CHAPTER ONE

INTRODUCTION AND OBJECTIVE

1.0 Historical Background and Perspective of the Project

The earliest recorded evidence of the production of soap-like materials dates back

to around 2800 BC in Ancient Babylon. Inscriptions have been discovered that

indicate that the inhabitants boiled fat with ashes. It is unclear precisely what these

products were used for, although it is probable that their use was restricted to

garment washing until Roman times. It has been suggested that the word soap was

derived from Mount Sapo, which was a location for animal sacrifice. Melted

animal fats and wood ashes would be washed down from the mountain and, in the

clay along the banks of the River Tiber, a crude soap would form. (Butler, 2000)

From these very tentative beginnings the product became progressively more

refined as better-quality raw materials were used. The general use of soap as a

washing medium probably dates back 1000 years or so, when the countries around

the Mediterranean were producing modest quantities of soap, using a variety of

locally available fatty raw materials. In addition to animal fats, and vegetable oils

such as olive oil would have been used. (Butler, 2000)

.

1

Throughout the nineteenth century the chemistry of soap-making became better

understood with the discovery of the different fatty acids present in neutral fats and

oils and this, in turn, led to the establishment of the fundamentals of the modern-

day process involving the saponifications of neutral fats or fatty acids with the

appropriate caustic material. Caustic soda will produce harder sodium soap whilst

caustic potash will yield the softer potassium soaps. The selection of specific fats

and oils will yield a liquid soap. Although production methods and techniques may

have changed drastically from those earliest days it is worth remembering that the

basic chemistry of soap remains virtually unchanged. (Butler, 2000)

Today, even after several years work, research still plays a vital part in every soap

producer policy. The interaction between scientific discovery and social conditions

is as strong as ever. The consumer whose standards of living continue to rise,

demand better products all the time. The Chemical Engineers in their design of a

chemical plant apply scientific techniques to produce through library survey and

laboratory work a research product in order to meet customers’ demand before

proceeding to pilot plant and finally commercial production. It is on this note that

the motivation for this work comes about.

2

1.1 Implication of Identified Problem

Often times, there is need to blend oils for production purposes. Be it for

cosmetics, pharmaceuticals, biofuel, food, emulsions etc. These needs could be: to

optimize cost, to augment a low yield oil, to combine excellent properties of

different oils, to produce a customized product or to derive a unique formulary.

Palm oil has high yield while coconut oil has low. (Uppal, 2008) Palm oil

produces slow but sustained lather while coconut oil produces quick but short lived

lather. (Harry, 1963) Palm oil is rich in vitamin E and A (Ping et.al, 2000) while

Coconut oil is rich in antibacterial properties. (Beare-Roggers et.al, 2001) The

aforementioned makes Palm oil and Coconut oil great blend candidates for

production of Toilet Soap.

However, the need for blending of oils faces twin problem of adulteration of raw

materials and contamination of finished products. In this light, this work seeks

among other things, a scientific platform to achieve a trade off in optimization

(Cost minimization of raw materials and quality maximization of finished

products).

3

1.2 Experimental Hypothesis

Different composition of Palm Oil-Coconut Oil blend has effect on the industrial

characteristics of the oil and also on the quality of Toilet Soap produced.

1.3 Aims and Objectives

This is a process research work which is aimed at:

Studying the effect of different blend compositions on the industrial

characteristics of Palm Oil-Coconut Oil blend.

Producing a research product of Toilet Soap from Palm Oil-Coconut Oil

blend.

Studying the effect of different blend compositions on the quality of Toilet

Soap.

1.4 Significance of the Study

This work will provide scientific data that will permit the rational design of

manufacturing process of Toilet Soap with minimum time and equipment spent in

pilot plant. It will also guarantee that scale up of production plant for the process

operate under favourable conditions with respect to all variables such as feed

composition, materials and heat requirement. It will encourage the cultivation of

palm tree and coconut tree as well as the utilization of the oils from these trees for

4

industrial application. Finally, it will serve as a quality control reference in use of

blended organic oils in chemical process technologies.

1.5 Limitation

Due to time, finance, and equipment constraint, this work is limited to the use of

Palm Oil-Coconut Oil blend in the production of Toilet Soap. However, the result

obtained can be extended to production of other cosmetic and pharmaceutical

products, food and other industrial applications.

5

CHAPTER TWO

LITERATURE REVIEW

2.1 Fat and Oil

Fat is one of the lipids. Fats are the main constituents of the storage fat cells in

animals and plants, and are one of the important food reserves of the organism. We

can extract these animal and vegetable fats – liquid fats are often referred to as oils

– and obtain such substances as corn oil, coconut oil, cottonseed oil, palm oil,

tallow, bacon grease, and butter. (Morrison and Boyd, 1992)

Chemically, fats are carboxylic esters derived from the single alcohol, glycerol,

HOCH2CHOHCH2OH, and are known as glycerides. More specifically, they are

triacylglycerols. Each fat is made up of glycerides derived from many different

carboxylic acids. (Morrison and Boyd, 1992)

Figure 2. 1: A Triacylglycerol (A glyceride)

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The proportions of the various acids vary from fat to fat; each fat has its

characteristics composition, which does not differ very much from sample to

sample. With only a few exceptions, the fatty acids are all straight-chain

compounds, ranging from three to eighteen carbons; except for the C3 and C5

compounds, only acids containing an even number of carbon are present in

substantial amounts. (Morrison and Boyd, 1992)

Besides saturated acids, there are unsaturated acids containing one or more double

bonds per molecule. The most common of these acids are:

CH3(CH2)7CH=CH(CH2)7COOH (Oleic acid)

CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH (Linoleic acid)

CH3CH2CH=CHCH2CH=CHCH2CH=CH(CH2)7COOH (Linolenic acid)

(Morrison and Boyd, 1992)

2.2 Characterization of Coconut Oil

Synonyms: Copra Oil, Oleum Cocois (Harry, 1963). Coconut oil is an edible oil

extracted from the kernel or meat of matured coconuts harvested from the coconut

palm (Cocos nucifera). It has various applications in food, medicine, and industry.

Because of its high saturated fat content it is slow to oxidize and, thus, resistant to

rancidification, lasting up to two years without spoiling. (Fife, 2005)

7

The following is average fatty acid composition of Coconut oil – Saturated acids:

Caproic acid (0.2%), Caprylic acid (8.0%), Capric acid (7.0%), Lauric acid

(48.0%), Myristic acid (17.5%), Palmitic acid (8.8%) and Stearic acid (2.0%).

Unsaturated acids: Oleic acid (6.0%) and Linoleic acid (2.5%). Coconut oil occurs

as white semi-solid, lard-lime fat which readily becomes rancid on exposure to air.

It is sometimes hydrogenated to improve its stability. Coconut oil melts at 21°C to

25°C, and has the following characteristics: Saponification Value (251 to 264),

Iodine Value (8 to 10), Refractive index at 40°C (1.4485 to 1.4495), Acid value

(not greater than 6) (Harry, 1963)

2.3 Coconut oil in Food

Coconut oil is commonly used in cooking, especially for frying, and is a common

flavor in many South Asian curries. It has been used for cooking (in tropical parts

of the world) for thousands of years. (Clark, 2011) Coconut oil (along with laurel

leaf oil and palm kernel oil) contains a large proportion of lauric acid, which is

converted to monolaurin in the body, a fat otherwise found only in breast milk.

(Beare-Roggers et.al, 2001) Lauric acid is destroyed by some oil processing

methods.

Other culinary uses include replacing solid fats produced through hydrogenation in

baked and confectionery good. (Tarrago-Trani et.al, 2006) Hydrogenated or

8

partially hydrogenated coconut oil is often used in non-dairy creamers and snack

foods, including popcorn. The smoke point of coconut oil is 177 °C (351 °F).

(Katragadda et.al, 2010)

2.4 Coconut oil in Industry

Coconut oil has been tested for use as a feedstock for biodiesel to be used as a

diesel engine fuel. In this manner, it can be applied to power generators and

transport using diesel engines. Since straight coconut oil has a high gelling

temperature (22–25 °C), a high viscosity, and a minimum combustion chamber

temperature of 500 °C (932 °F) (to avoid polymerization of the fuel), coconut oil

typically is transesterified to make biodiesel. Use of B100 (100% biodiesel) is

possible only in temperate climates, as the gel point is approximately 10 °C (50

°F). The oil must meet the Weihenstephan standard for pure vegetable oil used as a

fuel, otherwise moderate to severe damage from carbonization and clogging will

occur in an unmodified engine.

The Philippines, Vanuatu, Samoa, and several other tropical island countries are

using coconut oil as an alternative fuel source to run automobiles, trucks, and

buses, and to power generators. Coconut oil is currently used as a fuel for

transport in the Philippines. Further research into the potential of coconut oil as a

fuel for electricity generation is being carried out in the islands of the Pacific,

9

although to date it appears that it is not useful as a fuel source due to the cost of

labour and supply constraints. (AGTD, 2011)

Coconut oil has been tested for use as an engine lubricant and as transformer oil.

Acids derived from coconut oil can be used as herbicides. (James and Rahman,

2005)

Coconut oil can be used as a skin moisturizer, helping with dry skin and reduces

protein loss when used in hair. Before the advent of electrical lighting, coconut oil

was the primary oil used for illumination in India and was exported as cochin oil.

(Brady, 2002)

Coconut oil is an important base ingredient for the manufacture of soap. Soap

made with coconut oil tends to be hard, although it retains more water than those

made with other oils and therefore increases manufacturer yields. It is more soluble

in hard water and salt water than other soaps allowing it to lather more easily. A

basic coconut oil soap is clear when melted and a bright white when hardened.

(Browning, 2003)

2.5 Characterization of Palm Oil

Synonyms: Oleum Palmae, Palm Butter. The following is the average fatty acid

composition of Palm Oil – Saturated acid: Myristic acid (1.0%), Palmitic acid

(42.5%), Stearic acid (4.0%), Lignoceric acid (trace). Unsaturated acid: Oleic acid

10

(43.0%), and Linoleic acid (9.5%). It is obtained from the ripe fruit of palm tree

(Elaies guineensis). Palm Oil occurs as a reddish-yellow to dark dirty-red fatty

mass with faint violet-like odour. Specific gravity (0.920 to 0.927), melting range

(27°C to 42.5°C ), refractive index at 60°C (1.451 to 1.4579), Saponification

value (200 to 205), Iodine Value (53 to 57) (Harry, 1963). Palm Oil is an important

source of vitamin A, which has been indicated as a good agent of good eye sight,

weight development and disease resistance (NAS, 1974). Palm oil is naturally

reddish in color because of a high beta-carotene content. (Reeves and Weihrauch,

1979) Red palm oil gets its name from its characteristic dark red color, which

comes from carotenes, such as alpha-carotene, beta-carotene and lycopene, the

same nutrients that give tomatoes, carrots and other fruits and vegetables their rich

colors. Red palm oil contains at least 10 other carotenes, along with tocopherols

and tocotrienols (members of the vitamin E family), phytosterols, and glycolipids.

(Ping and Yuen, 2000)

2.6 Palm oil in Cosmetics

Palm oil is known for its cleansing, moisturizing and anti-aging action in cosmetic

products. Palm oil contains the hard to find toctrienols, which are members of the

vitamin E family. The common form of vitamin E, tocopherol, has long been used

to treat many skin ailments and is found in many anti-aging products. Vitamin E is

11

a strong antioxidant that helps the skin to fight free radicals that damage the skin

and cause fine lines and wrinkles . Palm oil is found in shampoos, conditioners,

soaps, lotions, creams, foundations and more. It is found in shampoos and soaps

for its ability to remove oil and dirt from hair and skin. It also contains a refatting

agent that helps restore the hair and skin natural oils most soaps and shampoos

strip away letting moisture escape. In shampoos and conditioners, it also provides a

conditioning agent. It is added to skin care products not only for its anti-aging

properties, but also because it provides deep moisturizing properties making the

skin soft and supple. (Barron, 2014)

2.7 Methods of Extracting Coconut Oil and Palm Oil

2.7.1 Extraction of Coconut Oil

Dry Process

Dry processing requires the meat to be extracted from the shell and dried using

fire, sunlight, or kilns to create copra. The copra is pressed or dissolved with

solvents, producing the coconut oil and a high-protein, high-fiber mash. The mash

is of poor quality for human consumption and is instead fed to ruminants; there is

no process to extract protein from the mash. A portion of the oil extracted from

copra is lost to the process of extraction. (Grimwood et. al, 1975)

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Wet Process

The all-wet process uses raw coconut rather than dried copra, and the protein in the

coconut creates an emulsion of oil and water. The more problematic step is

breaking up the emulsion to recover the oil. This used to be done by prolonged

boiling, but this produces a discolored oil and is not economical; modern

techniques use centrifuges and pre-treatments including cold, heat, acids, salts,

enzymes, electrolysis, shock waves, or some combination of them. Despite

numerous variations and technologies, wet processing is less viable than dry

processing due to a 10–15% lower yield, even compared to the losses due to

spoilage and pests with dry processing. Wet processes also require investment of

equipment and energy, incurring high capital and operating costs. (Grimwood et.al,

1975)

Conventional coconut oil uses hexane as a solvent to extract up to 10% more oil

than just using rotary mills and expellers. The oil is then refined to remove certain

free fatty acids, in order to reduce susceptibility to rancidification. Other processes

to increase shelf life include using copra with a moisture content below 6%,

keeping the moisture content of the oil below 0.2%, heating the oil to 130–150 °C

(266–302 °F) and adding salt or citric acid. (Kurian, 2007)

Virgin coconut oil (VCO) can be produced from fresh coconut meat, milk, or

residue. Producing it from the fresh meat involves removing the shell and washing,

13

then either wet-milling or drying the residue, and using a screw press to extract the

oil. VCO can also be extracted from fresh meat by grating and drying it to a

moisture content of 10–12%, then using a manual press to extract the oil.

Producing it from coconut milk involves grating the coconut and mixing it with

water, then squeezing out the oil. The milk can also be fermented for 36–48 hours,

the oil removed, and the cream heated to remove any remaining oil. A third option

involves using a centrifuge to separate the oil from the other liquids. Coconut oil

can also be extracted from the dry residue left over from the production of coconut

milk. (Kurian, 2007)

A thousand mature coconuts weighing approximately 1,440 kilograms (3,170 lb)

yield around 170 kilograms (370 lb) of copra from which around 70 litres (15 imp

gal) of coconut oil can be extracted. (Bourke and Harwood, 2009)

2.7.2 Palm Oil

The main extraction steps are:

Sterilization: The bunches are cooked with live steam for 90 – 120 minutes.

Sterilization objectives are: Lipase enzyme inactivation, making fruits easily

release from bunches, making fruits softer, making nut/pulp separation easier, and

coagulation of proteins.

Threshing: After bunches are cooked they are fed to the thresher which is a drum

14

with holes in the side where bunches are centrifuged to separate the fruits. The

bunch waste is incinerated and the ash, a rich source of potassium, is used in a

compost.

Digestion: Digestion is the process of releasing the palm oil in the fruit through the

breaking down of oil-bearing cells. Fruits are lifted by a cup elevator to the top of

the digester vessel. This vessel contains a live steam heating system and agitator

shafts. The main aim during digestion is to break oily cells, in order to make oil

extraction easier. This process takes 30 minutes at 90 – 100 ºC.

Pressing: Pressing is made just after the material leaves the digestion vessels and it

produces a slurry made of approximately 53% oil, 40% water and 7% solids and

also a cake that consists of fiber and nuts. Method of pressing could be dry or wet.

Dry method is oriented on squeezing the oil out of the mixture of oil, moisture,

fibre and nuts by applying mechanical pressure on the digested mash. Wet method

uses hot water to leach out the oil.

Clarification, Purification, and Packaging: This step consists of separation of oil

from impurities (water and fine solids) made in settling tanks and three phase

decanters. Recovered oil is then purified in plate centrifuges and dried under

vacuum. Finally, the Extra Virgin Palm Oil is filtered to remove any remaining

particulate matter and packaged in drums.

Oil Extraction Losses: Empty bunches and solids from clarification are used as

15

organic fertilizers on certified organic plantation. Fibers still have around 7% oil

and shells are used in the boilers as fuel. As a result, all extraction mills are able to

generate their own electricity by steam turbines.

(http://www.naturalhabitats.com/en/blog/red_palm_oil_extraction_process.

Accessed, 24/12/2014)

2.8 Industrial Characteristics Of Organic Oils

2.8.1 Colour, Viscosity and density

Oils are mixtures of triglycerides (TGs) and their viscosity depends on the nature

of the triglycerides present in the oil. The viscosity changed due to the different

arrangement of the fatty acids on the glycerol backbone of the triglyceride

molecule. Therefore, viscosity is related to the chemical properties of the oils such

as chain length and saturation/unsaturation. It explains that the viscosity and

density decreases with an increase in unsaturation and increases with high

saturation and polymerization. Viscosity also depends on sheer stress and

temperature. Sheer stress does not have much effect on the storage of oils which

are used for edible purposes but the temperature does affect it. When the

temperature increases the kinetic energy also increases which enhanced the

movement of the molecules and reduces the intermolecular forces. The layers of

the liquid easily pass over one another and thus contribute to the reduction of

16

viscosity (Kim et al., 2010). The colour of oils and fats has a bearing on the final

product, in particular, and its assessement is of some importance industrially.

(Pearson, 1973)

2.8.2 Peroxide value

Peroxide value (PV) is used as a measure of the extent to which rancidity reactions

have occurred during storage. It could be used as an indication of the quality and

stability of fats and oils The peroxide value determines the extent to which the oil

has undergone rancidity (Ekwu and Nwagu, 2004). During the storage of oils and

fats, oxygen is absorbed at the unsaturated bonds, which react like those in

peroxides. At a certain level, volatile products are formed that have a deleterious

effect on the taste and odour, known as oxidative rancidity. During the storage of

most oils and fats, the peroxide value shows little increase during the early stages,

known as induction period, after which there is a marked increase. Therefore,

although fresh oils often give no titration, a comparative low peroxide value of,

say, 3ml of 0.002N thiosulphate per gram is likely just to precede a marked

increase, indicating oxidative rancidity. Values of the order of 10 – 20 are

synonymous with rancidity. (Pearson, 1973)

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2.8.3 Saponification value

The Saponification Value denotes the weight of potassium hydroxide in milligrams

required to saponify 1g of the oil or fat. Saponification value is inversely

proportional to the mean molecular weights of the fatty acid in the glycerides

present in oil or fat. (Pearson, 1973) Saponification value (SV) is an index of

average molecular mass of fatty acid in the oil sample. The lower value of

saponification values suggests that the mean molecular weight of fatty acids is

lower or that the number of ester bonds is less. This might imply that the fat

molecules did not interact with each other (Denniston et al., 2004). It gives

information concerning the character of the fatty acids of the fat- the longer the

carbon chain, the less acid is liberated per gram of fat hydrolysed. It is also

considered as a measure of the average molecular weight (or chain length) of all

the fatty acids present. The long chain fatty acids found in fats have low

saponification value because they have a relatively fewer number of carboxylic

functional groups per unit mass of the fat and therefore high molecular weight.

Oils with high saponificaton values such as coconut oil and palm oil are better used

in soap making. Soap manufacturers blend their oils with coconut oil because of its

high saponification value. (http://ethesis.nitrkl.ac.in/5371/1/109CH0476.pdf,

Accessed, 24/12/2014)

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2.8.4 Iodine value

The iodine value denotes the percentage by weight of halogen, calculated as

iodine, absorbed under the conditions of test. (Pearson, 1973) Iodine value (IV)

measures the degree of unsaturation in a fat or vegetable oil. It determines the

stability of oils to oxidation, and allows the overall unsaturation of the fat to be

determined qualitatively (AOCS, 1993 and Asuquo et al., 2012. The low iodine

contribute to its greater oxidative storage stability of oil. The oxidative and

chemical changes in oils during storage are characterized by an increase in free

fatty acid contents and a decrease in the total unsaturation of oils (Perkin, 1992).

High iodine value justifies utilization of the oil in soap and shampoo productions

Castor oil is an example of nondrying oils whose iodine numbers are less than 100;

they have the advantage of not undergoing oxidation to form a film, hence are

useful in the manufacture of soaps. The coconut oil has a very low iodine value

because of the saturated fatty acids present. The higher the number for an oil, the

greater the percentage of these acids, and thus the softer the soap produced from

the oil. The soft oils have high iodine numbers and are readily oxidized. The iodine

number thus indicates the hardness of the soap, the lower the number, the harder

the soap produced.The variation in colours is due to the degree of unsaturation of

the fatty acids. Increase in double bonds causes increase in intensity of colour.

(http://ethesis.nitrkl.ac.in/5371/1/109CH0476.pdf, Accessed, 24/12/2014)

19

2.8.5 Acid value and free fatty acid (FFA)

Acid value indicates the proportion of free fatty acid in the oil or fat and may be

defined as the number of milligrams of caustic potash required to neutralize the

acid in one gram of the sample. (Uppal, 2008) In free fatty acid analysis, the oil is

dissolved in neutral solvent and the acidity is titrated with standard alkali. The

value obtained represents the extent to which the glyceride in the oil have been

decomposed by lipase. The free fatty acids are usually calculated as oleic acid.

Maximum limits of edibility vary considerably according to the oil, but a critical

limit of 1% can be taken as a general guide. Maxima, calculated as acid value

(which is conveniently calculated by doubling the free fatty acid as oleic acid), are

prescribed for many oils e.g. olive oil 2.0, groundnut oil 0.5, almond oil 2.0.

During storage, the free fatty acid of oils and fats usually increases steadily. The

rate is, however, inhibited as the temperature is lowered. The main exceptions to

this are the higher values given by coconut oil and palm-kernel oil. (Pearson, 1973)

2.9 Blending of Organic Oils for Soap Production

One soap making oil in itself does not have all the properties. Different oils have

different composition of fatty acids which are responsible for different properties

of soaps made out of them. Therefore blends of oils are prepared taking 2 oils

together. Mishra D. (in http://ethesis.nitrkl.ac.in/5371/1/109CH0476.pdf,

20

Accessed, 24/12/2014) investigated production of soap using different blend

compositions with five (5) different types of oils (Coconut Oil, Castor Oil, Karanjia

Oil, Neem Oil, and Olive Oil). The result showed that the blend of coconut oil and

castor oil at 3:1 ratio was found out to be the best with 76.8% of Total Fatty

Matter and 89.46% of yield. It was found that the blend was having saponification

value of 230.4 (compare to 268 and 180 of Coconut Oil and Castor Oil respectively

reported by the researcher) and iodine value of 40 (Compare to 10 and 68 of

Coconut Oil and Castor Oil respectively reported by the researcher). He concluded

that soap prepared using blend of both these oils has better properties than the

soaps prepared by individual oils.

(http://ethesis.nitrkl.ac.in/5371/1/109CH0476.pdf, Accessed, 24/12/2014).

Girgis et.al (1998) investigated blends of Apricot Kernel Oil, Palm Kernel Oil, and

Palm Stearin. Eight soap samples were produced and labeled: 1 - (100:0:0); 2 –

(0:15:85); 3 – (10:15:75); 4 - (20:15:65); 5 – (30:15:55); 6 – (40:15:45); 7 -

(50:15:35); 8 – (60:15:25) in the proportion of Apricot Kernel Oil, Palm Kernel Oil

and Palm Stearin respectively. Result showed that The structure of soap samples

numbers 1 and 8 were sticky and with bad physical properties. On the other hand,

the physical characteristics of blends numbers 2, 3, 4, 5 and 6 had firm

consistency and creamy lather while, in soap number 7, it was moderate i. e.

21

medium hard makeup with fairly lather. After storage (6 months) on a shelf at

room temperature, all soaps (numbers 1 - 8) were declined in their moisture

content. On contrary, the total fatty acids of the same samples were augmented at

different ratios during storage. Physical characteristics of soap samples numbers 2,

3, 4, 5, 6 and 7 were increased after the storage time (6 months), their consistencies

were very firm with creamy lather and reducement in their erosion from

handwashing ratios was observed. They recommended that apricot kernel oil can

be used in the manufacturing of toilet soap until ratio 50% of the fatty blend (the

blend was bear palm stearin).

Girgis (1999) studied the production of toilet soap using Palm Oil, Tallow and

Palm Kernel Oil by blending the three oils at different compositions. Eight soap

samples were produced and labeled: 1 - (0:85:15); 2 – (85:0:15); 3 – (10:75:15); 4

- (20:65:15); 5 – (30:55:15); 6 – (40:45:15); 7 - (50:35:15); 8 – (60:25:15) in the

proportion of Palm Oil, Tallow, and Palm Kernel Oil respectively. Result revealed

that the moisture contents of soap samples numbers 2,7 and 8 were high compared

with the standard soap (sample number 1), subsequently their total fatty matters

became lower than that found in the control soap (sample number 1). The findings

marked that the unsaponifiable matter of soaps numbers 2,7 and 8 were higher

22

compared with the other soaps. No high differences were observed in the free

alkali of all soaps (range from 0.06 to 0.09%). On the other hand, high differences

were found in the free oil of all soap samples (numbers 2 - 8) compared with the

standard soap (sample number 1), except soap samples numbers 2,7 and 8, which

record very high. The best soap samples in the colour were in the following

increasing order: numbers 1 >3 > 4 > 5 > 6 > 7 > 8 > 2 , respectively. The results

showed that the better soap samples in the physical properties were in the

following increasing order: soap numbers 3> 4> 5> 6 compared with the standard

soap (sample number 1), where from firm structure with high foam, while the other

soap samples (numbers 2,7 and 8) were poor quality (i.e., low lathering properties

with deep colours). He concluded that mucilage palm oil can be used as a new fatty

material for toilet soap manufacturing at ratio of 40% from the fatty blend.

Kuntom et.al (1996) in Eke et.al (2004) in a soap manufacturing study done in

Malaysia using blends of distilled fatty acids of palm oil (PO) and palm-kernel oil

(PKO), showed that there is an increase in acid value and hardness, while the

iodine value decreases as the ratio of PKO increases. Eke et.al (2004) used blend

of shearbutter and palm kernel oil to produce soap. They saw that 150:350

(Shearbutter oil to Palm Kernel Oil) blend gave best soap judging by TFM while

the 350: 150 blend gave a better soap than the former in terms of foam stability.

23

2.10 Stability of Vegetable Oils

2.10.1 Environmental Factors

The Environmental factors that can affect the stability of oil are light, gaseous

atmosphere, temperature, and moisture. Light is an initiator of reactions with

oxygen that ultimately result in deterioration of fats and oils. Sensitizers such as

chlorophyll may play a role in promoting photo-oxidation. Oxygen is the most

critical factor affecting stability. It causes formation of hydroperoxides, the

components normally associated with rancid oil. A suggested mechanism for the

hydroperoxide formation begins with the reaction of the free radical, which reacts

readily with unsaturated sites to form the hydroperoxide and a free radical, thereby

perpetuating the chain. These reactions increase in rate and intensity in the

presence of light, heat, and prooxidants such as chlorophyll and heavy metals

(Applewhite, 1985)

2.10.2 Auto oxidation

Lipid oxidation occurs via auto oxidation or lipoxygenase catalysis. Auto oxidation

refers to a complex set of reactions which result in the incorporation of oxygen in

lipid structures. Auto oxidation reactions are seen to progress more rapidly in oils

that contain predominantly unsaturated fat molecules; other relevant factors

include the presence of light, transition metal ions, oxygen pressure, the presence

24

or absence of antioxidants and pro oxidants, temperature and moisture content.

Auto oxidation reactions occur at an increasing rate after the initial induction

period. This behavior can be explained by assuming that oxidation proceeds by a

sequential free radical chain reaction mechanism. Relatively stable radicals that

can abstract hydrogen atoms from the allylic methylene groups in olefinic

compounds are formed. Hence auto oxidation is a radical induced chain reaction

which proceeds through the traditional stages of initiation, propagation and

termination. Detailed proposed mechanisms for these free radical chain reactions

are available in literature (http://pubs.caritasuni.edu.ng Accessed, 21/11/2014)

Lipoxygenases are metal proteins with an iron atom as the active center. They

catalyze the oxidation of unsaturated fatty acids to hydroperoxides as with auto

oxidation. Enzyme activation usually occurs in the presence of hydroperoxides,

even though enzyme catalyzed oxidation can occur even in the absence of

hydroperoxides. As earlier stated, the more unsaturated the fatty acid involved is,

the greater its susceptibility to oxidative rancidity. For instance, the linolenic acid

esters present in soybean oil (with twice the unsaturation as monounsaturated

esters) is particularly sensitive to even oxidation of the slightest kind, commonly

referred to as flavor reversion, resulting in beany, grassy or painty flavors. A

highly saturated fatty acid level is confirmed to be of benefit in terms of storage

25

ability when compared to more unsaturated vegetable oils. Indeed, the tendency of

an oil to combine with oxygen of the air and become gummy (known as drying) is

measured with the iodine number, which in fact is merely a measure of the level of

unsaturation of the oil in question (a higher iodine number will indicate higher

unsaturation seeing that iodine is absorbed primarily by the mechanism of addition

to the double bonds characteristic of unsaturation) (http://pubs.caritasuni.edu.ng

Accessed, 21/11/2014).

2.10.3 Antioxidants

Vegetable oils in their natural form possess constituents that function as natural

antioxidants. Amongst them are ascorbic acids, _-tocopherole, _-carotene,

chlorogenic acids and flavanols. Tests conducted to investigate the effectiveness

of natural anti-oxidants contained in red pepper oil added to soybean and

sunflower oils indicate that they provide variable protection against light induced

auto-oxidation. In the above mentioned study on the inhibitive effect of natural

antioxidants contained in red pepper oil, it was additionally observed that the

phenolic anti-oxidant butylated hydroxytoluene (BHT) shows more effectiveness

generally than natural anti-oxidants. (http://pubs.caritasuni.edu.ng Accessed,

21/11/2014).

26

2.11 Science and Technology of Soap Production

Soap is a salt of a fatty acid (McNaught and Wilkinson, 2010). The chemical

formula is R.COOB. Where R.COO = the fatty acid radical and B = the metal base

used. Soap is the product of the reaction occurring between a fatty acid and a base.

(Harry,1963)

Figure 2.2: Equation for Formation of Soap

2.11.1 Types of Soaps

(i) Household Soap: After mixing into the soap stock the required perfume and

any preservatives or colouring matter which are to be added, the soap stock is

cooled either in a large metal container or in water-jacketed slabs. (Harry, 1963)

Fillers or builders, such as sodium silicate, sodium phosphate, sand, soda ash,, or

rosin soap are added in various proportion (Uppal, 2008)

27

(ii) Toilet Soap: In the manufacture of toilet soap, the soap stock is dried to

reduce its water content from 30 percent to about 13 to 14 percent. (Harry, 1963)

Toilet soap contains no fillers, except occasionally a little resin soap (Uppal, 2008).

The good quality toilet soaps have the following important characteristics:

1. Easy solubility in water with profuse lathering.

2. Persistence of the soap fragrance.

3. Non dyeability of the skin or fabric by the colour of the soap.

4. Smooth glossy appearance without any cracks.

(Uppal, 2008)

(iii) Soap flakes: the soap stock is dried in order to reduce its water content from

30 percent to about 10 percent and after perfuming, is fed into a roller mill from

which the soap is scraped off in the form of flakes. (Harry, 1963)

(iv) Shaving Soaps and Creams: such soaps are characterized by their ease of

lathering and the stability of the lather produced. They are finished so as to be free

from alkali by using an excess of free fatty acids in their preparation. Because

potassium stearate forms a close creamy lather it is widely employed – in

conjunction with saponified coconut oil – in such preparations. (Harry, 1963) The

shaving soap must be capable of producing lather that persists for long time and

should also be neutral and non-irritating to skin. These qualities can be obtained by

28

using best quality tallow and coconut oil as the source of glycerides and a mixture

of caustic soda and caustic potash lyes as the saponifying agents. (Uppal, 2008)

(v) Shampoos: liquid soap shampoos may consist either of potash-coconut oil

soaps which lather very readily but which suffer from the disadvantage that they

may be irritant to some persons, or they may be a saponified mixture of coconut

and olive (or other suitable) oils. Sometimes potassium or sodium carbonate,

sodium sesquicarbonate, etc., may be added in an endeavour to improve the

lathering properties of these shampoos when used in hard water areas. The addition

of sodium hexametaphosphate or sodium pyrophosphate is sometimes made in an

effort to reduce the tendency of soaps to scum in hard water. (Harry, 1963)

2.11.2 Raw Materials for Soap Making

(i) Source of glyceride: The main sources of slow lathering hard oils are

tallow, lard, palm oil, fish oil, greases etc. Quick lathering hard oils include

coconut oil, palm kernel oil etc. soft oils are soyabean oil, cotton seed oil, unedible

olive oil etc. (Uppal, 2008)

(ii) Rosin: A plant exudiation product which mainly contains abietic acid. Thee

colourless variety of rosin is used in manufacture of laundry soaps and dark variety

is used in the manufacture of coloured soaps. Rosin makes lather formation faster,

increases the cleansing action of soap and also in the softening of hard soaps.

29

Rosin requirement of tallow soap is about 40 – 50 percent, while that of greases is

only 25 percent. (Uppal, 2008)

(iii) Caustic Soda: It is available in the form of flakes, blocks and sticks as well

as in solutions of various strengths such as 70° (90.32% NaOH), 72° (92.9%

NaOH) and 74° (95.48% NaOH). In soap making, block form of NaOH is

generally employed. Special quality soft soaps, shaving creams etc. make use of

caustic potash of 18.5 – 20% strength. (Uppal, 2008)

(iv) Sodium Chloride: It is used for salting out of soap. About 12.5 parts per

100 parts of oil to be saponified is used. (Uppal, 2008)

(v) Binding Materials: The cleansing capacity of ordinary soaps is improved

by adding certain materials such as sodium silicate (5%), soda ash (Na2SO3),

trisodium phosphate and borax. The binding materials improve soap texture,

correct the alkalinity of the solution and prevent the formation of precipitates in

hard water. Soda ash is available in various forms, but 58° variety is commonly

used in soap making to the extent of 5 – 10%. Borax is used in 1 – 2% CWT of

soap. (Uppal, 2008)

(vi) Fillers: The bulk or weight of the soap is increased by adding certain fillers

such as talc (5 – 10%), starch (2%), glauber salt, pearl ash etc., without affecting

the detergency. (Uppal, 2008)

30

(vii) Colouring Matter: Organic dyes and inorganic pigments are generally

used. As a soap dye, the colouring matter should be inert to alkali used in making

the soap, should not separate out on cooling the blended soaps, should not impede

in any way the fragrance of the soap and should reproduce the natural shade.

Common colouring matters are methyl violet for violet shade, Brismark brown,

Rhodamine or safframine for red, zinc oxide for white, chrome green for green,

cadmium yellow or metanil yellow for yellow, ultramarine or methylene blue for

blue, eosin for pink and vermilion for rose shade. Intermediate shades can be

prepared by mixing these colouring materials. (Uppal, 2008)

(viii) Perfumes and Perfume Fixatives: the essential oils, known as perfumes

impart fragrance to the soap. They may be natural or synthetic. Examples of

natural perfumes are sandal wool oil, lemon grass oil, clove oil, eucalyptus oil,

lavender oil, bergamot oil, cinnamon oil etc. Examples of synthetic perfumes are

jasmine (Benzyl acetate), rose (Phenyl ethyl alcohol), lilac (Terpeneol) and musk

(Benzoate). Certain fixatives such as tolu-balsam, Gum-Benzoin etc. are mixed

with perfumes as a result of which assence of the soap is not easily lost. (Uppal,

2008)

Some other additions in soaps include:

Superfatting agents such as lanolin (a fatty material isolated from sheep’s

wool) is added in order to supplement the skin fat removed by the action of

31

soap and it prevents the skin from becoming rough and dry. It is added to the

soap in 2% concentration and also improves glass and texture of the soap,

helps in steady lather formation and also prevents cracks on soap when dry.

Extracts of various plants such as neem, eucalyptus, chaulmoogra etc. are

added as disinfectants.

Mercuric iodide is added as germicide in mercury soaps. Sulphur is added as

a cure for dandruff and pimples, hexa chlorophene as an effective germicide

against skin micro-organisms.

(Uppal, 2008)

2.11.3 Manufacture of Soap

Soap is either made by hot, semi-hot, or cold process. Usually, laundry soap and

toilet or bath soaps are manufactured by hot process. Transparent and other special

types of soap are produced by cold process. In most cases, soap obtained by the hot

process is settled or grained and separated from the spent lye containing the

glycerol in solution. The glycerol is recovered as a by-product of soap industry.

(Uppal, 2008)

32

2.11.3.1 Hot Process

The process is started by putting the melted oil into the boiling tank and running a

weak caustic soda solution into the oil. The mixture is then slowly boiled to start

the saponification. The beginning of is denoted by the formation of emulsion.

When saponification has started caustic soda of higher strength was frequently

added in small quantities with continued boiling.Rapid addition of caustic alkali in

the initial stages can also entirely delay saponification and in this case water should

be added and the boiling continued till the excess alkali is taken up for the

saponification to proceed. The end of saponification is determined by the „ribbon‟

and „taste‟ tests. When saponification is completed, the soap becomes very firm

and dry with a permanent faint caustic like flavour on the tongue when cooled. The

soap, which now consists of this imperfect soap together with water in which is

dissolved glycerine and any slight excess of caustic soda, is then ready for graining

out. The objective of this is to separate the waste lye which is a mixture of

glycerine produced during the soap boiling process and excess caustic soda

solution from the soap. This is brought about by small use of common salt in dry

form or as brine. The term “graining” is used here because after the introduction

of the salt, the homogeneous soap gives the appearance of grains. The graining is

complete when the soap is practically free from foam and floats as clean soap on

the lye. At this stage, this sample of soap taken from the tank consists of distinct

33

grains of soap and a liquid portion which is easily separated.

(http://ethesis.nitrkl.ac.in/5371/1/109CH0476.pdf, Accessed, 24/12/2014)

2.11.3.2 Semi-Hot Process

The soft and hard oils or their blends are very suitable for this process in which the

fat is first of all melted, followed by treatment with a weak 9-10% caustic soda

solution followed by boiling of the mixture. The quantity of caustic soda required

for the saponification of the oil is 14-15% of the weight of the oil. This weight of

caustic soda is dissolved in ten times its weight of water to obtain a 9% solution.

When the caustic solution is added into oil, then saponification starts when an

emulsion is formed as the soap is stirred. More caustic solution is then added in to

prevent the thickening of mass. After sufficient solution is added bit by bit to

complete the saponification and the boiling of the mass continues until the soap

was clear. During the boiling process moderate heat was maintained and each

addition of caustic soda solution must be allowed to react with the oil before the

next addition is made. A hurried addition in the initial stages of the process may

retard the saponification, or at the final stages of the saponification may result in

the drying of the soap, while judicious addition will keep the mass in a form of

smooth homogeneous emulsion. If the soap shows any signs of separation and

graining, further water is added to bring the mass to a homogeneous state. The

34

ribbon test involves taking a small sample of the soap from the pan and cooling it.

When a little quantity of this cooled soap is pressed in between the thumb and

forefinger, the soap does not come out in the form of firm shiny ribbons with slight

opaque ends and be clear when held against the light. If this cooled sample draws

out in threads, there is excess water present in the soap, and more boiling is

required to evaporate more water. If opaque ends appear and vanish, the soap is

more oily and requires more caustic, while if the soap is graining, or turbid and

white, it indicates a high level of presence of un reacted caustic, and requires more

oil. A physical test - the taste test – is also done to determine the level of alkali.

This test involves cooling a small quantity of the soap, and tasting it with the tip of

the tongue. A sharp bite indicates too much caustic in the soap, while small bite

indicates a high level of unsaponified fat or oil. A good soap gives a faint bite on

the tongue.

After the completion of the boiling process, the fire is taken off, and the soap is

allowed to cool with little stirring. At this point, perfume and colour can be added

into the soap.

This process is not suitable for the production of toilet soap, can be used to

produce laundry and all other types of soft and liquid soaps. The process does not

permit the removal of waste alkali which contains the glycerine produced in the

35

soap making process, and hence the glycerine, which tends to decrease the

hardening property of the soap and improves the cosmetic property,

is retained in the finished soap. This method has some advantage over the other

two since large quantities of good soap can be produced within a short time. The

use of this method also allows a high percentage of fillers to be added in soaps,

thus it increases the soap bulk. (http://ethesis.nitrkl.ac.in/5371/1/109CH0476.pdf,

Accessed, 24/12/2014)

2.11.3.3 Cold Process

This process involves the treatment of fat or oil with a definite amount of alkali

and no separation of waste lye. Although it is possible with lot care to produce

neutral soap by this process the soap is very liable to contain both free alkali and

unsaponified fat. The process is usually based on the fact that the glycerols of

certain low fatty acids oils (nut oils like coconut and palm kernel oils) readily

combines with strong caustic soda solutions at low temperatures, and generate little

heat to complete the saponification reaction.

In this process, it is absolutely necessary to use high grade raw materials. Oils and

fats should be freed from excess acidity because caustic soda rapidly neutralizes

the free fatty acids forming granules of soap which grain out in the presence of

strong caustic solution, and since the grainy soap is very difficult to remove

36

without heat increase, the soap tends to become thick and gritty and sometimes

discolors. The caustic soda being used should also be pure,it must contain as little

carbonate as possible, and the water must be soft and all other materials carefully

freed from all particles of dirt.

The process involves stirring into the milled fat in a tank, half of its weight of

caustic soda solution at the temperature of 24°C for coconut and 38°C to 49°C for

the blend. The pushing of the caustic solution into the oil must be done not only

slowly and continuously.

When the solution is being run into the oil, the mixture must bestirred in only one

direction. When all the caustic soda solution had been run into the oil and the

mixture stirred for 30 to 45 minutes, chemical reaction takes place with lot of

generation of heat, finally resulting in the saponification of the oil. The content of

the tank looks thin, but after some few hours it becomes a solid mass. The edges of

the soap becomes more transparent as the process advances further, and when the

transparency has extended to the full mass, the soap is ready, after perfuming to be

poured into moulding boxes for hardening, cutting and stamping.

A little caustic potash solution is used to blend the caustic soda solution which

greatly improves the appearance of the given soap, making it smoother and milder.

(http://ethesis.nitrkl.ac.in/5371/1/109CH0476.pdf, Accessed, 24/12/2014)

37

2.11.4 Cleaning Action of Soap

The cleansing action of soap depends on its physical properties as well as on its

chemical properties. There are several factors such as adsorption, surface tension,

electrostatic forces of the polar molecules, its wetting action, emulsifying power

etc., which are of great importance in deciding the cleansing action of soap. Soap

lowers the surface tension of water and this property of soap is very important in

its cleansing power, because it enables the water to wet and so come into close

contact with even a greasy surface. Soap wets the surface of fabric due to the

decrease in surface tension of water. Soap solution also have another important

property of emulsifying oils and fats. Hence they emulsify grease, oil etc., that hold

the dirt particles. Soap forms a protective film on the surface of a fabric and makes

it difficult for grease and the dirt particles to come together again. The dust and

grease particles can easily be removed by shaking vigorously with water. It should

be noted that soap attracts both polar as well as non-polar compounds

simultaneously because of the presence of hydrophilic –COONa group and

hydrophobic –R groups in its molecule. (Uppal, 2008)

2.11.5 Dermatological Action of Soap

Under normal conditions of use, soap may be considered innocuous to the normal

healthy skin. The overwhelming majority of people with healthy skin find the

38

average toilet soap a completely safe and effective cleanser. Irritation to soap –

when it does occur – may be due to:

Hypersensitivity to the soap base or to other added constituents. Or

To excessive exposure of skin to the action of the soap. It is a fact that no

substance known at present which can truthfully be claimed to be non-

allergic, hence a true allergic reaction to the fatty acids of a soap must

always be considered a “possibility” though the consensus of opinion is that

soap when it does give rise to irritation does so merely in virtue of being a

mild primary irritant. Proof that a pure soap base itself can act as a

“sensitizer” (as apart from a primary irritant) is lacking. Possible

sensitization from added colouring matters, perfumes, or antioxidants

incorporated should, however, be borne in mind. (Harry, 1963)

2.10.6 Industrial Application of Soap

Apart from washing and bathing, soap serves several other industrial purposes.

These purposes include:

Processing of Wool: Raw wool contains impurities which must be removed

in a soap bath. Because of the harmful effect of high temperature on wool

fibres, the scouring bath is maintain below 140°F and frequently between

110 to 120°F. For this purpose a soap of low titer is preferable because it is

39

more readily soluble at low temperature and better rinsing than high titer

tallow soap. (AOCS, 1952)

Processing of Silk: The processing of silk in the initial stage is carried out

in a boiling operation which lead to the term boil off. In this operation the

gum is removed from the silk by the solvent action of a neutral low titer

soap. The alkalinity of the soap solution serves to dissolve acidic

constituent in the silk gum, and the silk fibre remain as a softer, finer,

lighter, and more lustrous_material.(AOCS,1952)

Soaps are key components of most lubricating greases, which are usually

emulsions of calcium soap or lithium soaps and mineral oil. These calcium- and

lithium-based greases are widely used. Many other metallic soaps are also useful,

including those of aluminium, sodium, and mixtures of them. Such soaps are also

used as thickeners to increase the viscosity of oils. In ancient times, lubricating

greases were made by the addition of lime to olive oil (Thorsten, 2005)

40

CHAPTER THREE

MATERIALS AND METHODS

The raw materials (Palm fruit and Coconut fruit) for this work was locally sourced

at Ikot Usoekong community of Eket Local Government Area, Akwa Ibom State.

The extracted Palm Oil and Coconut Oil were analyzed individually and thereafter

the oils were blended in the ratio 75:25; 50:50 and 25:75 mass of Palm Oil to

Coconut Oil respectively. 5x5x2 (5 variables, 5 determination and 2 repeatability)

factoral design was employed to design this experiment.

3.0 Extraction of the oils

Palm oil: The fresh palm fruits were washed and boiled. The boiled fruits were

pounded. It was strained to separate the emulsion from the chaff and kernel. The

emulsion was boiled for the palm oil to float on the surface. The palm oil was

scooped while the water and other impurities were left behind.

Coconut oil: The coconut shell was broken and the coconut grated. The coconut

milk was strained from the chaff. The milk was allowed to ferment for the oily part

to float on the water. This was scooped and boiled till the oil was separated from

the cake. The oil was decanted.

41

3.1 Characterization of the oils

Saponification Value, Iodine Value, Free Fatty Acid Content, Peroxide Value, and

Ester Value was determined using methods described by Pearson, 1973.

3.1.1 Determination of Saponification Value:

Apparatus: Conical flasks of 300 – 500ml capacity fitted with water-cooled reflux

condensers or long air condensers (at least 110cm long) were used.

Reagent: Alcoholic Potassium hydroxide:40g of KOH pellets was dissolved in

20ml of water and diluted to 1 litre with 95% v/v alcohol. The solution was

allowed to stand for a day, and then filtered. The concentration was about (but not

less than) 0.5N

Procedure: About 2g of the oil was measured into flask A. All the subsequent

operations was performed on both A and the Blank (B). Exactly 25.0ml of the

approximately 0.5N alcoholic KOH solution was added, the reflux condenser was

attached and the flask immersed in boiling water for 60min. The flask was swirled

frequently during the heating. After refluxing, 0.5ml of 1% phenolphthalein was

added and titrated very carefully, whilst still hot, with 0.5N HCl (accurately

standardized). Volumes of 0.5N HCl used were Aml (sample) and Bml(Blank):

42

3.1.2 Determination of Iodine value (Wijs’ Method):

Wij’s Reagent: 8g of iodine trichloride was dissolved in about 200ml of glacial

acid and a solution containing 9g of iodine dissolved in 300ml of carbon

tetrachloride was mixed. The mixture was diluted to 1000ml with glacial acetic

acid.

Procedure: Two dry, stoppered reagent bottles, A and B, of 250 – 400ml capacity

was used. 0.24g of oil was weighed. Then 5ml of carbon tetrachloride was added

from a dry measuring cylinder into both A and B. All the subsequent operations

were performed on both A and B.

Exactly 10.0ml of wijs’ solution was added. The solution was swirled round and

the stopper inserted, which was previously moistened with 10% potassium iodide

solution, in the bottle. It was allowed to stand in the dark for 30min, then 10ml of

10% KI solution was and 50ml of distilled water were added. The solution was

swirled and titrated carefully with 0.1N sodium thiosulphate solution. From time to

time during the titration, the stopper was inserted and the bottle shakened. When

43

the aqueous layer became very pale yellow after shaking, starch solution was

added and the titration continued.

Volume of 0.1N thiosulphate used was Aml (sample) and Bml (Blank):

3.1.3 Determination of Free Fatty Acid (FFA):

Procedure:20ml of alcohol (95%) was mixed with 20ml of diethyl ether, 1ml of

phenolphthalein indicator (1% in alcohol) was added and the mixture was

neutralized by adding 0.1N KOH from a burette. 5g of sample was weighed out

into a beaker-flask (250ml capacity). Then the solvent was added to the oil, swirled

and titrated with 0.1N KOH until a pink colour persist for 15s

Titration = Vml of 0.1N of KOH and W = Weight of sample taken (g), then:

3.1.4 Determination of Peroxide Value (Lea’s Rapid Method):

Procedure: 1g of Oil was weighed into a boiling-tube, 1g of KI and 20ml of

solvent mixture (2:1 glacial acetic acid – chloroform) were added and placed in

boiling water for 60s. Immediately, the hot liquid was poured into a flask

44

containing 20ml of 5% KI and washed with 10ml of water. Starch solution was

added and titrated with 0.002N sodium thiosulphate (Titre = Tml, which did not

exceed 10ml)

Where W = weight of sample taken (g)

3.1.5 Determination of Ester Value

Ester Value = Saponification Value – Acid Value

Where Acid Value = 2 x Free Fatty Acid

3.2 Laboratory Scale Production of Toilet Soap

Soda Solution: This was prepared by mixing 15ml of caustic soda and 7.5ml of

Carboxymethyl Cellulose with 45ml of water.

Soda Ash Solution: This was prepared by mixing 15ml of soda ash and 7.5ml of

Sodium bicarbonate with 45ml of water.

The two solutions were mixed together, 7.5ml of sulphonic acid and sodium

silicate were added respectively. The final mixture was mixed with 180ml of oil

and stirring was done until it traced. It was heated in a water bath at 110ºC. The

heating continued until the gelling. Thereafter glycerine was decanted off and

45

essential oil and colourant were added. The soap was poured into mould. It was left

in the mould till it sets. The soap was removed from the mould and allowed to cure

for three weeks after which samples were taken out for quality analysis.

3.3 Analysis of Quality Parameters of Soap

The soap produced was analyzed for the following quality parameters: Total Fatty

Matter, Free Alkali, Moisture Content, Foam Stability, and pH using methods

described by AOAC, 1980.

3.3.1 Determination of Total Fatty Matter (TFM):

5 gm of soap was weighed and transferred into 250 ml beaker. To completely

dissolve the soap 100 ml hot water was added. 40 ml of 0.5 N HNO3 was added to

the mixture until contents were slightly acidic. The mixture was heated over water

bath until the fatty acids were floating as a layer above the solution. Then the

mixture is cooled suddenly in ice water in order to solidify the fatty acids and

separate them. 50 ml of chloroform was added to the remaining solution and

transferred into a separating funnel. The solution was shakened and allowed to

separate into 2 layers and the bottom layer was drained out. 50 ml of chloroform

was added to the remaining solution in the separating funnel. The fatty acid

dissolved chloroform was again separated as in the previous case and it was

46

transferred to the collected fatty matter. The fatty matter was weighed in a

previously weighed porcelain dish. From the difference in weight, the % of fatty

matter was calculated in the given soap sample.

where:

A – weight of the porcelain dish, g;

B – weight of the porcelain dish + soap after drying, g;

C – weight of the initial sample of soap, g.

3.3.2 Determination of Free Alkali:

A sample of the scrapped soap (10 g) was placed in a conical flask and 100 cm3of

neutralized alcohol added. The flask and the content was placed on a water bath

and heated until the soap dissolved. The 10 cm3 of 10% Barium chloride solution

and 2 to 3 drops of phenolphthalein indicator was added. The whole content was

titrated against O.IN H2SO4 until the solution became colourless. The free alkali

will then be calculated.

where:

47

M – molarity of H2SO4 solution, mol·L-1;

V – volume of H2SO4 solution used in titration, mL;

W – weight of the soap sample, g

3.3.3 Determination of Moisture content:

A sample of the scrapped soap (l0g) was introduced into a dish and placed in an

oven for 1 hour at 110°C. It was allowed to cool down and then weighed. The

moisture content in percentage was calculated.

3.3.4 Determination of Foam stability:

The soap produced was used to form lather in water and the time for the foam to

collapse was determined using a stopwatch.

3.3.5 Determination of Alkalinity:

1% of soap solution is prepared by dissolving about 0.5 g of the soap in 50 mL of

deionized water. Heat was applied to dissolve the soap completely. Using a pH

meter the alkalinity of the soap solution was determined. The electrode of the pH

meter was dipped inside the soap solution. The pH value of the solution was

recorded.

48

CHAPTER FOUR

RESULTS AND DISCUSSION

In this section, results obtained from the experimental design are treated using

tables and arithmetic mean. Descriptive statistical tool (scatter diagram) is used to

show a pictorial representation of results obtained. An inferential statistical tool

(correlation coefficient) is employed to test the experimental hypothesis.

The correlation coefficients were calculated using:

(Udoh and Etim, 2008)

Where x is the independent variable and y is the dependent variable.

Table 1: Industrial Characteristics of Palm Oil-Coconut Oil blend

SAMPLE BLEND

COMPOSITION

(PO:CO)

FFA SAP

VALUE

ESTER

VALUE

IODINE

VALUE

PEROXIDE

VALUE

1 100:00 0.48 201 200 55.7 4.8

2 75:25 0.45 232 231 43.1 5.0

3 50:50 0.49 248 247 28.9 4.6

4 25:75 0.42 257 256 15.6 4.9

5 00:100 0.46 262 261 8.5 3.8

FFA – Free Fatty Acid; SAP – Saponification; PO – Palm Oil; CO – Coconut Oil

49

Result here represents average of two replications

Free Fatty Acid – (as Oleic Acid), mg KOH/g

Saponification Value - mg KOH/g

Ester Value – mg KOH/g

Iodine Value – gI2/100g

Peroxide Value – Meq KOH/g

Table 2: Effect of coconut oil composition on industrial characteristics of the blend

INDUSTRIAL CHARACTERISTICS CORRELATION COEFFICIENT

Free Fatty Acid -0.40

Saponification Value +0.94

Ester Value +0.94

Iodine Value -0.99

Peroxide Value -0.69

50

Figure 4.1: Graph of Free Fatty Acid and Saponification Value

51

Figure 4.2: Graph of Ester Value and Iodine Value

52

Figure 4.3: Graph of Peroxide Value

4.1.1 Free Fatty Acid

Free fatty acid is usually present in oils as a result of decomposition of glyceride

by lipase. A high value indicates a stale oil stored under improper conditions. The

values obtained for Palm Oil and Coconut Oil fall within limits published in

literatures. A weak negative correlation was observed for the different blend

compositions. This indicates that free fatty acid for oils is a quality parameter that

is a function of storage and handling of the individual oils but is independent of the

blend composition of the oils. The values obtained here give evidence that the

individuals oils and the blends are suitable in production of Toilet Soap and other

industrial applications.

53

4.1.2 Saponification Value

Saponification Value helps to determine the amount of alkali needed to react with a

given amount of oil in soap production. It also indicates the extent of adulteration

of an oil. The values obtained for Palm Oil and Coconut Oil fall within limits

published in literatures. It was observed that with blending of Coconut Oil in Palm

Oil, the Saponification value of Palm Oil increased with increase in composition of

Coconut Oil. The results indicate that blending Coconut Oil in Palm Oil helps to

improve the Saponification Value of Palm whereas blending Palm Oil in Coconut

Oil lowers the Saponification value of Coconut Oil. The values obtained for the

oils and the blend reveals that both the individual oils and the blend of Coconut Oil

in Palm Oil will give optimum yield of Toilet Soap.

4.1.3 Ester Value

Ester Value is a relative measure of the amount of ester present. Esters which are

reaction products of fatty acid and alcohols are used in the manufacture of

pharmaceutical products, cosmetics, textiles, as emulsifier for agricultural

products, and as synthetic lubricants. It was observed that ester value increased

when coconut oil was blended with palm oil and decreased when palm oil was

blended in coconut oil.

54

4.1.4 Iodine Value

Iodine Value indicates the degree of unsaturation of acids in oils. Palm oil was

observed to have a higher value than coconut oil – Palm Oil being highly

unsaturated while Coconut Oil is highly saturated. These values are within limit of

those reported in literatures. Result showed that blending coconut oil in palm oil

greatly reduce the iodine value of palm oil. This will guarantee an increase of

oxidative stability of the palm oil – an evidence that coconut oil can be used as a

natural antioxidant to other oils. Also, since palm oil with a high iodine number

normally produces soft soap, blending the palm oil with a proportion of coconut oil

will add a relative hardness to the soap which will give a product that lasts.

4.1.5 Peroxide Value

Peroxide Value is a measure of oil deterioration. It gives the extent to which

rancidity reactions have occurred during storage. Result obtained for both palm oil

and coconut oil falls within limit reported in literatures. This indicates that both

oils were fresh and of good quality as at the time of extraction, characterization and

use. It was observed that there was a weak negative correlation with different blend

compositions. This reveals that peroxide value is an indication of quality and

stability of oil and it is independent of blend composition.

55

Table 3: Quality Parameter of Toilet Soap produced with the blend

SAMPLE BLEND

COMPOSITION

(PO:CO)

TFM

(%)

FREE

ALKALI

MOISTURE

CONTENT

(%)

pH FOAM

STABILITY

(MIN.)

1 100:00 75.5 0.78 13.7 9.7 3.6

2 75:25 74.7 0.89 14.3 9.9 3.1

3 50:50 69.9 1.21 16.9 10.0 2.8

4 25:75 66.8 1.67 20.6 10.2 2.2

5 00:100 62.6 1.95 22.7 11.3 1.6

TFM – Total Fatty Matter; PO – Palm Oil; CO – Coconut Oil

Result here represents average of two replications

Table 4: Effect of coconut oil composition on quality parameter of the toilet soap

QUALITY PARAMETER CORRELATION COEFFICIENT

Total Fatty Matter -0.98

Free Alkali +0.98

Moisture Content +0.98

pH +0.88

Foam Stability -0.99

56

Figure 4.4: Graph of Total Fatty Matter and Free Alkali

57

Figure 4.5: Graph of Moisture Content and pH

58

Figure 4.6: Graph of Foam Stability

4.2.1 Total Fatty Matter

This is the total fatty matter that the soap contains. The higher the fatty acid

content the better the quality of the soap. Total Fatty Matter accepted for toilet

soap is greater than 76%. It is the Total Fatty Matter that gives soap the soapy feel.

It was observed from the result above that Total Fatty Matter is affected by blend

composition of the oil. The greater the composition of Coconut oil in the blend the

lower the value obtained for Total Fatty Matter. This reveals that palm oil-coconut

oil blend with a greater percentage of coconut oil in the blend will lower the

quality of toilet soap produced in terms of Total Fatty Matter.

59

4.2.2 Free Alkali

Free alkali gives insight into the amount of excess alkali present in soap. Free

alkali is injurious to the skin, hence the quality of toilet soap is determined by how

free the soap is to free alkali. It is however noted that free alkali was present in the

research soap samples produced. This is because the soap samples were in their

crude form, without refining. In most cases, these free alkalis will neutralize out if

soap produced are given enough time to cure. It was observed from the result that

the presence of free alkali increased as the composition of coconut oil in the oil

blend increased.

4.2.3 Moisture Content

This is the amount of water present in the soap sample. Moisture affects the

lathering and cleansing property of soap. In addition, if moisture content is too low

in a soap, then the soap is liable to crumble during tablet milling, will not compress

satisfactorily and the finished tablet may have a tendency to crack and contain

gritty particles so objectionable in use. If on the other hand, the soap is left too

moist, it is apt to stick to the rollers and mill with difficulty, and during

compression the surface assumed a blistered and sticky appearance. It was

observed from the result obtained that the moisture content in the soap produced

increased with increase in composition of coconut oil in the blend. Soap makers

60

uses this as an advantage in that it will increase the yield of the soap produced. It

should however be noted that this will have a negative effect in the finishing

process of the soap making. Also, it will have the tendency of producing a off spec

soap in terms of quality parameter for toilet soap which moisture content should be

between 11 – 14 percent.

4.2.4 pH

pH is an important quality parameter for soap. It is the quickest indicator that

reveals the progress of a successful soap making. It determines the friendliness or

otherwise of soap to the skin. The quality set for soap in terms of pH is between 9

to 11. The closer the soap is to neutrality the better the soap quality. It was

observed that the pH of soap produced increased with increase in coconut oil

composition.

4.2.5 Foam Stability

Foaming makes soap different from other products. It is the foam produced that

reduces the surface tension between dirt and surfaces making it possible for

cleansing to take place. Foaming increases with time when the soap has fully

cured. Foam stability is the duration with which foaming is sustained when soap is

dissolved in water. It was observed from the result obtained the soap produced had

61

a satisfiable foam stability. However, this stability decreased with increase in

coconut oil composition in the oil blend. This could be explained by the fact that

coconut oil though it produces a better foaming in soap compared to palm oil, this

foam is only short lived. This short lived foam tendency in imparted to the oil

blend used in the soap produced. Another reason for the decrease in the foam

stability is as a result in moisture content which increases as coconut oil

composition is increased in the oil blend.

62

CHAPTER FIVE

CONCLUSION AND RECOMMENDATION

5.1 CONCLUSION

Industrial characteristics that are considered to be of utmost importance when

working with organic oils for soap production are saponification value, iodine

value, free fatty acid, ester value and peroxide value. Out of these characteristics,

some like saponification value, iodine value and ester value was observed to be

affected by varying composition of the oil blend being researched. While others

like iodine value and peroxide value were not affected but indicate the quality of

the oils and the blend in terms of freshness and stability to storage.

Results obtained from this research revealed that by blending coconut oil in palm

oil, the industrial characteristics of the palm oil is greatly improved thereby making

it better for industrial applications rather than using a single oil – either only

coconut oil or palm oil.

In the same vein, quality parameter of toilet soap such as total fatty matter, free

alkali, moisture content, pH, and foam stability was also investigated for both soap

produced by individual oils and the oil blend. Result indicated that the soap

produced was within specification compared to quality standards published in

63

literatures. However, it was observed that the soap quality parameter was reducing

as the composition of coconut oil was increased for the soap making.

To this end, it can be concluded that in order to achieved an improved industrial

characteristics from palm oil-coconut oil blend as well as attain a within spec

quality parameter for toilet soap, palm oil and coconut oil should be blended in the

proportion of 75 percent is to 25 percent composition.

5.2 RECOMMENDATION

Having carried out this research and the result analyzed, it can be seen that palm

oil and coconut oil can be blended to obtain an excellent industrial characteristics

for a wide range of industrial applications. The blend can used to produced toilet

soap with quality parameter that is within specification and at the same time rich in

ingredients imparted by both oils.

It is recommended that a commercial plant should be designed and setup to extract

these oils and blended for industrial use. The enhanced toilet soap obtained for this

work as a research product should be further studied for economics and a pilot

plant be setup to incorporate effort in finishing of the product to obtained a toilet

soap that will be both rich in quality and at the same time possess aethestic appeal.

64

Thereafter, a commercial plant should be designed and built to produce the toilet

soap for the consumers. This will creates jobs and boost the nation’s gross

domestic product (GDP). The venture will have technical, economical and

environmental feasibility because the oils are renewable resources and are

biodegradable.

65

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APPENDIX

Raw Materials used

Oils Extracted

Set up for Determination of Saponification Value

Soap samples produced

72