT USING SOXHLET METHOD............. 19

EXP 3: DETERMINATION OF MOISTURE CONTENT IN FOOD SAMPLES .............. 23

EXP 4: DETERMINATION OF VITAMIN A IN FORTIFIED FLOUR ............................ 27

EXP 5: DETERMINATION OF β-CAROTENE .................................................................. 29

PROXIMATE ANALYSIS OF FLOUR SAMPLE .............................................................. 31

3.2. TOUR TO OTHER PRODUCTION DEPARTMENTS IN THE INSTITUTE ................ 32

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A TOUR TO THE DAIRY PROCESSING PLANT ............................................................ 32

A TOUR TO THE FOOD PROCESSING PLANT .............................................................. 33

A VISIT TO THE JUICE PROCESSING PLANT ............................................................... 34

3.3. ANALYSIS OF FRUIT JUICES ....................................................................................... 35

EXP 6: DETERMINATION OF VITAMIN C ..................................................................... 35

EXP 7: DETERMINATION OF TOTAL TITRATABLE ACID IN FRUIT JUICES ......... 39

EXP 8: PROTEIN CONTENT DETERMINATION IN FRUIT JUICES ............................ 41

3.4 SOAP ANALYSIS .............................................................................................................. 44

EXP 9: DETERMINATION OF pH VALUE OF SOAP SAMPLE ..................................... 44

EXP 10: DETERMINATION OF INORGANIC SALTS ..................................................... 44

3.5. WATER ANALYSIS ......................................................................................................... 47

CHAPTER FOUR: RECOMMENDATIONS, CONCLUSION AND REFERENCES .............. 48

4.1. LIST OF SKILLS ACQUIRED ......................................................................................... 48

4.2. RECOMMENDATIONS ................................................................................................... 48

4.2. CONCLUSION .................................................................................................................. 49

4.3. REFERENCES................................................................................................................... 50

APPENDIX ................................................................................................................................... 51

STANDARD OPERATING PROCEDURES (S.O.PS) ........................................................... 51

WASTE MANAGEMENT ....................................................................................................... 53

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LIST OF FIGURES

Figure 1: UIRI location and UIRI main block ................................................................................ 2

Figure 2: A representation of Soxtec System ................................................................................. 6

Figure 3: A representation of pH meter .......................................................................................... 7

Figure 4: A representation of Muffle furnace ................................................................................. 8

Figure 5: A representation of Atomic Absorption Spectrum (AAS) ............................................ 10

Figure 6: A representation of UV/VIS spectrophotometer ........................................................... 11

Figure 7: A representation of an Oven.......................................................................................... 12

Figure 8: A representation of a water bath.................................................................................... 13

Figure 9: A representation of Maji-Meter..................................................................................... 13

Figure 10: A representation of an Analytical balance................................................................... 14

Figure 11: A representation of a Kjeltec system........................................................................... 15

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ACRONYMS

1. UIRI……………. Uganda Industrial Research Institute

2. UNBS …………..Uganda National Bureau of Standards

3. RSD…………….. Relative Standard Deviation

4. SD………………. Standard Deviation

5. pH………………...Potential of hydrogen

6. ID ………………...Identification

7. AR……………… Analytical Reagent

8. QC……………….. Quality Control

9. QA……………….. Quality Assurance

10. M………………... Molarity

11. N………………….. Normality

12. SOPs…………… standard operating procedures

13. Psig …………….pounds per square inch gauge

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CHAPTER ONE: INTRODUCTION

1.1.UGANDA INDUSTRIAL RESEARCH INSTITUTE (UIRI) BACKGROUND AND

LOCATION

UIRI was formally established by an Act of Parliament in 2002 by H.E. the President to the

Act on 30th July 2003. It is a progeny of the East African Industrial Research Organization

(ESIRO) of the non-operational East African Community (EAC)]. After the end of the then

EAC in 1977, the three member states continued with the splintered Industrial Research

Organizations, and hence was born:

Kenya Industrial Research and Development Institute (KIRDI)

Tanzania Industrial Research and Development Institute (TIRDI)

Uganda Industrial Research Institute (UIRI)

With Uganda's economic dislocation of the 70s and 80s, UIRI did not become fully

operational until 1997 when, with a grant from the Government of People's Republic of

China (GPRC) a campus was built and some technologies for pilot plants installed. The

formal handover of the modern facility to Uganda Government was done in the year 2000.

UIRI's mandate is to engage in activities that will lead to rapid industrialization of Uganda.

UIRI's Vision and Mission

To be the model institution and regional center of excellence, for incubation of industry and

pioneering industrial Research and Development activities that could elevate the level of

technology in Uganda and the region.

UIRI's mission:

1. To improve capacity and competence of indigenous entrepreneurs in undertaking viable

industrial production processes and in their ability to produce high quality marketable

products.

2. To provide demand driven Scientific Industrial Research and Development and

Internationally competitive technical services that will lead to rapid industrialization for the

benefit of the people of Uganda.

UIRI's Mandate and Objectives

UIRI's mandate derived from the statute that established the institution is to undertake

applied research, and develop and acquire appropriate technology in order to create a strong,

effective and competitive industrial sector for the rapid industrialization of Uganda.

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In order to fulfill its mandate, UIRI has established the following corporate objectives:

1. To undertake Applied Industrial Research for the development of optimal production

processes for Uganda's nascent industry.

2. To develop and/or acquire appropriate technology in order to create a strong, effective, and

competitive industrial sector for the rapid industrialization of Uganda.

3. To provide the necessary expert input towards Government Development Initiatives.

Location of the organization

Uganda Industrial Research Institution is located in Nakawa Industrial Area, Plot 42A

Mukabya Road, P .O. Box 7086, Kampala Uganda. Website http://www.uiri.org

Figure 1: UIRI location and UIRI main block

Organization and Governance of UIRI

UIRI is governed by a Board of Directors, with an Executive Director as the Chief Executive

responsible for day-to-day operations and policy implementation. The departmental structure

is comprised of the following organizational units:

1. Administration

Responsible for the welfare of staff, the operability of facilities, financial diligence, logistical

optimality, and inter-departmental coordination

UIRI boasts of a competent well-trained management team. The core management team, led

by the Executive Director is comprised of a Deputy Executive Director, Administrative

Officer, Chief Technical Advisor, Research Officers (Heads of Departments). Current staff

totals 50.

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The combined experience in Training, Research, Business Analysis, and Engineering

Operations is in excess of 145 years, ranging from a low of 2 to a high of 29 years, and

averaging around 12 years.

A significant number of the management team has handled several projects of small, medium

to large, both in size and complexity.

1. Food Science and Technology

Undertakes research in industrial processes and technology for adding value to food products

The division is responsible for running pilot plants for processing dairy, meat, bakery, fruits

and vegetable products. Although the products from the pilot plants are available for sale to

the public, the cardinal role of the pilot plants is to train entrepreneurs and others from

tertiary and university institutions.

2. Ceramics

Responsible for research, design and production of high quality ceramics products

Department maintains a showcase at the Institute and some of their products are available for

sale to the public.

3. Training

Coordinates a spectrum of training programs from basic to advanced skill levels, and from

the starting to the fully formed entrepreneur Most training is conducted in-house and

programs are run by the staff of the institute.

4. Analytical Laboratories

Support internal research and offer services to the public in such areas as product analysis -

content and context, physical and chemical properties, or any analytical service that the client

might desire. Laboratories are divided into Analytical Chemistry, Microbiology and Mineral

laboratory.

5. Engineering and Manufacturing

This runs a maintenance engineering workshop as well as a carpentry shop, Provides all

engineering and technical maintenance services to the entire Institute, and coordinates any

engineering/technical services that may be contracted from outside.

Operations and Functions

In fulfillment of its mandates, UIRI performs the following functions:

1. Identify and develop appropriate technologies and processes for the exploitation of our

nation's natural resources.

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2. Upgrade and strengthen the existing indigenous technologies through basic and applied

research.

3. Set-up pilot plants to demonstrate the operation and benefits of new technologies, and

otherwise perform the role of an incubator for new industrial enterprises.

4. Design, develop and adapt machinery, tools, equipment and instruments suitable for small-

scale enterprises, especially in rural areas.

5. Maintain a comprehensive data bank on industrial research, technologies, materials and

products.

6. Facilitate the provision of technical advice and other assistance to existing enterprises in

order to improve their competences and their operational efficiencies.

7. Provide research findings to entrepreneurs to assist them in setting up new projects.

8. Collaborate with other organizations, both nationally and internationally, to create

synergies to improve knowledge, networking and capacity building for the benefit of our

client base and for rapid industrialization through technology transfer.

9. Serve as a production technology reference center.

1.2.THE CHEMISITRY LABORATORY

EQUIPMENT SAFETY GUIDELINES

Do not operate any equipment without permission

Carefully follow operating instructions when handling a given equipment

Switch off equipment after use

Report equipment malfunction immediately

Do not operate faulty equipment

HOUSE KEEPING

Before starting any task, the following are put into consideration;

All necessary things (reagents, equipment) should be returned to their places and only

required things are brought.

The work place should be cleaned

After doing any task, the following are considered;

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Collecting and cleaning the apparatus

All apparatus should be returned to storage

Cleaning the work place

At the end of the day, all apparatus should be returned to the place of storage and

work place cleaned and organized.

LABORATORY SAFETY GUIDELINES

Always wear gloves when handling corrosive substances

Keep your place and your place of work tidy

Clean up any spillages, acid or alkaline spillages should be neutralized first before

cleaning them up

Label reagents, samples, drawers clearly

Always use the fume hood when handling highly toxic substances

Always screw reagent bottle caps and chemical bottle tops tightly

Keep chemicals, apparatus and equipment in such a way that they will not fall down

Do not eat, drink or smoke in the laboratory

Do not pour corrosive substances into the sink but pour in glass dispersal bottles or

discard bottles

Do not add water to acid but acid to water

Do not pipette poisonous or hazardous solutions using your mouth, always use pipette

fillers

Do not handle reagent bottles by their necks

Report any accident that occurs immediately

Never leave potentially hazardous work unattended to

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CHAPTER TWO: INSTRUMENTATION

2.0. SOXTEC SYSTEM

This was used to analyze fat and oils in the samples. The Soxtec system provides a means of

safe and fast solvent extraction of foods, feeds and many more matrices. Extraction is used to

isolate soluble matter such as crude fat, additives, pesticides and minor constituents from

complex materials.

Extraction analysis is traditionally based on the Soxhlet principle because of its worldwide

accuracy and reproducibility. However convectional Soxhlet analysis involves tedious and

time consuming manual work and explosion risks. The patented design of Soxtec system HT

2 makes it possible to perform extractions using a wide range of solvents in a quicker, safer

and more economical way compared to the Soxhlet extractions. The combination of the

Soxtec extraction technique and wide range of solvent use makes the HT 2 Soxtec system a

flexible and powerful tool in the analysis of soluble compounds from materials such as; food,

feed, chemical technical products and pharmaceuticals.

Figure 2: A representation of Soxtec System

2.1. pH METER

A pH meter is an electronic device used for determining the acidity or alkalinity of a solution

(though special probes are sometimes used to measure the pH of semi-solid substances). A

pH meter consists of a special measuring probe (a glass electrode) connected to an electronic

meter that measures and displays the pH reading. At the bottom of the probe there is a bulb

which is the sensitive part of the probe as it contains a sensor. For every precise work, the pH

meter should be calibrated before each measurement. For normal use, verification should be

done at the beginning of each day using standard buffers of known pH. This is so because the

glass electrode does not give a reproducible electromotive force over long periods of time.

Verification should be done with at least two standard buffer solutions that span the range of

values to be measured.

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Operation

The solution whose pH is to be measured is put into a container and the probe is dipped into

it. When the values on the meter screen have stabilized, a button with the label “READ” is

pressed, the pH and the temperature are recorded.

After each single measurement, the probe is rinsed with distilled water or deionized water to

remove any traces of the solution, cleaned with tissue to absorb any remaining water that

could dilute the sample and hence alter the reading, and then quickly immersed in another

solution.

Note: The probes should be ocassionary cleaned (at least once a month) and this can be done

using pH electrode cleaning solution; generally a 0.1 M solution of hydrochloric acid is used

(having a pH of one). Alternatively, a dilute solution of ammonium fluoride (NH4F) can be

used.

Figure 3: A representation of pH meter

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2.2. MUFFLE FURNACE

A muffle furnace is used for providing extremely high temperature for example in

determination of ash content in a given sample.

PROCEDURE FOR OPERATION OF MUFFLE FURNACE

1. Plug equipment into power supply

2. Turn on the ‘on/off’ button on the front panel of the equipment.

3. Press ‘T’ on the front panel

4. Move cursor (in form of a dot) using the arrows on the front panel while adjusting

temperature by changing the number using the up ↑ and down ↓ arrows.

5. After setting the temperature move cursor at end of set temperature then press ‘start’.

Figure 4: A representation of Muffle furnace

2.3. ATOMIC ABSORPTION SPECTROMETER (AAS)

The A Analyst 400 Atomic Absorption Spectrum is a double –beam atomic absorption

spectrometer for flame or manual mercury hydride determinations. It is a sophisticated

analytical system capable of performing automated single element determinations.

OPERATING PROCEDURE

1. Read the safety information before you operate the system.

2. Turn on the Acetylene gas and adjust the outlet gauge pressure to the recommended

value of 14 Psig. NEVER allow the outlet gauge pressure to exceed 103kPa (1.03 bar,

15 Psig); acetylene can explode spontaneously above this pressure.

3. Turn on the Air compressor and adjust the outlet gauge pressure to the recommended

range of 70 to 80 Psig.

4. Open the lamp door and install the required lamp for the analyte element. Please note

the position for mercury, its either position 1 or 2.

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5. Switch on the spectrometer using the operational on/off switch. Close the lamp door

and wait for the spectrometer to complete initialization for about 5 minutes.

6. Activate the WinLab32 for AA software on the computer. Leave it to complete

initialization for about 2 minutes.

7. In WinLab32 for AA software select the Method icon and define the element of

interest. The wavelength and slit fields will automatically have the correct values.

8. Still under the Method icon, click “setting” and enter the current which is set to

10Afor all other elements except for Mercury which is 15A. Click “calibration” and

then select standard calibration, enter name of the Blank, standards and their

respective concentrations. Go to the “FILE icon” then select method, name the

method and save it.

9. In WinLab32 for AA software select the Sample info icon and then enter the sample

ID. Go to the “FILE icon” then select sample info, name the file and save it.

10. In the Flame Control window, select the on side of the flame On/Off switch to light

the flame and leave to initialize for 2 minutes.

11. Select “Manual window” and enter the name of the result file where you want to

save your results. OR you can create new folder for the results and save it. Select save

data and print log in the Manual window.

12. Load the Blank sample first onto the equipment, wait for 30 seconds and then select

“Analyze Blank” on the Manual window. This will activate analysis of the Blank.

Do not remove the Blank until “idle” is indicated on the window.

13. Load the standard samples onto the equipment and follow the order as entered in the

method icon (Standard concentration), wait for 30 seconds and then select “Analyze

Standard” on the manual window. This will activate analysis of the standard. Follow

the procedure for all the standards but first rinsing with blank before each analysis.

14. After analyzing the standards, Load the test sample on the equipment and follow the

order as entered in the sample info window, wait for 30 seconds and then select

“Analyze sample” on the manual window. Follow the same procedure for all

samples but first rinsing with blank before each analysis.

15. You can select the Results icon to view the results.

16. After analysis of the samples, select the Flame Control window select the off side of

the Flame On/Off switch to turn off the flame.

17. Turn off the acetylene gas by closing the valve. Wait for 2 minutes and then select the

‘Bleed gases” on the Flame Control window. Do it at least 2 times.

18. Turn off the WinLab32 for AA software and then switch off the spectrometer by

using the operational on/off switch. Switch off any other accessories.

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NOTE

Make sure that the sample loop is always immersed in de-ionized water.

Dispose of hazardous or corrosive solutions properly and refer to your local safety

regulations for proper disposal procedures

Figure 5: A representation of Atomic Absorption Spectrum (AAS)

2.4. UV/VIS SPECTROPHOTOMETER

For a beam of light incident on the sample part of the light is absorbed and the other emitted

using the principle of beer’s law samples can be analyzed.

Procedure for operation of UV/VIS spectrophotometer

Switch on power supply, switch on power stabilizer, turn on the UV/VIS

spectrophotometer using the green button on the top of the equipment and finally

switch on the computer.

Wait for equipment to initialize until it shows previously used method /wavelength.

On the computer programs is UV-win lab under which you should click Lambda Bio

20. The method window will open up.

Select method to be used for example scan, or Time drive.

Under the selected method set the required parameters like wavelength, number of

references, or number of samples.

Fill blank sample in one of the two marching Cuvettes (cells) and insert it in one of

the porches inside the spectrometer where light beams pass.

Click start. The equipment will ask for next sample blank so insert next sample blank

in remaining porch where light beam passes

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Taking an example of the concentration method the equipment will then ask for

consecutive references /standards.

Figure 6: A representation of UV/VIS spectrophotometer

2.5. OVEN

Connect the power cable of the oven to the power outlet.

Ensure that the temperature setting potentiometer is set to a minimum.

Switch the On/Off key to the ‘ON’ position.

Adjust the temperature setting potentiometer to set the desired temperature.

Wait until the orange indicator lamp starts flashing continuously and the thermometer

is indicating the desired temperature, to insert items into the oven.

Close oven door and leave items inside for the desired period of time.

Remove the items from the oven, once the desired period of time has elapsed.

Set the temperature setting potentiometer to a minimum.

Switch the On/Off Key to the ‘OFF’ position.

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Figure 7: A representation of an Oven

2.6. WATER BATH

On heating, water increases in temperature and on reaching 100oC it boils hence heating up

whatsoever is in its contact

Procedure for operation of water bath

Check that the level of water is above the tray inside the water bath.

Plug equipment onto power supply

Press red button on front panel to switch on power in the equipment.

Set required temperature by pressing the “+” or “-” buttons corresponding to the

position of number. The green light will be lit up to show that equipment is gaining

the set temperature.

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Figure 8: A representation of a water bath

2.7. MAJI-METER

The Maji-Meter is capable of measuring up to 11 parameters in the field simply by

submerging the probe into a water course and using the control unit to run the test and view

results. It was used to determine pH, Turbidity, electrolytic conductivity (EC), dissolved

oxygen (DO), total dissolved solids (TDS), altitude, latitude and longitude of water samples

in the field. An integrated GPS system allows users to identify exactly where results were

taken and record other location information, providing more informative analyses. The Maji-

Meter can be used to analyze both surface and ground water in a variety of settings such as

rivers, lakes, industrial systems, wells and bore-holes.

Figure 9: A representation of Maji-Meter

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2.8. ANALYTICAL BALANCE

Procedure for daily use

i. Press ON/OFF button once to turn on the instrument

ii. Place a weigh boat on the balance pan. iii. Press the Tare control to zero the balance.

iv. Wait a few seconds until the reading has stabilized until the small box goes away v. Add the substance or chemical to be weighed. vi. Wait until the reading stabilizes and the small box goes away.

vii. Record the results.

Maintenance

i. The balance is calibrated annually with a standard set of weights by UNBS

ii. At the first time of weighing every day, a standard mass (5g) is used for verification. This helps to tell the need and agency for calibration. This acts as a quality control

(QC)measure Figure 10: A representation of an Analytical balance

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2.9. KJELTEC SYSTEM

The Kjeltec Distillation Unit provides a simple and reliable solution for safe and semi-

automatic distillation. The procedure for its use is elaborated in the experiment for protein

digestion.

Figure 11: A representation of a Kjeltec system

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CHAPTER THREE: ANALYSIS

3.1. FOOD ANALYSIS

EXP 1: DETERMINATION OF ASH CONTENT

Ash content is a measure of minerals in the food. Ash refers to the inorganic components

remaining after either ignition or complete oxidation of organic matter in a foodstuff. The

importance of Ash in Food analysis is to proximate the nutritional evaluation and it is the

first step in the preparation of food sample for specific elemental analysis.

Mineral content is a measure of the amount of specific inorganic components present within

a food, such as Ca, Na, K and Cl. Determination of the ash and mineral content of foods is

important for the following reasons:

Nutritional labeling: The concentration and type of minerals present must often be

stipulated on the label of a food.

Quality: The quality of many foods depends on the concentration and type of

minerals they contain, including their taste, appearance, texture and stability.

Microbiological stability: High mineral contents are sometimes used to retard the

growth of certain microorganisms.

Nutrition: Some minerals are essential to a healthy diet (e.g. Calcium, phosphorous,

potassium and sodium) whereas others can be toxic for example lead.

There are two types of ashing used that is;

1) Dry Ashing: it refers to the use of a muffle furnace that is capable to maintain

temperatures of 500-600°C. Water and volatiles are vaporized and organic substances

are burned in the presence of oxygen in air to CO2, and oxides of N2. Most minerals

are converted to oxides, sulfates, phosphates, chlorides, and silicates.

2) Wet Ashing; this is a procedure for oxidizing organic substances by using acids and

oxidizing agents or their combinations. Minerals are solubilized without

volatilization. Wet ashing is often preferable than dry ashing as a preparation for

specific elemental analysis.

PROCEDURE

The weight of the crucible was first determined and recorded. 5g sample were weighed into a

tarred crucible and then heated first to evaporate the volatile matter. The crucibles were

placed in muffle furnace. Their order of arrangement in the furnace was recorded. The

furnace was ignited for 6 hours at 550oC.The muffle furnace was turned off and later opened

when the temperature had dropped to 250oC. The sample in crucible should be completely

white with no black spots. Using safety tongs, the crucibles were removed, re-labeled using

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the recorded arrangement and transferred to a desiccator and allowed to cool prior to

weighing. After cooling the sample was weighed and results recorded in the work book.

NOTE

1) If carbon is still present following initial incineration, add several drops of water or

nitric acid; the sample should be re ashed. If the carbon persists, such as with high

sugar samples follow this procedure;

Suspend the ash in water and filter through ash less filter paper because this residue tends

to form a glaze. Dry the filtrate Place paper and dried filtrate in muffle furnace and re dry

2) Warm crucibles will heat air in the desiccator. With hot samples, a cover may bump

to allow air to escape. A vacuum may form on cooling. At the end of the cooling

period, the desiccator cover should be removed gradually by sliding to one side to

prevent a sudden in rush of air. Covers with ground glass sleeve or fitted for a rubber

stopper allow for slow release of vacuum.

TABLE OF RESULTS

Sample ID: 166/2014

Replicate 1 Replicate 2 Replicate 3

Weight of crucible (g) 61.9818 67.8837 67.1456

Weight of sample (g) 5.0021 5.0057 5.0021

Weight of sample + crucible (g) 62.2274 68.1269 67.3158

TREATMENT OF RESULTS

Weight of Ash = (Weight of Ash + crucible) - weight of crucible

Percentage of Ash = weight of Ash

weight of sample x 100%

Replicate 1

Weight of Ash = (62.2274 – 61.9818)

= 0.2456g

Percentage of Ash = 0.2456g

5.0021g x 100%

= 4.91%

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Replicate 2

Weight of Ash = (68.1269– 67.8837)

= 0.2432g

Percentage of Ash = 0.2432g

5.0057g x 100%

= 4.86%

Replicate 3

Weight of Ash = (67.3158– 67.1456)

= 0.1702g

Percentage of Ash = 0.1702g

5.0021g x 100%

= 3.40%

Calculation of mean percentage

Mean =∑𝒙

𝒏 =

(𝟒.𝟗𝟏+ 𝟒.𝟖𝟔+𝟑.𝟒𝟎)

𝟑= 𝟒. 𝟑𝟗%

Calculation of standard deviation

Percentage X Deviation (X— X ) Square deviation (X— X )2

4.91 0.52 0.2704

4.86 0.47 0.2209

3.40 -0.99 0.9801

∑ (X— X )2 = 1.4714

Standard deviation = √(∑(X— X )2)

𝒏−𝟏

=√(1.4714)

𝟐= 𝟎. 𝟖𝟓𝟕𝟕%

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Calculation of Relative standard deviation (RSD)

RSD = 𝑺𝒕𝒂𝒏𝒅𝒂𝒓𝒅 𝒅𝒆𝒗𝒊𝒂𝒕𝒊𝒐𝒏

𝒎𝒆𝒂𝒏 =

(0.8577)

4.39 x 100%

RSD = 19.54%

RECOMMENDATION

The experiment should be repeated because the relative standard deviation is greater than 5%

(RSD > 5%)

EXP 2: DETERMINATION OF FAT CONTENT USING SOXHLET METHOD

Total Fat refers to the sum of triglycerides, phospholipids, wax ester, sterols and minor

amount of non-fatty materials

Apparatus

Extraction unit 1043 Soxtec System HT6 - service unit 1046, Soxtec System HT6

Extraction cups

Cup holder

Tongs for extraction cups

Thimbles and adapters

Reagents - petroleum ether

PROCEDURE

PREPARATION OF ALUMINIUM CUP

The aluminium cup was first washed with acetone and rinsed with distilled water

The aluminium cup was dried in an oven for 5 hours.

The dried aluminium cups were kept in a desiccator ready for use.

PREPARATION OF SAMPLE

2g of dried sample were weighed out accurately into a cellulose thimble of already

determined dry weight. Care was taken not to spill sample powder outside thimble. A

thimble was then placed in an aluminium cup.

SETTING UP THE EXPERIMENT

A thin layer of cotton wool was placed on top of the sample in the thimble.

The adapter was inserted on top of cotton wool in the thimble.

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On the extraction unit, the adjustable nob of each side of the unit was raised upward

and the thimbles (for two samples) were attached in their positions tightly.

The knobs were lowered to allow thimbles to lift up and give space for fixing the

aluminium cups.

60ml of petroleum ether were measured in a measuring cylinder and transferred to

each of the aluminium cups.

The rubber ring was placed on each of the aluminium cups.

Each cup was placed on top of the extraction hot plates and then adjusted using the

lower knobs so as to attach each cup under its corresponding thimble as labeled, that

is, 1 for 1, or 2 for 2.

The upper adjustable knob was raised in the boiling position so as to allow the

thimble units get inserted into the petroleum ether (solvent) in each aluminium cup

NOTE

1. Care is taken to ensure that all fittings are air tight

2. Aluminium cups must not be interchanged

The tubings connected from the service unit and tap (water) to extraction unit

were kept in position as required and air tight.

Tap water was opened, and confirmed that it flows to the condensing unit and

returns to the sink through drain.

STARTING TO RUN THE EXPERIMENT (boiling)

The mains of the service unit was switched on.

The extraction temperature was adjusted to 1000C and set the safety knob to

1500C.

The extraction process was monitored. Condensation of the solvent was seen

rolling down back to the sample through the extraction unit taps in open position.

When condensate was seen rolling down (checked by closing and opening taps

temporarily and leaving open), the timer was turned in the clockwise direction to

the 30minute mark so that boiling should run for 30minutes.At the end of boiling

time, timer rings while returning back to the 60/0 minutes mark.

RINSING

At the end of boiling, thimbles were raised out of the solvent by pressing the

upper buttons to the RINSE position.

Timer was immediately set to 30 minutes.

At the end of the rinse time (30 minutes), taps of extraction unit were closed to

stop solvent from condensing through the thimbles.

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Solvent was left to condense and collect above the taps at the base of the

condenser. This process was left to run until no more solvent was condensing.

DRYING RESIDUE AND EVAPORATION OF SOLVENT

The compressed air valves were raised upward to open them (on the extraction

unit).

On the service unit, compressed air supply was switched on and set timer15

minutes.

NOTE: compressed air facilitates drying of the residue in the thimbles and evaporation

of the solvent further from the thimbles and aluminium cups

CLOSING DOWN

At the end of drying, compressed air was switched off, air taps closed, power

switched off, and the flow rate of the cooling water reduced.

The apparatus was left to cool for 15 minutes

Cooling water was turned off completely.

Aluminum cups were removed carefully (should be having oil).

The cups were put in the oven, set at 1050C, and left to dry for two hours.

At the end of 2hours, oven was switched off and left to cool to 400C without

opening its door.

At 400C, the cups were removed, put in the desiccator, and left to cool in there for

exactly 30 minutes.

At the end of 30 minutes, each cup was weighed, obtaining weight W3

The percentage fat content in food samples was determined using the following

formula;

% fat = (W3 − W2)

W1 x 100

Where W3= Weight of extraction cup + residue weight (g)

W2 = Weight of extraction cup (g)

W1 = original sample weight (g)

TABLE OF RESULTS

Dry weight of cup (W2) (g) No.1 No.2

38.7855 38.6098

Weight of the sample (W1) (g) 3.0094 3.0016

Weight of cup + residue weight (W3) (g) 39.1003 38.8828

Weight of Oil (g) 0.3148 0.273

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TREATMENT OF RESULTS

% fat = Weight of Oil

Weight of Sample x 100%

Replicate 1

% fat = 0.3148

3.0094 x 100%

% fat = 10.46%

Replicate 2

% fat = 0.273

3.0016 x 100%

% fat = 9.10%

Calculation of mean percentage

Mean =∑𝒙

𝒏 =

(10.46+9.10)

2= 9.78%

Calculation of standard deviation

Percentage X Deviation (X— X ) Square deviation (X— X )2

10.46 0.68 0.4624

9.78 0.68 0.4624

∑ (X— X )2 = 0.9248

Standard deviation = √(∑(X— X )2)

𝒏−𝟏

=√(0.9248)

𝟐−𝟏= 𝟎. 𝟗𝟔𝟏𝟕%

Calculation of Relative standard deviation (RSD)

RSD = 𝑺𝒕𝒂𝒏𝒅𝒂𝒓𝒅 𝒅𝒆𝒗𝒊𝒂𝒕𝒊𝒐𝒏

𝒎𝒆𝒂𝒏 =

(0.9617)

9.78 x 100%

RSD = 9.83%

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Recommendation

The RSD is greater than 5% because one of the sides of the Soxtec machine leaks so the

petroleum ether used for extraction leaks which leads to low mass of the fat extracted. Thus

replicate 1 result is the correct one.

EXP 3: DETERMINATION OF MOISTURE CONTENT IN FOOD SAMPLES

PRINCIPLE

Moisture determination is one of the most important analyses performed on a food sample

and yet one of the most difficult from which to obtain accurate and precise data.

The dry matter that remains after moisture removal is referred to as Total solids. This

analytical value is of great economic importance to a food manufacturer because water is

inexpensive filler.

Moisture is a quality factor in the preservation of some food products and affects the food

stability for example, in dried milks and dehydrated vegetables and fruits.

Computation of nutritional value of foods requires that you know the moisture content.

Moisture data are used to express results of other analytical determinations on a uniform

basis (such as, dry weight basis)

EQUIPMENT AND MATERIALS

Usual laboratory apparatus not otherwise specified, and the following items

o Electric drying oven

o Petri dishes

PREPARATION OF GLASSWARE

The glassware were washed and rinsed with distilled water.

Dry glassware was placed in electric oven for 4 hours at1050c

Glassware were removed from the oven and then cooled in the desiccator for 30

minutes

After 30 minutes, the glassware was weighed and recorded the weights respectively.

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PROCEDURE

5g of sample was weighed into the petri-dish. The sample was heated in an electric oven for

4hours set at 1050C. After, the sample was removed from the electric oven then transferred to

the desiccator to cool to room temperature for 30 minutes. After the sample and the petri-dish

were weighed results recorded.

The moisture content calculations were determined using the formula

%moisture = 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑤𝑒𝑡 𝑠𝑎𝑚𝑝𝑙𝑒−𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑑𝑟𝑦 𝑠𝑎𝑚𝑝𝑙𝑒

𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑤𝑒𝑡 𝑠𝑎𝑚𝑝𝑙𝑒 ×100

% Total solids =𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑑𝑟𝑦 𝑠𝑎𝑚𝑝𝑙𝑒

𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑤𝑒𝑡 𝑠𝑎𝑚𝑝𝑙𝑒 ×100

PRECAUTIONS TAKEN

These were taken to minimize unintended moisture losses or gain that occurs during these

steps. Any exposure of the sample to the open atmosphere should be as short as possible.

Any heating of the sample during grinding should be as short as possible. Head space in the

sample storage container should be minimal because the moisture is lost from the sample to

equilibrate the container environment against the sample.

TABLE OF RESULTS

Sample ID: 166/2014

Replicate 1 Replicate 2 Replicate 3

Weight of dry petri dish (g) 98.3656 86.3502 95.1140

Weight of sample (g) 5.0008 5.0002 5.0020

Weight of sample + dish (g) 102.8194 90.8057 99.5736

Sample ID: 167/2014

Replicate 1 Replicate 2 Replicate 3

Weight of dry petri dish (g) 95.0000 90.1142 90.1140

Weight of sample (g) 5.0011 5.0012 5.0024

Weight of sample + dish (g) 99.4652 94.5803 94.5821

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TREATMENT OF RESULTS

Weight of Dry sample = (Weight of dry sample + dish) - weight of dry petri dish

Replicate 1

Weight of dry sample = 102.8194 – 98.3656

= 4.4538g

Percentage moisture = weight of wet sample−weight of dry sample

weight of wet sample x 100%

Percentage total solids = weight of dry sample

weight of wet sample x 100%

Percentage moisture =(5.0008 −4.4538)g

5.0008g x 100%

= 10.94%

Percentage total solids = 4.4538

5.0008 x 100%

= 89.06%

Replicate 2

Weight of dry sample = 90.8057 – 86.3502

= 4.4555g

Percentage moisture =(5.0002 −4.4555)g

5.0002g x 100%

= 10.89%

Replicate 3

Weight of dry sample = 99.5736 – 95.1140

= 4.4596g

Percentage moisture =(5.0020 −4.4596 )g

5.0020g x 100%

= 10.84%

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Calculation of mean percentage

Mean =∑𝑥

𝑛 =

(10.94+10.84+10.89)

3= 𝟏𝟎.𝟖𝟗%

Calculation of standard deviation

Percentage X Deviation (X— X ) Square deviation (X— X )2

10.94 0.05 0.0025

10.84 -0.05 0.0025

10.89 0 0

∑ (X— X )2 = 0.005

Standard deviation =√(∑(X— X )2)

𝒏−𝟏

=√(0.005)

𝟐= 𝟎.𝟎𝟓%

Calculation of Relative standard deviation (RSD)

RSD = 𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛

𝑚𝑒𝑎𝑛 =

(0.05)

10 .89 x 100%

RSD = 0.46%

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EXP 4: DETERMINATION OF VITAMIN A IN FORTIFIED FLOUR

METHOD: UV method

REAGENTS

Sodium chloride AR

2-propanolAR

Dichloromethane AR

n-heptane AR

PROCEDURE

Flour (27.0081g) was weighed into a 500ml Erlenmeyer conical flask, distilled water (100ml)

added and shaken vigorously for 5 minutes. 2-propanol (80ml) was added to the flask and

shaken vigorously for 5 minutes. n-heptane (50ml) was also added to the flask and shaken

vigorously for 5 minutes. Sodium chloride (5g) was then added to improve the separation and

then shake slightly. The solution in the flask was kept in dark room for 10minutes for

separation of phases. The top most organic phase was carefully removed using a Pasteur

pipette into a 50ml amber volumetric flask and made up to the mark using dichloromethane.

The contents in the 50ml amber volumetric flask were transferred into a 50ml centrifuge

tube. The tubes were placed into a centrifuge bucket and the centrifuge set at 1000 RPM for

ten minutes. After the tubes were removed from centrifuge and rapped using aluminium foil

to protect them from light. Using a Pasteur pipette the organic phase was carefully removed

and transferred into the UV spectrophotometer cuvettes and the absorbance read at 325nm.

Dichloromethane was used as the blank.

RESULTS AND TREATMNET

Sample ID 104/2014

Weight of sample (g) Absorbance

27.0081 0.8105 0.8123 0.8110

Sample ID 105/2014

Weight of sample (g) Absorbance

27.0084 0.4498 0.4494 0.4493

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Sample ID 108/2014

Weight of sample (g) Absorbance

27.0063 0.5300 0.5288 0.5269

Using the standard calibration equation obtained from vitamin A standard that is

y = 8.4937x + 0.0813 where,

y – Concentration and x- absolute absorbance

Absorbance corrected = Absorbance of sample – Absorbance of the blank

Absorbance of the blank = 0.0000

Sample ID 104/2014

Average absorbance = (0.8105 +0.8123+0.8110 )

3 = 0.8113

y = (8.4937x0.8113) + 0.0813

y = 6.9722

Retinol concentration = (6.9722 𝑋 50)

27 .0081 = 12.9077g/g

Sample ID 105/2014

Average absorbance = (0.4498 +0.4494 +0.4493 )

3 = 0.4495

y = (8.4937x0.4495) + 0.0813

y = 3.8992

Retinol concentration = (3.8992 𝑋 50 )

27 .0084 = 7.2185g/g

Sample ID 108/2014

Average absorbance = (0.5300 +0.5288+0.5269)

3 = 0.5286

y = (8.4937x0.5286) + 0.0813

y = 4.5708

Retinol concentration = (4.5708 𝑋 50)

27 .0081 = 8.4619g/g

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EXP 5: DETERMINATION OF β-CAROTENE

PIGMENT EXTRACTION OF β-CAROTENE ANALYSIS

This was carried out according to the method of the association of official chemist (AOAC,

1980). Into a conical flask containing 95% ethanol (50ml), macerated sample (10g) was

placed and maintained at a temperature of 70-800C in a water bath for 20 minutes with

periodic shaking. The supernatant was decanted, allowed to cool and its volume was

measured by means of a measuring cylinder and recorded as initial volume. The ethanol

concentration of the mixture was brought to 85 % by adding 15ml of distilled water and it

was further cooled in a container of ice water for about 5minutes. The mixture was

transferred into a separating funnel and 25ml of petroleum ether was added and the cooled

ethanol was poured over it. The funnel was swirled gently to obtain a homogeneous mixture

and it was later allowed to stand until 2 separate layers were obtained. The bottom layer was

run off into a beaker while the top layer was collected into a 250ml conical flask. The bottom

layer was transferred into the funnel and re-extracted with 10ml pet-ether for 5 times until the

extract became fairly yellow. The entire petroleum ether was collected into a 250ml conical

flask and transferred into a separating funnel for re-extraction with 50ml of 80% ethanol. The

final extract was measured and poured into sample bottles for further analysis.

MEASUREMENT OF ABSORBANCE

The absorbance of the extracts was measured using a spectrophotometer (model22UV/VIS)

at a wave length of 436 nm. A cuvette containing petroleum ether (blank) was used to

calibrate the spectrophotometer to zero point. Samples of each extract were placed in

cuvettes and readings were taken when the figure in display window became steady. The

operation was repeated 5 times for each sample and average readings were recorded. The

concentration of β-carotene was calculated using Bear- Lamberts law which states that the

absorbance (A) is proportional to the concentration (C) of the pigment as represented by the

equation:

A ∞L (if concentration (C) is constant)

A= ECL; C = 𝐴

𝐸𝐿

Where: C= concentration of carotene

A= absorbance

E= extinction coefficient

L= thickness of cuvettes (path length) = 1cm

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E of β-carotene = 1.25×104µg/L

Sample ID: TB Sample

Table Showing Absorbance of the Sample

Replicate Absorbance

1 0.0771 0.0795

2 0.0668 0.0642

Average Absorbance = (0.0771+0.0795)

2 = 0.0783

Concentration C = 𝐴

𝐸𝐿

Concentration C = 0 .0783

12500 𝑋 1

= 6.26 x 10-6

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PROXIMATE ANALYSIS OF FLOUR SAMPLE

Sample ID 178/2014

MOISTURE CONTENT DETERMINATION

Replicate 1 2 3

Weight of dry petri dish 85.8412 95.0268 87.1906

Weight of the sample 5.0013 5.0091 5.0007

Weight of the dry sample + petri dish 90.4325 99.6185 91.8278

Weight of the dry sample 4.5913 4.5917 4.6372

Moisture percentage 8.20 8.33 7.27

DETERMINATION OF ASH CONTENT

Replicate 1 2

Weight of dry crucible 61.9672 67.0590

Weight of the sample 5.0035 5.0016

Weight of the dry sample + crucible 62.0391 67.1304

Weight of the ash 0.0719 0.0714

% ash content 1.44 1.43

Average ash percentage 1.435

FAT CONTENT DETERMINATION

Replicate 1 2

Weight of dry aluminium cup 39.2008 38.7858

Weight of the sample 3.0028 3.0085

Weight of the oil + aluminium cup 39.3540 38.9309

Weight of the oil 0.1532 0.1451

% oil 5.10 4.82

Average percentage oil 4.96

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3.2. TOUR TO OTHER PRODUCTION DEPARTMENTS IN THE INSTITUTE

A TOUR TO THE DAIRY PROCESSING PLANT

The products produced include; fresh milk, butter, low fat yoghurt, gee and ice cream. The

production process starts with receiving and testing milk. Testing is usually done by boiling,

use of alcohol and use of lactometer. By boiling, contaminated milk clots and when alcohol

is used, it ferments. This is followed by passing the milk in the de-aerator which removes air

then filtering and cooling the milk to a temperature of 4 0C.

The cooling system is used for cooling water to 4 0C and the compressor is used for cooling

water. These are connected to pumps that cool the product in the cycle using water. Milk

cooling is necessary to preserve milk for a long period of time.

Pasteurizer: the milk passes the balance tank to the first chamber at 40-500C. The second

chamber is at 65-700C. The pasteurizer is used to homogenize the milk. It is then passed the

secondary plate heat exchanger which cools it from 750C to 40C and then sent to the

balance/pressure tank.

Packing machine is sterilized using ultra violet (U.V) light. It packs 1 and 1

2 liter packs at an

expiry date of 5 days. The packed milk is taken to the cooling room or chiller at a

temperature of 40C.

For the case of ice cream milk is put in the tank which is double jacket. Water is filled in the

jacket and milk is put at a temperature of 500C. Ingredients and sugar are added at this

temperature. The temperature is then raised to 900C. Useful bacteria are also added at this

stage. Flavors are added in the order strawberry followed by vanilla and lastly chocolate then

food color. The product is then placed in deep freezers or in the cold room for chilling

allowing it to cool to very low temperatures. They are then taken to the incubator where U.V

light is passed for sterilizing. Yoghurt is not heated to high temperatures because it has

important bacteria which help in the fermentation process

Cleaning process

Hot water at a temperature of 800C is mixed with 2% sodium hydroxide. The water is heated

by steam and the size of the tank is 500,000mL. Cleaning is done before and after

production.

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A TOUR TO THE FOOD PROCESSING PLANT

There are two sections involved that is training section and commercial section. Training

section involves students, entrepreneurs, product development. The products processed are

beef sausages, pork, chicken and vegetable sausages (which are still under research and

development). The challenge with vegetable sausages is that the water content is high so they

have to be first heated or dried. Salt is added to the sausages to enhance taste. Nitrate salts

added as sodium nitrate serve three uses; it improves taste, used to enhance color (reduces the

red color), finally used for preservation that is it prevents bacterial attack. In the production

rooms there are low temperatures to reduce on the susceptibility of microbial attack.

In the production process there are various unit operations such as size reduction of meat and

fat to form mist meat, meat mixing by the meat mixing machine. This is followed by bowl

cutter where ingredients are added. Animal fat is used mostly compared to vegetable fat

because animal fat has a high binding capacity.

Cleaning; this is done using liquid soap, jik, hot water. Perfumed detergents are not used.

Storage facilities; the processed product are kept at -180C and for raw materials they are

stored at 0 to -20C. The deep frozen product has a shelf life of a year.

The bowl cutter temperatures are controlled at 130C by adding some ice. This ice also

dissolves the ingredients added that is phosphate, common salt, garlic powder and ginger

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A VISIT TO THE JUICE PROCESSING PLANT

The raw materials processed include fruits and vegetables. Fruits are not attacked by bacteria

because they have a low P.H while vegetables have a high P.H. The section deals with

processing of wine, vegetables, juice both local and herbal. The following activities take

place;

a. Reception; the fruits are received and quality confirmatory tests are carried out for

example determining the sugar content by determining brix in juice, determination of

P.H (depends on the degree of ripeness), determination of titratable acidity citric acid

or malic acid, physical tests such as color, defects, hygiene of the truck delivering

them.

b. Weighing and sorting; this is intended to reduce bad ones from bad ones

c. Washing; this removes the physical dirt, and then rinsed with warm water and

disinfected with sodium metabisulphite 0.05%.

d. This is followed by peeling, slicing when the fruits are few.

e. Then the product is taken to the processing room where pulping occurs. This involves

the following machines.

1) Crusher; this acts as a big blender which should be first cleaned before use.

2) Passion pulper; this crushes passion, water melon and tomatoes

3) Pineapple and mango pulper and the holding tank for temporary storage and then to

the mixing tank

f. The product is then channeled to the blending tanks which are two each of 1000ml.

water, sugar, thickeners’ i.e. CMC, and stabilizers are added.

g. This is then directed to the de-aerator which removes air because air facilitates

oxidation which turns the juice brown. It is at a pressure of -0.02 to -0.06. This is then

directed to the balance tank.

h. This is then passed in the sterilizer (between 150 and 1200C) or pasteurizer below

900C. This is connected to the heat exchanger which acts in the counter current

direction.

i. This is then channeled to the homogenizer to prevent phase separation.

Packaging; this involves the buffer tank which removes juice at 400C which is connected

to the balance tank. This packs 1,1

2 and

1

4 liters. It has conveyer belts and sensors which

aid in packaging.

CIP (cleaning in place)

It uses the acid to remove acidic particles and after a base is passed to neutralize the

acidic P.H

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3.3. ANALYSIS OF FRUIT JUICES

EXP 6: DETERMINATION OF VITAMIN C

Vitamin C (ascorbic acid) is an antioxidant that is essential for human nutrition. Vitamin C

deficiency can cause a disease called scurvy, which is characterized by abnormalities in the

bones and teeth, many fruits and vegetables contain vitamin C but cooking destroys the

vitamin, so raw citrus fruits and juices are the main source of ascorbic acid for most people.

One way to determine the amount of vitamin C in food is to use a redox titration. The redox

reaction is better than an acid base titration since there are additional acids in juice, but few

of them interfere with the oxidation of ascorbic acid by iodine.

Iodine is relatively insoluble but this can be improved by complexing the iodine with iodide

to form tri-iodide.

I2 (aq) + I- (aq) ⇋ I3-(aq)

Tri iodide oxidizes vitamin C to form hydro ascorbic acid.

C6H8O6 + I3-(aq) + H2O (l) ⇋ C6H6O6 +I2 (aq) +2H+ (aq)

As long as vitamin C is present in the solution the tri-iodide is converted to iodide ion very

quickly. However, when all the vitamin C is oxidized iodine and tri-iodide will all be present

which reacts with starch to form a blue -black complex. The blue –black is end point of the

titration. The titration procedure is appropriated for testing the amount of Vitamin C in

vitamin C tablets, juices, and fresh, frozen, or packaged fruits and vegetables. The titration

can be performed using just iodine solution and not iodate, but the iodate solution is more

stable and gives a more accurate result.

Purpose

The goal of this laboratory exercise is to determine the amount of vitamin C in samples such

as fruit juice.

PROCEDURE

Preparing solutions

1% starch indicator solution

Soluble starch (0.5g) was added to distilled water and then heated to near boiling. The

solution was mixed well and allowed to cool before use.

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Iodine solution

Potassium iodide (5.0030g) and potassium iodate (0.2681g) were dissolved in distilled water

(200ml) and 3M sulphuric acid solution (30ml) was then added. This solution was poured

into a 500ml graduated cylinder and filled to the mark with distilled water. The solution was

mixed properly and then transferred to a 600ml beaker. The beaker was labeled as iodine

solution.

Vitamin C standard solution

Vitamin C (0.2509g) was dissolved in distilled water (100ml) in a 250ml volumetric flask

and then diluted to the mark. The flask was labeled vitamin C standard solution.

Standardizing solutions

Vitamin C standard solution (25.00ml) was added to Erlenmeyer flask and 1% starch solution

(10 drops) were then added. The burette was rinsed with small volume of the iodine solution

and then filled. The initial volume was recorded. The solution was titrated until the end point

was reached (when the first sign of the blue color that persists after 20 seconds of swirling

the solution).The final volume of iodine solution was recorded. The volume that was required

is the final volume minus the starting volume. The titration was repeated once. The juice

samples were exactly titrated the same way as the standard. The initial and final volume of

iodine solution required to produce the color change at the end point were recorded in the

table as shown below.

RESULTS AND TREATMENT

Mass of Ascorbic Acid = 0.2509g

Potassium iodide = 5.0030g

Potassium Iodate = 0.2681g

Starch = 1.0003g

Table of Results

Vitamin C standard

Volume of solution taken = 25ml

Replicate 1 Replicate 2

Final burette reading (ml) 27.80 30.30

Initial burette reading (ml) 9.20 11.80

Volume of iodine solution used (ml) 18.60 18.50

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Sample ID: 064/2014

Volume of solution taken = 25ml

Replicate 1 Replicate 2 Replicate 3

Final burette reading (ml) 8.50 9.60 10.60

Initial burette reading (ml) 7.40 8.50 9.60

Volume of iodine solution used (ml) 1.10 1.10 1.00

Sample ID: 065/2014

Volume of solution taken = 50ml

Replicate 1 Replicate 2 Replicate 3

Final burette reading (ml) 9.50 9.80 10.20

Initial burette reading (ml) 9.00 9.50 9.80

Volume of iodine solution used (ml) 0.50 0.30 0.40

Sample ID: 173/2014

Volume of solution taken = 50ml

Replicate 1 Replicate 2 Replicate 3

Final burette reading (ml) 11.80 12.10 12.50

Initial burette reading (ml) 11.50 11.80 12.10

Volume of iodine solution used (ml) 0.30 0.30 0.40

Sample ID: 174/2014

Volume of solution taken = 50ml

Replicate 1 Replicate 2 Replicate 3

Final burette reading (ml) 13.30 13.90 14.50

Initial burette reading (ml) 12.50 13.30 13.90

Volume of iodine solution used (ml) 0.80 0.60 0.60

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Sample ID: Orange

Volume of solution taken = 50ml

Replicate 1 Replicate 2 Replicate 3

Final burette reading (ml) 17.00 19.40 21.80

Initial burette reading (ml) 14.50 17.00 19.40

Volume of iodine solution used (ml) 2.50 2.40 2.40

TREATMENT OF RESULTS

Using the relation,

ml of Iodine solution in the standard

0.2509g of vitamin C =

ml of Iodine solution required for the sample

x g of vitamin C in the sample

Average volume of vitamin C standard = 18.60+18.50

2 = 18.55ml

Sample ID: 064/2014

Average volume of vitamin C in sample = 1.10+1.10+1.00

3 = 1.067ml

18.55ml

0.2509g of vitamin C =

1.067

x g of vitamin C in the sample

X =(1.067 x 0.2509

18.55 ) g = 0.0144g

Concentration of vitamin C = 0.0144g

0.025L

= 0.577g/L

Similarly the concentration of vitamin C in the samples were calculated and recorded in the

table below.

Sample ID Vitamin C concentration (g/L)

065/2014 0.1082

173/2014 0.09

174/2014 0.1803

Orange 0.658

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EXP 7: DETERMINATION OF TOTAL TITRATABLE ACID IN FRUIT JUICES

APPARATUS

Analytical balance

Burette

Conical flasks

Pipette

250ml volumetric flask

Filter paper whattman No.40

PROCEDURE

Juice samples (30ml) were measured, dissolved in distilled water in a 250ml volumetric flask

and topped up to the mark. The solution was filtered and the filtrate (100ml) titrated with 0.1

N sodium hydroxide using phenolphthalein as indicator. When the alkali is added a brownish

color might develop which may mask the end point. Add more distilled water and use more

indicator than is normally required. The end point should have light pink color.

RESULTS AND CALCULATION

Sample ID: 064/2014

Volume of solution taken = 100ml

Replicate 1 Replicate 2

Final burette reading (ml) 15.80 10.10

Initial burette reading (ml) 14.50 8.70

Volume of NaOH solution used (ml) 1.30 1.40

Sample ID: 065/2014

Volume of solution taken = 100ml

Replicate 1 Replicate 2

Final burette reading (ml) 18.80 21.80

Initial burette reading (ml) 15.80 18.80

Volume of NaOH solution used (ml) 3.00 3.00

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Sample ID: 173/2014

Volume of solution taken = 100ml

Replicate 1 Replicate 2

Final burette reading (ml) 15.50 16.40

Initial burette reading (ml) 14.20 15.40

Volume of NaOH solution used (ml) 1.30 1.00

Sample ID: 174/2014

Volume of solution taken = 50ml

Replicate 1 Replicate 2

Final burette reading (ml) 13.90 14.20

Initial burette reading (ml) 13.50 13.90

Volume of NaOH solution used (ml) 0.40 0.30

Sample ID: Orange

Volume of solution taken = 50ml

Replicate 1 Replicate 2

Final burette reading (ml) 22.80 15.00

Initial burette reading (ml) 16.40 8.90

Volume of NaOH solution used (ml) 6.40 6.10

Acidity as anhydrous citric acid =𝑡𝑖𝑡𝑟𝑒 𝑣𝑎𝑙𝑢𝑒 ×𝑛𝑜𝑟𝑚𝑎𝑙𝑖𝑡𝑦 𝑜𝑓 𝑎𝑙𝑘𝑎𝑙𝑖 ×64×𝑣𝑜𝑙𝑢𝑚𝑒 𝑚𝑎𝑑𝑒 𝑢𝑝×100

𝑚𝑙 𝑜𝑓 𝑓𝑖𝑙𝑡𝑟𝑎𝑡𝑒×𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑎𝑚𝑝𝑙𝑒×1000

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EXP 8: PROTEIN CONTENT DETERMINATION IN FRUIT JUICES

Principle

The sample is prepared which includes, grinding for solid samples, it is digested in

concentrated sulphuric acid and 1% copper sulphate (Kjeldahl) tab as catalyst, then

distilled in 40% sodium hydroxide, the ammonium liberated is absorbed in (4%) boric

acid having methyl red / bromocresol green as indicator and later titrated with 0.1N

hydrochloric acid or sulphuric acid.

The boiling temperature is elevated by addition of potassium sulphate. The elevated boiling

temperature is necessary to break the peptide bonds and convert amino groups in protein to

ammonium ions. A copper catalyst is added to enhance reaction rate. After digestion the

digest mix is diluted with water to avoid mixing concentrated alkali with concentrated acid

and to prevent the digest from solidifying. Ammonia is the liberated by alkaline distillation

and quantified by titration with standardized acid.

Reagents and materials

Concentrated sulphuric acid AR grade

Copper sulphate (CuSO4) AR grade

Sodium pellets, AR grade

Boric acid

Methyl orange indicator

Bromocresol green indicator

Distilled water

Lysine chloride – 99.9 % C11H12N2O2 or C6H15ClN2O2

Catalyst use copper tablets, kjel tabs

PROCEDURE

Digestion

The sample was added in the digestion tube followed by 1 tab of Kjeldahl catalyst,

and then concentrated H2SO4 (12ml).

Note: A similar digestion tube is set as blank i.e. without sample, and should go through

same treatment).

The content was shaken gently to “wet” the sample. The exhaust was positioned and

aspirator turned on. The digestion unit was turned on and temperature set at 410°C.

The digestion was allowed to run at this temperature for 1hour until the digestion tube

content became colorless, light blue or green. After digestion power was switched off

and unit allowed to cool down to 40 – 30°C.

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Distillation

Cooled digest was diluted with 50ml distilled water, and the tube fixed tightly at its

position in the distillation unit. 25ml of receiver solution (H3BO3) and 5 drops of

indicator (Methyl red / Bromocresol green) were added in a conical flask. The

conical flask was fixed at its position in the distillation unit ensuring that the tip of

plastic tube enters below the surface of the receiver solution.

Using the handle for alkali dispensing on the right hand of the distillation unit, 50ml

of 40% NaOH solution were added to the diluted digest to avoid over reaction.

Note: Need to mark off the 50ml level above the level of the diluted cooled digest on the

digestion tube.

The distillation apparatus was switched on. When boiling starts, timer was set to 4min

and steam immediately opened using the close-open button. When the bell of the

timer rings, then distillation is ending, when the bell stops ringing, power was

immediately switched off and steam closed. The set up was left for about 3minutes to

allow all the condensate to collect into the receiver solution. The plastic tubing was

rinsed with little distilled water into the receiver solution as the flask is being

removed.

Titration

The H3BO3 – HN3 solution was titrated in receiver flask with Standard 0.1N HCl (or 1M

HCl) or H2SO4 solution. End point was from light blue to pale yellow.

TABLE OF RESULTS

Sample ID 064 065 066 173 174

Weight of sample taken (g) 1.3395 1.6588 1.8092 1.7095 1.2247

Volume of HCl (ml) 0.45 0.40 1.45 0.40 0.30

%age nitrogen 0.0366 0.0253 0.1045 0.0246 0.0229

% age protein 0.2288 0.1584 0.6531 0.1537 0.1430

Blank titre =0.10ml

Concentration of the acid = 0.1N

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% Kjeldah nitrogen =(𝑉𝑠−𝑉𝑏 )×𝑁×14.01

𝑊 ×10

Vs. = ml of standardized acid used to titrate the sample

Vb =ml of standardized acid used to titrate the blank

N = normality of standard HCl

14.01= atomic weight of nitrogen

W= weighted the sample or standard

10 = factor to convert nitrogen to protein mg/g percent

The % age crude protein is calculated according to the formula below.

% age crude protein = % Kjeldah nitrogen x F

F – Factor used to convert nitrogen to proteins. Factors are;

6.25 – feeds, meat, and other samples not specified

5.70 – wheat

Sample calculation

Sample ID: 064/2014

% Kjeldah nitrogen =(𝑉𝑠−𝑉𝑏 )×𝑁×14.01

𝑊 ×10

= (0.45−0.10)×0.1×14.01

1.3395×10

= 0.0366%

% age crude protein = % Kjeldah nitrogen x F

= 0.0366 x 6.25

= 0.2288%

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3.4 SOAP ANALYSIS

EXP 9: DETERMINATION OF pH VALUE OF SOAP SAMPLE

1.0ml of the test sample was dissolved in 100mls of distilled water and the pH measured at

room temperature, using a pH meter equipped with a glass electrode capable of measuring

pH values with an accuracy of 0.1

RESULTS

Sample ID A B

Replicate 1 2 1 2

pH of soap 6.24 6.23 2.94 2.91

Temperature (0C) 25.8 25.8 25.5 25.5

Average PH 6.236 2.925

EXP 10: DETERMINATION OF INORGANIC SALTS

PROCEDURE

The sample (5.0060g) was weighed into a crucible and placed on a heating mantle to

evaporate volatile matter. After evaporation, the crucibles are placed in a muffle furnace set

at 4500c for 6 hours. The dish and its contents were cooled and a few drops of concentrated

sulphuric acid added. The mixture was then heated again to dryness, cooled and weighed.

The process of heating, cooling and weighing was repeated until constant mass was obtained.

The experiment was then repeated with another replicate of 5.0119g and another sample.

RESULTS AND TREATMENT

Sample A

Replicate 1 Replicate 2

Weight of crucible + sample

before heating (g)

127.8244 121.2784

Weight of crucible (g) 122.8184 116.2668

Weight of sample (g) 5.0060 5.0119

Weight of Ash + crucible (g) 123.0380 116.4861

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Sample B

Replicate 1 Replicate 2

Weight of crucible + sample

before heating (g)

130.1164 130.5936

Weight of crucible (g) 125.1072 125.5809

Weight of sample (g) 5.0092 5.0127

Weight of Ash + crucible (g) 125.3630 125.8349

The inorganic salts content is given, as a percentage by mass, by the formula

(𝑀1 − 𝑀3)

(𝑀1 − 𝑀0) × 100

Where MO is the mass in grams of the dish

M1 is the mass in grams of the dish and the sample before heating

M3 is the mass in grams of the dish and the residue

Sample A

Replicate 1

% inorganic solids = (127 .8244−123.0380

127 .8244−122.8184 ) 𝑥100%

= 95.61%

Replicate 2

% inorganic solids = (121 .2784−116.4861

121 .2784−116.2668 ) 𝑥100%

= 95.62%

Calculation of mean percentage

Mean =∑𝒙

𝒏 =

(𝟗𝟓.𝟔𝟏+𝟗𝟓.𝟔𝟐)

𝟐= 𝟗𝟓.𝟔𝟏𝟓%

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Calculation of standard deviation

Percentage X Deviation (X— X ) Square deviation (X— X )2

95.61 -0.005 0.000025

95.62 0.005 0.000025

∑ (X— X )2 = 0.00005

Standard deviation = √(∑(X— X )2)

𝒏−𝟏

=√(0.00005)

𝟐= 𝟎. 𝟎𝟎𝟓%

Calculation of Relative standard deviation (RSD)

RSD = 𝑺𝒕𝒂𝒏𝒅𝒂𝒓𝒅 𝒅𝒆𝒗𝒊𝒂𝒕𝒊𝒐𝒏

𝒎𝒆𝒂𝒏 =

(0.005)

94 .615 x 100%

= 0.0053%

Sample B

Replicate 1

% inorganic solids = (130 .1164−125.3630

130 .1164−125.1072 ) 𝑥100%

= 94.89%

Replicate 2

% inorganic solids = (130 .5936 −125 .8349

130 .5936 −125 .5809 ) 𝑥100%

= 94.93%

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USING THE SAME PROCEDURE

Mean = 94.91

Standard deviation = 0.02%

RSD = 0. 0211%

3.5. WATER ANALYSIS

Water was basically analyzed using the multi-probe Maji meter which analyses pH,

Turbidity, electrolytic conductivity (EC), dissolved oxygen (DO), total dissolved solids

(TDS), Altitude, latitude and longitude.

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CHAPTER FOUR: RECOMMENDATIONS, CONCLUSION AND

REFERENCES

4.1. LIST OF SKILLS ACQUIRED

I acquired new knowledge and practical experiences for example in handling different

lab equipment and carrying out different tests such as protein analysis, fat

determination moisture determination, ashing, among others which improved my

confidence in problem solving.

I obtained skills in relating with employees and different class of people as the

organization had a wide category of people.

I also obtained time management skills because we were supposed to reach in time

during the course of training.

I was able to apply the principles and techniques theoretically learnt in class into real-

life problem solving situations carried out in the laboratory.

I acquired practical skills in operation and safety of laboratory apparatus and

machines involved in activities of an operational environment, and perfecting in

various operating techniques, for example operating an Atomic Absorption

Spectrophotometer.

I managed to perform individual assignments on how to conduct experiments and

operating equipment when performing laboratory activities or tests.

4.2. RECOMMENDATIONS

A. To The Organization (UIRI)

More glass ware or apparatus should be provided for example the test tubes and

burettes for efficiency at work

Adopting a practice of weekly rotations in other related sections other than just a one

day tour. This will ensure an appropriate training for example in production systems

where unit operations are very common.

Repair of the un-functional equipment and replacement of broken glass ware which

may lead to accidents of glass cuts and toxic reagents harming the personnel handling

the experiment.

Implementation of systems and processes that may improve on the trainee’s skills, for

example planning in advance the work to be carried out in a week. This ensures a

better understanding of the experiments to be worked on since there is time to

research before carrying out the experiments, and delegation of work this will ensure

responsibility and time management of the trainees.

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B. To The University

Providing marks allocation forms to the organizational supervisor such that they can

also allocate marks because they understand students better since they usually work

with them daily

Increasing on the number of pages of the log book because the space where to write

the daily activities was not enough.

Introduction of course unit(s) about research project such that students are acquainted

with enough information about the research project.

4.2. CONCLUSION A lot of experience has been acquired in this training period most especially food, water, and

soap analyzes which are very important in my career. Also I got a chance to see the relevant

unit operations which exist in other sections of the organization such as dairy and fruit

production section. It also improved on my interpersonal skills on how to relate with fellow

workmates, proper record keeping, as well as time management.

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4.3. REFERENCES

Pearson D, Melon H. K, and Ronald S, (1976). Chemical Analysis of Food. (8th edition).

Churchill Livingstone. (Pages 60-63).

Kirk, R.S. and Sawyer, R. (1991): Pearson's Composition and Analysis of Foods, Longman

Scientific and Technical. 9th Edition, England.

Ranganna, S. (1986): Handbook of Analysis and Quality Control for Fruit and Vegetable

Products, 2nd edition, Tata McGraw Hill Publishing Co. Ltd., New Delhi.

G.H.Jeffery, J.Bassett, Mendham, R.C.Denney, (1989) Vogel’s Text book of Quantitative

Chemical Analysis, 5th Edition, Pearson Edu.ltd.Singapore.

William T. Hall. (1916). Analytical Chemistry. “Quantitative Analysis”. (Volume 1).

Chapman and Hall. John Wiley and Sons, Inc. London. New York.

Lehninger. A. (1993). Principles of Biochemistry. (3rd edition). Worth publishers. New York.

(Pages 184-185).

Dyke S. F. (1960). The Carbohydrate. (Volume 5). Inter science Publishers. New York.

(Pages 120-125).

www.labpro.co.uk/pHmeters/technical2012 European Instrumentation on 22/July/2014 at

9:50am.

http://www.uiri.0rgwednesday,01/october/2014.09:07.

Britton G. (1995). Carotene. www.microsoftencarta/carotene.com. 27/June/2014 04:00pm

http://en.wikipedia.org 02/August/2014 03:00pm

http://www.biocompare.com/Lab-Equipment/7929 02/August/2014 03:05pm

http://sellwoodsoap.wordpress.com 12/August/2014 02:00pm

http://www.bris.ac.uk/nerclsmsf/techniques/gcms.html 12/August/2014 02:00pm

Association of Official Analytical Chemists International. (1995). Official Methods of

Analysis of AOAC International. (16th edition). Method 4.1.10 (942.015), AOAC

International. Maryland. United States of America.

Atomic Absorption Spectroscopy. “Analytical methods”. (1996). Perkin-Elmer Corporation.

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APPENDIX

STANDARD MARK

Uganda Industrial Research Institute Logo

STANDARD OPERATING PROCEDURES (S.O.PS)

a) WORK INSTRUCTION FOR ANALYSIS OF RECEIVED SAMPLES

This S.O.P explains the procedure for analyzing samples after reception in the laboratory in

order to ensure systematic analysis, record keeping and good results. This is to ensure that

analysis for all samples is done in a traceable manner and that all received samples are

analyzed using appropriate methods

PROCEDURE

- Check in the sample reception book for any pending sample for analysis

- Pick the sample from the sample cabinet

- Use the suitable valid method according to the List of methods

- Prepare your personal work book for recording results.

- Run the experiment as per the method selected

- Record the observations and results as per work instruction UIRI/CHEM/SOP/05.

- Return used apparatus, equipment and reagents to their storage areas as per Lab ware

storage list.

- Clean your work bench

- Hand over your results for calculation and checking as per work instruction

UIRI/CHEM/SOP/06.

b) WORK INSTRUCTIONS FOR CLEANING LABORATORY EQUIPMENT.

Cleaning equipment requires a special level of safety awareness. Keep these things in mind.

Read and follow all instructions on the equipment you are handling.

Unplug equipment from power and water supply.

Read safety requirements for the equipment

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The aim of this SOP is to keep all equipment clean and in safe working environment. This

improves performance of equipment

PROCEDURE

Unplug the equipment from power and water supply.

Wear protective gloves

Dust equipment with a dry towel.

Dust the equipment table.

Use a moist towel previously dipped in dilute liquid soap to clean the equipment

Wipe the equipment completely dry with a dry towel.

Record and sign in the equipment log book.

Obtaining 3M sulfuric Acid used in vitamin C determination

Molarity = % Assay x Density

RFM x 1000

= 96.5

100 x

1.84

98.08 x 1000

Molarity of the stock solution = 18.1036M

Using the relation,

Concentration of conc solution x volume = concentration of dilute solution x volume

C1V1 = C2V2

18.1036 x V1 = 3 x 50

V1 = 3 x 50

18.1036 = 8.29ml

Therefore 8.29ml of the stock solution was taken and diluted to the 50ml mark using distilled

water.

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WASTE MANAGEMENT

Waste produced Management

Water Drained in septic tank

Ash Poured into bins and collected by waste removal

company

Alcoholic beverage solutions and

soft drinks

Collected, diluted and poured down the drain

Residual samples for example flour

grains

Removed from their packaging, poured into bins and

collected by a contracted waste removal company

Solutions of acids used (nitric,

hydrochloric, sulphuric, caustics among others)

Diluted adequately with water and poured in the

septic tank

Broken glass Collected in one container later taken by the waste removal company

Empty reagent containers (glass and

plastic)

Collected by waste removal company