OPTIMIZATION OF THE EFFECTS OF DEGUMMING PARAMETERS ON THE REMOVAL OF PHOSPHOTIDES, AND THE STABILITY OF REFINED PALM OIL

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International Journal of Scientific Research Engineering & Technology (IJSRET), ISSN 2278 – 0882Volume 4, Issue 9, September 2015

OPTIMIZATION OF THE EFFECTS OF DEGUMMING PARAMETERS ON THE

REMOVAL OF PHOSPHOTIDES, AND THE STABILITY OF REFINED PALM OIL.

EGBUNA S.O.1

Department of chemical engineering, Enugu State University of Science and Technology, Enugu.

ABSTRACT: This work investigated the effects of degumming parameters of the degumming stage on the stability of

refined palm oil. The raw palm oil used in the investigation was obtained from Adah palm Oil mill, Imo State, in the South – Eastern province of Nigeria. The oil was characterized before and after refining and used in the investigation. CentraComposite Design,(CCD), a type of Response Surface Methodology (RSM), was used to optimize the process conditions of

degumming acid, contact time and process temperature. The result showed that quality of final product of palm oilrefining depends on the conditions of degumming, and on the nature of the degumming chemicals used. The degummingwas done at a temperature range of 40 to 120oC, and the optimum temperature was found to be 80oC, at the contact timeof 40 minutes, and acid concentration of 1%. It was established that colour fixation during deodorization is mainly due tothe decomposition of the oxidation products of aldehydes and ketones at the deodorization temperature of 200oC and

above. The stability standard of the refined oil was however, measured in terms of colour,2.5 Red units, Free Fatty Acid(FFA) 0.01%, Peroxide Value(PV) 2.8m.eq/kg, Anisidine Value(AV) 6.8m.eq/kg, Iodine Value(IV) 4.9, Iron (Fe) 4.3 x103(Ppb), and Phosphorous content 0.03(mg/l), all of which were compared with those of the American Oil ChemisSociety (AOCS),[1].

KEY WORDS: Optimization, Degumming, Characterization, RSM, phosphotides, Stability.

1.0 INTRODUCTION In the past few years demand for refined vegetable oils has increased worldwide, Worldbook Encyclopedia,2001

Gunstone,2002, and Rauken, 1993. This might be due to increase in world population, rising standard of living andconsumer preference. Vegetable oils find applications as cooking and frying oils, as well as in the manufacture ofmargarine, shortening, baker’s fat, soap, grease, lubricants, creams, as well as biodiesel, Pahl, 2005, and hence the need to

stabilize its quality for these purposes.

Palm Oil fruit, is a monocotyledonous fruit obtained from oil palm (Elaeis Guinensis) found in abundance in the Eastern part of Nigeria, Http://en.m.eikipedia.org/wiki/Vegetable_oil. It is 0.5 to 5mm long, and oval in shape and weighs about 6- 8g on the average. The oil content of the fruit is about 50%,Mahatta, 1985, Nkpa et al 1989. Human beings have known

how to extract oils from their natural sources since ancient time, and make them fit for their use. The oils were consumedcrude, since very little treatment was done order than filtration or decantation. In Nigeria, palm oil is still consumed crudeHttp://en.m.eikipedia.org/wiki/peroxide_value.

Two methods are used in the extraction of the oil in the recent times, namely mechanical expression and solvent

extraction Dawodu, 2009, and Egbuna and Aneke, 2005. The former is pressure dependent, while the latter works withdiffusion principles, making use of hexane as solvent, Egbuna et al, 2013(a). The oil contains considerable amount ofimpurities like Free Fatty acid, carotene and chlorophyll pigments, phosphotides, odour, and oxidation products, which

are usually removed by refining, because they impart unpleasant odour and flavour to the finished product, per oxideEgbuna 2013.

Two refining methods are available, Egbuna et al, 2013(b), and Belaw and Tribe, 1972; the chemical process, which

makes use of caustic lye to neutralize the FFA content, and the physical process, which came into use by the 20th

century,[7]. The latter was so much improved upon at the deodorization stage, with the effect of reduction in overall

processing cost.[12].

Practical experience has distinguished the two process routes. There is a substantial colour reduction at the neutralization

stage, and fuel savings on steam distillation of the chemical process, due to the moderate temperature applied to preserve


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the anti oxidants, sterol and tocopherol present in oil, Anderson, 1962. Capacity is also improved, and quality is assured.The physical process offers advantages of improved deodorizer efficiency, low water consumption, reduced oil loss

savings on chemical, manpower reduction, less corrosion and pollution tendencies, and equally high quality stability, andhence its choice of the process method, [12].

Hoffman, 1989, had shown that bleaching stage of the refining of palm oil and the nature of the bleaching clay used playa vital role in the stability of the finished product. Hymore and Ajayi, (1996), have also demonstrated that Local activated

Clay can effectively remove caroteniod from palm oil.

Many factors influence the stability of refined oils, and have been the subject of much study, Olaofe et al, 1994. Amongthem are; type of raw oil, its colour, Phosphotides, Free fatty acid content, taste, and other physical and chemicalcharacteristics. To be refined, the raw oil has to be degummed, Egbuna et al, 2007, Mbah, and Njoku, 2007, and Ige, et al

1984, bleached and deodorized in order to remove its objectionable properties,[3]. The degumming process is a well-established operation in the processing of edible oils, and is one of the major stages for the stabilization of the refined oilsAll the colloidal and suspended particles, and soluble phosphotides would have been removed at this stage

Anderson,1997, Danh et al,2009, and Ruddy, 2011, had, in one time or the other used design expert, statistical method orapplied RSM in their work to optimize the process conditions during extraction or refining of vegetable oils. NIST/SEMATECH 2012, and Ejikeme et al 2013, had also used RSM to optimize the bleaching of Oil using a locally activatedclay.

In this work, we have;

shown how the stability of the refined palm oil is affected by the conditions under which the degumming iscarried out.

shown why degumming stage of palm oil refining remains a vital part of palm oil refining

demonstrated how an effective degumming stage can lead to good oil quality,

tried to optimize the degumming process parameters of time, Temperature and acid concentration, with a view toobtaining the optimal values for the degummed palm oil.

2.0 EXPERIMENTAL 2.1 Materials/Equipment: The materials and equipment used in the investigation include; raw (crude) palm oil received

from Adah palm Industry, South Easter province of Nigeria[10], bleaching earth (Activated Ngwo clay), test chemicalstitration apparati, a set of sieves, Lovibond Tintometer, Steam/vacuum apparatus, Distillation apparatus, conical flasks, beakers, and test tubes, magnetic stirrer, and steam bath. Table 1 shows the physio-chemical properties of the palm oi

used in the investigation.

(a) Properties : The properties of the oil that were determined include, the PO4 (Ppm), FFA(%), PV(m.eq/kg)AV(m.eq/kg), Colour, Fe(Ppb), etcetera, of the degummed, bleached and deodorized palm oil. This was done by usingthe American Oil Chemists Society (AOCS) standard test methods. Their values are presented in Table 3.

(b) Sample : The crude and refined oil samples used for the stability tests were stored in full, glass bottles at 313K for 28

days. Colour, phosphorous, FFA , PV, and AV, were measured at intervals. The activated bleaching clay used was sievedto 70 - 5 microns and the same sample was used throughout the experiment.

2.2 Experimental procedure:(a) Degumming Process : Degumming of crude Palm oil was done to reduce the phosphotide so as to minimize the

foaming tendency of the finished product observed during frying. The experiment was done using Citric acid, phosphoricacid and water, and the results compared with international values presented in Fig. 1


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Table I Physico -Chemical properties of the palm oil used in the investigation AOAC,[1], Bockish, 1998

Characteristics Crude palm oil

Physical Colour Deep orange red

Odour Slight palm oil odour

Taste Palm fruit taste

Sp. Gravity 0.9182Slip/Melting point 35oC

Moisture 1.3%

Refractive index 1.4512

Free fatty acid (FFA) 3.8%

Colour in 1 inch cell 23Red units

Anisidine value m.eq/kg 8.2

Peroxide value m.eq/kg 5.8

Acid value 9.8

Phosphorous (Ppm) 9.0

Iodine value 48.0

Iron (Ppb) 3.0

Table II Laboratory experimental results compared with the international standard. (Test temperature is 80oC

and bleaching earth dosage is 1%)

Parameters Laboratory experiment International standard

Degummed

Oil

Bleached

Oil

Deodorized

Oil

Degummed

Oil

Bleached

Oil

Deodorized

Oil

Colourin1inchcell

19.5 Redunit

11.5Redunits

3.2Red units 20.0 Redunit

10.5Redunits

2.5 Redunits

FFA% 3.5 2.8 0.12 3.2 3.5 0.1

PV m.eq/kg 5.8 4.2 3.00 4.8 3.2 1.0

AV m.eq/kg 7.5 6.4 4.05 6.6 6.0 3.7

IV (Ppb) 50.6 45.2 45.0 50.6 46.0 45.0Phosphorous 0.035 0.03 0.015 0.52 0.35 0.012

Iron 350 20.0 4.30 280 200 0.05

One per cent (1%) by weight each of citric acid and phosphoric acid were added to 100g of the crude oil sample in a

conical flask. The mixture was heated to a constant temperature of 353K, and stirring done with the magnetic stirrer for 40minutes. The whole mass was poured into a separating funnel and allowed to settle for 30 minutes. The lower layer (thelecithin), was run off through a valve. Temperature was subsequently varied.

(b) Bleaching: The aim of bleaching was to reduce the carotene pigments so as to minimize the formation of

hydroperoxides during deodorization and storage. The experiment was done with the activated clay.

One per cent (1%) by weight of the clay was added to 100g of the oil sample. The mixture was heated to a constantemperature of 373K, with stirring for 30 minutes. The oil was then filtered at the same temperature, and the filtratecharacterized. The results are shown in Table III.

(c) Deodorization: Deodorization, which essentially is steam distillation, was aimed at removing odour, colour, FFA and

undesirable flavour in the oil. This was done at a temperature of 473oC and for 60 minutes. At these conditions, the β -

Carotene pigment bonds were broken and the pigments, as well as iron metal which is apro-oxidant was removed with theodoriferous materials, thereby improving the colour and taste of the refined product.


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1 liter of degummed oil was taken into the distillation equipment and pre - heated to a temperature of 373K. Steam wasgenerated by heating water in a around bottom flask and passed into the oil through a delivery tube. Temperature was then

increased to 473 K, and vacuum was applied by means of the vacuum pump and maintained at 20mmHg absoluteVaporized moisture, odoriferous matter, FFA, and colour pigments were condensed in the reflux condenser in whichwater is used as a cooling medium. The condensate which was essentially Fatty acid , was collected in a beaker. This is a

batch process. The refined oil was then analyzed for FFA, colour, PV, AV, PO4 and Fe.

2.3 Characterization of degummed, bleached and deodorized oils, [1], Betiku et al., 2012.

The degummed, bleached and deodorized oil samples were subjected to analyses to determine their physical andchemical properties. Among the properties determined, which will be reported here include; colour, FFA, PV,AV, PO4and Fe contents

(a) Phosphorous: The phosphorous in the oil sample was determined by ashing. The phosphate obtained was transferredinto phosphomolybdate which was reduced to a blue- coloured compound . The concentration of the blue compound wasdetermined by comparison with blue colored glass disks.

Procedure: 5g oil sample was weighed into a platinum dish, and 0.5g calcium oxide added and both ashed. The ash wasdissolved in 10 - 15 cc of 2N hot dilute hydrochloric acid, and filtered into a 100cc volumetric flask. The dish was washedinto the volumetric flask and filtered, and, made up to 100cc. A blank experiment was similarly prepared, but with no oil

sample present. 5cc of the filtrate was taken in a tube and 2cc and 1cc of molybdate and hydroquinone solution added inthat order. The mixture was allowed to stand for 5 minute for the green phosphate colour to develop. 2cc ofcarbonate/sulphate solution was quickly added and stirred, ( CO2 evolved). Both the test experiment and its blank were

placed in the comparator against a uniform light for comparison. The result was reported as ;

Phosphorous (Ppm) =10000

326.05

Gxvx

x AxVx 1

Where A - comparator scale reading of PO4 (Ppm), V - Volume of ash solution, v - volume of ash solution taken for the

colour development, G - weight of oil sample.

(b) Colour pigments: Colour pigments present in Palm oil include; carotenoids, chlorophyll, and gossypol. The carotenehas been found to be an excellent indicator of crude oil quality.

Procedure: Lovibond Tintometer with 1-inch cell was used for the analysis of colour, and the latter read in terms of redcolour band that matched the colour of the refined oils.

(c) Free Fatty acid: Free fatty acid results from chemical or enzymatic hydrolysis of the fatty acid glycerides. Its presence in oil sample is a measure of the quality of the crude and refined oils.

Procedure: 2.8ml of oil of known FFA, was measured into a conical flask and diluted with 25ml of ethanol. A drop o

phenolphthalein was added. This was titrated against 0.1N sodium hydroxide until a permanent pink colour wasregistered, and the results recorded.

FFA(%) =

W

VxMxN

10

2

Where, N - Normality of NaOH; V - Volume of NaOH; W - Weight of oil sample, M- Molecular weight of oil sample

used.

(d) Oxidation products: When an unsaturated fatty acid chain reacts with air at room temperature, (a process known asautoxidation), hydroperoxides are formed. At high temperature, these peroxides break down to hydrocarbons, aldehydes

and ketones. These cleavage products impart odour and flavour to oil and must be removed.

(i) Peroxide Value; This is a measure of primary oxidation whose product is hydrocarbons. These hydrocarbons arefurther oxidized to water, which causes rancidity of the oil on storage.


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Procedure: 30ml of chloroform - glacial ethanoic acid mixture in the volume ratio of 1:2 was transferred to a conicaflask connected to a reflux condenser. The mixture was then heated to boiling and the vapour condensed in the lower part

of a jacketed tube. When the reflux became steady, about 1.6 ml of potassium iodide was added from the top of thecondenser. The precipitate of KI was dissolved by adding 5 drops of water. The mixture was heated for 5 minutes and 2mlof the oil was pipetted into the mixture through the top of the condenser also. The pipette was rinsed with 2ml ofchloroform into the boiling mixture, and boiling continued for 5 minutes. 50ml of distilled water was added, and 2ml ofthe sample was then titrated with 0.02N thiosulphate solution, using starch solution as indicator. The result is reported as;

PV =G

VxNx1000 3

Where V - vol. of thiosulphate used (ml), N - normality of thiosulphate solution, and G - vol. of sample (ml)

(ii) Anisidine value ; This measures the amount of secondary oxidation in a sample of oil. Its products are aldehydes andketones, whose oxidation induces higher rancidity effect to the oil.Procedure; The procedure for analysis for AV is the same as in the PV, except that the temperature at which these

cleavage products are formed is higher.

(e) Iron (Fe): This is a metal element which, with copper, induces oxidation of the unsaturated fats and oils at the double bond. Removal of iron will reduce the rate of oxidation reaction at the high temperature of deodorization.

Procedure: 0.2mg Fe stock solution was pipetted into 100ml conical flask. 10ml of 10% hydroxylamine hydrochloridewas added. The solution was diluted with water and mixed. 10ml of 0.25% phenolphthalein was added and allowed to

stand for 15 minutes and diluted to the mark. Using about 5ml test tube, the transmittance was read in spectrophotometer20 at 510 UV light.

2.4 Optimization with CCDOptimization of the factors for the degumming of palm oil using phosphoric acid was carried out using Centra

Composite Design, a type of Response Surface methodology, RSM. The CCD had two factorial level with 3 numericfactors, which also has 6 axial points and 6 centre points, Betiku, et al 2012. The factors and levels used for the CCD are

shown in Table IV, while the design matrix with the responses is shown in table V.

Table I I I , Factors and levels for the RSM (CCD)

Table IV Design matrix with responses for PO4 removal, (mg/l)

Std Run Acid conc Time Temp. Response

Order Order (%) (mins) (o

C) (mg/l)3 1 1.00 40.00 40.00 0.10086 2 2.00 20.00 80.00 0.0541

2 3 2.00 20.00 40.00 0.184215 4 1.50 30.00 60.00 0.0612

10 5 2.50 30.00 60.00 0.1915 6 1.00 20.00 80.00 0.042512 7 1.50 50.00 60.00 0.05421 8 1.00 20.00 40.00 0.102120 9 1.50 30.00 60.00 0.0946

Variable Units - -1 0 +1 +

Acid Conc. w/v(%) 0.05 0.10 0.15 0.20 0.25

Temperature oC 40 60 80 100 120

Contact time Min 20 40 60 80 100


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13 10 1.50 30.00 20.00 0.137511 11 1.50 10.00 60.00 0.0931

4 12 2.00 40.00 40.00 0.17859 13 0.50 30.00 60.00 0.02458 14 2.00 40.00 80.00 0.045618 15 1.50 30.00 60.00 0.085317 16 1.50 30.00 60.00 0.0784

14 17 1.50 30.00 100.00 0.03457 18 1.00 40.00 80.00 0.032919 19 1.50 30.00 60.00 0.077916 20 1.50 30.00 60.00 0.0759

3.0 DISCUSSION

3.1 Variation of degumming conditions

3.1.1 Temperature:

Table V presents the degummed oil colour, (Red unit), as a function of temperature. The subsequent deodorization colouris shown when deodorized at constant temperature, while table V shows the stability results of storing the refined oil for28 days.

Table V The effect of Degumming temperature on the Colour, PV, AV, FFA, PO4, and Fe of physically refined

palm oil.

Table VI The ef fects of degumming on the keeping quali ty of refi ned palm oil .

From table V, the degummed oil colour reduces as temperatures increases, with optimum at 80oC. The corresponding bleached temperatures is optimized at the degumming temperature in the range of between 70 and 90oC, while the

deodorized temperature is optimized at a degumming temperature of 80 - 90oC. The peroxide value of the

TempoC

Colour in 1 inch cell PV

m.eq/kg

AV

m.eq/kg

FFA

%

PO4(Ppm)

Fe

(Ppb)DegummedOil

Bleached

oil

Deodor

oil

40 21.2 14.2 3.8 6.8 3.5 0.62 0.83 8.1

50 20.8 13.8 3.6 6.5 3.55 0.61 0.65 8.0

60 20.6 13.5 3.5 5.3 3.72 0.58 0.48 7.8

70 20.3 13.3 3.2 5.0 3.85 0.55 0.22 7.3

80 20.2 12.6 3.0 4.2 3.92 0.38 0.15 6.890 20.4 12.7 2.9 2.0 4.00 0.40 0.18 5.0

100 20.5 13.0 2.8 1.12 4.20 0.43 0.20 4.3

110 20.8 13.2 3.0 1.50 9.8 0.48 0.25 4.2

120 21.0 13.3 3.8 1.28 12.4 0.52 0.28 4.0

Time(days) Colour (red), 1” Cell PV Deodorized oil

Degummed at

80oC

Degummed at

100oC

Degummed at

80oC

Degummed at 100oC

1 3.20 5.8 0.00 0.004 3.26 5.9 0.46 1.80

7 3.30 6.2 0.82 2.00

14 3.40 6.8 1.17 2.32

21 3.45 7.4 1.50 2.80

28 3.81 8.6 1.75 3.48


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degummed/bleached oil, is reduced as degumming temperature increases, but the rise in Anisidine Value is an indicationthat oxidation products of aldehydes and ketones are not effectively removed at high temperature. This is confirmed on

storage as shown in Table V, when the PV of degummed oil rises more rapidly for oil degummed at 100oC than 80 oCThe FFA, and PO4 are gradually reduced up to the degumming temperature of 80

oC, beyond which they start to rise

again. However, Fe continued to reduce even at the degumming temperature of 120oC.

Table VI, also, there is colour reversion during storage for deodorized oil degummed at any given temperature, but

reversion is much more when degummed at higher temperatures than 80oC. This gives a darker oil as shown by a suddenchange observed from the 14

th day.

3.1.2 Chemical concentration : Figure 1 shows the effects of chemical concentration on the phosphorous content ofrefined palm oil.

0.7

0.6

0.5

0.4

P h o s p h

o r o u s ( m g / l )

Citric acid degumming

phosphoric acid degumming

0.4 0.8 1.2 1.6

Fig 1 The eff ects of chemical concentration on the phosphorous content of refi ned palm oil .

From the figure, it is observed that for any given degumming chemical, bleached oil colour continues to reduce as the

chemical concentration is increased. There appeared to be an optimum at a concentration of between 0.5 and 1.0%,

beyond which colour starts to rise again, and this colour is fixed at the high temperature of the deodorizer. However, itwas noticed that bleached oil colour reduces sharply when degummed with citric acid than phosphoric acid, but thecorresponding deodorized oil colour gives minimum with phosphoric acid than citric acid. It then means that best colourreduction can be achieved at a concentration range of between 0.8 and 1.2 with optimum at 1.0%. However, H 2PO4 offers

better colour reduction than citric acid.

3.1.3 Contact time : A contact time of 30 - 60 minutes at the degumming temperature, is enough to reduce the PV tominimum. Beyond this time, the PV begins to rise, Fig.2. AV and PO4, decrease marginally, but AV reduces at a rate

greater than the PO4. The colour however, is not so much affected by prolonged contact time, provided the degummed oiltemperature is not beyond 80oC.

PV

AV

30 60 90 120 150 180 210

Time (Min.)

P V ,

P o 4

A V o f d e g u m .

O i l m

. e q / k g

25

20

15

10

5

PO4

Fig 2 The eff ects of contact time on the colour , PV, AV and PO 4 of physicall y refi ned palm oil.


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3.2 Optimization of parameters

Numerical optimization was used to search the design space using the model created to find the factor setting tha

met the desired goal of maximal removal efficiency. With 20 solutions founds (table V), the optimal conditions wereselected based on the highest desirability. The optimum conditions are: Acid concentration of 1%, Contact time of 40 min.and Process temperature of 80oC The optimum conditions were validated by repeating the degumming at the predicatedoptimum conditions.

3.2.1 Analysis of Variance (ANOVA)

Analysis of variance is a method of dividing the variation observed in experimental data into different parts, eachattributable to a known source. It shows if the factor or models in the experiments are significant, the result is shown intable VII.

Table VI I I , ANOVA Table

Sum of Mean of F- P- value

Source Squares df Square Value Prob > F Model 0.042 4 0.010 25.43 < 0.0001

A-Acid concent 0.017 1 0.017 40.57


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3.2.3 Model Validation

Table VIII Validation

Standard Actual Predicted

Order Value Value Residual 1 0.10 0.082 0.020

2 0.18 0.18 3.791E-003

3 0.10 0.069 0.0324 0.18 0.17 0.011

5 0.043 0.041 1.291E-003

6 0.054 0.072 -0.018

7 0.033 0.028 4.554E-003

8 0.046 0.059 -0.014

9 0.025 0.023 1.697E-003

10 0.19 0.15 0.039

11 0.093 0.10 -7.203E-003

12 0.054 0.075 -0.020

13 0.14 0.16 -0.025

14 0.035 0.013 0.022

15 0.061 0.087 -0.026

16 0.076 0.087 -0.01217 0.078 0.087 -9.040E-003

18 0.085 0.087 -2.140E-003

19 0.078 0.087 -9.540E-003

20 0.095 0.087 7.160E-003

To validate the model equations obtained for adequacy in predicting response, residual plots were usedANOVA assumed that residuals were independent of each other and are distributed according to a normal distributionwith constant variance. This is shown in table IX, where the predicted, actual and residual values were given accordingthe standard order

3.2.4 Normal Plot of Residuals

Design-Expert® SoftwarePhosphorus (mg/l)

Color points by value of Phosphorus (mg/l):

0.191

0.0245

Internally Studentized Residuals

N o r m

a l %

P r o b a b i l i t y

Normal Plot of Residuals

-2.00 -1.00 0.00 1.00 2.00 3.00

1

5

10

20

30

50

70

80

90

95

99

Fig. 3 Normal Plot of Residuals

The normal probability plot indicates whether the residuals follow a normal distribution, in which case the pointswill follow a straight line. Some moderate scatter, even with normal data were observed. Definite patterns like an "S-

shaped" curve, which indicates a transformation of the response may provide a better analysis. This is shown in Fig. 3.


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3.2.5 Residuals vs Predicted Plot.

The plot is shown in Fig. 4

Design-Expert® SoftwarePhosphorus (mg/l)

Color points by value of Phosphorus (mg/l):

0.191

0.0245

Predicted

I n t e r n a l l y

S t u d e n t i z e d

R

e s i d u

a l s

Residuals vs. Predicted

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

0.00 0.05 0.10 0.15 0.20

Fig. 4 Residuals vs Predicted Plot

This is a plot of the residuals versus the ascending predicted response values. It tests the assumption of constant

variance. The plot should be a random scatter (constant range of residuals across the graph.) Expanding variance("megaphone pattern


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3.2.7 Predicted vs Actual

Design-Expert® Software

Phosphorus (mg/l )

Color points by value of

Phosphorus (mg/l ):

0.191

0.0245

Actual

P r e d i c t e d

Predicted vs. Actual

0.00

0.05

0.10

0.15

0.20

0.00 0.05 0.10 0.15 0.20

Fig. 6 Predicted vs Actual

Figure 6, is the graph of the actual response values versus the predicted response values helps to detect a value, or

group of values, that are not easily predicted by the model. The data points should be split evenly by the 45 degree line

3.3 Model Graphs

(a) One Factor Plots

The One Factor Plots of Acid concentration, Contact Time and Process temperature, are shown in Fig. 7

Design-Expert® SoftwareFactor Coding: ActualPhosphorus (mg/l)

CI BandsDesign Points

X1 = A: Acid concentr

Actual Fact orsB: Contact time = 30.00C: Temperature = 60.00

1.00 1.20 1.40 1.60 1.80 2.00

A: Acid concentr

P h o s p h o r u s

( m

g / l )

0

0.05

0.1

0.15

0.2

Warning! Factor involved in AC interaction.

22

One Factor


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Design-Expert® SoftwareFactor Coding: Actual

Phosphorus (mg/l)

CI Bands

Design Points

X1 = B: Contact time

Actual Factors A: Acid concentr = 1.50

C: Temperature = 60.00

20.00 25.00 30.00 35.00 40.00

B: Contact time

P h o s p h o

r u s

( m

g / l )

0

0.05

0.1

0.15

0.2

22

One Factor

Design-Expert® Software

Factor Coding: Actual

Phosphorus (mg/l)

CI Bands

Design Points

X1 = C: Temperature

Actual Factors

A: Acid concentr = 1.50

B: Contact time = 30.00

40.00 48.00 56.00 64.00 72.00 80.00

C: Temperature

P h o s p h o r u s ( m

g / l )

0

0.05

0.1

0.15

0.2 Warning! Factor involved in AC interaction.

22

One Factor

Fig. 7 Model plots of Acid concentration, Contact Time and Process temperature

Fig. 7, shows the effects of the process variables on the degumming efficiency of the Phosphotic acid. It can beseen that the three factors of acid concentration, time and temperaturehad serious effects on the degumming efficiency of

the acid. It therefore means that as the values of the factors increased, the removal efficiency is affected. . Fig. 7 (a),shows that the removal efficiency of phosphorous continues to increase as the acid concentration is increased.

This could be attribited to the high surface area available foe adsorption. There tend to be no limit to acid concentration

but sound jugement is to stop concentration increase at the optimum point when any additional increase did not result to acorresponding removal of PO4 In Fig 7 (b), PO4 removal also increased with time, as noted by Egbuna et al 2009. This is

because, according to [12], phosphorous removal is affected by the resident time, which in turn is affected by temperature

The effect of temperaturee on removal efficiency of PO4 is shown in Fig.7(c). As shown, the removal efficiency reduceswith increase in temperature. It follows then that the higher the process temperature, the higher the removal efficiency,

until the optimum temperature of 80oC is reached.

(b) Two Factors

The Interacting effects of Acid concentration and temperature of the process, is shown in figure 8


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Design Points0.191

0.0245

X1 = A: Acid concentr X2 = C: Temperature

Actual Factor B: Contact time = 30.00

1.00 1.20 1.40 1.60 1.80 2.00

40.00

48.00

56.00

64.00

72.00

80.00

Phosphorus (mg/l)

A: Acid concentr

C

: T e m

p e r a t u r e

0.05

0.1

0.15

6

Fig. 8, Interacting effects of Acid concentration and process temperature.

Fig. 8 gives the interacting effect of acid concentration and temperature on the PO4 removal efficiency with

H2PO4. It is observed that as acid concentation is increased at both low and high Temprature values, the removaefficiency is increased.

(c) 3D Plot

The 3D plot of the interacting effect is shown in Figure 9


Design points above predicted valueDesign points below predict ed value0.191

0.0245

X1 = A: Acid concentr X2 = C: Temperature

Actual Factor B: Contact time = 30.00

40.00

48.00

56.00

64.00

72.00

80.00

1.00

1.20

1.40

1.60

1.80

2.00

0

0.05

0.1

0.15

0.2

P h o s p h o r u s

( m

g / l )

A: Acid concentrC: Temperature

Fig. 9, 3D plot of acid concentration and temperature.The 3D plot of the interactive effect of acid concentration and temperature is shown in Fig. 9. The resul

confirmed that the model is linear. The surface is sloppy showing that the removal efficiency was reduced as the

temperature and acid concentration were reduced, and the maximum efficiency was obtained at the moderate values of both factors.

4.0 CONCLUSION

The optimal process parameters on the degumming of palm Oil, with Phosphoric acid has been investigatedResponse Surface Methodology, a type of Central Composite Design, was successfully applied in the experimental designin order to study the effect of the key parameters of Time, Temperature and acid concentration on the degumming


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efficiency, and the conditions for the optimal degumming efficiency were found to be, time, temperature and Acidconcentration of, 40min. 80oC and 1% by weight acid concentration, respectively, with phosphorus of 0.0283463mg/l in

the degummed oil. The predicted concentration of 0.28% has a good correlation with the actual value of 0.033%Validation was done by repeating the experiments at the predicted optimum conditions as shown in table VIII. The resultsobtained from the optimization of the degummed Palm oil parameters showed that the degumming efficiency is linearlyaffected by Concentration of degumming acid, and contact time, and quadratic dependent on degumming temperature, asthese can be interpreted from graph and chart shown above. Concentration, and Contact time invariably increase the

degree of degumming PO. The good correlation between the predicted and experimental values shows that the methodadopted is good enough for the process and that the process variables of acid concentration, contact time, and temperaturewere significant. The results obtained, have demonstrated that the quality and stability of finished palm oil product, can begreatly influenced by the degumming stage. Variation of the degumming conditions has shown how temperaturedegumming chemicals and time conditions can affect the stability of the final product.

5.0 REFERENCES

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[2] The Worldbook Encyclopedia, 2001, Vol.14 Pp707, Worldbook Inc. Chikago

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[4] Rauken, M.D., Kill, R.C., 1993, Fats and Fatty foods; Food Industries manual, 3 rd ed. Pp288 – 327; LongmanInc.London.

[5] Pahl G., 2005, Biodiesel growing a new energy economy, White River Junction VT; ChelseaGreen Publishing Co.

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[10] Dawodu, F.A., 2009, Physico-chemical studies of oil Extraction Processes from some Nigerian grown plantSeeds., Electronic Journal of Environmental, Agricultural and Food Chemistry *(2) Pp102 – 110.

[11] Egbuna S.O; Aneke N. A. G. 2005, “Evaluation of the Quality Stability in a Physically Refined Palm Oil”Proceedings of the 35th Annual Conference and AGM of the NSChE, Kaduna,146 – 152.

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[13] Egbuna, S.O., 2010, Design of an oil Extractor and optimization of of Process conditions forVegetable oil Refining, Unpublished Ph.D Thesis, Dept. Of Chemical Engineering, Enugu State

University of Sc. and Technology, Enugu, Nigeria

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[14] Egbuna S.O; Ozonoh M; Aniokete T .C; 2013, Diffusion Rate Analysis In Palm Kernel Oil Extraction UsingDifferent Extraction Solvents. International Journal of Research in Engineering and Technology, V0l 2 issue 11, 639 –

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[16] Anderson A.J.C. (1962), “Refining of oil for edible purposes,” 2nd ed. Pergamon Press London.

[17] Hoffman G. (1989), “The Chemistry and Technology of edible oils and fats and their high far products,” AcademicPress, New York.

[18] Hymore F.K; Ajayi A.F. (1989), “ Use of Local Clay in the Refining of Palm Oil”, J. NSChE, Vol. 8, No 2

[19] Olaofe, O., Adeyemi, F.O., and Adediran, G.O., 1994,Amino Acid, Mineral Composition and Functional Properties

of some oilseeds., J.Agric. Food Chemistry., 42, 878 – 881

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[21] Mbah, G.O. and njoku C.C.,2007, Effects of process conditions on the yield of oil from African Oil Bean Seed(Pentaclethra Macrophylia), Proceedings of the 37th Annual conference of the Nigeria Society of Chemical EngineersEnugu, Pp250 – 253.

[22] Ige, M.N., Ogunsua, A.O., and Okon, O.L., 1984, Functional properties of some Nigera Oil Seeds; Casophor Seedsand Three Varieties of some Nigeria Oil seeds; Food Chemistry 33: 822 - 825.

[23] Andeson, M., 1997, Design of Experiment; American Institute of Physics. The Industrial Physicist Pp 24

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[25] Ruddy, K.2011, Ckecking Assumptions about Residuals in Regression Analysis, The Minitab Blog.

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Characterization; Abstract Submitted to 5th Workshop on Fats and Oils as Renewable Feedstock for the Industry

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Documents

OPTIMIZATION OF THE EFFECTS OF DEGUMMING PARAMETERS ON THE REMOVAL OF PHOSPHOTIDES, AND THE STABILITY OF REFINED PALM OIL