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Coconut Milk and Coconut Oil: Their Manufacture Associated with Protein Functionality


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Coconut palm (Cocos nucifera L.) is an economic plant cultivated in tropical countries, mainly in the Asian region. Coconut fruit generally consists of 51.7% kernel, 9.8% water, and 38.5% shell. Coconut milk is commonly manufactured from grated coconut meat (kernel). Basically, coconut milk is an oil‐in‐water emulsion, stabilized by some proteins existing in the aqueous phase. Maximization of protein functionality as an emulsifier can enhance the coconut milk stability. In addition, some stabilizers have been added to ensure the coconut milk stability. However, destabilization of emulsion in coconut milk brings about the collapse of the emulsion, from which virgin coconut oil (VCO) can be obtained. Yield, characteristics, and properties of VCO are governed by the processes used for destabilizing coconut milk. VCO is considered to be a functional oil and is rich in medium chain fatty acids with health advantages.
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Concise Reviews &
Hypotheses in Food Science
Coconut Milk and Coconut Oil: Their Manufacture
Associated with Protein Functionality
Umesh Patil and Soottawat Benjakul
Abstract: Coconut palm (Cocos nucifera L.) is an economic plant cultivated in tropical countries, mainly in the Asian
region. Coconut fruit generally consists of 51.7% kernel, 9.8% water, and 38.5% shell. Coconut milk is commonly
manufactured from grated coconut meat (kernel). Basically, coconut milk is an oil-in-water emulsion, stabilized by some
proteins existing in the aqueous phase. Maximization of protein functionality as an emulsifier can enhance the coconut
milk stability. In addition, some stabilizers have been added to ensure the coconut milk stability. However, destabilization
of emulsion in coconut milk brings about the collapse of the emulsion, from which virgin coconut oil (VCO) can be
obtained. Yield, characteristics, and properties of VCO are governed by the processes used for destabilizing coconut milk.
VCO is considered to be a functional oil and is rich in medium chain fatty acids with health advantages.
Keywords: coconut milk, coconut proteins, emulsion stability, oil-in-water emulsion, virgin coconut oil
Coconut (Cocos nucifera L.) is monocotyledon palm from the
Palmaceae family (Ohler, 1999). Cocos nucifera L. is generally called
as a coconut palm and is one of the most useful trees in the world.
Well-known products of coconut palm include coconut oil, co-
conut milk, coconut water and coconut meat. Coconut milk is
generally extracted from grated coconut meat after pressing or
squeezing with or without the addition of water. Coconut milk
has been used as a major ingredient for several cuisines such as cur-
ries and desserts (Tansakul & Chaisawang, 2006). Besides serving as
a food ingredient, coconut milk is used for the production of virgin
coconut oil (VCO), for which collapse of coconut milk emulsion
is required. Coconut milk emulsion stability is generally governed
by some proteins in the aqueous phase (Peamprasart & Chiewchan,
2006). Thus, to maximize the yield of VCO, the emulsion of co-
conut milk must be collapsed to a high degree, in which oil can
be released and separated effectively. To obtain VCO from the
wet extraction process, destabilization of coconut milk emulsion
has been implemented via several processes such as physical ex-
traction, fermentation, and enzymatic extraction (Raghavendra &
Raghavarao, 2010). VCO is commonly manufactured from co-
conut meat (wet kernel) by natural or mechanical means without
or with the application of heat. Chemical refining, bleaching, or
deodorizing methods are omitted. Therefore, the nature of result-
ing VCO is not changed (Villarino, Dy, & Lizada, 2007). VCO or
coconut oil consists of medium chain fatty acids (MCFAs), mainly
lauric acid. VCO is not similar to other vegetable oils because of its
high MCFAs content (Dayrit, 2014). Because of high stability and
various health benefits, VCO has become the subject of consumer
and processor interest (Carandang, 2008). This review covers char-
acteristics and functional properties of coconut proteins, especially
their role in emulsifying or stabilizing coconut milk. In addition, a
summary of production, quality, and applications of VCO, mainly
by induction of emulsion collapse, is revisited.
JFDS-2018-0183 Submitted 2/9/2018, Accepted 5/29/2018. Authors are with
Dept. of Food Technology, Faculty of Agro-Industry, Prince of Songkla Univ., Hat
Yai, Songkhla, 90112, Thailand. Direct inquiries to author Benjakul (E-mail:
Coconut (Cocos nucifera L.) is economically important and gen-
erally used in many traditional foods of Pacific and Asian regions
(DebMandal & Mandal, 2011). Asia is the major coconut producer
all over the world and 90% of the world’s total coconuts are cul-
tivated in Indonesia, Philippines, India, Sri Lanka, and Thailand.
About 70% of coconuts are consumed domestically, and over half
of the crop is consumed fresh (Grimwood, 1975). The edible co-
conut products are mostly obtained from meat (solid endosper m)
and water (liquid endosperm) (Grimwood, 1975). Coconut has
been also used as traditional medicine, crafting material and fuel.
In general, fruits take about one year for the entire development.
First, the husk and shell grow and cavity of embryosac enlarges
considerably. This cavity is filled with liquid. After about four
months, the husk and shell become thicker. The solid endosperm
begins to form against the inner wall of the cavity after six months.
This first layer is thin and gelatinous. About eight months later,
the soft white endocarp becomes hard and dark brown. The fruit
becomes mature within 12 months (Ohler, 1999). The mature
coconut (MC) fruit (about 12 months) contains 35% husk (fi-
brous coat of fruit), 12% shell (inner hard coat of fruit), 28% meat
(solid endosperm), and 25% water (liquid endosperm; Grimwood,
1975). A cross-section of a coconut is illustrated in Figure 1.
To obtain the edible portion, coconut is subjected to removal of
the shell, followed by paring and draining of water. Subsequently,
coconut meat can be collected manually and grated with the aid
of rotary wedge cutter machine (Senphan & Benjakul, 2015).
The composition of the mature kernel is dependent on cultural
practices, variety, maturity of the nut, and geographical location.
Patil, Benjakul, Prodpran, Senphan, and Cheetangdee (2017) re-
ported that different maturity stages had the marked impact on
the chemical composition of coconut meat and milk. Proximate
compositions of MC meat are listed in Table 1. Coconut meat
can be consumed fresh. Moreover, coconut meat is grated, mixed
with or without water and pressed to extract the coconut milk
(Grisingha, 1991).
Coconut proteins
Apart from oil, coconuts also contain proteins with moder-
ately well-balanced amino acid profile in term of nutritive value
(Gonzales & Tanchuco, 1977; Gunetileke & Laurentius, 1974;
C2018 Institute of Food Technologists R
doi: 10.1111/1750-3841.14223 Vol. 0, Iss. 0, 2018 rJournal of Food Science 1
Further reproduction without permission is prohibited
Concise Reviews &
Hypotheses in Food Science
Coconut milk and coconut oil . . .
Table 1–Proximate composition of mature coconut kernel.
Composition (%)
Moisture Protein Oil Crude fiber Ash Carbohydrates References
44.0 3.6 38.1 3.1 1.3 9.9 Dendy and Timmins (1973)
42–48 4.0 36.0 2.0 7.20 Grimwood (1975)
35.37 5.5 44.01 3.05 0.77 6.57 Balachandran et al. (1985)
36.0 4.5 41.5 1.1 16.9 Chakraborty (1985)
40.9 3.8 35.2 Kwon et al. (1996)
61.07 3.95 20.86 1.14 13.05 Patil et al. (2017)
Figure 1–Coconut fruit cross-section.
Kwon, Park, & Rhee, 1996; Rasyid, Manullang, & Hansen, 1992).
To recover or extract coconut proteins, protein isolates from co-
conut skim milk were prepared by ultrafiltration, salt precipitation,
isoelectric precipitation, and heat coagulation (Capulso, Gonzales,
& Celestino, 1981; Raghavendra & Raghavarao, 2010).
Isolation and fractionation
Several procedures for isolation of protein from coconut skim
milk have been developed. Those include isoelectric (pI) precipi-
tation, heat coagulation, combined isoelectric precipitation as well
as heat coagulation, and co-precipitation with a calcium salt. High
yield of protein was achieved by heat coagulation followed by pI
precipitation. Similarly, Capulso et al. (1981) studied the effect
of heat coagulation, isoelectric precipitation and simultaneous pH
and heat coagulation on the recovery of coconut proteins from
skim milk. Eighty-four percent of proteins in the skim milk were
precipitated with HCl at pH 4 and further coagulated by heat at
90 °C for 30 min. Proteins were extracted using alkaline extraction
process from coconut milk press cake using saturated Na3PO4and
the yield of 47% was obtained (Chambal, Bergenst˚
ahl, & Dejmek,
Coconut proteins are generally classified according to their sol-
ubility and amino acid composition (Rasyid et al., 1992). Co-
conut proteins can be fractionated into five fractions using dif-
ferent solvents. Water, sodium chloride, isopropanol, acetic acid,
and sodium hydroxide soluble fractions are designated as albumin,
globulin, prolamin, glutelin-1, and glutelin-2 fractions, respec-
tively. The predominant proteins in coconut endosperm or kernel
are classified as globulin (salt-soluble) and albumin (water-soluble),
which account for 40% and 21% of total protein, respectively
(Balachandran, Arumughan, & Mathew, 1985; Kwon et al., 1996).
Distribution of proteins in defatted coconut meal, classified based
on solubility, is shown in Table 2. For protein content in coconut
skim milk, 75% is accounted for globulin, whereas the remaining
(25%) is albumin (Garcia, Arocena, Laurena, & Tecson-Mendoza,
2005). Globulin fraction of coconut has a high level of charged
amino acids. Those are aspartic acid, glutamic acid, arginine, and
lysine (Kwon et al., 1996; Patil & Benjakul, 2017). The albumin
fraction has higher proportions of amino acids with polar side
chains. The relative proportion of each protein fraction affects the
functional properties and the nutritional quality. The differences
in maturation stage, fertilizer, climate, starting material, and so on,
also result in varying proportion of various proteins in coconut
meat (Patil & Benjakul, 2017).
Molecular weight (MW) of five coconut protein fractions (i.e.,
albumin, globulin, prolamin, glutelin-1, and glutelin-2) from de-
fatted coconut flour analyzed by SDS-PAGE with reducing agent
(β-mercaptoethanol) was reported by Kwon et al. (1996) and
Sringam (1997). The albumin fraction had MW ranging from 18
to 52 kDa. MW of globulin fraction was below 60 kDa. Cocosin
as the major protein (65%)withMWof55kDawasobservedin
the endosperm of coconut (Garcia et al., 2005). Patil and Benjakul
(2017) also documented that both albumin and globulin fractions
contained major protein with MW of 55 kDa. Prolamin fraction
had MW with the range of 17 to 56 kDa, whereas the glutelin-1
fraction had MW ranging from 14 to 100 kDa. Coconut globulin
consist of two major types, named 11S and 7S globulin. Cocosin,
a globulin, is one of seed storage proteins identified as 11S glob-
ulin, accounting for 86% of the total globulin (Balasundaresan,
Sugadev, & Ponnuswamy, 2002). Cocosin is generally hexameric
quaternary in structure, of which the MW is about 300 to 360 kDa
and each subunit has MW of 55 kDa. The subunits consist of the
basic (22 to 24 kDa) and acidic (32 to 34 kDa) polypeptides linked
via disulfide bridge. Basic and acidic chains are dissociated under
the reducing conditions (Garcia et al., 2005). The 7S coconut
globulin is a type of vicilins, which are characterized as trimer
having an oligomeric MW of 150 to 190 kDa, with each single
chain subunit of about 55 kDa (Garcia et al., 2005). The coconut
7S globulin is unglycosylated and lack of sulfur-containing amino
acids (Carr, Plumb, Parker, & Lambert, 1990). Protein pattern of
coconut milk at different stages of maturity under reducing con-
ditions showed several major protein bands with MW of 55, 33,
31, 25, 21, 20, 18, and 16 kDa. However, nonreducing condition
showed six protein bands with MW of 55, 46, 33, 25, 18, and
16 kDa (Patil et al., 2017).
The coconut protein can be separated as high MW (HMW)
and low MW (LMW) fractions by Sephadex G-200 column using
0.95 M NaCl in 0.01M Na2HPO4(pH8.2)aselutionbuffer
(Hagenmaier, Cater, & Mattil, 1972). The HMW (150 kDa) and
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Concise Reviews &
Hypotheses in Food Science
Coconut milk and coconut oil . . .
Table 2–Distribution of proteins in defatted coconut meal.
Fraction Extraction solvents Samson et al. (1971) Kwon et al. (1996) Sr ingam (1997) Patil and Benjakul (2017)
Albumin Water 30.6a21.0 22.7 19
Globulin NaCl (1–0.5 M) 61.9 40.1 46.1 36
Prolamin Isopropyl alcohol (70%) 1.1 3.3 2.0 2
Glutelin-1 Glacial acetic acid (50%) 14.4 12.5 10
Glutelin-2 NaOH (0.1 M) 4.7 4.8 1.2 4
Unextractable protein Residue 1.8 16.4 13.4
aValues are expressed as % for individual fraction.
the LMW (24 kDa) were found approximately 84% and 14% of
the total proteins, respectively. Kwon et al. (1996) separated the
major fractions of protein (albumin and globulin) from defatted
coconut flour using Sephadex G-200 column and found that the
albumin was separated into two major peaks with MW of 12 and
141 kDa, whereas one minor peak had MW about 27 kDa. The
globulin showed five peaks with MW of 186, 120, 46.7, 21.4, and
14.6 kDa, respectively.
Amino acid compositions
Coconut proteins generally provide good nutritional value with
a relatively balanced amino acid profile (Gonzales & Tanchuco,
1977; Gunetileke & Laurentius, 1974; Kwon et al., 1996; Rasyid
et al., 1992). Those proteins contain a high amount of essen-
tial amino acids (71% to 77%) and a digestibility of 86% to 94%
(Hagenmaier, Mattil, & Cater, 1974; Molina & Lachance, 1973).
In coconut skim milk, the limiting amino acids are methionine,
isoleucine, threonine, and tryptophan (Hagenmaier, Lopitakwong,
& Verasestakul, 1975). Amino acid composition of three coconut
protein fractions, as well as coconut flour in comparison with
Food and Agriculture Organization (FAO) amino acid scoring,
are shown in Table 3. Generally, coconut proteins have compar-
atively high level of glutamic acid (17.0% to 27.2%), arginine
(14.2% to 17.9%), and aspartic acid (5.6% to 8.9%) but are de-
ficient in methionine (1.2% to 2.9%; Kwon et al., 1996). Most
amino acid levels are lower in the albumin fraction, except glu-
tamic acid, arginine, and lysine, which are higher than those found
in glutelin-1 and globulin fractions. The coconut globulin con-
tains a high amount of essential amino acids including valine and
phenylalanine but has less glutamic acid, lysine, and arginine than
the albumin (Kwon et al., 1996). The leucine and phenylalanine
of globulin fraction are comparable to those guided by FAO, while
the globulin and glutelin-1 fractions show higher valine content.
Threonine, cysteine, and methionine seemed to be the limiting
amino acids for coconut proteins (Kwon et al., 1996).
Functional properties
Functional properties of coconut proteins depend strongly on
their solubility. The solubility of coconut proteins is gener-
ally low between pH 4 and 5, and is increased when pHs are
above or below such pHs. The proteins of coconut endosperm
from different regions were reported to have different solubility
(Balachandran et al., 1985), associated with different amino acid
profiles. The minimum solubility of major protein components of
coconut protein isolate, coconut skim milk, and the extracts of
coconut endosperm was observed between pH 4 and 5, known as
a range of isoelectric point of those proteins (Balasubramaniam &
Sihotang, 1979; Gonzales & Tanchuco, 1977; Hagenmaier et al.,
1974; Kwon & Rhee, 1996). Nevertheless, the maximum solubil-
ity was reported at pH 10.3 (Balasubramaniam & Sihotang, 1979).
Foaming capacity of coconut protein isolate was also affected by
pH. At pH 2 and 11, foam expansion was highest but foam stability
was low (Gonzales & Tanchuco, 1977). Proteins in coconut milk
play a profound role in emulsion stability. Onsaard, Vittayanont,
Srigam, and McClements (2006) stated that proteins isolated from
coconut skim milk effectively stabilized emulsions that are fairly
viscous. However, the lower efficacy of the proteins extracted from
coconut cream was observed, compared to whey protein isolate, by
either producing small oil droplets by the homogenizer or avoid-
ing droplet aggregation to obtain a stable emulsion (Onsaard et al.,
2006). In general, ionic strength, pH, and especially temperature
drastically influence emulsifying properties of coconut proteins
(Kwon & Rhee, 1996; Onsaard et al., 2006). Proteins form a pro-
tective barrier film around oil droplets, in which repulsion (e.g.,
electrostatic and steric) between the oil droplets prevent their co-
alescence. Effects of sonication (120 W, 20 kHz and 250 W, 20
kHz) on the stability of sunflower oil-in-water emulsions prepared
by coconut milk protein was studied by Lad and Murthy (2012).
The emulsion containing coconut milk protein (1.2%) with the
application of ultrasound was very stable. Solubility and emulsifi-
cation properties of a crude freeze-dried alkaline protein extract
(APE) was studied by Chambal, Bergenst˚
ahl, and Dejmek (2013).
Solubility and emulsification properties of APE increased at pH
above and below 3 to 4. Rodsamran and Sothornvit (2018) studied
physicochemical and functional properties of protein concentrate
from a by-product of coconut processing. Protein powders from
milk cake showed higher oil and water absorption capacities. How-
ever, protein powders from oil cake showed better emulsifying and
foaming properties. Patil and Benjakul (2017) fractionated albu-
min and globulin from defatted coconut meat and comparatively
studied emulsifying properties of these protein fractions. Globulin
fraction was more competent as an emulsifier in the oil-in-water
emulsion as compared to albumin. The differences in emulsifying
property of coconut proteins (albumin fraction and globulin frac-
tion) were possibly related to varying amino acid compositions.
Variation in the distribution of amino acids and the proportion
of nonpolar and polar amino acids, mainly on the surface of the
protein, determine emulsifying property. Generally, hydrophobic
proteins with nonpolar side chains exhibits high emulsifying prop-
erties (Patil & Benjakul, 2017).
Thermal property
Coconut proteins have been shown to be highly sensitive to
heat. They undergo denaturation and coagulation upon heating
to 80 °C (Kwon et al., 1996). Differential scanning calorimetric
studies of raw undiluted coconut milk revealed several endother-
mic transitions in the range of high temperature (80 °C to 120
°C). This result reflects the varying thermal denaturation behav-
ior and complex protein composition of coconut proteins (Kwon
et al., 1996; Seow & Goh, 1994). The exposure to heat at high
temperatures for a long time, results in denaturation and precipita-
tion of proteins in the coconut milk. The denaturation of coconut
Vol. 0, Iss. 0, 2018 rJournal of Food Science 3
Concise Reviews &
Hypotheses in Food Science
Coconut milk and coconut oil . . .
Table 3–Amino acid composition of three major protein fractions and coconut flour.
Amino acid (g/100g of protein) Albumin Globulin Glutelin-1 Coconut flour FAOa
Isoleucine 2.8 4.1 3.7 4.2
Leucine 3.9 6.5 6.5 7.4 7.0
Lysine 5.1 3.5 3.5 4.7 5.5
Methionine 1.2 2.9 2.1 1.8 3.5
Phenylalanine 2.7 5.9 4.6 5.1 6.0
Tyrosine 3.0 3.7 3.1 1.8
Threonine 3.3 3.3 3.2 2.5 4.0
Tr y pt o p ha n 1 .0
Valine 3.5 7.5 6.7 5.4 5.0
Histidine 1.8 1.9 1.9 1.8
Aspartic acid 5.6 8.9 8.3 9.3
Proline 2.7 3.4 3.2 3.6
Serine 3.1 5.0 3.9 5.3
Glutamic acid 24.5 17.5 17.0 22.4
Glycine 4.0 4.9 4.5 5.1
Alanine 2.9 4.1 3.9 4.8
Arginine 17.9 15.0 14.2 12.3
aValue guided by food and agr iculture organization (FAO).
protein by heat is enhanced at the acidic and basic pH regions
(Onsaard, Vittayanont, Srigam, & McClements, 2005). However,
coconut protein is more resistant to heat denaturation when salts,
polyols, and sugars are presented (Seow & Goh, 1994).
Coconut milk
Coconut milk can be prepared at home from grated meat by
squeezing with hand, whereas industrial or commercial scale em-
ploys the screw press or hydraulic to extract the milk. Basically,
coconut milk is an oil-in-water emulsion, in which continuous
phase is water and oil is dispersed phase (Figure 2). The oil droplets
in coconut milk emulsion are surrounded by a film of interfacial
active protein and emulsion stability is depending on these proteins
(Dendy & Timmins, 1973). The composition of coconut milk is
generally depending on that of the coconut meat used for ex-
traction. The efficiency of extraction and composition of coconut
milk from coconut meat are governed by operation parameters
such as the temperature of added water and the pressing condi-
tion (Grisingha, 1991). The difference in the water: coconut meat
ratio, ranging from 1:1 to 20:1, had no effect on oil and protein ex-
traction into coconut milk (Dendy & Timmins, 1973). Thungkao
(1988) also documented that protein contents were not affected
by temperatures (30 °C, 55 °C, and 80 °C) used for coconut milk
extraction when the grated coconut meat and water ratio of 1:1
was employed. Nevertheless, the fat content of the coconut milk
extracted at 55 °C was the highest, while those of coconut milk
extracted at 30 °Cand80°C were not significantly different.
Grisingha (1991) compared the oil and protein extractability in
coconut milk prepared using three different methods including (1)
twice pressing with water adding in the second time, (2) twice
pressing with water adding in both times, and (3) once pressing
with water adding. Protein and fat contents of extracted coconut
milk were not significantly different. Coconut milk extraction
from a fresh coconut is the most important step in wet or aqueous
processing. The wet process is a promising alternative method to
the traditional mechanical pressing of copra to manufacture the oil
(Seow & Gwee, 1997). In this case, the breakdown of emulsion is
crucial for the effective recovery of both protein and oil.
Coconut milk is naturally stabilized by proteins and phospho-
lipids (Monera & Del Rosario, 1982). The aqueous phase of co-
conut milk emulsion contains some proteins, which act as an emul-
sifier to stabilize oil droplets (Peamprasart & Chiewchan, 2006).
Hydrophilic and hydrophobic groups of these molecules can min-
imize the interfacial tension among two phases and promote the
dispersion of oil droplets in the aqueous phase, thereby enhancing
emulsion stability (Monera & Del Rosario, 1982). Hydrophobic
domains or nonpolar side chains of the proteins were able to in-
teract with hydrocarbon chains on fatty acids. This interaction
can promote physical entrapment of oil. The interactions between
oil droplets depend on the quantity and quality of the proteins
(Patil & Benjakul, 2017). When repulsive forces are dominant, the
oil droplets have a tendency to persist as individual entities, thus
forming a stable emulsion. Tangsuphoom and Coupland (2005)
investigated the colloidal stability of coconut milk as affected by
homogenization and heat treatment. Both non-homogenized and
homogenized samples were subjected to heat at different temper-
atures from 50 °Cto90°C for 1 hr. Homogenization minimized
the primary emulsion oil droplets size from 10.9 to 3.0 μm.
Processing operations, which tend to produce smaller glob-
ules, are expected to yield more stable emulsion (Onsaard et al.,
2005). Coconut milk fat structure affected by homogenizing pres-
sure was investigated by Chiewchan, Phungamngoen, and Siriwat-
tanayothin (2006). Homogenized sample had smaller oil droplet
size than nonhomogenized counterpart. Homogenization can re-
duce droplet size by the high shear force applied to dispersed phase
(Floury, Desrumaux, & Legrand, 2002). Smaller oil droplet size
was achieved at higher homogenizing pressure and was associated
with more stable emulsion. The effect of sonication on homog-
enization of coconut milk was reported by Iswarin and Permadi
(2012). Ultrasonic treatment (7 W for 25 min) was an effective
technique for reducing fat globule size up to 3.64 μm. Reduction
in fat globule size by ultrasound was caused by cavitation effect
(Iswarin & Permadi, 2012).
Proteins act as emulsifiers, which stabilize the oil droplets in
coconut milk (Senphan & Benjakul, 2015). Emulsifiers perform
two roles in the stability of emulsion: (1) lower the interfacial ten-
sion between water phases and oil; and (2) form a mechanically
cohesive interfacial film surrounding oil droplets, thus preventing
coalescence. Patil et al. (2017) carried out a comparative study
to evaluate the physicochemical properties and emulsion stabil-
ity of coconut milk obtained from the coconut at three different
maturity stages. Stability of coconut milk emulsion depended on
4Journal of Food Science rVol. 0, Iss. 0, 2018
Concise Reviews &
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Coconut milk and coconut oil . . .
Figure 2–Coconut milk model oil-in-water emulsion. (A) Stable emulsion and (B) instable emulsion.
intrinsic factors, mainly pH and protein content. pH can affect
the net charge of proteins surrounding the oil droplets. At pI,net
charge on the protein is zero. Therefore, repulsion of protein film
surrounding the oil droplets is lower. As a result, emulsion stability
of coconut milk is decreased. High protein content can lead to
efficient localization of protein films at the oil–water interphase.
As a consequence, the stability of coconut milk emulsion is in-
creased (Patil et al., 2017). To increase the shelf-life of coconut
milk, heat treatment has been introduced. However, such a harsh
treatment can induce instability of emulsion in coconut milk. Bao,
Wang, and Li (2004) suggested the optimal conditions to prepare
sterilized coconut milk drink as follows: coconut: water ratio 1:10,
pH 6.5, sugar 4%, homogenization at 20 to 25 MPa and steriliza-
tion at 121 °C for 20 min. The combined effect of the amount of
emulsifier, emulsifier types and sonication time on the droplet size
of the emulsion to stabilize coconut milk was studied by Jena and
Das (2006). Emulsifiers (maltodextrin and gum acacia) were added
to coconut milk at different emulsifier/fat ratios (4, 2.75, and 1.5).
Droplet size of coconut milk treated with ultrasound (about 2 to
2.5 min) was decreased with increasing emulsifier/fat ratio. Jena
and Das (2006) also documented that distribution of particle size
modeling by Rosin–Rambler–Sperling–Bennet relation could be
a promising tool for prediction of uniform distribution and average
droplet size of sonicated coconut milk. Linear regression equations
provided a suitable model to predict the sonication time required
to obtain the certain degree of reduction in droplet size. Effect of
coconut sugar (10% to 30%) and stabilizing agents, namely Mon-
tanox 60 (0.6% to 1.0%) and carboxymethyl cellulose (CMC, 0.6
% to 1.0%) on physical properties of sterilized high-fat coconut
milk (30%) was studied by Jirapeangtong, Siriwatanayothin, and
Chiewchan (2008). Coconut sugar, as well as stabilizing agents,
had marked effect on both rheological properties and emulsion
stability of coconut milk with high-fat. An emulsion contain-
ing sugar required a higher concentration of stabilizing agents to
stabilize the colloidal system. For the production of high stabil-
ity sweetened coconut milk, 0.8% to 1.0% of Montanox 60 and
CMC were recommended. The effect of surface-active stabiliz-
ers (whey protein isolate [WPI], sodium caseinate, Tween 20, or
SDS at concentration of 0 to 1 wt%) and homogenization on the
microstructure and colloidal stability of coconut milk was elu-
cidated by Tangsuphoom and Coupland (2008). Coconut milk
added with small-molecule surfactant (Tween 20 and SDS) either
before or after homogenization (10 MPa) completely displaced
the interfacial coconut proteins and produced a stable emulsion.
Coconut milk added with stabilizers (sodium caseinate and WPI)
prior to homogenization competed with coconut proteins to ad-
sorb at the newly-formed oil–water interface, thus yielding a sta-
ble emulsion. However, stability and oil–water interface of non-
homogenized coconut milk was not affected by the addition of
stabilizers. Coconut milk stabilized by different emulsifiers (WPI,
sodium caseinate, Tween 20, or SDS at concentration of 0 to 1
wt%) was subjected to various cooling (5 °C for 24 hr), freezing
(10 and 20 °C for 24 hr) and heating treatments (70 °C, 90
°C, and 120 °C for 1 hr) and the changes in microstructure and
bulk properties were monitored by Tangsuphoom and Coupland
(2009). The coconut milk added with 1 wt% stabilizer (WPI or
sodium caseinate) had smaller oil droplets (0.4 μm) and were sta-
ble against chilling at 5 °C. Sodium caseinate added sample was
stable against freeze-thawing (10 °Cor20 °C), whereas WPI
emulsion was unstable. The microstructure of sodium caseinate
stabilized coconut milk emulsion was not changed by heating (70
°C, 90 °C, or 120 °C) for 1 hr. However, oil droplets of WPI sta-
bilized coconut milk flocculated and coalesced when subjected to
heat at 90 °C or 120 °C for 1 hr. No marked change was observed
in droplet size of the emulsion heated at a temperature of 70 °C.
Small-molecule surfactants added to coconut milk showed better
emulsion stability against heat treatments but were completely un-
stable upon freeze-thawing because of their thin interfacial film
surrounding oil droplet which was less efficient to protect oil
droplets against coalescence (Tangsuphoom & Coupland, 2009).
Sucrose esters can be used as a good alternative to petrochemically
synthesized Tweens for preparation of coconut milk emulsions
with improved stability. Ariyaprakai, Limpachoti, and Pradipasena
(2013) compared emulsifier and interfacial properties of sucrose
ester (monostearate) with Tween 60 for application in coconut
milk. Sucrose ester had a moderately good capacity to minimize
the interfacial tension between the oil-water interface of coconut
milk. Sucrose ester also showed a marked effect on the thermal
properties of coconut milk. The complex between coconut pro-
tein and sucrose ester could protect coconut milk against freeze
and heat damages (Ariyaprakai et al., 2013).
The freshly prepared coconut milk appears stable and homoge-
nous. However, coconut milk is physically unstable and is prone to
phase separation into two distinct phases (cream phase and aqueous
phase) after a few hours (Seow & Gwee, 1997). There are three
main mechanisms that can contribute to emulsion instability: (1)
creaming, (2) flocculation, and (3) coalescence (Walstra, 1987).
Creaming is due to differences in density between the two phases,
which leads to phase separation (Beydoun, Guang, Chhabra, &
Raper, 1998). In coconut milk, cream separates from the aqueous
phase within 5 to 10 hr of production (Seow & Gwee, 1997). The
separated milk, however, can be easily re-homogenized by shak-
ing (Escueta, 1980). Flocculation is the aggregation of oil droplets
due to weak repulsive forces and strong attractive forces between
oil droplets (Verwey, 1947). During flocculation, oil droplet of
the dispersed phase will be attached to each other, but retain
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Coconut milk and coconut oil . . .
their individual structural integrity. This results in the separation
of cream from the aqueous phase (McClements & Demetriades,
1998). However, during coalescence, protein films surrounding
the oil droplets are disrupted and two oil droplets will for m a single
larger droplet. The severe coalescence brings about the separation
of oil from emulsion, including coconut milk. The main reason for
coconut milk emulsion instability is the low surface activity and
poor emulsifying properties of coconut proteins (Monera & Del
Rosario, 1982). The rate of emulsion collapse is strongly affected
by environmental conditions (pH, temperature, etc.), processing
condition and composition. The coconut milk was poorly stable
over the pH range of 3.5 to 5 but exhibited stability maxima at
pH 6.5 as well as pH 1.5 to 2 (Monera & Del Rosario, 1982).
In coconut milk, oil droplet size and pH are the most paramount
factors affecting the emulsion stability. Coconut milk emulsion
can be destabilized by adjustment of their pH between pH 5.6
and 3 (Marina, Man, Nazimah, & Amin, 2009c). Raghavendra
and Raghavarao (2010) studied the coconut milk emulsion desta-
bilization at different temperature and pH levels. Coconut milk
emulsions were very unstable at pH 7 to 8 and pH 3 to 6. Because
proteins have polar groups, their intra- and intermolecular inter-
action are directly affected by changes in pH of the emulsion. The
low pH of coconut milk could enhance the destabilization of the
emulsion, by lowering the repulsion of protein film surrounding
the oil droplets (Patil et al., 2017). Acetic acid (25%, w/v) disrupt
the coconut milk emulsion because coconut milk proteins were
plausibly coagulated and precipitated at pH 4 (Zakaria et al., 2011).
Furthermore, protein denaturation was observed in coconut milk
when heated at a higher temperature. Coconut proteins were re-
ported to coagulate and denature at 80 °Corhighertemperature
(Kwon et al., 1996; Raghavendra & Raghavarao, 2010). Thermal
denaturation of coconut proteins influences the surface charge
of oil droplets and causes droplets aggregation in coconut milk.
This results in unstable coconut milk emulsion. Coconut milk is an
abundant source of oil. Therefore, to obtain coconut oil, emulsion
must be destabilized at a high degree.
Virgin coconut oil
VCO is the purest form of coconut oil with natural characteris-
tics coconut smell and taste. At low temperature, VCO is solidified
but when liquefied, it becomes colorless like water (Marina et al.,
2009c). VCO exhibits good digestibility mainly due to medium
chain fatty acids (MCFAs). MCFAs are burned up immediately
after consumption and therefore the body uses it instantly to make
energy, instead of storing it as body fat (Patil, Benjakul, Prodpran,
Senphan, & Cheetangdee, 2016). Lauric acid is converted into a
very valuable compound known as monolaur in, which has an-
tibacterial and antiviral properties (DebMandal & Mandal, 2011).
VCO is rapidly gaining popularity because of high stability and
various health advantages (Carandang, 2008). VCO also possesses
antioxidant properties that boost the immune system. Therefore,
consumption of VCO may help protect the body from infections.
VCO does not undergo any hydrolytic and atmospheric oxidation
as confirmed by its low peroxide value as well as very low free
fatty acid content (Marina et al., 2009c; Patil et al., 2016).
Dry extraction. Coconut is served as a raw material for co-
conut oil production. Dry and wet materials are generally known as
dry coconut (copra) and wet coconut, respectively. Both raw ma-
terials can be used for extraction of oil. Dry processing is the most
commonly applied for extraction. In this process, clean ground
copra is pressed by screw press, wedge press, or hydraulic press to
release the coconut oil, which is subsequently subjected to refining
processes, namely degumming, bleaching, and deodorizing.
Wet extraction. Recently, wet process has become very popu-
lar to produce coconut oil or VCO and does not need the refining
process. Two major steps are involved in the extraction of VCO by
a wet process; first, the extraction of an emulsion (coconut milk)
from the coconut meat, and second, the breaking of this emulsion
to separate oil and protein components (Gunetileke & Laurentius,
1974). Wet extraction is superior as no high heat treatment or
chemical is used and the oil obtained has been called as VCO.
Alteration of VCO is negligible (Marina et al., 2009c). VCO has
a fresh coconut smell that can be mild to intense, dependent upon
the process used for extraction of oil. The separation of VCO can
be further enhanced by several methods.
Physical extraction. Gravitational separation is mostly related to the
slow creaming process of an oil-in-water emulsion. In general,
centrifugation is used to accelerate this creaming process, in which
higher rotation frequencies are allowed to separate the cream effec-
tively. Centrifugation process is desirable to the simple gravitation
method (Nour, Mohammed, Yunus, & Arman, 2009). Gravita-
tional separation may be very slow due to the closeness between
oil droplets and the aqueous phase, or due to attractive forces
holding the oil droplets together (Nour et al., 2009). Gravitational
separation is time-consuming, although centrifugal separation is
accomplished within a short time. It is possible to break down
the emulsions by centrifugation in order to separate dispersions
of fine oil droplets. Consequently, the coalesced disperse phase is
separated as VCO from the water phase (Coulson & Richardson,
1991; Nour et al., 2009).
Chilling and thawing techniques have been used to destabi-
lize oil-in-water emulsion. Gunetileke and Laurentius (1974) re-
ported that the protein and oil can be separated from coconut
cream obtained from centrifugation of coconut milk by chilling at
10 °C for 4 hr, followed by thawing at 40 °C. The emulsion was
centrifuged (3585 x gfor 10 min) prior to chilling and thawing
for close packing of coconut oil droplets (cream). Coconut milk
was subjected to chilling at various temperatures (5 °C, 10 °C,
15 °C, and 20 °C) for 6 hr, followed by thawing at room tem-
perature (29 °C±2°C). During thawing process, oil droplets
coalesce and form the large size droplets. The cream was cen-
trifuged at 4880 x gfor 15 min to obtain oil and the highest oil
recovery (92%) was obtained at 5 °C (Raghavendra & Raghavarao,
2010). Similarly, VCO was obtained from the chilling method by
centrifugation of coconut milk at 3600 x gfor 10 min and the
cream was removed from the upper layer. Subsequently, the cream
was chilled at 5 °C for 24 hr and thawed in a water bath at 50
°C. Oil recovery of 86.62% was obtained from chilling and thaw-
ing process (Mansor et al., 2012). Raghavendra and Raghavarao
(2010) documented that combined treatments (the use of Aspartic
protease at 37 °C, followed by chilling and thawing) on coconut
milk yielded the highest oil recovery (94.5%).
Fermentation process. Natural fermentation process is the conven-
tional method to produce VCO, where coconut milk is allowed
for fermentation using microorganisms (Marina, Man, & Amin,
2009b). Coconut milk can be fermented with normal flora, al-
lowing the oil to separate on the top portion within 24 to 48 hr.
The separated oil can be collected. Fermentation enhances the
breakdown of the emulsion, probably by microbial proteases. The
contamination with microorganisms can take place because co-
conut milk is the abundant source of moisture, carbohydrates, and
6Journal of Food Science rVol. 0, Iss. 0, 2018
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Coconut milk and coconut oil . . .
proteins. This environment can promote the growth of microor-
ganisms (Tansakul & Chaisawang, 2006). Distilled water was added
to fresh coconut milk at 1:1 ratio. Baker’s yeast (Saccharomyces cere-
visiae) of 2.0 g was added to 1 L of the mixture as an inoculum for
the fermentation process. The mixture was then allowed to stand
at room temperature for 36 hr. As the water and oil layers became
separated, the top layer of oil was simply decanted (Mansor et al.,
2012). Nevertheless, coconut milk may spoil by some microor-
ganisms, resulting in a low quality of VCO (generally in yellow
color) with oil recovery of 65% (Mansor et al., 2012). Therefore,
the major drawbacks of fermentation process are fermented odor
and low oil recovery (Raghavendra & Raghavarao, 2010). In ad-
dition, during the fermentation process, lipolytic enzymes in the
presence of water could produce high free fatty acid (FFA). Co-
conut milk emulsion can also be destabilized by adjustment of pH
between pH 3 and 5.6 and added with bacterial cultures (Chen &
Diosady, 2003). Man, Karim, and Teng (1997) extracted VCO via
an induced fermentative process using 5% inoculum (Lactobacillus
plantarum)at70°C for 6 hr under semicontrolled conditions. The
yield of VCO was 95.06%. The temperature of 45 °C, pH of 5,
inoculum (Lactobacillus plantarum 2%), fermentation time of 48 hr,
and anaerobic conditions was found as an optimum condition for
the induced fermentation process of VCO (Satheesh & Prasad,
Enzymatic extraction. Enzymes can be used in the aqueous extrac-
tion process of oil. Enzymatic pretreatment has been known as
a potential means to obtain the high yield of oil (Marina et al.,
2009b). VCO can be extracted from coconut milk by using enzy-
matic hydrolysis process (Senphan & Benjakul, 2016). Enzymatic
extraction is the most promising method among all processes for
extracting oil from coconut milk (Tano-Debrah & Ohta, 1997).
Enzymatic hydrolysis, particularly mediated by proteases, effec-
tively destabilize the coconut emulsion and release the oil (Ra-
hayu, Sulistyo, & Dinoto, 2008). Coconut milk proteins play a
role as the emulsifier to stabilize the oil droplets in the emul-
sion. After enzymatic hydrolysis of those coconut proteins, the
emulsion was unstable with concomitant release of oil from the
emulsion (Patil & Benjakul, 2017). The use of enzyme can shorten
the extraction time of VCO. Furthermore, higher yield of VCO
with prime quality was attained (Senphan and Benjakul (2015).
VCO obtained by enzymatic hydrolysis method has safety and is
more beneficial than the oil produced from copra by the traditional
method because the latter is often infected via aflatoxin or insects
producing molds related with toxicity problem during production
(Handayani, Sulistyo, & Rahayu, 2009). VCO aqueous extraction
involved the mixture of enzymes such as 0.075% (w/v) pectinase,
0.05% (w/v) protease, and 0.05% (w/v) amylase. The process re-
sulted in high extraction yields (76.4%) of oil, as compared with
a nonenzymatic process, in which the yield was less than 20%
(Barrios, Olmos, Noyola, & Lopez, 1990). Coconut milk was
added with papain (0.1%, w/w) and left to stand for 3 hr at 55 °C.
The mixture was subsequently subjected to centrifugation at 4900
xgfor 25 min to collect the oil and the recovery was 65% (Mansor
et al., 2012). Enzyme concentration and substrate, pH, incubation
time, and temperature affected the hydrolytic reaction (Handayani
et al., 2009). These factors determined extraction yield of oil dif-
ferently (Rahayu et al., 2008). Protease efficiency in enhancing
extraction yield of oil was found in descending order as follows:
alkaline protease >neutral protease >acid protease. Raghavendra
and Raghavarao (2010) documented that coconut milk subjected
to hydrolysis using papain showed 60.09% oil yield. Neutrase
Table 4–Essential composition and quality parameters of virgin
coconut oil (VCO) appointed by Asian Pacific Coconut Commu-
nity (APCC).
Serial no. APCC parameters APCC standards
1. Moisture (%) Max 0.1
2. Refractive index at 40°C 1.4480–1.4492
3. Relative density 0.915–0.920
4. Specific gravity at 30°C/30°C 0.915–0.920
5. Iodine value (g I2/100 g oil) 4.1–11
6. Saponification value (mg KOH/g oil) 250–260
7. Free fatty acid (%) Max 0.2
8. Peroxide value (meq O2/kg) Max 3
1.5 MG (0.3%, w/w) and Viscozyme L (0.6%, w/w) at pH of 7,
the temperature of 60 °C and total incubation time of 30 min were
used to achieve the maximum extraction yield of oil (Sant’Anna,
Freitas, & Coelho, 2003). Enzyme mixture (α-amylase, cellu-
lase, protease, and polygalacturonase) at 1% (w/w) and pH 7.0
with extraction temperature of 60 °C were used for VCO ex-
traction by Man, Asbi, Azudin, and Wei (1996). The 73.8% of
oil recovery with fine quality of oil were gained. Senphan and
Benjakul (2015) used proteases from shrimp hepatopancreas as an
alternative for commercial enzymes to reduce the cost of VCO
production. Senphan and Benjakul (2015) reported that VCO ex-
tracted with aid of crude protease extract (from hepatopancreas
from Pacific white shrimp; 10 unit/g protein) for 6 hr at ambient
temperature had the maximum yield of oil (92.39%). Patil et al.
(2016) extracted VCO from coconut milk with three different ma-
turity stages including immature coconut (IMC), MC, and overlay
mature coconut (OMC) using Alacalase at a level of 0.5% (v/v).
Highest oil recovery of 95.64% was obtained in OMC, followed
by MC (84.45%) and IMC (61.06%). Among all wet extraction
processes, the enzymatic extraction has been known to be less time
consuming and effective. Moreover, the maximum yield of VCO
could be attained Senphan and Benjakul (2015).
Quality of VCO
Essential composition and quality parameters of VCO appointed
by Asian Pacific Coconut Community (APCC) standards are en-
listed in Table 4. Different types of raw materials, namely incubated
and desiccated coconut meat, incubated coconut milk as well as
freeze-thawed coconut milk affected physicochemical properties
of VCO (Marina et al., 2009b). However, no drastic differences
in overall VCO quality were observed. Physical and chemical
qualities must comply with the Philippine standards for VCO
and the Codex standard for coconut oil (Dia, Garcia, Mabesa, &
Tecson-Mendoza, 2005). Mansor et al. (2012) characterized VCO
obtained from different methods including chilling, fermentation,
fresh-drying, and enzyme treatment. Various methods slightly af-
fected the quality but the difference was not significant. Marina
et al. (2009c) reported the chemical properties of commercial
VCO available in Indonesia and Malaysia. Chemical properties
of VCO was not changed among the samples. The FFA, per-
oxide, iodine, and saponification values reported for commercial
VCO samples were in accordance with the specification guided
by Codex standard (2003) for refined coconut oil. Senphan and
Benjakul (2015) also stated that VCO extraction aided by Alcalase
(10 unit/g protein) or crude protease extract (from the hepatopan-
creas of Pacific white shrimp) at 60 °C for 90 min had no influence
on the resulting VCO quality. Patil et al. (2016) studied character-
istics as well as the quality of VCO as influenced by maturity stages.
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Coconut milk and coconut oil . . .
Maturity stages of coconut had no profound effect on oxidative
stability and quality of VCO.
Marina, Che Man, Nazimah, and Amin (2009a) reported the
fatty acid composition of commercial VCO available in Malaysia
and Indonesia. Lauric acid (46% to 48%) was dominant fatty acid
and the content was within the standard limit for VCO accord-
ing to Asian and Pacific Coconut Community (APCC, 2003) and
Malaysian Standard (2007). VCO samples obtained by different
processes had differences in fatty acid compositions (Mansor et al.,
2012). Lauric acid (with the range of 46.36% to 48.42%) was
found in all VCO samples. However, VCO separated from co-
conut milk with three different maturity stages had a similar fatty
acid composition (Patil et al., 2016).
Uses of VCO
VCO is gaining popularity as a functional oil with increasing
public awareness (Mar ina et al., 2009b). VCO serves as a signif-
icant source of energy in the diet (Boateng, Ansong, Owusu,
& Steiner-Asiedu, 2016). VCO provides lubricating action in
dressing and enhances food flavor (Carandang, 2008). In addi-
tion, medium chains are similar to the fats presented in mother’s
milk, which provides immunity for babies against disease. Simi-
lar advantageous effects are also found in adults (Maria & James,
2013). VCO possesses anti-inflammatory, antimicrobial, and an-
tioxidant properties and boosts the immune system (Carandang,
2008). VCO also showed high antimicrobial activity and inhib-
ited various pathogenic bacteria for example Listeria monocytogenes
(Wang & Johnson, 1992). It was also reported that coconut oil
in combination with menhaden oil was able to reduce mammary
tumor in animal study (Craig-Schmidt, White, Teer, Johnson, &
Lane, 1993). Effect of VCO on LDL oxidation in cholesterol,
blood coagulation factors, and lipid levels fed Sprague–Dawley
rats were studied by Nevin and Rajamohan (2008). Antioxidant
levels were higher and also reduced the triglycer ide and choles-
terol levels in VCO fed animals. VCO, without bile, can easily
digest and goes directly to the liver for conversion into energy
(DebMandal & Mandal, 2011). VCO has been using to treat fat
malabsorption patients, as it contains medium chain fatty acid
(Carandang, 2008). The effect of consumption of VCO on HDL
cholesterol and waist circumference (WC) in coronary artery dis-
ease (CAD) patients was studied by Cardoso, Moreira, de Oliveira,
Raggio Luiz, and Rosa (2015). Diets rich in VCO decrease WC
and increase HDL-cholesterol concentrations, thus supporting
the secondary prevention for CAD patients. VCO increases the
metabolism and therefore support weight management (Liau, Lee,
Chen, & Rasool, 2011). Protective effect of VCO against liver
damage in albino rats challenged with the anti-folate combina-
tion, trimethoprim–sulfamethoxazole (TMP–SMX), was studied
by Otuechere, Madarikan, Simisola, Bankole, and Osho (2014).
The active components of VCO had protective effects against the
toxic effects induced by TMP-SMX administration, mainly in the
liver of rats. Arunima and Rajamohan (2014) studied the effects of
VCO in comparison with olive oil and sunflower-seed oil on the
synthesis and oxidation of fatty acids and the molecular regulation
of fatty acid metabolism in normal rats. VCO had the beneficial
effects on lipid parameters by decreasing lipogenesis and enhanc-
ing the rate of fatty acid catabolism, thus reducing coronary heart
disease. VCO can be used for cooking and frying because of its
high resistance against rancidity development (Patil et al., 2016).
Gani, Benjakul, and Nuthong (2017) reported that VCO (5%) can
be used as an alternative to other vegetable oils in surimi gel, as it
contains MCFAs, therefore, health advantages can be claimed.
The information on coconut proteins and their role in emulsion
stability could provide the better understanding of destabilization
or enhancement of coconut milk emulsion. Hence, coconut milk
emulsion can be stabilized or collapsed to obtain the desired prod-
ucts, named coconut milk and oil, respectively. To stabilize coconut
milk, additional stabilizer can be employed to work in conjunc-
tion with coconut proteins. The combined methods should be
developed to enhance destabilization of coconut milk, in which
the shorter processing time and lower cost can be achieved to
manufacture VCO. The applications of VCO as ingredient and
exploitation of its unique property can lead to the new products
with desired characteristics.
Authors’ Contributions
Umesh Patil gathered the information from literature and
drafted the review article. Soottawat Benjakul helped with the
editing of the review article.
This work was supported by the Thailand’s Education Hub for
Southern Region of ASEAN Countr ies (TEH-AC, 2015) schol-
arship. Halal Inst., Prince of Songkla Univ. (Hat Yai, Songkhla,
Thailand) was also acknowledged for the financial support.
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... Yet, soy protein is considered an allergen, and soy milk carries a higher risk of allergy [5]. Coconut protein does not have the risk of allergy, and it contains a large number of essential amino acids (71-77%), which is more easily digested and absorbed by the body [6]. Moreover, compared with soy milk, coconut milk contains more minerals (particularly calcium, phosphorus and potassium) and vitamins (i.e., vitamins C, E, B1, B3, B5 and B6), which have strong antioxidant activity [3]. ...
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In the food industry, coconut milk has a unique flavor and rich nutritional value. However, the poor emulsifying properties of coconut proteins restrict its development. In this study, the effect of ultrasound combined with preheating on coconut globulin and coconut milk was evaluated by physicochemical properties and structural characteristics. The results showed that ultrasound and 90 °C preheating gave coconut protein better emulsifying and thermal properties, demonstrated by higher solubility (45.2% to 53.5%), fewer free sulfhydryl groups (33.24 to 28.05 μmol/g) and higher surface hydrophobicity (7658.6 to 10,815.1). Additionally, Fourier transform infrared spectroscopy and scanning electron microscopy showed obvious changes in the secondary structure. Furthermore, the change in the physicochemical properties of the protein brought a higher zeta potential (−11 to −23 mV), decreased the thermal aggregation rate (148.5% to 13.4%) and increased the viscosity (126.9 to 1103.0 m·Pa·s) of the coconut milk, which indicates that ultrasound combined with preheating treatment provided coconut milk with better thermal stability. In conclusion, ultrasound combined with preheating will have a better influence on modifying coconut globulin and increasing the thermal stability of coconut milk. This study provides evidence that ultrasound and other modification technologies can be combined to solve the problems encountered in the processing of coconut protein products.
... Because it is rich nutrition and it has a unique flavor, it is often used in cooking, especially in Thailand and Southeast Asian cuisine (Schiassi et al., 2020;Tansakul & Chaisawang, 2006). In addition, it is often used in desserts, ice cream, and yoghurt (Góral et al., 2018;Patil & Benjakul, 2018). However, coconut milk is thermodynamically unstable and readily flocculates and separates into layers. ...
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Abstract Coconut milk is a traditional subtropical food, but its quality and flavor stability are the biggest challenge for promotion and commercialization. In this study, the effect of dynamic high-pressure microfluidization (DHPM) on texture and flavor properties of coconut milk was investigated under different pressures. The mean particle size decreased from 24.04 ± 1.17 μm (blank sample) to 8.21 ± 0.11 μm, reaching the minimum at 18000 psi. Microfluidization technique has positive effect on the taste of coconut milk, reducing the bitterness value from 13.39 ± 0.23 to 11.50 ± 0.20 (p > 0.05) using electronic tongue; simultaneously, the other tastes were retained. The flavor of coconut milk is less affected by pressure, and the flavor is essentially not lost in the appropriate pressure range. This work provides a new understanding of quality and flavor changes of coconut milk using DHPM in the future processing process.
... Coconut (Cocos nucifera L.) is an important commercial plant of palm family Arecaceae. Coconut milk is obtained by pressing grated mature coconut endosperm (kernel) with or without added water (Patil and Benjakul, 2018). It is mainly used as a culinary ingredient in traditional cuisines around the world. ...
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A coconut milk powder manufacturing plant encountered about 4.7% solid loss. This study was undertaken to identify measures to minimize this solid loss. Solid losses through different modes were quantified. Sample size for determination of total solid in coconut milk and conductivity cutoff point of the drain plate were optimized. Solid losses (kg run-1) through the dryer (2,954.6±106.2), drain plate (2,575.1±734.1) and due to over estimation of total solid in coconut milk (394.7±69.1) accounted for 46.5, 40.5 and 6.2% of the total solid loss, respectively. About 63% reduction in solid loss through the drain plate was evident when the conductivity cutoff point reduced from 4 to 1 mS cm-1. It was also revealed 92% reduction in over estimation of total solid when the sample size of coconut milk reduced from 2.0 to 1.5 g. In conclusion, sample size of 1.5 g for rapid total solid determination and 1 mS cm-1 conductivity cutoff point for the drain plate are recommended to minimize solid loss of this plant.
... Alternative dairy sources are rich in phytosterols and polyphenolic compounds of enormous health benefits [21]. In this chapter, we are highlighting some of the most common dairy substitutes, which are categorized as functional foods, such as soya [22], coconut [23], sesame [24], pea [25], almond [26], and cashew [27]. The prime focuses are several types of functional fermented products, especially yogurts [28] fortified with essential nutrients for enhanced immune functions. ...
The ever-escalating health care costs and public consciousness in recent years have given more attention to probiotic foods, like milk and dairy products. On the other hand, lactose intolerance and other medical and ethical reason for not using diary-based products have brought nondairy products to the limelight. These products include flavonoid-rich fruit beverages. They can be used as a vehicle for probiotics or mixed with dairy products, as well as nondairy products. Yogurts are plant seed protein-based, which may further be fortified with essential fatty acids and other phenolic compounds to improve their nutritive value. The inherent stability issues of these products can be overcome by implementing nanotechnology. The aim of this chapter is to introduce the latest non-dairy yogurts to evaluate newly formulated nanoparticles-induced nondairy yogurt as a functional food in curing lifestyle disorder diseases.
... The distribution of amino acids is roughly the same in coconut residues, skim milk, milk sediments, and alkaline extracts (Chambal et al. 2012). The molecular mass of proteins varies from 15 to 220 kDa, with the presence of 11S and 7S globulin; the isoelectric point of the coconut proteins is in the pH range of 3.5 to 4 (Patil and Benjakul 2018). Coconut proteins contain all the 9 essential amino acids, mainly leucine, lysine, arginine and valine, and non-essential amino acids such as glutamic and aspartic acids. ...
Alternative methods for wet extraction of coconut oil and protein assisted by ultrasound or microwave were developed and compared. Coconut milk was prepared by milling the pulp (5:1 water to coconut pulp ratio), further destabilised at pH 4 and centrifuged to obtain the cream and cream protein fractions (control process). Microwave-assisted treatment applied in milk (1 min, 3 pulses of 20 s; 2.5 GHz; 4.31 kW/kg by pulse) generated a significant increase in cream obtained, and in the coconut oil extraction yield (~ 20%) compared to its control. The ultrasound-assisted treatment (2.5 min; 24 kHz; 0.573 kW/kg, 6.85 W/cm2) also improved oil extraction (10–16%). Moreover, a higher protein yield was achieved in ultrasound treated samples when compared to their control (49.6–86.1%). Large particles of 11 mμ, probably aggregates of particles, and smaller particles of 3.6 mμ, were detected in coconut milk, which were reduced by ultrasound effect. Alternative treatments caused a greater liberation of total phenols in coconut cream. Coconut proteins in water (0.1%) showed high negative electrokinetic potential. The surface pressure of coconut proteins at the air/water interface was not modified by assisted treatments.
... Additionally, for Kueh Dadar, it uses coconut milk to prepare. The main amino acid in coconut milk is glutamic acid (39). It has been reported that glutamic acid could be a possible acrylamide precursor because during heating of coconut milk, it was observed that only glutamic acid decreased as the amount of acrylamide increased (40). ...
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Acrylamide is a carcinogen that forms in foods processed at high temperatures. In this study, acrylamide contents of 30 local snacks commonly consumed by the three ethnic groups (Malay, Chinese, and Indian) in Singapore were analysed by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These snacks were chosen because they were consumed regularly by people of different classes and age groups in Singapore. Our results showed that the average content of acrylamide in Indian snacks (102.23 ng/g) was higher than those in Malay (75.14 ng/g) and Chinese snacks (70.78 ng/g). The high acrylamide levels in several snacks was probably due to the processing methods and the usage of acrylamide-inducing raw materials. Same snacks prepared by different manufacturers contained different levels of acrylamide, suggesting the possibility of acrylamide reduction in these snacks. This study provides an insight into the acrylamide levels of snacks commonly consumed by the three different ethnic groups in Singapore.
Plant-based milk substitutes, or simply plant milk, are produced from the breakage of the interesting raw material, reducing its size, with subsequent extraction in water and homogenization. Soymilk is still the most consumed, but there is a variety of options for vegetable milk production. The raw materials used can be classified into cereals, leguminous plants, nuts, seeds, and pseudocereals. Cow’s milk is usually consumed in liquid form, powdered or as dairy products, and the same can be expected from plant-based substitutes. Following this opportunity, studies with vegetable milk from different raw materials for the production of powdered plant milk and its derivatives, such as cheese, yogurt, fermented, probiotics, kefir, and ice cream, have had increasing appeal.
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In this work, routinely measured physicochemical indices and lipid profiling of oil extracted from spent coffee grounds (SCG) were evaluated to assess the suitability of SCG as a new candidate for oil production. The obtained results reveal that the oil yield was 18.55±1.5 g/100g. Physicochemical indices were comparable to those of widely consumed vegetable oils in the range set in several studies. The main fatty acids of SCG oil were linoleic acid 43.20±2.19 g/100g, palmitic acid 31.78±2.02 g/100g, and oleic acid 12.68±1.15 g/100g dry basis. For sterol composition, β-sitosterol was the most abundant sterol (44.70±0.01%), followed by stigmasterol (27.57±0.01%) and campesterol (12.16±0.01%). In conclusion, this composition is typical for many other vegetable oils. Therefore, this oil may be considered a good alternative for vegetable oil production for new multi-purpose products such as cosmetic and industrial pharmaceutical uses. © 2021 by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (
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Present study was designed to produce the Virgin Coconut Oil in induced fermentation by Lactobacillus sp. Virgin Coconut Oil is a Value Added Product of coconut which have different applications. Natural fermentation is one of the commercial methods to produce Virgin Coconut Oil, where the natural microorganisms are playing a major role. In such process, contamination is one of the main problems; to overcome this, induced fermentation was performed in the controlled conditions by using probiotic microorganisms like Lactobacillus plantarum. Studies were conducted to determine the effect of major parameters, to produce higher yields of Virgin Coconut Oil in induced fermentation. It was conformed that the pH 5.0±0.1, temperature 45±1°C, inoculum concentration 2%, incubation time of 48 hrs and anaerobic conditions were the optimum conditions for the efficient production of Virgin Coconut Oil by induced fermentation with L. plantarum.
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Characteristics and quality of Virgin Coconut Oil (VCO) extracted from coconut with three different maturity stages including immature coconut (IMC), mature coconut (MC) and overlay mature coconut (OMC) were comparatively studied. The highest recovery (95.64%) was found in VCO from OMC (p < 0.05), followed by those from MC (84.40%) and IMC (61.06%), respectively. All VCO samples had water-like appearance and contained medium chain fatty acid (MCFA), especially lauric acid (C12:0) as a major fatty acid, (49.74-51.18 g/100g). Myristic acid (C14:0) in the range of 18.70-19.84 g/100g was present in all VCO. Quality parameters of all VCO samples complied with Asian Pacific Coconut Community (APCC) standards. All VCO samples had low lipid hydrolysis and oxidation, indicating that maturity stages had no influence on oil oxidative stability. Thus, maturity stages played an essential role in recovery, but showed no impact on fatty acid composition and physicochemical properties of resulting VCO.
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Virgin coconut oil (VCO) was extracted from coconut milk with the aid of crude protease extract (CPE) from hepatopancreas of Pacific white shrimp at different levels (5-15 unit/g protein) at 60C for various hydrolysis times (0-180 min). Yield of VCO increased within the first 90 min (P<0.05). However, Alcalase showed higher efficacy in VCO extraction, compared with CPE and the control (without enzyme) (P<0.05). No differences in lipid oxidation of all VCOs extracted by different proteases were observed (P>0.05). Alcalase and CPE increased the creaming index and induced the collapse of oil droplets in coconut milk, as determined by the confocal laser scanning microscopy and the phase contrast microscopy. VCOs contained medium chain fatty acid, especially lauric acid (C12:0), as the most abundant fatty acid, followed by myristic acid (C14:0). Therefore, VCO could be extracted using CPE or Alcalase at the optimal temperature (60C) for 90 min. Practical Applications: Pacific white shrimp hepatopancreas has been known as a potential source of trypsin that can be used to hydrolyze proteins stabilizing emulsion in coconut milk. Trypsin from Pacific white shrimp hepatopancreas could therefore serve as a potential aid for virgin coconut oil extraction with the shorter processing time, particularly when applied under the optimal condition. As a consequence, the cost associated with commercial enzymes could be reduced and the prime quality of virgin coconut oil was still obtained.
Effects of virgin coconut oil (VCO) at various levels (0–25%) on the properties of croaker surimi gels were studied. As the levels of VCO increased up to 15%, breaking force continuously decreased. No differences in breaking force, deformation and fracture constant were noticeable when VCO of 15–25% was incorporated. Based on texture profile analysis, hardness and chewiness decreased as the level of added VCO increased up to 10%, while no marked changes were observed with the addition of 10–25% VCO. Addition of VCO had no profound impact on springiness, cohesiveness and resilience. No remarkable change in protein pattern among all surimi gel samples was noticed, regardless of VCO levels. Lower elastic (G′) as well as loss moduli (G″) of surimi paste were observed when VCO was added, compared to the control. Nevertheless, there was no marked difference in the moduli among samples containing VCO at all levels. Whiteness of surimi gel increased, whereas expressible moisture content decreased as VCO levels increased. Microstructure study revealed that VCO droplets were distributed uniformly in gel network. Overall likeness of surimi gel was also increased for gel added with VCO. Therefore, VCO addition directly affected textural properties and improved the whiteness as well as sensory property of surimi gel.
Coconut cake, a by-product from milk and oil extractions, contains a high amount of protein. Protein extraction from coconut milk cake and coconut oil cake was investigated. The supernatant and precipitate protein powders from both coconut milk and oil cakes were compared based on their physicochemical and functional properties. Glutelin was the predominant protein fraction in both coconut cakes. Protein powders from milk cake presented higher water and oil absorption capacities than those from oil cake. Both protein powders from oil cake exhibited better foaming capacity and a better emulsifying activity index than those from milk cake. Coconut proteins were mostly solubilized in strong acidic and alkaline solutions. Minimum solubility was observed at pH 4, confirming the isoelectric point of coconut protein. Therefore, the coconut residues after extractions might be a potential alternative renewable plant protein source to use asa food ingredient to enhance food nutrition and quality.
Coconut and palm oils which were the major sources of dietary fats for centuries in most of West Africa have been branded as unhealthy highly saturated fats. Their consumption has been peddled to supposedly raise the level of blood cholesterol, thereby increasing the risk of coronary heart disease. This adverse view has led to a reduction in their consumption in West Africa and they have been substituted for imported vegetable oils. Recent information however, indicates some beneficial effects of these oils particularly their roles in nutrition, health and national development. There is the need for a better understanding of their effects on health, nutritional status and national development. This paper therefore attempts to review the roles which coconut and palm oils play in these respects in developing countries, as a means of advocating for a return to their use in local diets. Funding: None declared.
Albumin and globulin were fractionated from defatted coconut meat. Characteristics and emulsifying properties of these protein fractions were comparatively studied. Both fractions had protein with MW of 55 kDa as predominant and glutamine/glutamic acid were the major amino acids. However, differences in the protein pattern and amino acid composition were observed between two fractions. Higher average hydrophobicity was found in globulin fraction, compared with albumin. Additionally, globulin fraction was more hydrolyzed by Alcalase, in comparison with albumin. Coconut milk oil-in-water model emulsion was prepared using albumin and globulin protein fractions and stability of these emulsions was evaluated. Oil droplets with larger size caused by coalescence along with higher polydispersity were observed in albumin stabilized emulsion after 24 h of storage time. Conversely, globulin stabilized emulsion showed smaller oil droplet with low coalescence index and flocculation factor. Thus, emulsion stabilized by globulin fraction was more stable than that containing albumin fraction. However, the higher oil recovery was found in the globulin stabilized emulsion when treated with 1% Alcalase for 90 min, compared with albumin counterpart. This was caused by the higher susceptibility towards hydrolysis of globulin fraction. Therefore, globulin fraction mainly determined coconut milk stability and must be hydrolyzed by protease to release oil for virgin coconut oil production.
Based on chemical analysis, mature coconut (MC) milk had the highest moisture content (p<0.05), followed by immature coconut (IMC) and overlay mature coconut (OMC) milk, respectively. OMC milk had the highest lipid content while IMC milk showed the lowest lipid content (p<0.05). The lowest protein and carbohydrate contents were found in MC milk (p<0.05). Cocosin with MW of 55 kDa was observed as the major protein in all coconut milks; however, the band intensity slightly decreased with increasing maturity stages. Increase in oil droplet size was observed with increasing maturity stages. Therefore, maturity stages have an influence on the chemical compositions, properties and emulsion stability of coconut milk.
Based on biochemical and nutritional evidences, lauric acid (C12) has distinctive properties that are not shared with longer-chain saturated fatty acids: myristic acid (C14), palmitic acid (C16), and stearic acid (C18). Because medium-chain saturated fatty acids C6 to C12 show sufficiently different metabolic and physiological properties from long-chain saturated fatty acids C14 to C18, the term “saturated fatty acid” does not convey nutritionally accurate information and chain length should be specified as “medium-chain” and “long-chain”. Many of the properties of coconut oil can be accounted for by the properties of lauric acid. Lauric acid makes up approximately half of the fatty acids in coconut oil; likewise, medium-chain triglycerides which contain lauric acid account for approximately half of all triacylglycerides in coconut oil. It is, therefore, justified to classify coconut oil as a medium-chain vegetable oil. There is no link between lauric acid and high cholesterol. © 2014, Science and Technology Information Institute. All rights reserved.