physico-chemical and quality characteristics of virgin coconut oil – a

�

L. Kamariah, A. Azmi, A. Rosmawati, M.G. Wai Ching, M.D. Azlina, A. Sivapragasam, C.P. Tan and O.M. LaiJ. Trop. Agric. and Fd. Sc. 36(2)(2008): 000– 000

Physico-chemical and quality characteristics of virgin coconut oil – A Malaysian survey(Ciri-ciri kimia fizikal dan kualiti minyak kelapa dara – Tinjauan di Malaysia)

L. Kamariah*, A. Azmi*, A. Rosmawati*, M.G. Wai Ching*, M.D. Azlina*, A. Sivapragasam**, C.P. Tan*** and O.M. Lai****

Key words: identity characteristic, quality characteristic, virgin coconut oil, contaminant

AbstractA total of �0 virgin coconut oil (VCO) samples from Malaysian market were collected and analysed for their physico-chemical and quality characteristics. Two of the samples were produced using MARDI’s technologies i.e. dry and wet processes. The remainders of the samples were produced either through natural fermentation or mechanical process. The analyses were divided based on physico-chemical characteristics and quality characteristics. As for the physico-chemical characteristic, eight types of analysis were performed i.e. relative density, refractive index, saponification value, iodine value, unsaponification matter, specific gravity, slip melting point and fatty acid composition. In addition, six types of analysis were carried out to determine the quality of the VCO. Physico-chemical characteristic analysis of all VCO samples fall within narrow ranges. However, for quality characteristics, some samples showed bad quality oil especially for the free fatty acid and peroxide value. The percentage of free fatty acid obtained from these samples were >0.5% and peroxide value >3 meq/kg. Total plate counts of most samples were zero. In terms of contaminants, copper, lead and arsenic were found to be below detectable levels except for iron. A few samples had high iron content (more than 5 mg/kg) which may enhance oxidative deterioration in the oil.

*Biotechnology Research Centre, MARDI Headquarters, Serdang, P.O. Box �230�, 50774 Kuala Lumpur, Malaysia**Rice and Industrial Crops Research Centre, MARDI Headquarters, Serdang. P.O. Box �230�, 50774 Kuala Lumpur, Malaysia***Faculty of Food Science and Biotechnology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia****Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia 43400 UPM Serdang, Selangor, MalaysiaAuthors’ full names: Kamariah Long, Azmi Azali, Rosmawati Abdullah, Mary Goh Wai Ching, Azlina Mohd. Danial, Sivapragasam Annamalai, Tan Chin Ping and Lai Oi MingE-mail: [email protected]©Malaysian Agricultural Research and Development Institute 2008

IntroductionVirgin coconut oil (VCO) is the miracle oil for health, beauty and strength. It has abundant utility in the functional foods, health foods, pharmaceuticals, nutriceuticals, infant foods and cosmoceuticals and thus has multifunctions and uses in human life. The health and benefits that can be derived

from consuming VCO have been recognized in many parts of the world. One of the emerging applications of VCO is its medical use and functional benefit to human health. Coconut oil in its virgin form is clear in colour and has a distinct coconut flavour and aroma. VCO may mean the minimally processed product which has not undergone

2

Virgin coconut oil

any further processing such as refining, bleaching and deodorization. It can be produced either from processing of fresh coconut meat, coconut milk, or coconut milk residue. VCO is known for its medium chain triglycerides (MCT) and high content of lauric acid (about 50%). In vitro studies showed that these medium chain fatty acids and its corresponding monoglycerides have antifungal, antibacterial, antiviral properties including human pathogens like herpes simplex virus and antiprotozoal (Kabara �978; Shibasaki and Kato �978; Welsh et al. �979; Thormar et al. �987; Isaacs et al. �995). Currently there are many types and brands of VCO available in the Malaysian market. Most of them were VCO from countries likes Indonesia and the Philippines where prices are relatively cheaper. They are produced either by natural fermentation or mechanical process. The fermentation process involves splitting the nut, grating the meat to fine particles, squeezing the milk either manually or mechanically with or without adding of water and allowing the milk to ferment for 36–48 h. The skim milk at the bottom is discarded, the oil is filtered and the cream which contains part of the oil is gradually heated to further recover the oil. On the other hand, mechanical process uses minimal heat to quick-dry the coconut meat and the oil is pressed using coconut oil expeller. Methods which can separate the oil from the water include boiling, fermentation, refrigeration, enzyme and mechanical centrifugation. The quality and physico-chemical characteristics of the VCO produce are very much dependent on the process and the raw materials used. Because of the growing popularity of VCO, the price and demand for VCO has increased. There is also the possibility of oil adulteration in which VCO is blended with other oils to give a product of unknown and variable quality. It is thus essential that the physico-chemical and quality characteristic of the VCO be

analysed to identify possible authentication. Such determinants will prevent incidences of VCO adulteration with cheaper oils as well as allowing enforcement of food regulations in Malaysia. VCO prices in the Malaysian market in 2006 are between RM20/�20 ml and RM60/�20 ml. This paper reports a survey on the physico-chemical and quality characteristic of VCO in the Malaysian market.

Materials and methodsTen samples of VCO were selected and analysed for physical and chemical characteristics. Two samples of VCO namely A and B were produced using MARDI’s technologies i.e. dry and wet processes. The remaining eight samples of VCO were purchased from suppliers in Malaysia and were coded as samples C, D, E, F, G, H, I, and J. Samples C, D, E and J were produced through natural fermentation process whereas samples F, G, H and I were obtained through mechanical process. The relative density of the oil was measured at 25 °C by using 50 ml pycnometer (with stopper fitted with calibrated thermometer) according to ISO/FDIS 6883 (2000). The refractive index of the oil was measured according to ISO/FDIS 6320 (�999) at 40 °C, using a refractometer equipped with sodium vapour lamp as light source. Refractive index of the oil was measured within the range nD= �.3000 to �.7000. The saponification value determination was determined as described in AOCS (�997). Samples were saponified with 0.5 N potassium hydroxide solution. The samples were then titrated with 0.5 N hydrochloric acid with phenolphthalein solution as an indicator. Iodine value of oil samples was determined by Wijs method as described in PORIM (�995). 0.� N sodium thiosulphate solution was used to titrate the liberated iodine.

3

L. Kamariah, A. Azmi, A. Rosmawati, M.G. Wai Ching, M.D. Azlina, A. Sivapragasam, C.P. Tan and O.M. Lai

Unsaponifiable matter in the oil was determined according to AOCS (�997). Saponification of the oil was first done with ethanolic potassium hydroxide solution. Extraction of the unsaponifiable matter was then carried out with petroleum ether for at least six times. The specific gravity of oil sample was determined using 50 ml pycnometer (with stopper fitted with calibrated thermometer) as described in AOCS (�997). Slip melting point of oil was determined using AOCS (�997). Heat was increased at rate � °C/min to heat the oil sample in capillary tube. As the slip point was approached, the rate was slowed to 0.5 °C/min. The temperature at which the oil in column rose was reported as the slip melting point. Fatty acid composition of VCO was determined using gas chromatography (GC Hewlett Packard 5890 Series II, SGE 30 m x 0.25 i.d. BPX5 column) with a FID detector according to the AOCS (�997). Helium was the carrier gas. About 0.5 µl sample was injected into the system at 200 °C injector temperature. The oven was operated isothermally at �70 °C for �2 min. The amount of free fatty acid present in oil sample was determined according to the method of Cocks and Van Rede (�966) with slight changes. Five grammes of sample was weighed and titrated with 0.02 N sodium hydroxide solution using autotitrator (Mettler Toledo DL50) and end point titration was employed. The peroxide value of the VCO was determined according to PORIM (�995). In this method, the liberated iodine is titrated with 0.0� N thiosulfate. Moisture content of oil was determined according to AOCS (�997). Karl Fisher Mettler DL 38 Coulometer was used. End point titration was determined by Karl Fisher reagent. Insoluble impurities of oil were determined according to ISO 663 (�992). Materials insoluble in petroleum ether were collected in Gooch crucible and were

then weighed to determine the amount of insoluble impurities present in each oil sample. The colour of the oil was determined with a Lovibond tintometer (�0 mm light path). Results were expressed in red and yellow values according to ISO/FDIS �5305 (�998). Total viable count in oil sample was determined according to the method recommended by Messer et al. (�984). About � ml of oil sample was aseptically poured/spread onto a petridish containing plate agar (Oxoid). The oil sample was then mixed/spread immediately and was incubated at 32 °C or 37 °C for 48 h. Colony formed was then counted and expressed as cfu/ml. The content contaminant such as iron, copper and lead in oil sample was determined according to AACC (�994) by using inductively couple plasma-optical emission spectroscopy (ICP/OES). A calibration curve of concentration of iron, copper and lead (standard solution) against absorbance was plotted to determine the concentration of each element in test sample. The trace amount of arsenic in oil sample was determined according to AOAC (2005) by using atomic absorption spectrophotometry (AAS) equipped with arsenic hollow cathode lamp and arsenic electrodeless discharge lamps. A calibration curve of concentration of arsenic (standard solution) against absorbance was plotted to determine the concentration of arsenic in test sample. The matter volatile at �05 °C in oil sample was determined according to ISO 662 (�998). The test sample was heated at �05 °C until moisture and volatile matter were completely removed and the loss in mass was recorded. The result was expressed in percentage by mass.

Results and discussionRelative densityThe density of vegetable oils is temperature dependent and decreases in value when

4

Virgin coconut oil

temperature increases (Table 1). In this experiment, analysis was carried out at 20 °C. The relative density of the VCO in this survey ranged from 0.9�85 to 0.9�94 with a standard deviation of 0.0003. The value obtained from this survey was very close to the Asian Pacific Coconut Community (APCC) standard range (0.9�5–0.920).

Refractive index (RI)The RI of the oil measures the extent to which a beam of light is refracted on passing from air into oil. This can be a useful characteristic in that the determination is carried out with ease, speed and precision, using small amounts of oil. The RI can also be used for establishing oil purity. It is generalized that the RIs of oils increase with increase in the number of double bonds. With increase in temperature, the RIs of oil decrease. The RI can also be influenced by oxidative damage of the oil. For VCO in this survey, the RI was measured at 40 °C. This means RI was at �.447� with a standard deviation of 0.000� (Table 1). The range of the RI was found to be very narrow from minimum �.4467 to maximum �.4472.

Saponification value (SV)The SV is a measure of the free and esterified acids present in fats and oils. It measures the average molecular weight or equivalent weight of fatty materials in the oils. The range was minimum 258.8 to maximum 263.7 mg KOH/g oil with mean at 260.5 mg KOH/g and a standard deviation of �.4428 (Table 1).

Iodine Value (IV)The IV of oil is a measure of its total unsaturation. It is defined as the percentage by weight of which an oil or fatty acid will absorb halogens such as iodine under the test conditions. In palm oil, it is an important characteristic in determining the yield of olein during fractionation process. The mean IV of VCO was 6.��% with minimum of 5.5% and maximum of 7.3%. Ta

ble

�. P

hysi

o-ch

emic

al c

hara

cter

istic

s of

vir

gin

coco

nut

oil

Sam

ple

Rel

ativ

e R

efra

ctiv

e Sa

poni

ficat

ion

Iodi

ne

Uns

apon

ifica

tion

Spec

ific

Slip

mel

ting

de

nsity

in

dex

(at

40 °

C)

valu

e (m

g/g)

va

lue

(%)

mat

ter

(% )

gr

avity

(at

30

°C)

poin

t (º

C)

A

0.9�

90

�.44

70

259.

0 6.

� 0.

�50

0.9�

52

24.8

B

0.9�

92

�.44

67

260.

6 5.

6 0.

��5

0.9�

54

24.7

C

0.9�

88

�.44

72

259.

8 5.

6 0.

085

0.9�

64

24.9

D

0.9�

85

�.44

7�

26�.

� 7.

� 0.

��0

0.9�

90

25.0

E

0.9�

92

�.44

72

260.

2 6.

� 0.

�35

0.9�

95

24.3

F 0.

9�94

�.

4472

25

9.9

5.7

0.��

0 0.

9�80

24

.6G

0.

9�89

�.

447�

26

0.2

7.3

0.��

0 0.

9�95

24

.4H

0.

9�90

�.

447�

26

�.9

5.7

0.�0

0 0.

9�82

24

.9I

0.9�

90

�.44

7�

263.

7 5.

5 0.

�30

0.9�

97

25.0

J 0.

9�87

�.

4470

25

8.8

6.4

0.��

5 0.

9�87

24

.9

Val

ue r

ange

Min

0.

9�85

�.

4467

25

8.8

5.5

0.08

5 0.

9�52

24

.3 M

ax

0.9�

94

�.44

72

263.

7 7.

3 0.

�35

0.9�

97

25.0

Mea

n ±

SD

0.

9�90

± 0

.000

3 �.

447�

± 0

.000

� 26

0.5

± �

.442

8 6.

�� ±

0.6

42

0.��

6 ±

0.0

�84

0.9�

80 ±

0.0

0�7

24.8

± 0

.246

�

5


On the other hand, IV of VCO from Asian Pacific Coconut Council was between 4.�% and ��.0%. The standard deviation of IV from this survey was 0.642. Sample G shown highest IV (7.3%) and lowest IV was sample I (IV 5.5%), VCO from Sabah.

Unsaponifiable matterThe unsaponifiable matter of oil serves as a check for contamination by foreign materials such as mineral oils and damage to the oil by oxidation. Highly oxidized oils contain polymerized fatty acids which are extracted together with the unsaponifiable matter. The unsaponifiable components in VCO may include sterols, hydrocarbons (squalene, beta carotene), tocopherols and phenols. Coconut oil has a total of 470–��40 mg/kg sterols, 0–�7 mg/kg tocopherol and 0–44 mg/kg tocotrienols (Firestone 2006). The average unsaponifiable matters for �0 samples were found to be 0.��6 with a range from minimum of 0.085% to maximum 0.�35% and a standard deviation of 0.0�84 (Table 1). VCO from sample A has the highest unsaponifiable matters (0.�5%) compared with other VCO samples (~ 0.��%).

Slip melting point (SMP)This is an important characteristic of fatty compounds as it can be used for identification purposes and assessment of purity. The melting point or SMP of oil must be determined under strictly controlled conditions of sample pre-treatment and actual determination. The mean for SMP of VCO found in Malaysian market was 24.8 °C with a range stretching from 24.3 to 25.0 °C and a standard deviation of 0.246� °C (Table 1).

Fatty acid compositionVCO is characterized by its high level of lauric acid (C�2), which ranged from 47–50%. Other fatty acid composition include caproic acid (C6), caprylic acid (C8), caproic acid (C�0), myristic acid (C�4), palmitic acid (C�6), stearic acid (C�8), oleic acid (C�8:�) and finally linoleic acid (C�8:2) (Table 2). Tabl

e 2.

Gas

liq

uid

chro

mat

ogra

phy

rang

e of

fat

ty a

cid

com

posi

tion

of v

irgi

n co

conu

t oi

l

Sam

ple

C 6 C 8

C �0

C �2

C �4

C �6

C �8

C �8:�

C �8

:2

C �8:3

A 0.

93

8.85

6.

67

49.�

8 �7

.95

7.85

2.

93

4.84

0.

80

ND

B 0.

82

8.90

6.

55

48.4

2 �8

.07

8.�2

3.

�0

5.09

0.

93

ND

C 0.

87

8.45

6.

30

47.0

8 �8

.77

9.06

2.

63

5.97

0.

87

ND

D

0.88

8.

�2

5.96

47

.25

�9.2

7 8.

75

2.88

5.

8�

�.08

N

DE

0.9�

8.

6�

6.56

48

.73

�7.9

4 7.

95

2.79

5.

40

�.��

N

DF

0.94

8.

83

6.85

49

.50

�7.7

2 7.

86

2.78

4.

67

0.85

N

DG

0.

93

8.53

6.

49

48.0

5 �8

.09

8.43

2.

67

5.55

�.

25

ND

H

0.85

8.

7�

6.63

48

.85

�8.�

5 8.

�3

2.98

4.

83

0.86

N

DI

0.8�

8.

72

6.62

49

.�5

�8.4

7 8.

�0

2.89

4.

46

0.78

N

DJ

0.85

8.

46

6.46

48

.04

�8.�

� 8.

6�

2.65

5.

57

�.26

N

D

Valu

e ra

nge

Min

0.

8�

8.�2

5.

96

47.0

8 �7

.72

7.85

2.

63

4.46

0.

78

ND

Max

0.

94

8.90

6.

85

49.5

0 �9

.27

9.06

3.

�0

5.97

�.

26

ND

Mea

n ±

SD

0.88

± 0

.004

7 8.

62 ±

0.2

37�

6.5�

± 0

.240

7 48

.43

± 0.

8�67

�8

.25

± 0.

46��

8.

29 ±

0.4

097

2.83

± 0

.�54

� 5.

22 ±

0.5

�29

0.98

± 0

.�8�

5 N

D

6

Virgin coconut oil

It contains about 93% saturated fatty acids, 6% monounsaturated fatty acids and the rest is polyunsaturated fatty acids. The present survey show that more than 64% of its saturated fatty acids are medium chain fatty acids (C6–C�2), ~ 29% saturated long chain fatty acids (C�4– C�8) and 6.2% are unsaturated fatty acids which are the oleic acid (C�8:�) and linoleic acid (C�8:2) (Table 2). Linolenic acid (C�8:3) is not detectable in this survey.

Free fatty acids (FFA)This is the most important characteristic of VCO quality used in sales and contracts. The FFA is an indication of the care taken during VCO production. The mean FFA value of VCO obtained from Malaysian market in the present survey was 0.38% with a range of 0.20 to �.20% and a standard deviation of 0.3487% (Table 3). Range of free fatty acid in this survey was broader because of FFA content of sample G and H were at 0.78% and �.90% respectively. These values are considered too high and may not be acceptable to buyers and can be considered as low quality VCO. The recommended minimum FFA value suggested by the Asian Pacific Coconut

Council (APCC) standard ranges at ≤0.5% (Table 4).

Moisture contentWater is very slightly soluble in oils and fats, and its presence is confined only to very small amount. The Karl Fischer titration method offers the best accuracy for determination of very small amounts of water (0.�% and below) in oils and fats. In this survey the mean value for moisture content of VCO is in the region of 0.09% with ranging from 0.05% to 0.��% and standard deviation of 0.02��. The maximum moisture content of APCC standard range is 0.5% (Table 4).

Insoluble impuritiesThe term refers to extraneous substances such as dirt, debris and fibres. They are defined as those substances which remain insoluble and can be filtered off after the oil is dissolved in a specific solvent such as petroleum. The level of impurities in each VCO sample was small and fall within a narrow range from 0.003% to 0.008%. The mean value insoluble impurities were at 0.005% and standard deviation of 0.00�4. The APPC standard range for moisture is in the region of 0.�–0.5% (Table 4).

Table 3. Quality characteristic of virgin coconut oil

Sample Free fatty Peroxide Moisture Colour Insoluble Total plate acid (%) value contents impurities count (meq/kg) (%) (%) (cfu)

A 0.4� 0.7 0.07 0.�R 0.5Y 0.008 0B 0.� 0.2 0.05 0.�R 0.5Y 0.006 0C 0.�6 0.2 0.�� 0.�R 0.3Y 0.005 0D 0.�5 0.2 0.�� 0.�R 0.3Y 0.006 0E 0.�9 0.2 0.�� 0.�R 0.3Y 0.006 0F 0.29 5.5 0.09 0.�R 0.3Y 0.006 0G 0.78 0.8 0.09 0.�R 0.5Y 0.005 0H 0.90 0.2 0.08 0.�R 0.5 Y 0.003 0I 0.35 0.5 0.�� 0.�R 0.3Y 0.004 0J �.2 �.4 0.�� 0.�R 0.5Y 0.004 0

Value range Min 0.2 0.2 0.05 0.�R 0.3Y 0.003 0 Max �.2 5.5 0.�� 0.�R 0.5Y 0.008Mean ± SD 0.38 ± 0.3487 0.99 ± �.6326 0.09 ± 0.02�� 0.�R 0.5Y max 0.005 ± 0.00�4 0

7


Peroxide value (PV)Peroxide value gives an indication of the primary oxidation state of oil. One of the first products formed by oxidation of oil is a hydroperoxide. The most common method for determining oxidation is by measurement of PV. The test is based on the ability to liberate iodine from potassium iodide. Although the method is highly empirical, it is good guide to the quality of the VCO. A freshly refined oil should have nil PV. The peroxide value of most samples were within the range given by APCC standard ≤3 meq/kg (Table 4). However, sample F was

found to have PV out of range, 5.5 meq/kg. Most probably these samples have been stored for a long time.

ColourCoconut oil in its virgin form is clear in colour with distinct coconut flavour and aroma. It is obtained from the mature kernel of the coconut (Cocos nucifera L) by mechanical or natural means with or without the application of minimal heat. High heat exposure during deodorization process (230 °C) normally will lead to polymerization and consequently the oil will

Table 4. Identity and quality characteristics of VCO found in Malaysia market compared with APCC standard range

Malaysia market range APCC standard range

Identity characteristicRelative density 0.9�85 – 0.9�92 0.9�50 – 0.9200Refractive index �.4467 – �.4472 �.4480 – �.4492Moisture (%) 0.0500 – 0.��00 0.�000 – 0.5000Saponification value (mg/g) 258.80 – 263.70 250.00 – 260.00Iodine value (%) 5.5000 – 7.�000 4.�000 – ��.000Unsaponifiable matter (%) 0.0850 – 0.�500 0.2000 – 0.5000Specific gravity at 30 ºC 0.9�52 – 0.9�97 0.9�50 – 0.9200Slip melting point (ºC) 24.300 – 25.000 –

Gas liquid chromatography range of fattyacid composition (%)Caproic acid C6:0 0.80 – 0.95 0.40 – 0.60Caprylic acid C8:0 8.00 – 9.00 5.00 – �0.0Capric acid C�0:0 5.00 – 7.00 4.50 – 8.00Lauric acid C�2:0 47.0 – 50.0 43.0 – 53.0Myristic acid C�4:0 �7.0 – �8.5 �6.0 – 2�.0Palmitic acid C�6:0 7.50 – 9.50 7.50 – �0.0Stearic acid C�8:0 2.50 – 3.50 2.00 – 4.00Oleic acid C�8:� 4.50 – 6.00 5.00 – �0.0Linoleic acid C�8:2 0.70 – �.50 �.00 – 2.50Linolenic acid C�8:3 ND <0.5

Quality characteristicInsoluble impurities (%) 0.003 – 0.008 0.05Free fatty acid (%) 0.�00 – �.200 ≤0.5Peroxide value (meq/kg) 0.200 – 5.500 ≤3Total plate count (cfu) 0 <�0

ContaminantsMatter volatile at �05 ºC (%) 0.08 – 0.�50 0.2Iron (mg/kg) 0.45 – �4.53 5Copper (mg/kg) ND 0.4Lead (mg/kg) ND 0.�Arsenic (mg/kg) ND 0.�

8

Virgin coconut oil

turn yellow (Plate 1). Colour of VCO in this survey was in range of 0.� Red and 0.5 Yellow Max.

Total plate countThis is a very important analysis in determining good quality VCO. Occasionally, very limited number of microbes can grow on oils and fats because of the limited amount of water present. However, it is necessary for producers to have good manufacturer practices (GMP) as VCO is being directly consumed from the bottle without any treatments e.g. heat. Result from analysis showed that most

samples had zero or less than �0 colony forming unit (cfu) (Table 3).

Trace metalsTrace metals in VCO may originate from soil and fertilizers or contaminants from the processing equipment and also during storage. Thus trace metals may be picked up along the production line. The presence of trace metals could also be attributed to the presence of suspended solid impurities in the oil (Yeoh �976). Oxidatively stable oils contain minimal amounts of trace metals. Cu and Fe are known prooxidants as they catalyse the decomposition of hydroperoxides in oil to free radicals. Of the two metals, Cu is more potent being �0 times more active than Fe. The mean level of Cu content in this survey was below detectable level (<0.0� mg/kg). Cu is useful test to determine the possible cause of high oxidation. Peroxide value (PV) does not gives a true indication of the state of oxidative deterioration in an oil because hydroperoxides are only transient species and Cu accelerates the hydroperoxide destruction rate. In the present survey, the mean iron content was at 4.73 mg/kg with minimum value from 0.73 to �4.53 mg/kg (Table 5). Sample G had the highest iron content at �4.53 mg/kg followed by sample J at ��.73 mg/kg. This probably because

Plate I . Refined bleached and deodorized (RBD) coconut oil (left) and virgin coconut oil (right)

Table 5. Contaminants of virgin coconut oil

Sample Iron Copper Lead Arsenic Volatile matter (mg/kg) (mg/kg) (mg/kg) (mg/kg) at �05 °C

A �.5 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.08B 5.66 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.�3C 5.9 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.�5D 2.2� N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.�4E 0.45 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.�5F 0.96 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.��G �4.53 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.�4H 3.64 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.�I 0.73 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.�3J ��.73 N.D<< 0.0� N.D<< 0.0� N.D<< 0.05 0.�3Value range Min 0.73 ND ND ND 0.08 Max �4.53 0.�5Mean ± SD 4.73 ± 4.8737 ND ND ND 0.�3 ± 0.0227

9


VCO samples from G and J were exposed to oxidation during handling and/or storage. The APCC standard range of iron in VCO was at ≤5mg/kg (Table 4).

ConclusionOverall, the identity and quality characteristics of VCO sold in Malaysian market were comparable to APCC standard range. However, the qualities of two VCO samples were bad because of high FFA and high PV content. Obviously, arsenic, lead and copper were not detectable in all VCO samples. Although the sample size was small i.e. only involved �0 samples, it is actually representative samples from different regions and different methods of producing. Consequently, we hope the results obtained from this survey could be used as a guideline to develop a draft for Malaysian VCO standard.

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�0

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AbstrakSejumlah �0 sampel minyak kelapa dara yang terdapat di pasaran Malaysia telah dikumpulkan dan dikenal pasti ciri-ciri dan kualitinya. Dua daripada sampel tersebut telah dihasilkan dengan menggunakan teknologi MARDI iaitu secara proses kering dan basah. Sampel yang selebihnya dihasilkan sama ada melalui proses fermentasi secara semula jadi atau melalui proses mekanikal. Analisis dibahagikan kepada dua iaitu mengenal pasti ciri-ciri dan kualiti minyak kelapa dara. Bagi mengenal pasti ciri-ciri, lapan jenis analisis telah dijalankan iaitu ketumpatan relatif, indeks refraktif, nilai penyabunan, nilai iodin, bahan bukan penyabunan, graviti khusus, titik gelincir cair dan komposisi asid lemak. Sementara itu, enam jenis analisis telah dijalankan untuk mengenal pasti kualiti minyak kelapa dara. Ciri-ciri kimia fizikal bagi semua sampel menunjukkan ciri yang hampir sama. Walau bagaimanapun, dari aspek kualiti sebahagian sampel menunjukkan kualiti yang rendah terutamanya asid lemak bebas dan nilai peroksida. Peratusan asid lemak bebas yang diperoleh daripada sampel tersebut melebihi 0.5% dan nilai peroksida melebihi 3 meq/kg. Tiada pertumbuhan koloni dikesan. Dari aspek pencemaran, kandungan plumbum, kuprum dan arsenik didapati berada di bawah aras yang dibenarkan kecuali ferum. Terdapat beberapa sampel yang menunjukkan kandungan ferum yang tinggi (melebihi 5 mg/kg) yang mungkin menyebabkan kerosakan pada minyak akibat daripada proses pengoksidaan.

Accepted for publication on 12 August 2008

Yeoh, G.H. (�976). A study on the nature and effect of iron contamination in plam oil. Proc. of Malaysian international symposium on palm oil processing and marketing, (Theme: International development in palm oil). Kuala Lumpur: Incorporated Society of Planters

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