ABSTRACT
The quality of palm oil samples obtained from different markets in Abia North senatorial Zone, Nigeria were examined in terms of physicochemical properties. The result obtained showed that the saponification value (SV) ranged from 176.80 - 200.30 of oil. The free fatty acid (FFA) of the palm oil sample ranged from 2.16 - 3.84%, the peroxide value (P.V) ranged from 4.96-6.28meq/kg, the melting point ranged from 15.40-36.900C, carotenoid content ranged from 149.70 – 1134.10mg/kg, moisture content of the oil samples ranged from 0.260 – 0.690%, the specific gravity ranged from 1.390-1.459g/cm3, the smoke point ranged from 113.45-117.80oc, the impurity level ranged from 0.13-0.19%, the unsaponifiable matter ranged from 7.38-7.87g/kg and the iodine value (I.V) ranged from 75.86-90.16. The result obtained after the statistical analysis showed that there were no significant differences in the saponification value, free fatty acid value, iodine value, moisture content, unsaponifiable matters, smoke points and melting point of the palm oil samples. However there was marked differences in the the values of the impurity level, peroxide value of the samples and the carotenoid contents (185.60 – 1134.10mg/kg).
TABLE OF CONTENT
Title Page i
Certification ii
Dedication iii
Acknowledgement iv
Table of Content v
List of Tables vi
Abstract ix
CHAPTER ONE:
INTRODUCTION
1.1 Background of the study 1
1.2 Statement of the problem
7
1.3 Objective of the study 7
1.4 Significant of the study
8
CHAPTER TWO:
LITERATURE REVIEW
2.1 An over view of palm oil 9
2.1.1Botanical information on Palm
Oil 13
2.1.2 Food and non -food uses of palm
oil 14
2.1.3 Nutrient content of palm oil 15
2.1.4 Impurity and contaminants in
palm oil 15
2.2Anti-oxidants in palm oil 16
2.2.1Carotene Value 16
2.2.2Effects of carotenoids 16
2.2.3Effects of Tocopherols and
Tocotrienol 17
2.2.4Fatty acids 18
2.2.5 Free Fatty acids 19
2.2.6 Peroxide Value 19
2.2.7 Sterols 20
2.2.8. Polar Lipids 20
2.2.9Phenols 20
2.3 Food uses of palm oil 21
2.3.1 Margarines 21
2.3.2Shortenings 21
2.3.3 Vanaspati 21
2.3.4 Frying Fats 21
2.3.5 ConfectioneryFats 22
2.4 Benefits of Palm Oil 22
2.4.1 Controversies of Palm Oil 23
2.4.2 Effects of Palm Oil on Health 23
CHAPTER
THREE: MATERIALS AND METHODOLOGY
3.1 Study area 25
3.2 Study Design 26
3.3 Sampling Techniques 26
3.4 Collection of Samples 26
3.5Laboratory Analysis 26
3.5.1 Melting Points 27
3.5.2Iodine Value Determination 27
3.5.3Free Fatty Acid Determination 27
3.5.4Determination of Saponification
Value 28
3.5.5 Determinationof Peroxides Value
29
3.5.6 Determination of Carotene
Value 29
3.5.7
Moisture content determination
30
3.5.8
Impurity determination 30
3.5.9 Specific gravity
determination 31
3.6 Statistical Data Analysis 31
CHAPTER
FOUR: RESULTS DISCUSSION
4.1 Free fatty acids
content of the palm oil samples 32
4.2 Melting Points
Content of Palm Oil Sample 34
4.3 Saponification Value
of Palm Oil Samples 35
4.4 Peroxide Values of
Palm Oil Samples
36
4.5 Specific gravity of palm oil samples
38
4.6 Iodine Value of Palm
Oil Samples 39
4.7 Carotenoid Content of palm oil samples 41
4.8 Moisture content of
palm oil 42
4.9
Smoke points of palm oil samples 43
4.10 Impurity level of palm oil
samples
44
4.11 Unsaponifiable matters of palm
oil samples 45
CHAPTER FIVE: CONCLUSION AND RECOMMENDATION
5.1
Conclusion 48
5.2
Recommendation 48
REFERENCES 49
LIST OF TABLES
Table 4.1: Free Fatty
acids (FFA), Melting points, Saponification values, Iodine values, Peroxides values and Specific
gravity of palm oil samples 31
Table 4.2: β-carotene,
moisture content, smoke points, impurity level and unsaponifiable matters of palm oil samples 40
CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
The oil palms
(Elaeis) comprise two species of the Aracaceae family. They are used in
commercial agriculture in the production of palm oil. The African oil palm
(Elaeisguineensis)
is native to West Africa, the palm fruit takes five to six month to mature from
pollination to maturity. Nigeria used to be the world’s largest producer of oil
palm (Elaeisguineensis), before the
crude oil boom era and now Malaysia has taken the leading position (Onwubuyaet al., 2012). The fruit is reddish and each fruit is made
up of an oily, fleshy outer layer (the pericarp), with a single seed (the palm
kernel) also rich in oil. Oil is extracted from both the pulp of the fruit and
the kernel. Palm oil plant is the highest oil producing plant, Ngandoet al., (2011) estimated an average of
3.5tonnes of oil in a year. The oil is extracted from the mesocarp of the
fruit. Since 2006, palm oil has become the world’s most important edible oil
(Udensi and Iroegbu, 2007). Mathew (2009) stated that many plantations of oil
palm have and are being established in West Africa, but most palm produce is
obtained from growing wild. The bulk of palm oil that is produced goes into
food applications; hence its nutritional properties have been extensively
studied. Palm oil is currently the second largest traded edible oil and
accounts for about one quarter of the world’s fats and oil supply
(Ibekwe,2008).
The palm fruit
(ElaeisguineensisJacq.) is the source
of both palm oil (extracted from the palm fruit) and palm kernel oil (extracted
from the fruit seeds) (Edem, 2002; Lin, 2011). Berger (2005) opined that
Malaysia, Indonesia and Nigeria are the major producers of palm oil. According to Akusuet al. (2000) in Nigeria the oil is
extracted by different methods in different locations, and this oil production
is an important support of home agriculture. Palm fruit oil processing in Abia
may be categorized into two methods; traditional
and industrial. In both methods, palm plantations are often very far from local
processing plants. The palm fruit is harvested when the fruits are ripe. The
fruit is manually threshed by cutting the fruit laden spikelets from the bunch
stem with an axe and then separating the fruit from the spikelets by hand. The
fruit is then transported by human, animal or truck for delivery in the
courtyards of industries and/or farms, which means a week or more before
processing (Gomes et al., 2010).
According to traditional methods, the fruit processing is followed by
maceration and pilling, or an animal-driven instrument that consists of a stone
or cement wheel that crushes oil from the palm fruits (Mesquita, 2002). The
mixture is placed with water in a half gallon container or any vessel that can
be heated. After extraction, the recovered oil is heated again to remove the
residual water and, when cool, is bottled and stored for consumption (Gomes et al., 2010).
In Nigeria, palm oil tree grows in the coastal
belt of Nigeria which varies in depth from 100 to 150 miles and a riverine belt
which follows the valleys of the Niger and Benue for a distance of about
450miles from the sea and naturally, production of palm oil usually occurs
along these locations (Food and Agriculture Organization (FAO), 2002).
Palm oil is naturally
reddish in colour because it contains a high amount of beta carotene. Palm oil
has been used in food preparation for over 5,000 years (Poku, 2002).
Chandraseklamet al. (2000) reported
that it is the most widely produced edible vegetable oil in the world and it’s
nutritional and health attributes have been well documented. Palm oil is
usually one of the products produced from the oil palm tree which is a
perennial crop that originates from the tropical rain forest of west African.
The main palm
oil producing states in Nigeria include Cross River, Abia, AkwaIbom, Imo,
Rivers, Anambra, Enugu, Ogun, Delta, Edo, Oyo and Ekiti (FAO, 2002).
Market and Oil
The marketers
and consumers of the products play a significant role in the overall acceptance
of such product by the final consumers. It is the role of the marketers to
transport palm oil produced in oil palm densely produced area (Izah et al., 2014)).
Ohimainand
Izah (2014) emphasized that marketers can also encourage consumers to patronize
palm oil produced locally. Though it’s very difficult to determine the palm oil
imported and the ones produced locally at the market level. The marketers
usually buy the palm oil in large quantity and store them in 20 liters’ jerry
cans, Izahet al. (2014) reported that
during storage, the palm oil could also get degraded by the activities of
microorganisms, thereby, leading to changes in its quality assessment. The
microbial quality could also be impaired during marketing especially during
retailing. Containers, plates, bottles are used for selling palm oil and
sometimes the microbial quality of the materials used in selling are not put
into consideration by the marketers (Ohimain and Izah, 2014). This is common
phenomenon in busy markets especially during wet season in rural areas in
Nigeria (Ekine and Onu, 2008).
There is a
wide spread speculation that palm oil is being adulterated for the sole purpose
of profit maximization. The adulteration ranges from the use of colours, dyes,
water and other illegal food additives which could affect the quality of palm
oil in terms of nutritive value, wholesomeness, utilization, safety and
shelf-life. Adulteration is the process in which the quality of food is lowered
either by addition of inferior quality material or by extraction of valuable
ingredient. It not only includes the intentional addition or substitution of
the substances but biological and chemical contamination during the period of
growth, storage, processing, transport and distribution of the food products,
is also responsible for the lowering or degradation of the quality of food
products. The expertise put to use in the production of this oil has made it
practically impossible to physically differentiate between a good palm oil and
the fake. Many consumers look for redness before buying their palm oil. Of
course, that is one major attribute of the oil. Oftentimes, these improperly
made bottles or kegs of oils are more expensive than the properly made ones as
consumers tends to rush them unknowingly (Centre for Science in the Public
Interest (CSPI), (2005). Adulterants are those substances which are used for
making the food products unsafe for human consumption.
The quality of
crude palm oil (CPO) is essential in determining its applications. The quality
is associated with the method of processing. In Nigeria, there are three types
of oil palm processors, traditional (mostly manual), semi-mechanized
andmechanized processors (Foundation for Partnership Initiatives in the Niger
Delta (FPIND, 2011). To a larger extent, smallholder/traditional processor
dominate the sector accounting about 80%, smallholders use rudimentary/
manual/traditional equipment for processing (Ohimainet al., 2012). According to Okechaluet al. (2011) smallholder processors maintain low level of hygiene
in the processing mills. These have resulted to low quality of CPO. The major
processing activities irrespective of kind of processing that could affect the
quality of CPO produced include bruises during transportation, fermentation
prior to threshing, clarification and storage (Ohimain and Izah, 2013b).
According to
Akinolaet al. (2010) CPO is orange
red to brownish or yellow-red in color, semi-solid at room temperature and is
highly saturated. Palmitic acid
increases in palm oil are mostly associated with oils produced from over-ripe,
bruised and crushed fruits, fruits subjected to severe impacts from loading and
off-loading bunches and oils stored over long periods (Tagoe, 2008).
The importance
of quality palm oil in our diet cannot be overemphasized. It is the main
vegetable oil consumed in the world today, accounting for 33% of all oils
consumed globally, closely followed by soya oil with 31% (Iceland Stock
Exchange (ISEX, 2014).Grapevine (2008) reported that in the previous decade,
world palm oil consumption has more than doubled from around 16.7 million
tonnes in 1997/98 to over 40 million tonnes in 2007/08 and this figure is
estimated to surpass 70 million tonnes by 2020. Palm oil is very nutritious.
They are useful for bone, joint, and skin health. Not only is palm oil a rare
source of medium chain fatty acids, it is also a source of healthy unsaturated
fats. It is a well-balanced fat, with 39% oleic acid (omega-9) and 10% linoleic
acid (omega-6) (Ugwuet al., 2002).
These essential fatty acids help to lower blood cholesterol levels in the body.
It is the richest vegetable oil source of tocotrienols – which are potent forms
of vitamin E. Vitamin E strengthens the immune system, and protects skin cells
from toxins and ultraviolet radiation (Ugwuet
al., 2002). From its reddish-orange colour, palm oil is also a good source
of β-carotene, a nutrient found in sweet potatoes, carrots, and other orange
foods.
Ugwuet al. (2002) stressed that palm oil
contains fat soluble carotenoids which are responsible for its high vitamin A
content. β-Carotene is useful as a precursor to vitamin A (retinol) in the
body, it is a powerful antioxidant and act to reduce the risk of certain cancer
and heart diseases (Tanumiharjo, 2002).The high nutritional value especially
its high oil content greatly predisposes it to deterioration. Tagoe (2008)
opined that the quality of palm fruits, processing techniques, handling and
storage are critical points to be considered in the production of quality palm
oil. This is in a bid to minimize the mould load, free fatty acids (FFA),
aflatoxin contents, moisture content and other anti-nutritional and
deteriorating factors as their presence especially in high values exceeding
permissible levels, reduces quality which are undesirable and hazardous to
health of consumers. Moulds are known to effect various biochemical changes in
all classes of crops (Tagoe, 2008).A relatively new output from the oil palm
fruit is the water soluble phenolic flavonoid rich antioxidant complex, which
has potent antioxidant properties coupled with beneficial effects against skin,
breast and other cancer.
Its water solubility is being currently tested
for use as nutraceutical and in cosmetics with potential benefits against skin
aging (Sundram, 2003). Various microorganisms have been implicated in the
deterioration of palm oil and other vegetable oils examples,Aspergillusflavus, A. niger, A fumigatus,
Penicillumfrequentans, Rhizopusstoloniferand others. According to Okechaluet al. (2011) these moulds have
lipolytic activities and their growth results in lipolysis (spoilage) of the
palm oil. In general, the rate of lipolysis is proportional to the amount of
the free fatty acid already present in the oil. Frying and cooking of the oil
can reduce the microbial load to the minimum level, but the fact that some
individuals consume this product raw is of concern as this may result in health
problems in such individuals when the microbial load is high (Okechaluet al., 2011).
Apart from
moulds capable of digesting and exhausting nutrient content of crops, more to
be feared is the added danger of aflatoxin production in the oils. Aflatoxins
are highly undesirable in palm oil as they are very toxic and carcinogenic
compounds that have been implicated as causative agents in human hepatic
carcinogenesis. High saponification as well as high moisture in palm oil
samples is equally undesirable. High saponification value in palm oil is an
indication that the oil is more suitable for soap making than for consumption.
While high moisture predisposes palm oil to quick deterioration and spoilage as
it provides an enabling environment for microbial proliferation and activity
(Enemuor et al., 2012).
1.1
Statement of
Problem
Adulteration
is posing a serious threat to edible oil trade in Abia North Senatorial
Zone.There are a lot of palm oil in the markets nowadays that when used in
cooking, it doesn’t give the desired taste and colour. Because palm oil has
high nutritional value and is also important in socio economic activities, it
is very necessary to examine the quality of palm oil that is consumed by the
local communities in Abia North Senatorial Zone.
1.2
Objectives of the Study
The general
objective of this study is to assess the quality of the palm oil sold in major
markets in Abia North Senatorial Zone, Nigeria.
The specific
objectives are to:
1.
determine the percentage of free fatty acid.
2. determine the
saponification value.
3. determine the
iodine value.
4. access the
peroxide level.
5. access the melting
point.
6. determine the
carotenoid value.
7. determine the
moisture content.
8. access the
smoke point.
9. access the
impurity level.
10. determine the
specific gravity.
11. determine the
unsaponifiable matters.
1.3
Significance
of the Study
This study
will serve as a reference for governmental and non-governmental organization
board to research extensively to provide sufficient researched work concerning
palm oil production, storage, handling and preservation.
This study
will help consumers and marketers to know the best palm oil and what happens
around palm oil production and marketing.
This study
will make effort to identify the nutritive value of palm oil produced and sold
in markets.
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