Principles of Rice Processing

PRESENTED BY UMAR ADAMU WAZIRI B.TECH (HONS) ED. AGRIC TECHNOLOGY

CHAPTER ONE

INTRODUCTION AND THE BACKGROUND OF STUDY

1.0 INTRODUCTION ON SIWES

Student Industrial Work Experience Scheme (SIWES) is

an acceptable skills training programmed for student

in tertiary Institutions, at district levels to

acquire practical knowledge and experience in their

various fields of specialization. It is an effort

taken to bridge the gap between theoretical concepts

in the scientific world.

As part of the minimum academic standard, the

programmed enhance professional ethics, experience,

technological skills of students and revitalize the

employers contact with students and involvement in

the educational system.

1.1 THE OPERATORS OF SIWES PROGRAMME ARE:-

Agric Technology Education (Modibbo Adama University of Technology Yola) Page 1


Industrial Training Fund (ITF)

Supervising Agents, for example the Nigerian

University Commission (NUC).

The participants in the SIWES programmed are:-

Universities, includes Federal, state and

private Universities.

Polytechnics; includes Federal, state and

private polytechnics.

Colleges of Education; includes federal, state

and private colleges of educations.

1.2 BRIEF HISTORY OF SIWES/ITF

The Industrial Training Fund (ITF) was established

by the decree of October 1971 No.48 and was financed



by the Federal Ministry of commerce and industries.

Student Industrial Work Experience Scheme (SIWES)

was introduced to the higher institutions in the

year 1974 through the help of the Industrial

Training Fund (ITF) aimed at promoting the

acquisition of Indigenous skills and expertise

sufficient to meet the ever growing skilled manpower

need of the nation’s economy.

The Student Industrial Work Experience Scheme came

in to existence as a result of various researches

carried out at that time. The findings of

researchers revealed that majority of the expertise

in Nigeria’s indigenous industries were mostly

imported (expatriate workers), Hence there was a

strong need of developing these much needed

manpower, skills and expertise locally for our

Indigenous industries and economy to thrive.



The activities of the fund are controlled from its

national headquarters in Jos, Plateau State of the

country.

1.3 REPORT PROBLEMS

Statement of problems: It has been evident that only

few students that graduate from Nigerian Tertiary

Institutions have industrial skills and experience

relevant to their field of study. This is the

aftermath of the gap between the theoretical aspect

and practical aspect of learning.

1.4 AIMS AND OBJECTIVES OF STUDENT WORK EXPERIENCE

SCHEME (SIWES)

AIM OF SIWES

The aim of SIWES is to train students in the

acquisition of professional skills, development of



their practical ability and exposing them to the

industrial world.

OBJECTIVES OF SIWES

To enable students acquire practical skill and

experience.

To provide an opportunity for students to apply

the theoretical knowledge gained in their

tertiary institutions to practical situations

and use the practical knowledge to supplement

their theoretical knowledge acquired in school.

To expose students to machines, equipments,

tools and professional work methods, techniques

and ways of safeguarding the work area and

workers in organizations and industries.

To develop indigenous skilled manpower in the

country.



Lastly, to immensely contribute to the

improvement of our indigenous industries and

other establishments with time as it equip and

prepare students for working society.

CHATER TWO

2.1 PLACE OF ATTACHMENT



I was attached to the Al-Uma Lau Rice Enterprise

(Rice Processing Factory) situated behind Taraba

State Universal Basic Education Board Jalingo from

10th June to 6th December, 2013, where I was posted

to the Production Unit and that afford me to gain

experience of the other sections of the Factory.

2.2 BRIEF HISTORY OF THE COMPANY

AL-UMA LAU is a private limited liability company

incorporated in Nigeria under the company and allied

matters decree 1990. On 23rd December, 2002 with

registration number RC: 469372 and NAFDAC Number A1-

4964.

The company is situated behind Taraba State

Universal Basic Education Board Jalingo. Board

Members are season farmers in crops and rice

production in particular. It is this experience of



the board members and staff that stimulated the

expansion of the rice processing factory through

large scale mechanized farm for the company and

financing the out growers with support from the

Federal Government Rice Transformation Agenda

implemented by His Excellency President Goodluck

Ebele Jonathan.

The Rice Transformation provides improved high breed

seeds and fertilizers to the teaming Rice farmers in

Taraba State for production of high quality paddy

for processing in AL-UMA LAU Rice Processing Factory

in Jalingo the headquarter of Taraba State and to

all rice mills in the state.

Fig 1 premises of the company.

2.3 INCENTIVES TO CUSTOMERSAgric Technology Education (Modibbo Adama University of Technology Yola) Page 8


1. 4% discount for the purchase of 100 bags of

50kgs and above

2. Free transportation to customer’s destination

for purchase of 500 bags of 50kgs and above.

2.4 DEVELOPMENT AND RE-CIRCULATION OF BI-PRODUCTS

The company used the bi-product as:

1. Use of bi-product for organic fertilizers

2. Straw from the harvested rice plants is used as

bedding for livestock.

3. Oil extracted from discarded rice bran is used

in livestock feed.

4. Hulls are used to produce mulch that will

eventually be used to recondition the farm soil.

5. Supply of bi-product to customers as per

requirements.



FIG 2 This is hulls, chaff, and straw outlet directly from

the milling machine.

2.5 OBJECTIVES OF THE COMPANY

The aims and objectives of Al-Uma Lau Nigeria

Enterprises Limited are as follows:

1. To carry on the business of food processing,

rice cultivation and agricultural mechanization.

2. To carry on the business as trades, buyers and

sellers in industrial agricultural products.

3. To carry on the business of arable and fruits

farming, millers and manufacturers of cereal

products.

4. To undertake commercial agriculture inclusive of

ranching, poultry, piggery and livestock



breeding generally and to rear all types of

birds, animals, fish and other marine products.

5. To create employment opportunities and to

improve the standard of living of the people.



2.6 ORGANOGRAM OF AL-UMA LAU NIG. ENTERPRISES LTD

KEY:

P.O Purchasing OfficerS Sales Person


Production Manager

Finance Manager

Directors

Secretaries

SalesManager

ChiefEngineer

P.O S S S

T.A

PP P P F.A

ManagingDirector


T.A Training AssistantP Production WorkerF.A Finance Assistant

CHAPTER THREE

RICE PROCESSING

3.1 INTRODUCTION

Rice is the seed of the monocot plants Oryza

sativa (Asian rice) or Oryza glaberrima (African rice).

As a cereal grain, it is the most widely

consumed staple food for a large part of the world's

human population, especially in Asia. It is the

grain with the second-highest worldwide production,

after corn, according to data for 2010.

Since a large portion of maize crops are grown for

purposes other than human consumption (as green

manure and forage) etc; rice is the most important



grain with regard to human nutrition and caloric

intake, providing more than one fifth of

the calories consumed worldwide by humans.

Genetic evidence has shown that rice originates from

a single domestication 8,200–13,500 years ago, in

the Pearl River valley region of China. Previously,

archaeological evidence had suggested that rice was

domesticated in the Yangtze River valley region in

China. From East Asia, rice spread to Southeast and

South Asia. Rice was introduced to Europe, Africa

through Western Asia, and to the Americas through

European colonization.

CULTIVATION

Rice cultivation is well-suited to countries and

regions with low labor costs and high rainfall, as



it is labor-intensive to cultivate and requires

ample water. However, rice can be grown practically

anywhere, even on a steep hill or mountain area with

the use of water-controlling terrace systems.

Although its parent species are native to Asia and

certain parts of Africa, centuries of trade and

exportation have made it commonplace in many

countries worldwide.

3.2 HOW RICE IS PROCESSED

Rice milling is the process which helps in removal of

hulls and barns from paddy grains to produce polished

rice.

Rice in its basic form is known as “rough rice”

(Rice as it comes from the field) and is still

covered by a non-edible hull or husk. At the mill,

rough rice is processed through sorting machines

that clean the kernels and remove foreign matter.Agric Technology Education (Modibbo Adama University of Technology Yola) Page 15


The hull is then removed leaving brown rice with the

bran layers still surrounding the rice kernels.

Grains of brown rice may be milled by removing the

bran layers, revealing white rice. Because the most

nutritious layers of the rice grain have been

removed in the milling process, the white rice is

enriched to restore the original levels of thiamin,

niacin and iron.

Some of the rice is separated to go through an extra

initial processing step that will turn it into

parboiled rice. Parboiled rice is subjected to

steaming or parboiling while still a brown rice,

causing nutrients from the outer husk to move into

the grain itself.

3.3 OBJECTIVE OF COMMERCIAL MILLING

A commercial rice miller will have following

objectives:



- produce edible rice that appeals to the

customer, that is rice that is sufficiently

milled and free of husks, stones, and other

non-grain materials

- maximize the total milled rice recovery out of

paddy minimize grain breakage

3.4 EQUIPMENT USED BY THE COMPANY

1. Commercial Rice Milling Machine: This is the major

machine found in the company. It has seven

elevators that served different functions.

Elevator I: Carry up the parboiled or un-

parboiled paddy from deep hole into the paddy

cleaner – De-stoner where all foreign objects

like stones are separated from the main grain.

Elevator II: Convey the paddy to the Rubber

Roll Piece Huller where the husk is separated

from clean paddy.



Elevator III: After husk is separated from the

clean paddy, then it is conveyed to paddy

separator to separate the milled from un-milled

grain. The milled grain moves to the next

elevator while the un-milled return back to the

huller again for further milling.

Elevator: IV: This elevator conveys the brown

rice to the polisher where is it smoothened and

given a shine by passing it through a series of

rollers.

Elevator V: This passes the polished rice

(white rice) to the grader screen where the

grain will be sorted into 4 classes.

Elevator: VI: The great ‘A’ grain finally

passes through this elevator into the funnel

where weighing and bagging take place while the

other classes pass out from different outlets.



2. Dam: Is used for socking raw rice to remove all

dust and dirt thereby increasing it moisture

content.

3. Elevator: Is a machine used for carrying up the

socked rice from the dam into the cooking pot.

4. Boiler Tank: for boiling water so as to send the

steam to cook the brown rice fed into the

cooking pot.

5. Drying pan: Is used for drying the cooked paddy

through heat pressure from perforated holes.

6. Sewing Machine: This is a machine that is used

for sewing the bag of rice and it is powered by

generator.

7. Conveyor: This transferred the dried parboiled

rice to the milling machine for onward

processing.



Fig 3 Fig 4

De-stoner & HullerPolisher

Fig 5 Fig 6 Fig

7

Cooking Pot Side view

Conveyor



Fig 8 Fig 9 Fig 10

Length Grader Dam & Elevator

Sewing Machine

3.5 TERMINOLOGIES IN RICE PROCESSING

To understand the different objectives of ricemilling, one should know the following terms: Rough rice: Also called paddy rice. Rice as it comes

from the field. Rice kernels are still encased in

their inedible, protective hull.



Brown rice, husked rice or cargo rice: The least

processed form of rice. It has the outer hull

removed, but still retains the bran layers that give

it a characteristic tan color and nut-like flavor.

Brown rice is edible but chewier texture than white

rice. Cooking time of brown rice is longer than

milled rice

Milled rice: This is also called white rice, or rice

after milling which includes removing all or part of

the bran and germ from the rough rice.



Milling recovery: Total milled rice obtained out of

paddy; this is expressed as weight percentage of

milled rice (including brokens) obtained from a

sample of paddy. The maximum milling recovery is 69-

70% depending on rice variety, but because of grain

imperfections and the presence of unfilled grains,

commercial millers are happy when they achieve 65%

milling recovery. Some village type rice mills have

55% or lower milling recovery.

Milling degree: This is a measure of the amount of

bran removed from the brown rice.

Head rice: Milled rice with length greater or equal

to three quarters of the average length of the whole

kernel. It is often expressed on a % paddy or rough

rice basis (on 14% Moisture content basis).

Head rice recovery: Weight percentage of head rice

(excluding brokens) obtained from a sample of paddy.



Under controlled conditions head rice recovery can

be as high as 84% of the total milled rice or 58% of

the paddy weight. Commercial rice mills turn out 55%

head rice on average, whereas head rice recovery of

village type rice mills is in the order of 30%.

Whole kernel: This is a milled rice grain without

any broken parts.

Broken kernel or Brokens: Depending on the rice mill

this can be only one fraction or it can contain

several fractions of different size:

Large broken kernel: 50-75% of the whole kernel

size

Medium broken kernel: 25-50% of the whole

kernel size

Small broken kernel: less than 25% of the

kernel size, can not pass through a sieve with

1.4mm diameter holes



Chips: fragments of a kernel which pass through

a sieve with 1.4mm diameter holes

Fig 11

Brokens outlet

Impurities: This refers to the materials in the rice

that are not part of the milled rice kernel. It may

include stones, husk, chaff, and weed seeds, etc.



CHAPTER FOUR

PROCESSING AND MILLING OF PARBOILED RICE

4.1 Introduction

Parboiled rice is a kind of processed rice, which is

produced in some countries of Asia, principally

India,) as well as Africa, Europe and America.

Parboiling process involves the hydrothermal

treatment of paddy before milling. The advantage of

the parboiling process stems from the gelatinization

of rice starch and hardening of rice kernel that it

brings about. As a result, breakage losses during

milling of rice can be minimized.

Five major steps in the parboiling process are

required, as follows;

1) Soaking paddy in water (cold or lukewarm water)

to increase the moisture content.



2) Steaming paddy to achieve partial

gelatinization.

3) Drying paddy to save the moisture content for

storage and milling.

4) Husking to remove paddy husk from paddy kernel.

5) Milling to remove bran from brown kernel.

4.2 PHYSICAL, CHEMICAL AND NUTRITIONAL CHANGES IN

PARBOILING RICE

1) The milling yield is higher and quality improved

as there are fewer broken kernels.

2) The preservation of parboiled paddy and milled

rice is longer and better than in the raw state.

Germination is no longer possible and the



endosperm has a compact texture making it

resistant to attack by insect and microorganism.

3) The milled rice remains firm during cooking, and

its texture becomes unstiky.

4) A great amount of water is absorbed during

cooking causing the rice to swell

5) Its nutritional value is enhanced due to the

higher content in vitamins and minerals that

have spread into the endosperm during the

parboiling process.

4.3

Agric Technology Education (Modibbo Adama University of Technology Yola) Page 28Threshing


A DIAGRAM SHOWING THE PADDY PROCESSING STEPS


Cleaning

Drying

Hulling

Whitening

Polishing

Grading

Head

Cleaning

Parboiling

Drying

PaddySeparation

BranSeparation

BrokenSeparation

Brokens

PADDY

RICE


4.4 PRE-HULLING OPERATIONS

1. Threshing:

This is the process of loosening the edible part

of cereal grain (or other crop) from the scaly,

inedible chaff that surrounds it. It is the step

in grain preparation after harvesting and

before winnowing, which separates the loosened

chaff from the grain. Threshing does not remove

the bran from the grain.

Threshing may be done by beating the grain using

a flail on a threshing floor. Another

traditional method of threshing is to make

donkeys or oxen walk in circles on the grain on

a hard surface. A modern version of this in some

areas is to spread the grain on the surface of a



country road so the grain may be threshed by the

wheels of passing vehicles.

Hand threshing was laborious, with a bushel of

wheat or rice taking about an hour. In the late

18th century before threshing was mechanized, it

took about one-quarter of agricultural labor.

In a nutshell, threshing is a part of the

harvesting process. It involves separating the

grains from the straw either by impact, friction

or combing action.

2. Cleaning:

After harvesting and threshing rice, it is

transferred to the processing plant where



foreign objects and like stones and tree stumps

are removed using de-stoner.

3. Parboiling:

This refers to the partial boiling of paddy

through the introduction of steam from the

boiler tank. Parboiling can also be used for

removing poisonous or foul-tasting substances

from foodstuffs.

4. Drying:

This is a process where the paddy is subjected

to heat from the drying pan or traditionally

under the sun to dry.

METHOD OF DRYING RICE

There are basically two methods of drying rice

1. Mechanized method

2. Traditional methodAgric Technology Education (Modibbo Adama University of Technology Yola) Page 32

http://en.wikipedia.org/wiki/Boiling


Mechanized method of drying rice is the process

of drying parboiled rice by the used of electric

driven drying pan. In this method, electric

motor is used to send hot air through perforated

holes in the drying pan so as to have proper

rice drying. This method is usually carried

during rainy season where sun is inadequate. It

is capital intensive than traditional method,

since it involves skilled labour, high cost of

fuel consumption and machine maintenance.

Traditional Method is the process whereby rice is

subjected to drying under sun. It is done during

dry season; it is also carried out immediately

after parboiling in which both skilled and

unskilled labour can take part. The parboiled

rice would be carried out and poured on the

ground for drying where we turn it each and



every ten minutes so as it can be quickly dry.

This method is less expense compared to

mechanize system. Due to the unstable weather

condition, the rice may be over/under drying, if

such happen the company will incur so much loss.

Proper attention is needed for the maintenance

of rice during drying.

4.5 POST HULLING OPERATIONS

Hulling:

Husk is separated from clean paddy. After the

husk is removed, the product is called brown

rice and is ready for the milling process. Paddy

graders and paddy cleaners are used to separate

brown rice a process known as Paddy Separation.

Milling:



This stage removes the bran layer of rice

turning brown rice into white rice. Milling is a

crucial step in post-production of rice. The

basic objective of a rice milling system is to

remove the husk and the bran layers, and produce

an edible white rice kernel that is sufficiently

milled and free of impurities a process known as

Bran Separation. Depending on the requirements of

the customer the rice should have a minimum of

broken kernels.

Polishing:

The surface of rice is smoothened and it is

given a shine by passing it through a series of

rollers.

Sorting:



Discolored, yellow and immature rice is removed

in this stage adding value to rice.

Grading:

It is a process in which broken rice is

separated out and separating head rice into

different lengths.

Head Rice:

Milled rice with length greater or equal to

three quarters of the average length of the

whole kernel is referred to as head rice.

Fig 12 Head Rice Outlet

Weighing and Bagging



In Al-Uma Lau Enterprises the finished product

(white rice) is packed into bags of different

sizes such as 50kg, 25kg and 10kg.The finished

product is then stored to be delivered to valued

customers.

Fig 13

Head rice recovery, weighing and bagging

CHAPTER FIVE

SUMMARY, CONCLUSION AND RECOMMENDATION

5.1 SUMMARY



The six months Students Industrial Work Experience

Scheme (SIWES) program, where I was attached to the

Al-Uma Lau Rice Enterprises (Rice Processing

Factory) has been worthwhile. I was posted to the

Production Department of the Company and that afford

me the opportunity to experience other sections of

the company such as Purchasing, Sales and

Administration Department.

The processes of milling parboiled and un-parboiled

rice using commercial milling machine by analyzing

the relationship between processing conditions

(soaking, steaming, drying and milling) and

properties of milled rice were part of the training

I acquired.

I came in contact with various equipment and

machines in the period of the SIWES program, most of

which I had no chance of using prior this period.Agric Technology Education (Modibbo Adama University of Technology Yola) Page 38


The application of concepts in theoretical

Agriculture was understood, since I was involved in

the process of application. I was given series of

assignments which I was made to submit to my

industrial based Supervisors in a given frame of

time.

The programmed gave me the opportunity to learn much

practical method and improved my interpersonal

relationship with people from different background.

It has also integrated my mind as to worth the

working environment. In the course of the SIWES

program, some problems encountered are observed and

their possible solution is outlined below:-

5.2 PROBLEMS ENCOUNTERED

Inadequate power supply to aid efficient working

condition



Inadequate skilled personnel

Poor water supply

Poor marketing strategy

Inadequate safety equipment

Lack of Accommodation to IT students

5.3 POSSIBLE SOLUTION TO THE PROBLEMS

Government should provide steady power supply to

reduce cost of fueling.

The company should employ skilled personnel.

The company should re-strategies on their

marketing system by taking advantage of the

available media houses and opening up of new

sale outlets of the company.

Alternative source of water should be provided

by the company such as digging wells, drilling

of motorized borehole.



The company should provide adequate safety

equipment (First Aid Box, Fire extinguisher) to

avert inherent danger.

Companies should provide accommodation for the

IT students.

Finally, I would also love to state that any student

who is privilege to perform his/her SIWES program in

Al-Uma Lau Rice Enterprise (Rice Processing Factory)

should grab such opportunity and make optimum use of

it.



REFERENCES:

origin of domesticated rice". Proceedings of the National Academy of

Sciences 108 (20): 8351. doi:10.1073/pnas.1104686108.

Mossman, A. P. 1986. A Review of Basic Concepts in

Rice-drying Research.

Critical Review in Food Science and

Nutrition. 25(1):49-70

Al-Uma Lau Rice Processing Manual: Principles and

Practice.


http://dx.doi.org/10.1073%2Fpnas.1104686108

http://en.wikipedia.org/wiki/Digital_object_identifier

Principles of Rice Processing

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