![Vitamin composition of coconut inflorescence sap obtained with a Cocosap chiller (conventional method) and coconut sugar [14].](https://www.researchgate.net/publication/368672239/figure/tbl2/AS:11431281121419395@1676985947782/Vitamin-composition-of-coconut-inflorescence-sap-obtained-with-a-Cocosap-chiller_Q320.jpg)
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Int. J. Environ. Res. Public Health 2023, 20, 3671. https://doi.org/10.3390/ijerph20043671 www.mdpi.com/journal/ijerph
Review
Coconut Sugar: Chemical Analysis and Nutritional Profile;
Health Impacts; Safety and Quality Control; Food
Industry Applications
Ariana Saraiva 1, Conrado Carrascosa 1,*, Fernando Ramos 2,3, Dele Raheem 4, Maria Lopes 2,3 and
António Raposo 5,*
1 Department of Animal Pathology and Production, Bromatology and Food Technology, Faculty of
Veterinary, Universidad de Las Palmas de Gran Canaria, Trasmontaña s/n, 35413 Arucas, Spain
2 Faculty of Pharmacy, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
3 Associated Laboratory for Green Chemistry (LAQV) of the Network of Chemistry and Technology
(REQUIMTE), Rua D. Manuel II, Apartado 55142, 4051-401 Porto, Portugal
4 Northern Institute for Environmental and Minority Law (NIEM), Arctic Centre, University of Lapland,
96101 Rovaniemi, Finland
5 CBIOS (Research Center for Biosciences and Health Technologies), Universidade Lusófona de
Humanidades e Tecnologias, Campo Grande 376, 1749-024 Lisboa, Portugal
* Correspondence: conrado.carrascosa@ulpgc.es (C.C.); antonio.raposo@ulusofona.pt (A.R.)
Abstract: Consumers often wish to substitute refined sugar with alternative sweeteners, such as
coconut sugar, given growing interest in healthy eating and the public’s negative perception of
excess sugar intake. Coconut sugar is a healthier, sweetener option than the majority of other sugars
that are commercially available. Sap is collected from trees to be transported, stored, and evaporated
during processing, which are labor- and resource-intensive operations. Consequently, the cost of
production is higher than it is for cane sugar. Given its high nutritional value and low glycemic
index, people are willing to pay higher prices for it. However, one barrier is ignorance of its health
benefits. This review examines and deals in-depth with the most significant features of coconut
sugar chemical analyses to focus on several analytical methodologies given the increasing demand
for naturally derived sweeteners in the last 10 years. A deeper understanding of the quality control,
safety, health effects, nutritional profile, and sustainability issues corresponding to coconut sugar
is necessary to effectively implement them in the food industry.
Keywords: alternative sweeteners; coconut sugar; chemical analysis; health impacts; nutrition; food
industry
1. Introduction
In south/south-eastern Asian cuisine, coconut sugar is a popular sweetener [1] and is
made of phloem sap from coconut palm tree (Cocos nucifera L.) blossoms [2]. Workers
collect sap by scaling palm trees and use sickles to chop off unopened inflorescences. For
8–12 h, oozing sap is collected with bamboo or plastic containers. Lime is occasionally
added to the sap to stop it from fermenting [3,4]. Next, the sap is heated on open flames
and regularly shaken for it to thicken and crystallize [1]. During the production method,
sugar color can range from light to dark brown. Finally, sugar is hand-selected and sieved
to produce fine-grained produce [5].
One inflorescence is typically produced by each coconut palm tree once a month.
Approximately 1.5 L of sap is harvested twice a day (morning and evening) from all the
inflorescences. Based on the approximate 15 g of sugar per 100 g sugar content of
fresh coconut sap, boiling sap allows 200 g of sugar per inflorescence to be produced daily
[3,4].
Citation: Saraiva, A.; Carrascosa, C.;
Ramos, F.; Raheem, D.; Lopes, M.;
Raposo, A. Coconut Sugar: Chemical
Analysis and Nutritional Profile;
Health Impacts; Safety and Quality
Control; Food Industry
Applications. Int. J. Environ. Res.
Public Health 2023, 20, 3671.
https://doi.org/10.3390/
ijerph20043671
Academic Editor: Paul B.
Tchounwou
Received: 6 January 2023
Revised: 10 February 2023
Accepted: 15 February 2023
Published: 19 February 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license
(https://creativecommons.org/license
s/by/4.0/).
Int. J. Environ. Res. Public Health 2023, 20, 3671 2 of 25
Even at early ages, coconut palm trees can be utilized for sap collection purposes.
Every time phloem sap is tapped and harvested, 1–2 mm of spadix must be cut away.
Spadix can be diminished to a stump by repeating this technique. Following this
procedure, a single spadix can be tapped for 40–45 days. Coconut palm trees can be tapped
for a 20-year period [1,3].
Due to the growing interest that the public is showing in healthy diet and the
negative public perception of excess sugar use, consumers frequently attempt to
substitute refined sugars for alternative sweeteners like coconut sugar [6]. Traders
highlight coconut sugar’s traditional small-farmer producers, organic palm tree growth
in mixed farming with other crops, lower glycemic index (GI), and low fructose content
than regular refined beet sugar or cane [7]. Coconut sugar has a premium price that
consumers are willing to pay. One kilogram (kg) might cost something between €15 and
€46. In contrast, the price of a kg of traditionally refined sugar was only €0.88 in 2021 [8].
Customers today are increasingly more aware of natural ingredients. Consumers’
growing emphasis on naturalness has had a significant impact on the food industry [9,10].
Consumers in most nations often reject the food products that they do not perceive as
natural. The demand for sweeteners made from natural sources has skyrocketed in recent
decades [11].
In light of the above, the present review investigates the health effects and nutritional
profile linked with consuming coconut sugar, its potential food industry applications and
sustainability issues, and its primary safety–quality parameters, plus a chemical analysis
of its major components.
2. Chemical Analysis
Food attributes like color, consistency, texture, flavor, and smell are extremely
relevant for consumers and, consequently, for industry. In coconut sugar and syrup, these
characteristics derive from the quality of the sap from which they are produced and the
chemical reactions that occur during the heating process, namely non-enzymatic
browning via caramelization and Maillard reactions (MR) [12]. The latter involves a highly
complex reaction between reducing sugars and amino acids, and has major effects on
coconut sugar and syrup properties, including their nutritional and functional value,
color, aroma, and flavor [12–15]. Regarding flavor, the characteristics of MR products may
vary from a pleasant flowery aroma to a burnt aroma in accordance with the sugar and
amino acid compositions of the food matrix and the involved reaction pathways [13–16].
MR products, such as acrylamide and 5-hydroxymethylfurfural, have been directly linked
with the degree of coconut sugar browning, and high levels of these products can lead to
toxic health effects [13–17]. In this context, it is worth noting the study by Phaenon et al.
[18] in which the level of acrylamide was determined in both coconut sap and coconut
syrup, and, while in the first case this compound was not detected, the reported levels in
the latter were of 867 µg/kg. Many MR products exhibit beneficial biological functions,
such as potent antioxidant activity [13]. As a matter of fact, the coconut sugar and syrup
production process generates hundreds of distinct MR products that are more or less
desirable [19]. Bearing this in mind, it is easy to understand that coconut sugar and syrup
are much more than merely a concentrated sugar solution, and the study of their chemical
composition, which is fundamental to improve their nutritional and functional properties
and to guarantee consumer safety, is a complex and demanding task.
Several research works have been conducted to evaluate the physico-chemical,
microbiological, and antioxidant characteristics of coconut sap, sugar, and syrup. Some of
the most important ones are presented in Table 1 and focus on the analytical techniques
used and the main outcomes. Color determination, pH, and total soluble solids are some
of the analyses routinely performed in coconut sap, sugar, and syrup. However, despite
being fundamental for the quality control of these products, they provide limited means
for more specific quality profile analyses and, hence, the need for more advanced
analytical techniques arises.
Int. J. Environ. Res. Public Health 2023, 20, 3671 3 of 25
Coconut sugar and syrup contain well over 100 different types of compounds,
including carbohydrates, free amino acids, proteins, minerals, vitamins, aromatic
compounds, and phenolics. Table 2 provides an overview of some of the most recent
studies carried out to assess the inorganic and organic compositions of coconut sap, sugar,
and syrup. Atomic absorption spectroscopy (AAS) is the most commonly followed
technique reported for mineral analyses. The main issue in determining mineral
composition is the accurate quantification of these elements in a complex matrix, like that
of coconut sugar or syrup, which has other components and at much higher levels (e.g.,
sugars), while dealing with the problem of interferences from mineral elements other than
that being measured [20]. AAS is a technique with good detection limits. It is relatively
simple to perform and incurs low to moderate acquisition and operation costs. It allows
only a limited number of elements to be analyzed [19]. Other techniques like ICP-MS
(inductively coupled plasma mass spectrometry) require costlier equipment and greater
proficiency to operate, but stand out for having better detection limits and allow the
quantification of many elements at ultra-trace concentrations in large numbers of samples.
Therefore, they should be increasingly used [20]. For studying organic constituents, the
non-volatile ones are analyzed mainly by high-performance and ultrahigh liquid
chromatography (HPLC/UHPLC) coupled to different detectors (e.g., refractive index
(RI), mass spectrometry (MS), UV-Vis), while volatile ones are determined mostly by GC–
MS (gas chromatography coupled to mass spectroscopy) (e.g., [21–23]). Indeed, coupling
a chromatography system (e.g., UHPLC/HPLC or GC) to a mass spectrometer is one of
the most powerful ways to identify and quantify compounds because this analytical
strategy provides two different types of data per run analysis: (i) retention time and (ii)
mass spectral pattern (molecular ion and fragmentation), for each separated compound.
This information can be used to make comparisons to appropriate reference standards or
literature data [24].
As part of quality control, another critical aspect is the need to develop swift and
accurate analytical methods for fraud detection. Like honey, agave syrup, and maple
syrup, coconut sugar and syrup are prone to adulteration via the addition of less
expensive exogenous sugars, such as cane sugar, beet sugar and corn sugar. In fact, the
addition of a minor quantity of cane sugar, i.e., less than 5% w/v, to coconut sugar for
“seed” purposes and to accelerate its crystallization is common and well-accepted in the
industry [25]. The risk of fraud is a major issue given the important economic advantage
of adding an extra amount of cane sugar or another inexpensive sugar [25]. Some of the
most relevant analytical approaches recently proposed to combat this problem are
presented in Table 3. Technologies like NMR (nuclear magnetic resonance) and IRMS
(isotope ratio mass spectrometry) are noteworthy, as shown by the results obtained with
the studies of Bachmann et al. [26] or Rogers et al. [25], respectively. NMR is a non-
destructive technique that provides fast results and requires easy sample preparation.
However, it implies using a large amount of sample to obtain an adequate signal [27].
IRMS, however, requires a considerably smaller amount of sample than in NMR analyses
and displays 0.2‰ precision on the δ-scale [28]. One important limitation of IRMS is the
fact that it only provides the global δ13C values of the analyte [28]. Specifically, in the
coconut sugar and syrup adulteration context, applying the IRMS tool involves a
significant disadvantage because, although it is highly successful for detecting the
addition of cane and corn sugar to coconut sugar and syrup, it does not allow the detection
of beet sugar addition [18,29]. This is because coconut is a C3 plant-like beet, while cane
and corn are C4 plants. The 13C/12C ratio of C3 plants is lower than that of C4 plants, and
it is on this difference that the IRMS technique is based because it is impossible to detect
admixtures of beet sugar with coconut sugar [29] Notwithstanding, both IRMS and NMR
have a high potential, and their combined approach could shed considerable light on the
food fraud and adulteration issue. Energy-dispersive X-Ray fluorescence (ED-XRF) is an
alternative tool with a very high potential for detecting coconut sugar adulterations with
both cane and beet sugars, as evidenced by Zdiniakova and Calle [29]. ED-XRF offers the
Int. J. Environ. Res. Public Health 2023, 20, 3671 4 of 25
excellent advantage of requiring almost no sample preparation and can be performed with
portable devices, but has relatively high quantification limits [29,30]. That said, from an
analytical point of view and despite important advances, there is still a lot of work to be
done to gain fast and eco-friendly methods that can be performed with portable devices
and used by both consumers and producers quickly to easily detect adulterations.
In addition to food fraud, another aspect that cannot be neglected is food safety.
Coconut sugar and syrup undoubtedly provide consumers with important nutritional
and functional benefits when produced from high-quality sap that is properly collected,
preserved, and processed, i.e., following good manufacturing practices (GMP). However,
employing sap of inferior quality and its processing under unhygienic conditions are real
problems that deserve our utmost attention because they pose the risk of contamination
by insects and microorganisms (see Table 4). In this context, the dire need to carry out
studies to determine the risk of other contaminants occurring is noteworthy. Research
work on contaminants from food processing (acrylamide), agrochemicals (e.g., pesticide
residues), heavy metals (e.g., mercury, lead, arsenic, cadmium, etc.), microorganism
toxins (e.g., mycotoxins), and cleaning agents (e.g., detergents) or disinfectants
(quaternary ammonium, detergents) has been increasingly performed in other natural
sweeteners and sugar products, but is still almost nonexistent for coconut sugar and
syrup.
Table 1. Physico-chemical, microbiological, and antioxidant characteristics of coconut sap, sugar,
and syrup.
Studies
Samples
Methodology
Analytical Details
Principal Outcomes
Ref.
No.
Kind
Origin
Physico-
Chemical
Parameters
Color
2 *
Coconut sap
(collected by
two different
methods)
India
(Kasaragod)
Sensory analysis
A panel of 50
evaluators used a 5-
point hedonic scale.
The authors assessed the color attributes of the sap collected
by (1) the traditional approach using a lime-coated clay pot;
(2) a novel “coconut-sap chiller method”. It was designed to
collect fresh non-fermented sap free of foreign matter. The
coconut sap collected by the traditional method was found to
be oyster white, while that collected by the new method was
golden brown.
[21]
3 *
Coconut
syrup
(produced by
three different
methods)
Malaysia
(Jelai)
Colorimetry
Outcomes were
included in the
CIELAB system: L*
(lightness/darkness); a*
(redness/greenness); b*
(yellowness/blueness).
The authors investigated processing coconut sap in syrup by
alternative processes compared to the conventional open heat
evaporation technique. The L* parameter ranged from 23.84 to
35.61, a* from 2.31 to 3.746, and b* from 17.71 to 23.30.
[22]
107 *
Coconut
sugar
Indonesia,
Philippines,
and unknown
origin
Sensory analysis
A descriptive test was
carried out according
to the official German
methodology. For this
purpose, a panel made
up of 18 trained
evaluators was
selected.
The most expensive coconut sugars were light brown.
[17]
6 *
Coconut
sugar and
coconut syrup
Philippines
(Makati)
Colorimetry
Outcomes were
included in the
CIELAB system: L*
(lightness/darkness); a*
(redness/greenness); b*
(yellowness/blueness).
The color of both coconut sugar and coconut syrup was
evaluated for 6 months. For coconut sugar, the L* parameter
ranged from 53.38 to 63.50, a* from 7.50 to 9.08, and b* from
24.02 to 28.28. For coconut syrup, L* ranged from 17.87 to
19.96, a* from 7.72 to 8.26, and b* from 1.44 to 1.67.
[31]
Consistency
and texture
107 *
Coconut
sugar
Indonesia,
Philippines,
and unknown
origin
Sensory analysis
A descriptive test was
carried out according
to the official German
methodology. To do
so, a panel made up of
18 trained evaluators
was selected.
The more expensive products, i.e., those that were light
brown, were characterized as fine powders, while the cheaper
ones were described as being coarse-grained.
[6]
Int. J. Environ. Res. Public Health 2023, 20, 3671 5 of 25
Smell
2 *
Coconut sap
(collected by
two different
methods)
India
(Kasaragod)
Sensory analysis
A panel made up of 50
evaluators used a 5-
point hedonic scale.
The sap collected by the traditional method had a fetid smell,
which was not detected in the sap collected by a novel
“coconut-sap chiller method” that the authors put forward. It
is noteworthy in the traditional method that the collection
system is open. This allows the emission of volatile molecules
by sap to attract insects like bees, which leads to sap
contamination. As the method developed by the authors is a
closed system, this contamination does not occur.
[21]
107 *
Coconut
sugar
Indonesia,
Philippines,
and unknown
origin
Sensory analysis
A descriptive test was
applied in accordance
with the official
German methodology.
For this purpose, a
panel made up of 18
trained evaluators was
selected.
In cheaper coconut sugars, i.e., those with a darker color, the
sweet aroma predominated, while the caramel aroma was
particularly dominant in the expensive products.
[6]
Flavor
2 *
Coconut sap
(collected by
two different
methods)
India
(Kasaragod)
Sensory analysis
A panel was made up
of 50 evaluators who
used a 5-point hedonic
scale.
The flavor of the sap obtained by a novel “coconut-sap chiller
method” was sweet and delicious, but that traditionally
collected had a foul astringent aftertaste.
[21]
107 *
Coconut
sugar
Indonesia,
Philippines,
and unknown
origin
Sensory analysis
A descriptive test was
carried out according
to the official German
methodology. A panel
made up of 18 trained
evaluators was
selected.
The coconut sugar flavor was described as mainly sweet. For
the expensive products, i.e., those lighter in color, malty and
caramel attributes were added.
[6]
pH
2 *
Coconut sap
(collected by
two different
methods)
India
(Kasaragod)
pH meter
NR **
The pH of the coconut sap collected by the traditional method
was <6, whereas the sap collected by a new “coconut-sap
chiller method” had a pH of 7–8. The sap collected by the
novel method was fresh and non-fermented, but the
traditionally collected sap was partially fermented.
[21]
2 *
Coconut sap
(with and
without
preservative,
i.e., limestone
solution)
Kemloko
(Indonesia)
NR **
NR **
The pH levels of the fresh coconut sap, both with and without
added preservative/s, were 4.26 and 4.68, respectively.
[32]
6 *
Coconut
sugar and
coconut syrup
Philippines
(Makati)
pH meter
NR **
The pH levels in coconut sugar and coconut syrup were
evaluated over 6 months and ranged from 5.11 to 5.79 for the
former, and from 4.28 to 4.45 for the latter. It should be noted
that pH levels lowered in both products over time, which may
be related to microbiological contamination.
[31]
Density
2 *
Coconut sap
(collected by
two different
methods)
India
(Kasaragod)
Refractometry
A refractometer
measured both total
soluble solids and Brix
values.
The soluble solids content was higher in the sap collected by a
new “coconut-sap chiller method” proposed by the authors
(15.5–18 a) compared to that determined in the sap collected
by the conventional procedure (13–14 a). This might be owing
to the metabolization of sugars in sap by the microorganisms
found in it, which were detected in much larger numbers in
the conventionally collected sap.
a—Values expressed as °Brix.
[21]
6 *
Coconut
sugar and
coconut syrup
Philippines
(Makati)
Refractometry
A refractometer
measured both total
soluble solids and Brix
values.
Brix was evaluated over 6 months for coconut sugar and
syrup, and ranged from 97.6 to 98.9 for the former and from
79.6 to 80.3 for the latter.
[31]
Microbiologi
cal
parameters
2 *
Coconut sap
(fresh and 12-
h fermented)
India
(Kasaragod)
Metagenomic
analysis
A culture-independent
metagenomic
methodology suitable
for bacterial and
fungal microbiome
determinations with
16S rRNA and ITS
amplicon sequencing,
respectively, was used
to perform the analysis
of the fresh and
fermented coconut sap.
The analysis of the microbiome of the fresh and fermented
coconut sap revealed that the former presented a considerably
larger number of bacterial species than the latter. In contrast,
the fresh sap showed lower fungi and yeast diversity than the
fermented sap. The fresh coconut sap displayed an abundance
of Leuconostoc spp., followed by akin proportions of
Acetobacter sp., Fructobacillus sp., and Gluconobacter sp. The
fermented coconut sap exhibited a substantial increase in
Gluconobacter sp. with a marked reduction in Leuconostoc spp.
Regarding fungi and yeast occurrence, the fresh sap showed a
predominance of species of the Saccharomyces genera and of
Hanseniaspora. The fermented sap showed abundance for
Cortinarius saturatus and Hanseniaspora guilliermondii.
[33]
Antioxidant
potential
3 *
Coconut sap
(collected by
two different
India
(Kasaragod)
Colorimetry
FRAP (ferric-reducing
antioxidant power)
assay.
According to the FRAP assay, the values of the conventionally
collected coconut sap, the coconut sap obtained by a novel
“coconut-sap chiller method” and the coconut sugar
[21]
Int. J. Environ. Res. Public Health 2023, 20, 3671 6 of 25
methods) and
coconut sugar
generated from the latter were respectively 8.34 a, 14.8 a, and
22.9 a
a—Values are expressed as mg of AEAC (ascorbic acid
equivalent antioxidant capacity)
2 *
Coconut
sugar
Thailand
(Samut
Songkhram
and
Phetchaburi)
Colorimetry
The DPPH (2,2-
Diphenyl-1-
picrylhydrazyl) radical
scavenging activity
assay.
The ORAC (oxygen
radical antioxidant
capacity) assay.
The DPPH free radical inhibition percentage and ORAC
values ranged between 25.7–87.37 a and 740.7–3815.6 b,
respectively.
a—Values shown as %;
b—Values shown as mg of trolox equivalents (TE)/100 g.
[34]
* Total number of samples analyzed in the study; ** NR—Not reported.
Table 2. Chemical analyses of the organic and inorganic constituents of coconut sap, sugar, and
syrup.
Studies
Samples
Methodology
Analytical Details
Principal Outcomes
Ref.
No.
Kind
Origin
Inorganic
constituent
s
9 *
Coconut sugar
Ivory Coast
Spectrometry
Sample preparation:
Coconut sugar was incinerated
until ash was obtained.
Sample processing:
The coconut sugar ash analysis
was performed by (SEM).
The mineral levels in coconut sugar samples fell
within the ranges of 101.77–128.95 a (K), 85.32–
94.66 a (Cl), 7.96–16.28 a (Mg), 12.68–15.87 a (Si),
8.33–14.57 a (P), 5.58–13.17 a (S), 8.05–11.65 a (Na),
1.23–2.19 a (Cu), and 1.73–2.09 a (Fe). Traces—1.04
a (Br) and 0.17 a (Zn).
a—Values expressed as mg/100 g.
[35]
1 *
Coconut sap
Malaysia
(Jelai)
FAAS (flame atomic
absorption
spectrophotometry)
Sample preparation:
Coconut sap was first diluted
(10×), then filtered and further
analyzed.
The predominant minerals were K (960.87 a), Na
(183.21 a) and Mg (22.91 a). The levels of Fe (1.36 a), Ca
(0.42 a), Zn (0.338 a), Mn (0.105 a) and Cu (0.065 a)
were also determined.
a—Values expressed as mg/L.
[36]
6 *
Coconut sugar
and coconut
syrup
Philippines
(Makati)
Atomic absorption
spectrophotometry
(AAS)
NR **
The mineral composition of both coconut sugar
and coconut syrup was evaluated for 6 months.
For coconut sugar, the K, Na, and Fe ranges were
954–1075 a, 99–112 a, and 0.5–0.6 a, respectively.
The Ca and Zn levels remained constant over
time and were 8 and 0.1 a, respectively. For
coconut syrup, the levels of K varied between
609–632 a, Na between 110–126 a, Ca between 1–2
a, and Zn between 0.1–0.2 a. The Fe levels were 0.4
a at the three different measurement times.
a—Values expressed as mg/100 g.
[31]
Organic
constituent
s
Non
volatiles
Amino
acids
3 *
Coconut sap
(collected by
two different
methods) and
coconut sugar
India
(Kasaragod)
Ninhydrin method
(for free amino acids
quantification)
UHPLC-TQD-MS/MS
(ultrahigh
performance liquid
chromatography
coupled to tandem
quadrupole mass
spectrometry) for the
amino acids profile
analysis
Amino acids profile:
Sample preparation:
Samples were hydrolyzed in a
vacuum using hydrochloric
acid, 6 M. Then, hydrolysates
were dried (also in a vacuum)
after neutralization. They were
dissolved in a known volume
of the mobile phase, filtered
(0.2 µm), and finally injected
into the analytical system.
Column:
Waters UPLC BEH-C18
column (2.1 × 50 mm; 1.7 μm),
protected by a Waters
Vanguard BEH C-18 guard
column (1.7 μm).
Mobile phase:
The total free amino acids content of the sap
attained conventionally, the sap obtained from a
“new coconut-sap chiller method”, and the sugar
produced from the latter was, respectively 0.413 a,
1.03 a, and 3.05 b. The following amino acids were
quantified in the coconut sap obtained by the
traditional method: (i) glutamic acid (359 c); (ii)
aspartic acid (83.7 c); (iii) serine (60.5 c); (iv)
alanine (16.2 c); (v) threonine (13.7 c); (vi) proline
(13.1 c); (vii) arginine (11.9 c); (viii) lysine (7.81 c);
(ix) valine (6.48 c); (x) citrulline (6.38 c); (xi)
methionine (5.90 c); (xii) phenylalanine (2.14 c);
(xiii) asparagine (0.86 c); (xiv) leucine (0.64 c); (xv)
histidine (0.42 c); (xvi) tyrosine (0.29 c); (xvii)
tryptophan (0.01 c). For the sap acquired by the
novel method, amino acids and respective levels
were as follows: (i) glutamic acid (626 c); (ii)
aspartic acid (118 c); (iii) serine (58.1 c); (iv)
arginine (17.3 c); (v) alanine (15.1 c); (vi) proline
(14.6 c); (vii) threonine (12.2 c); (viii) methionine
[21]
Int. J. Environ. Res. Public Health 2023, 20, 3671 7 of 25
0.1% formic acid in water-
methanol: water (1:1) with
0.1% formic acid.
(6.28 c); (ix) valine (6.10 c); (x) citrulline (6.07 c);
(xi) lysine (5.93 c); (xii) phenylalanine (2.56 c);
(xiii) asparagine (2.41 c); (xiv) histidine (0.65 c);
(xv) leucine (0.56 c); (xvi) tyrosine (0.16 c); (xvii)
tryptophan (0.01 c). In turn, sugar contained (i)
glutamic acid (394 d); (ii) aspartic acid (131 d); (iii)
proline (112 d); (iv) alanine (84.5 d); (v) serine (78.0
d); (vi) lysine (64.5 d); (vii) threonine (59.1 d); (viii)
arginine (53.7 d); (ix) valine (50.9 d); (x)
phenylalanine (50.7 d); (xi) tyrosine (26.0 d); (xii)
leucine (21.8 d); xiii) methionine (19.6 d); (xiv)
histidine (5.83 d); (xv) citrulline (5.79 d); (xvi)
asparagine (4.25 d); (xvii) 3,4-dihydroxy-
phenylalanine (0.76 d); (xviii) tryptophan (0.18 d).
a—Values appear as g/100 mL;
b—Values appear as g/100 g;
c—Values appear as mg/100 mL.
d—Values appear as mg/100 g
Carbohydra
tes
3 *
Coconut syrup
(produced by
three different
methods)
Malaysia
(Jelai)
HPLC-RID (high-
performance liquid
chromatography
coupled with
refractive index
detection)
Sample preparation:
Coconut syrup samples were
diluted (10×), filtered (0.45
µm), and further analyzed.
Column:
Merck LiChroCART® Single
bond NH2 column (250 × 4.6
mm; 5 µm).
Mobile phase:
Acetonitrile-water (80:20, v/v).
The authors investigated the processing of
coconut sap in syrup by alternative process
techniques compared to the conventional open
heat evaporation technique. The fructose,
glucose. and sucrose levels respectively ranged
between 18.27–35.07 a, 21.38–23.71 a, and 7.35–
25.67 a. The coconut syrup obtained by the rotary
evaporation technique displayed larger quantities
of glucose and fructose, but a smaller quantity of
sucrose, than that produced by the other
techniques. The total sugar content for all the
analyzed samples was between 64.89–65.66 a.
a—Values expressed as %.
[22]
1 *
Coconut sap
Malaysia
(Jelai)
HPLC-RID (high-
performance liquid
chromatography
coupled with
refractive index
detection)
Sample preparation:
Coconut sap was diluted,
(10×), filtered (0.45 µm), and
further analyzed.
Column:
Merck LiChroCART® Single
bond NH2 column (250 × 4.6
mm; 5 µm).
Mobile phase:
Acetonitrile-water (80:20, v/v).
Three sugars (sucrose, fructose, glucose) were
detected in coconut sap. Their respective values
were 6.91 a, 3.48 a, and 2.53 a.
a—Values expressed as %.
[36]
3 *
Coconut sap
(collected by
two different
methods) and
coconut sugar
India
(Kasaragod)
Phenol–sulphuric
acid method (for total
sugars content
determination)
Nelson-Somogyi’s
method (for reducing
sugars content
quantification)
NR **
The total sugars content of the sap acquired
traditionally, the sap obtained following a new
“coconut-sap chiller method”, and the sugar
produced from the latter was 9.20 a, 16.2 a, and
91.8 b, respectively. For the reducing sugars
content, the reported values were 1.24 a for the
sap obtained conventionally, 0.68 a for the sap
collected by the novel approach, and 4.69 b for
sugar.
a—Values shown as g/100 mL;
b—Values shown as g/100 g.
[37]
6 *
Coconut sugar
and coconut
syrup
Philippines
(Makati)
GC–MS (gas
chromatography-
mass spectrometry)
NR **
The sugar composition of both coconut sugar and
coconut syrup was evaluated for 6 months. For
coconut sugar, the sucrose, glucose, fructose, and
mannose levels ranged between 83.18–90.50 a,
9.40–11.45 a, 2.89–3.69 a, and 0.51–3.90 a,
respectively. For coconut syrup, they varied
between 35.85–38.96 a, 10.74–14.03 a, 15.39–15.57 a,
and 3.91–5.35 a, respectively.
a—Values expressed in mg/100 g.
[38]
4 *
Coconut sap
(with and
without
preservative,
i.e., limestone
solution) and
coconut sugar
(with and
Kemloko
(Indonesia)
HPLC-RID (high-
performance liquid
chromatography
coupled with
refractive index
detection)
Sample preparation:
For each sample, 1 g was
weighed, and then dissolved
in 100 mL of distilled water.
The mixture was filtered, and
the solution was injected into
the HPLC. system.
Column:
For the fresh sap to which no preservative was
added, lower sucrose content (1.76 a) and higher
fructose (5.76 a) and glucose (4.46 a) contents were
found compared to the sap with the preservative
whose sucrose, fructose and glucose levels were
5.76 a, 3.23 a, and 2.25 a, respectively. For coconut
sugar, the sucrose content of that prepared with
fresh coconut sap, but without adding a
[32]
Int. J. Environ. Res. Public Health 2023, 20, 3671 8 of 25
without
preservative)
Aminex HPX-87C.
Mobile phase:
Water.
preservative, was lower (49.41 a) than that of
coconut sugar produced with the fresh coconut
sap to which a preservative was added (49.41 vs.
57.05 a). Their glucose (15.90 a) and fructose (14.15
a) levels were higher than those of the coconut
sugar prepared from the fresh coconut sap to
which a preservative was added; that is, glucose
6.97 a and fructose 5.45 a.
a—Values expressed in %.
Phenolics
3 *
Coconut sap
(collected by
two different
methods) and
coconut sugar
India
(Kasaragod)
Folin’s Ciocalteu
method (for total
phenolic content
determination
purposes)
Ultrahigh
performance liquid
chromatography
coupled with
UHPLC-TQD-MS/MS
(tandem quadrupole
mass spectrometry)
for the phenolic
profile analysis
Phenolic profile:
Sample preparation:
The extraction of the
individual phenolics was
performed with 80% aqueous
methanol (v/v). Thereafter,
filtering the extracted sample
was performed (0.2 μm). This
sample was injected into the
analytical system.
Column:
Waters UPLC BEH-C18
column (2.1 × 50 mm; 1.7 μm)
protected by a Waters
Vanguard BEH C-18 guard
column (1.7 μm).
Mobile phase:
0.1% formic acid in water
0.2% formic acid in methanol
The total phenolics content of the sap acquired
traditionally, the sap obtained by a novel
“coconut-sap chiller method”, and the sugar
produced from the latter was 14.8 a, 21.7 a, and
47.2 b, respectively. The following phenolic
compounds were quantified in the coconut sap
obtained by the traditional method: (i) vanillic
acid (2.92 c); (ii) syringic acid (1.80 c); (iii) trans-
cinnamic acid (0.636 c); (iv) p-hydroxy benzoic
acid (0.308 c); (v) ferulic acid (0.302 c); (vi)
protocatechuic acid (0.182 c); (vii) 2,4-dihydroxy
benzoic acid (0.126 c); (viii) gentisic acid (0.104 c);
(ix) gallic acid (0.073 c); (x) o-coumaric acid (0.064
c); (xi) rutin (0.043 c); (xii) caffeic acid (0.042 c);
(xiii) salicylic acid (0.040 c); (xiv) umbelliferone
(0.030 c); (xv) p-coumaric acid (0.008 c). Regarding
the sap collected by the new method, the
identified phenolics were as follows: (i) vanillic
acid (3.54 c); (ii) trans-cinnamic acid (2.40 c); (iii) p-
hydroxy benzoic acid (0.963 c); (iv) syringic acid
(0.707 c); (v) salicylic acid (0.477 c); (vi) ferulic acid
(0.246 c); (vii) catechin (0.157 c); (viii) quercetin
(0.156 c); (ix) hesperetin (0.116 c); (x) myricetin
(0.105 c); (xi) caffeic acid (0.103 c); (xii) rutin (0.078
c); (xiii) protocatechuic acid (0.065 c); (xiv) o-
coumaric acid (0.062 c); (xv) umbelliferone (0.056
c); (xvi) gallic acid (0.044 c); (xvii) p-coumaric acid
(0.030 c); (xviii) gentisic acid (0.026 c); (xix) 2,4-
dihydroxy benzoic acid (0.015 c). In sugar: (i)
vanillic acid (12.8 d); (ii) benzoic acid (9.41 d); (iii)
trans-cinnamic acid (4.25 d); (iv) catechin (2.37 d);
(v) p-hydroxy syringic acid (1.96 d); (vi) p-
coumaric acid (1.27 d); (vii) ferulic acid (0.908 d);
(viii) o-coumaric acid (0.706 d); (ix) salicylic acid
(0.653 d); (x) myricetin (0.390 d); (xi) hesperetin
(0.327 d); (xii) quercetin (0.313 d); (xiii) apigenin
(0.230 d); (xiv) protocatechuic acid (0.224 d); (xv)
gallic acid (0.203 d); (xvi) rutin (0.192 d); (xvii)
gentisic acid (0.111 d); (xviii) caffeic acid (0.109 d);
(xix) umbelliferone (0.078 d); (xx) 2,4-dihydroxy
benzoic acid (0.037 d).
a—Values are mg of gallic acid equivalents
(GAE)/100 mL;
b—Values are mg of GAE/100 g;
c—Values are mg/100 mL;
d—Values are mg/100 g.
[21]
Vitamins
1 *
Coconut sap
Malaysia
(Jelai)
HPLC/UV-Vis (high-
performance liquid
chromatography
coupled with
ultraviolet-visible
detection)
Sample preparation:
Coconut sap was diluted (10x),
filtered, and further analyzed.
Column:
Agilent Poroshell 120 EC
column (100 × 4.6 mm; 4 μm).
Mobile phase:
Potassium dihydrogen
phosphate buffer (pH 3.4, 50
mM).
Vitamins C, B1, B2, B3, B4, and B10 were all
detected in coconut sap. Their levels were 116.19
a, 4.33 a, 0.084 a, 1.88 a, 0.53 a, and 0.33 a,
respectively.
a—Values expressed as µg/mL.
[36]
3 *
Coconut sap
(collected by
two different
methods) and
coconut sugar
India
(Kasaragod)
6-Dichlorophenol-
indophenol (DCPIP)
method for vitamin C
level measurements
(ultrahigh
performance liquid
Sample preparation:
Water-soluble vitamins:
Samples were extracted with
10 mM ammonium
acetate:methanol 50:50 (v/v)
that contained 0.1%
The following vitamins were detected and
quantified in the coconut sap obtained by the
traditional method: (i) vitamin C—16.3 a; (ii) B1—
0.021 c; (iii) B3—11.4 c; (iv) B5—1.64 c; (v) B6—1.32
c; (vi) B7—0.095 c; (vii) B9—0.031 c; (viii) D2—
0.028 c; (ix) D3—0.062 c; (x) E—2.94 c; (xi) K1—
[21]
Int. J. Environ. Res. Public Health 2023, 20, 3671 9 of 25
chromatography
coupled to tandem
quadrupole mass
spectrometry) for the
quantification of
other vitamins
butylhydroxytoluene and
centrifuged. Next, the
supernatant was (0.2 μm)
filtered and injected into the
analytical system.
Fat-soluble vitamins:
The residue from the
previously described
extraction (please refer to
“water-soluble vitamins”) was
re-extracted with ethyl acetate
that contained 0.1%
butylhydroxytoluene,
centrifuged and filtered (0.2
μm) before being injected into
the analytical system.
Column:
Waters UPLC BEH-C18
column (2.1 × 50 mm; 1.7 μm)
protected by a Waters
Vanguard BEH C-18 guard
column (1.7 μm).
Mobile phase:
Water-soluble vitamins:
0.1% formic acid in water-
acetonitrile.
Fat-soluble vitamins:
Acetonitrile—0.2% formic acid
in methanol.
0.601 c; (xii) K2—0.428 c. For the sap collected by a
new “coconut-sap chiller method”, the vitamins
and their respective levels were as follows: (i)
vitamin C—19.6 a; (ii) B1—0.068 c; (iii) B3—14.9 c;
(iv) B5—3.99 c; (v) B6—2.35 c; (vi) B7—0.073 c; (vii)
B9—0.036 c; (viii) D2—0.074 c; (ix) D3—0.056 c; (x)
E—7.20 c; (xi) K1—1.73 c; (xii) K2—0.771 c. Sugar
contained (i) vitamin C—3.98 b; (ii) B1—14.3 d; (iii)
B2—0.248 d; (iv) B3—34.7 d; (v) B5—2.53 d; (vi)
B6—101 d; (vii) B7—2.51 d; (viii) B9—0.260 d; (ix)
D2—0.171 d; (x) D3—0.256 d; (xi) E—19.6 d; (xii)
K1—7.35 d; (xiii) K2—5.57 d.
a—Values are given as mg/100 mL;
b—Values are given as mg/100 g;
c—Values are given as µg/100 mL;
d—Values are given as µg/100 g.
6 *
Coconut sugar
and coconut
syrup
Philippines
(Makati)
2,6-
Dichloroindophenol
titrimetric method
NR **
Vitamin C levels in both coconut sugar and
coconut syrup were evaluated over 6 months and
ranged from 16 to 44 a for the former, and from 19
to 30 a for the latter.
a—Values expressed as mg/100 g.
[31]
Volatiles
Aliphatic/ar
omatic
hydrocarbon
s, ketones,
aldehydes,
alcohols,
esters, fatty
acids,
furans,
pyrazines,
pyrans and
sulfur-
containing
compounds.
3 *
Coconut sap
(fresh,
clarified, and
fermented)
India
(Mandakalli)
GC–MS (gas
chromatography-
mass spectrometry)
Isolated volatiles:
Volatile compounds were
isolated by the SDE
(simultaneous distillation-
extraction) method with a
Likens-Nikerson apparatus.
The extractive solvent was
dichloromethane.
GC–MS:
Column:
Supelco-fused silica column
SPB-1 (30 m × 0.32 mm; 0.25
µm) coated with polydimethyl
siloxane.
Gas carrier:
Helium.
The following 21 compounds were identified in
the fresh coconut sap: (i) palmitic acid (2024 a); (ii)
palmitoleic acid (1042 a); (iii) ethyl lactate (560 a);
(iv) phenyl ethyl alcohol (357 a); (v) 3-hydroxy-2-
pentanone (236 a); (vi) tetradecane (167 a); (vii)
farnesol (125.5 a); (viii) 2-methyl tetrahydrofuran
(105 a); (ix) tetradecanone (104.5 a); (x)
tetradecanoic acid (94.0 a); (xi) nonanoic acid (84.8
a); (xii) dodecane (74.3 a); (xiii) dodecanoic acid
(52.6 a); (xiv) hexanoic acid (49.8 a); (xv)
pentadecane (48.4 a); (xvi) 2-hydroxy-3-pentanone
(45.6 a); xvii) nerolidol (44.9 a); (xviii) hexadecane
(37.2 a); (xix) 1-hexanol (27.3 a); (xx) hexadecanone
(25.9 a); (xxi) tridecanone (24.5 a). For the clarified
coconut sap, 13 compounds were identified,
which were as follows: (i) palmitic acid (342 a); (ii)
ethyl lactate (300 a); (iii) phenyl ethyl alcohol (195
a); (iv) palmitoleic acid (141 a); (v) 3-hydroxy-2-
pentanone (75.9 a); (vi) hexanoic acid (54.7 a); (vii)
tetradecane (46.9 a); (viii) 2-methyl
tetrahydrofuran (45.4 a); (ix) dodecane (30.5 a); (x)
1-hexanol (24.8 a); (xi) pentadecane (21.8 a); (xii)
hexadecane (16.4 a); (xiii) 2-hydroxy-3-pentanone
(14.0 a). In the fermented coconut sap, 11
compounds were identified, namely as follows:
(i) palmitoleic acid (14,603 a); (ii) isoamylalcohol
(7467 a); (iii) ethyl lactate (4636 a); (iv) phenyl
ethyl alcohol (4189 a); (v) palmitic acid (2421 a);
(vi) dodecanoic acid (1084 a); (vii) ethyl caprate
(797 a); (viii) ethyldodecanoate (709 a); (ix)
tetradecanoic acid (597 a); (x) ethyl caprylate (503
a); (xi) farnesol (224 a).
a—Values expressed as µg/L.
[12]
6 *
Coconut sap,
coconut syrup
Indonesia
(Blitar)
Gas
chromatography—
Isolated volatiles:
Volatile compounds were
isolated by a simultaneous
Five volatiles were isolated in the fresh coconut
sap: (i) 2-butanol (60.26–68.37 a); (ii) acetic acid
(25.83–30.43 a); (iii) 2-methylcyclohexane (0.66–
[37]
Int. J. Environ. Res. Public Health 2023, 20, 3671 10 of 25
and coconut
sugar
mass spectrometry
(GC–MS)
distillation–extraction (SDE)
method using a Likens–
Nikerson apparatus.
The extractive solvent was
diethylether.
GC–MS:
Column:
CBP-5 column (50 m).
Gas carrier:
Helium.
6.39 a); (iv) cyclohexyloctane (1.81–4.23 a); (v) 1,4
dimethyl-6,1-butyl acetate (0.91–1.11 a). For
coconut syrup, the following occurred: (i) 2-
butanol (45.35–51.02 a); (ii) acetic acid (24.56–6.47
a); (iii) dodecanoic acid (0.34–21.59 a); (iv) 2-furan
(1.97–6.73 a); (v) cyclohexane (3.56–4.41 a); (vi) 1,4
dimethyl-6,1-butyl acetate (0.40–10.26 a); (vii) 4,6
dimethyl-5-cyclo-hexo pyrimidine (0–2.25 a); (viii)
2,3 dimethylpirazine (0–0.77 a). Finally for
coconut sugar, the following compounds were
identified: (i) acetic acid (21.54–35.05 a); (ii) 2-
butanol (29.98–31.23 a); (iii) 1,4 dimethyl-6,1-butyl
acetate (1.7–15.50 a); (iv) N,N dimethyl 2-
(diphenylmetoxi)-ethylamine (9.31–13.26 a); (v)
cyclohexyloctane (0.0–17.01 a); (vi) dodecanoic
acid (0.0–12.41 a); (vii) methylpyrazine (1.46–1.81
a).
a—Values expressed as %.
1 *
Coconut sugar
Thailand
(Samutsongkhram)
GC–MS (gas
chromatography-
mass spectrometry)
GGO (gas
chromatography-
olfactometry)
Isolated volatiles:
Volatile compounds were
extracted three times with
diethyl ether. The combined
extract was left to concentrate
in a Vigreux column. Then, the
concentrated extract was
subjected to high vacuum
distillation and then
concentrated, first in a Vigreux
column and finally in a
nitrogen flow.
GC–MS:
Column:
Restek Stabilwax column (30
m × 0.25 mm; 0.25 µm) and an
Agilent DB-5MS column (30 m
× 0.25 mm; 0.25 µm).
Gas carrier:
Helium.
Descriptive sensory analysis:
The sensory evaluation panel
included nine properly trained
evaluators.
The following volatile compounds were
identified in coconut sugar: (i) acetic acid a; (ii)
2,3-pentanedione; (iii) acetoin; (iv) 2,5-dimethyl
pyrazine; (v) 2,3-butanedione; (vi) methional;
(vii) furfural; (viii) 5-methyl furfural; (ix) 2-
furanmethanol; (x) 4-methyl-5H-furan-2-one; (xi)
5-methyl-2-furan methanol; (xii) benzylalcohol;
(xiii) maltol [3-Hydroxy-2-methyl- 4H-pyran-4-
one]; (xiv) Furaneol® [2,5-dimethyl-4- hydroxy-
3(2H)-furanone]; (xv) vanillin [4-Hydroxy-3-
methoxybenzaldehyde].
The sweet, roasted, burnt, nutty, smoky, and
caramel notes of coconut sugar were attributed
mostly to pyrazine, furan, and pyran derivatives
being present. Benzyl alcohol and vanillin also
introduce sweet notes. In addition, acetoin, 2,3-
pentanedione and 2,3-butanedione were found to
be responsible for the buttery, cheesy, and
creamy aromas.
a—Major component identified; values not
reported.
[38]
2 *
Coconut sugar
Thailand
(Ampawa)
GC–MS (gas
chromatography–
mass spectrometry)
Isolated volatiles:
Volatile compounds were
extracted by SPME (solid-
phase microextraction).
GC–MS:
Column:
An Agilent DB-625 capillary
column (30 m × 0.25 mm).
Gas carrier:
Helium.
The identified volatile compounds were as
follows: (i) 2,3-diethyl-5-methyl pyrazine; (ii) 2,3-
dimethyl pyrazine; (iii) 2,5- dimethyl pyrazine;
(iv) 2-ethyl-3,5-dimethyl pyrazine; (v) 2-methyl
pyrazine; (vi) ethyl pyrazine; (vii) 5-methyl
furfural; (viii) furfural.
[12]
2 *
Coconut sugar
Thailand (Samut
Songkhram and
Phetchaburi)
GC–MS (gas
chromatography–
mass spectrometry)
Isolated volatiles:
Volatile compounds were
isolated by means of
headspace gas
chromatography.
GC–MS:
Column:
An Agilent DB wax-fused
silica capillary column (60 m ×
0.25 mm; 0.25 µm).
Gas carrier:
Helium.
The detected volatile components comprised the
following: (i) ethanol (9.48–52.21 a); (ii) 4-
methanol (19.58–27.85 a); (iii) acetaldehyde
(<0.01–16.33 a); (iv) 2-furanmethanol (<0.01–13.54
a); (v) acetic acid (<0.01–11.98 a); (vi) 1-hydroxy-2-
propanone (<0.01–10.24 a); (vii) acetone (2.63–9.98
a); (viii) 2-ethyl-3,6-dimethyl pyrazine (<0.01–6.46
a); (ix) 2-propanol (2.29–4.37 a); (x) hexanoic acid
(<0.01–2.93 a); (xi) 3-methyl hexanal (<0.01–2.35 a);
(xii) 2-furaldehyde (<0.01–1.48 a); (xiii) hydroxy-2-
butanone (0.0–1.10 a); (xiv) butanoic acid (<0.01–
1.01 a); (xv) 2-methyl propanal (0–0.91 a); (xvi) 3-
(methylthio)-propanal (<0.01 a); (xvii) 2,3-
butanedione (<0.01 a); (xviii) 2-methyl-3-buten-2-
ol (<0.01 a); (xix) 2-methyl-1-propanol (<0.01 a);
(xx) 2-ethyl-5-methyl pyrazine (<0.01 a); (xxi) 3-
methyl-butanol (<0.01 a); (xxii) 2-acetylfuran
(<0.01 a).
a—Values expressed as %.
[34]
Int. J. Environ. Res. Public Health 2023, 20, 3671 11 of 25
* Total number of samples analyzed in the study; ** NR—Not reported.
Table 3. Detecting adulterants in coconut sap, sugar, and syrup.
Adulterants
Works
Samples
Methodology
Analytical Details
Principal Outcomes
Refs.
No.
Kind
Origin
Cane and beet
sugar
21 *
Coconut
sugar
NR **
1H NMR (proton nuclear
magnetic resonance).
ULPC-Q-TOF-MS
(ultraperformance liquid
chromatography quadrupole
time-of-flight mass
spectrometry).
MRA (multivariate regression
analysis).
1H NMR:
Sample preparation:
To identify polar minor metabolites,
500 mg of every sugar sample were
dissolved in 1 mL of deuterium oxide
to be vortexed. Then, a 600 μL aliquot
was placed inside an NMR tube to be
analyzed. To study the non-polar
extracts, 1 mL of chloroform-d was
added to 500 mg of all the coconut
sugars. Then, suspensions were
vortexed and centrifuged. Finally, a
600-μL aliquot of the supernatant was
placed inside an NMR tube.
Analysis:
Spectra were recorded at 300 K.
UPLC-Q-TOF-MS:
Sample preparation:
Of each sample, 1 g was dissolved in
20 mL of water and the solution was
filtered (0.20 μm). A 2-μL aliquot of
this filtrate was diluted (10x) to be
then injected into the analytical
system.
Column:
Waters HSS T3 C-18 column.
Mobile phase:
15 mM acetic acid, 10 mM
tributylamine, 5% (v/v) methanol-2-
propanol.
Pyroglutamic acid has
been identified as a unique
marker for coconut sugar.
Additionally, coconut
sugars exhibited
substantially higher levels
of acetic, formic, lactic, and
succinic acids than both
cane and beet sugars.
Trans-aconitic acid was
shown to be a marker for
cane sugar, as was betaine
for beet sugar.
[26]
11 *
Coconut
sugar
Indonesia and
unknown
origin
Energy-dispersive X-ray
fluorescence
Soft independent modeling of
class analogies (SIMCA)
Sample preparation:
First, samples were ground, and
pellets were prepared. To do so, 5 g
of sugar needed to be mixed with 1 g
of wax.
Energy-dispersive X-ray fluorescence:
The irradiation time (s) was 200 for
Ca, Cl, Cu, Fe, K, P, and S, and 500 for
Br, Rb, and Sr.
Analytical parameters:
LOQ *** (mg/Kg): 1.7 Br; 118.4 Ca; 78
Cl; 1.2 Cu; 4.6 Fe; 566 K; 171 P; 4.2 Rb;
1.19 Sr.
Precision (%): 22 Br; 3.5 Ca; 2 Cl; 10.5
Cu; 6.5 Fe; 3 K; 6 P; 5 Rb; 8 Sr.
This research work
established the mass
fractions of Br, Ca, Cl, Cu,
Fe, K, P, Rb, S, and Sr in
the coconut, cane, and beet
sugar samples. On
average, all the
aforementioned elements
had significantly bigger
mass fractions in coconut
sugars than in cane and
beet sugars.
[13,20,30]
Cane and corn
sugar
109 *
Coconut
sugar
Indonesia
(Central Java)
δ13C IRMS (stable carbon isotope
ratio mass spectrometry).
Sample preparation:
First, 300 mg of all the coconut sugar
samples were dissolved in 5 mL of
deionized water in centrifuge tubes.
Tubes were then immersed in warm
water inside an ultrasonic bath (15
min). Then, solutions were (0.45 μm)
filtered and a 10-µL aliquot was
transferred to tin capsules, which
were dried at 40 °C. Finally, capsules
were crimped and subjected to
double encapsulation prior to the
analysis.
Carbon isotope analysis:
An isotope ratio mass spectrometer
interfaced with an elemental analyzer
(EA-IRMS) in the continuous flow
mode for δ13C measured isotopes.
The genuine coconut sugar
exhibited an average δ13C
value of −25.6‰ ± 0.4‰.
More positive δ13C values
(>−24.8‰) indicate the
addition of C4 sugar, i.e.,
cane or corn sugar/syrup.
More negative δ13C values
(<−26.4‰) should be
related to the use of
additives. On the whole,
the authors propose a
maximum acceptable δ13C
value of −24.1‰ for
authentic coconut sugars.
[25]
* Total number of samples analyzed in the study; ** NR—Not reported; *** LOQ—Limit of
quantification.
Int. J. Environ. Res. Public Health 2023, 20, 3671 12 of 25
Table 4. Detecting contaminants in coconut sap, sugar, and syrup.
Contaminants
Works
Samples
Methodology
Analytical Details
Principal Outcomes
Refs.
No.
Kind
Origin
Insects
NR **
Coconut sugar
NR **
NR **
NR **
The United Kingdom food safety authorities
have reported the occurrence of insect
fragments (500–800) in coconut sugar
commercialized in the country.
[39]
Microorganisms
2 *
Coconut sap
(collected by
two different
methods)
India
(Kasaragod)
Serial dilution, plus,
the spread plating
method
Microbial analysis:
The employed culture
media were Nutrient agar,
Martin Rose Bengal agar,
Sabouraud Dextrose agar,
and KenKnight &
Munaiers agar,
respectively, for bacteria,
fungi, yeasts, and
actinomycetes. Differing
sample dilutions were
plated in the respective
medium and incubated at
28 °C. Bacteria and yeast
colonies were scored as
colony-forming units
(CFU)/mL of sap after a
24-h incubation period,
fungi/yeasts after 48–72 h,
and those of
actinomycetes after 1
week.
The conventionally collected coconut sap
exhibited an extremely large number of
bacteria and yeasts. In contrast, the sap
collected by a new “coconut-sap chiller
method” had a significantly lower level of
microorganisms. The predominant
populations were bacteria, namely those of
the genus Bacillus. No actinomycetes growth
was observed in either sample.
[21]
4 *
Coconut sap
(with and
without
preservative,
i.e., limestone
solution) and
coconut sugar
(with and
without
preservative)
Kemloko
(Indonesia)
Total plate count
Microbial analysis:
The procedure was
performed in accordance
with the “Indonesian
National Standard for
Microbe Contamination
Test (Method 01-2897-
1992)”. The employed
culture medium was
Nutrient agar.
The microbial counts of sap with and without
a preservative were, respectively, “not
countable/g” and 1.2 × 102 colony-forming
units (CFU)/g. The microbial counts of
coconut sugar both with and without a
preservative were, respectively, 1.2 × 102
CFU/g and 3.6 × 102 CFU/g.
[32]
6 *
Coconut sugar
and coconut
syrup
Philippines
(Makati)
Counts of:
Aerobic plates.
Coliforms.
Moulds/yeasts.
Salmonella sp.
Microbial analysis:
An aerobic plate count
was performed based on
FDA-BAM-3; the coliform
count was conducted
based on FDA-BAM-4; the
mould and yeast count
was performed in
accordance with FDA-
BAM-18; the Salmonella sp.
count was carried out
following the FDA-BAM-5
procedure.
Coconut sugar exceeded the allowable limits
for Salmonella sp. (/25 g; microorganism
should not be detected) and coliform counts
(should be <10 colony-forming units
(CFU)/g). The values of the aerobic plate
count, and the fungal and yeast counts,
complied with legislation, i.e., they were
below 10 CFU/g. With coconut syrup, the
Salmonella sp. and coliform count values were
in accordance with the stipulated criteria. The
aerobic plate count exceeded the defined
limit (<10–< 250 CFU/g).
[31]
* Total number of samples analyzed in the study; ** NR—Not reported.
3. Food Industry Applications and Sustainability Issues
For the application of coconut sugar in food and beverage industries, it is important
to gain an understanding of the sap from which the sugar is processed. Coconut sap is a
nutritious fluid enriched with sugars, calcium, phosphorous, iron minerals, and vitamins
such as B complex and C [39,40]. It contains important phenolic compounds such as
antioxidants and can be categorized as a low glycemic index (GI 35) food [40]. The
nutritional composition of coconut sap is further described in Section 5.
Coconut sugar is made from the watery coconut sap found inside palm trees. It is
prepared by concentrating inflorescence sap, which is popularly known as ‘neera’ in
Kerala, India [23], and it is obtained by tapping the unopened coconut spadix. Coconut
sugar is brown and contains 2–3% moisture. As this sugar is plant-based, natural, and
Int. J. Environ. Res. Public Health 2023, 20, 3671 13 of 25
minimally processed, it can be readily applied in many vegan diets as a healthier option
[14,41].
The variation in coconut sugar manufacturing processes is extremely varied
according to local, traditional, and indigenous knowledge [4]. These factors account for
the vast variations in the appearance, taste, and flavor of the different coconut sugar types
that can be found on the market [42].
Coconut sap is produced from palm trees all year-round and there is no specific
season for tapping the spathe, however, the amount of sap produced from the trees
changes with the season [40]. In the traditional method, the sap trickling from the cut
surface is collected in an open earthen pot or bamboo sac, which is placed at the top of the
palm for at least 8–12 h. Lime is then coated on the inner surface of the pot to prevent
fermentation [43]. The sap collected by this method is oyster white in colour and emanates
a strong odour with contamination from insects, ants, pollen, and dust particles [3]. The
coco-sap chiller developed by Central Plantation Crops Research Institute (CPCRI) in
India has helped to improve the quality of unfermented coconut sap, reduced the
processing time, eliminated contaminants like ants, other insects, pollen, and dust
particles, and enabled better product diversification and market perspectives [3]. A
comparison of total sugars, reducing sugar, free amino acid, total flavonoids, and ferric
reducing antioxidant power from coconut sap collected traditionally and those from coco-
sap chillers are presented in Section 5. Similarly, a comparison of the water-soluble
vitamins and fat-soluble vitamins is presented in table for the employed processing
methods.
The Asian and Pacific Coconut Community describes how local operations are
performed by small-scale cottage industries with coconut sap to yield molded coconut
sugar. The traditional operation starts by collecting coconut sap from palms, which this is
normally carried out twice a day, morning and evening [44]. The obtained coconut sap is
then filtered through muslin cloth to remove ants, insects, and any other polluting
elements. The filtered sap is placed inside cooking vessels. Sap concentrates by
evaporating water to increase the sap concentration. This is achieved by boiling the
filtered sap in cooking vessels for 3 h at 100–110 °C [44]. The resulting material then turns
into a thick liquid. Upon boiling, foam forms that should be eliminated from vessels [44].
The usual procedure is to add a few drops of cooking oil or grated coconut to the resulting
mash to prevent foam from excessively forming.
This mash is heated for another hour and is occasionally stirred. To prevent sugars
from caramelizing, the must be heated slowly [7]. When the mash is very thick and
suitable for molding, cooking vessels are lifted from stoves and cooled to 60 °C. The cooled
mash is poured inside clean half coconut shells or bamboo vessels to be cooled and to set
[45].
The processing technique influences nutritional and health benefits, as described in
the previous section. To ensure product quality, the collected sap is tested for its acidity.
This is crucial because, if sap is fermented, it is not suitable for brown coconut sugar
manufacturing purposes.
Given its high sucrose content, during its storage, coconut sugar displays caking
properties. So, it is essential to add an anticaking agent like tricalcium phosphate (TCP)
for it to remain stable during food applications. TCP covers the coconut sugar powder
surface and its hygroscopicity significantly diminishes, which improves its flowability
[45].
Processing coconut sap into sugar syrup has been investigated following several
alternative processing techniques. The coconut sugar syrup obtained from the rotary
evaporation method has a better nutritional value than the microwave heating and open
heating methods [22]. The non-enzymatic browning that results from Maillard reactions
(MR) is enhanced when cooking sap at higher temperatures for a long period, which gives
the preferred dark-colored coconut sugar as an ingredient, but only for traditional dishes
[46]. Rotary evaporation is fast and gentle and performed at a lower temperature. All this
Int. J. Environ. Res. Public Health 2023, 20, 3671 14 of 25
results in evaporation with less thermal decomposition [47–49]. The rotary evaporation
method is the alternative processing method that the sugar processing industry applies to
produce coconut sugar. It operates in a 250-mbar vacuum at 60°C. It results in improved
physico-chemical qualities, minimum input energy, and shorter processing times [43].
The employed processing method influences the antioxidant properties and vitamin
contents of coconut sugar syrup. It allows coconut sugar production in a minimum time
period, but with high vitamin and antioxidant contents [50]. The coconut sugar syrup
produced by at 60 °C rotary evaporator (RE-60) shows significantly lower antioxidant
activities (DPPPH, ABTS, FRAP, and TPC) values (p ≤ 0.05) than that generated by other
techniques (open-heat evaporation, microwave, etc.). What this suggests is that the
coconut sugar syrup that is produced at a lower temperature (60 °C) in vacuum exhibits
significantly different and lesser antioxidant activities than all the other samples
generated by distinct evaporation techniques [11,45].
Employing coconut sugar syrup with vast amounts of antioxidants is a promising
food production ingredient. Former research works have observed how coconut sugar
with larger quantities of vitamins and minerals and that perform more antioxidant
activities can be used as an alternative natural sugar with improved chemical properties
[3,51].
The work by Saputro [52] reveals the use of low-glycaemic-index (GI) sugar, such as
(coconut sugar), to produce plain chocolate. They demonstrated that it was more
nutritious as a sugar containing more anti-carcinogenic compounds, antioxidants, and
minerals than commercial chocolates made with sugarcane sugar or sugar palm.
Moreover, if coconut sugar can be employed as an ingredient, it is able to generate more
antioxidant activity if food is processed at high temperatures. Very important compounds
such as pyroglutamic acid or hydroxymethylfurfural (HMF) form when heated [53].
Coconut blossom sugar is organic with a caramel aroma and has been the target of
adulteration and fraud [6,26]. A recent study identified minor metabolites, such as
chemical markers for coconut blossom sugar, by profiling these metabolites, which helped
to detect adulterations in products. Bachmann et al. [26] were unable to detect HMF in all
the samples. However, pyroglutamic acid was employed at a comparatively high
concentration, which exceeded other unambiguous metabolites in coconut sugar like
inositol or shikimic acid in coconut sugar [26]. Henceforth, HMF is an apparently suitable
marker metabolite for coconut sugar. The distinct metabolic profiles of coconut blossom
sugar can be better investigated and identified by combining LC-MS and NMR [54].
Coconut sap as a natural non-alcoholic beverage has high demand as an instant thirst
quencher. In India, tapping coconut sap has improved the income of farmers and
generated employment. Export of the sap is extensively carried out to countries like
Canada, South Korea, USA, Norway, France, Japan, Australia, and the Middle East [55].
Coconut water and juice from coconut sap are commercially canned as beverages in
Thailand and exported as ‘functional food‘ with health benefits (see Figure 1). These
beverages are flavoured with tropical fruits such as watermelon and pineapple. Globally,
the beverages industry was forecasted to reach $1.9 trillion in 2021 and continue to grow
at a compounded annual growth rate (CAGR) of 3% [56].
Int. J. Environ. Res. Public Health 2023, 20, 3671 15 of 25
Figure 1. Coconut sap as beverages, bought from a local ethnic shop in Rovaniemi, Finland. (Photo
credit: © Dele Raheem, July 2022).
Numerous organic food and drink firms increasingly employ natural alternative
sweeteners such as coconut sugar to substitute refined sugars. Coconut sugar is employed
thanks to its ecological credentials and nutritional properties. It has many widespread
applications in food and beverage industries to prepare bakery products like chocolate
(plain chocolate and drinking chocolate), cake, cookies, and brownies. It can be added to
juice, tea, or any beverage as a sweetener, and can be employed as a seasoning agent.
Adding coconut sugar to several food applications as a healthy option is well justified
because it contains important nutrients like vitamins E and C, minerals like zinc, iron,
potassium, and phosphorus, and phytonutrients like anthocyanidins, flavonoids,
polyphenols, and antioxidants [3,20,35]. This kind of sugar also contains a significant
amount of inulin (4.7 g 100 g−1), required for generating short-chain fatty acids like acetate,
butyrate, and propionate [15].
The sugar obtained from the sap of palm trees, which includes coconut sap, is utilized
mainly in desserts, sweet soy sauce, and beverages, and also in many other traditional
foods. This is especially due to its appreciated and accepted taste, color, and flavor when
producing drinks and foods [57–60]. Apriyantono [61] indicated that using palm sugar as
a soybean sauce sweetener strongly impacts soy sauce flavor because over 70 volatile
compounds are present. Employing palm sugar as a potential natural sweetener also
impacts cookies’ color, textural properties, and flavor [62], which lends this sugar to being
a potential natural sweetener.
Pure sucrose is the most widely used sugar as food sweetener. However, coconut
sugar is reported to offer health benefits thanks to its lower GI value. The GI values
previously obtained from coconut sugar [63,64] are below the GI values for pure sucrose,
i.e., refined cane sugar [65]. Pure sucrose is the most commonly employed sugar as food
sweetener. During baking operations, and as another research work reveals, palm sap
sugar-sweetened bread has a lower GI value than cane sugar-sweetened bread [66].
Moreover, Ref. [66] report that the palm sugars–corn starch mixture brings about a slow
digestion rate and, consequently, lower GI values than those made with refined cane
sugars. Coconut sugar displays good quality and possesses a high nutritive value if it is
processed from hygienic non-fermented sap; however, if poor-quality neera is employed,
its crystallization involves having to add several additives and chemicals (e.g., starch and
gluten, and adding sugars from C4 plants, palm, or coconut oil). During the
manufacturing process, coconut quarters are added to avoid overboiling sap [1].
Regarding sustainability and traceability issues, organic certification comes over as a
quality standard that helps to increase coconut sugar’s credibility in the European market.
In most cases, coconut sugar exporters are from developing countries. They should
Int. J. Environ. Res. Public Health 2023, 20, 3671 16 of 25
consider not only certification, but also natural and organic trends [7]. Consumers will
also show an interest in the story behind sustainable production. Export traders can
advertise that small farmers traditionally produce coconut blossom sugar, palm trees
organically grow mixed with other crops, and sugar has very low fructose contents and
lower GI values than traditional refined beet or cane sugar [7].
As the interest in climate change is growing, individual and planetary healthy
coconut-based ecosystems offer excellent possibilities to enhance carbon sequestration
with crop combinations that involve a range of plants, which include vine, food crops,
tubers, and tree crops. For climate-change adaptation intentions, annual intercrops
planted under coconuts can be managed to achieve optimum benefits for the whole
system. A holistic approach that focuses on the whole system’s overall productivity and
sustainability, and not on palms alone, is necessary to make coconut-based
agroecosystems resilient to climate change [67]. The demand for natural products is
expected to grow, and employing alternative sweeteners, such as coconut syrup and
sugar, will increase.
4. Safety and Quality Conditions for Control of Palm Sap Sugar Products
Both palm sap sugar (PSS) and sweet sap are alternative sweeteners prepared from
the sap and nectar tapped from the flowers of several palm tree species. For example,
palmyra palm (Borassus flabellifer), nipa palm (Nypa fruticans Wurmb), sugar palm (Arenga
pinnata) and coconut palm (Cocos nucifera). They have the potential to be incorporated into
food products as substitutes for sucrose [67]. This sweet sap can be consumed fresh,
processed as sugar or syrup, or be fermented as vinegar or an alcohol beverage [68]. This
sugar is commonly used in many traditional foods in southeast and southern Asia, and
plays a vital role in the color-flavor development of distinct food products [57–59]. One
major palm sugar exporting country is Indonesia. Based on the most recent data, the
exports of products made with palm sugar or coconut sap came to 36.5 thousand tons,
valued at US$49.3 million in 2019 [69]. These products destined for export must comply
with the food legislation of the country of destination, such as, the European countries
(EFSA) or United States (FDA).
The world’s PSS business is expected to reach a total of 1.7 billion dollars in 2027, and
is currently 630 million dollars [70]. This increase might be due to its potential to be
incorporated into food products as a substitute for sucrose [71]. This product is often
employed in many traditional foods in Asia, where it plays an important role in the color–
flavor development of different food products [57–59]. Unlike other natural sweeteners,
its production is located in a limited number of countries or in a certain geographical area;
for example, agave is produced mainly in Mexico and maple syrup in Canada and the
USA. However, PSS is produced in southeast and southern Asia, and the mainly
producing countries are the Philippines, Thailand, and Indonesia.
Around the world, there are more than 3000 different types of palm trees, but only
five are economically important. They offer good sugar palm production yields for any of
its different products. They are as follows: date palm (Phoenix dactylifera), betel nut palm
(Areca catechu), African oil palm (Elaeis guineensis), coconut (Cocos nucifera), and pejibaye
(Bactris gasipaes) [72]. Other authors include more palm species [73], such as the following:
• Coconut palm sugar (Cocos nucifera). It grows in coastal tropical regions of the Indian
and Pacific oceans. This sugar is generated from blossoms and is often known as
coconut blossom sugar.
• Date palm has two varieties (Phoenix sylvestris and Phoenix dactylifera). They can be
found in Asia and the Middle East, respectively. Date palms are grown mostly for
their fruit: dates.
• Palmyra palm (Borassus genus). It grows in the African continent and in Asia and New
Guinea. It is used for making hats, hatching, writing materials, and some food
Int. J. Environ. Res. Public Health 2023, 20, 3671 17 of 25
products. Obviously, its wood is employed. Palm sugar is generated from the sap
(called ‘toddy’) of tree flowers.
• Nipa palm (Nypa fruticans). It is found in tropical and coastal regions of the Pacific
and Indian Oceans. It lies particularity in its favored biome: mangroves. It is the only
palm tree that partially grows underwater. Its tap is rich in sugar, and it is employed
to produce palm sugar.
• Sugar palm (Arenga pinnata) is native to tropical and coastal regions in Asia. It is
grown mostly in Indonesia and China. The sap used to generate palm sugar is called
‘gur’ and ‘gula aren’ in India and Indonesia, respectively.
Nevertheless, other authors acknowledge 40 palm species, the tapping of which is
either destructive or non-destructive. Non-destructive exploitation with, for instance,
Phoenix canariensis on the Canary Islands (Spain) results in sustainable harvests during
palms’ lifetime [68].
Special attention is paid to harvest the sap tapping of Phoenix canariensis for its sugary
sap on the La Gomera Isle (Canary Islands). It is one of the most relevant cases of
sustainable native flora use. It supplies one of the best-known ethnobotany examples on
the Canary Islands and is not only a major tourist attraction for visitors, but also an
important local farming activity [68].
PSS is produced with the sap/nectar that is tapped from the flowers of several palm
tree species. Knowledge about the physico-chemical properties of this sugar should be
known if a high-quality product is to be obtained. PSS’ physico-chemical characteristics
are affected by its raw materials (sap/nectar) and processing techniques [37,52,73].
Further, the form that sugars come in (syrup, coarse/powder, solid) also determines its
properties. Coconut sap, the natural and sweet exudate from tapped unopened coconut
spathes or inflorescences (Cocos nucifera Lin.), is one of the major primary coconut pro-
ducts used for many food uses. It can be processed as natural and nutritious food
products, such as coconut granulated brown sugar, concentrate, juice, and vinegar.
Processes involve easy-to-follow procedures that require a few simple tools and
equipment.
Coconut sap juice is a healthy pasteurized beverage, and coconut sap concentrate is
a thick, free-flowing syrup. Both can be considered functional foods for consumers and
the food industry.
The inflorescence in good stands of coconut trees can produce an average of 2 L of
sap per tree a day [74]. An average yield of 1 kg of sugar can be obtained from four coconut
trees every day.
Under adequate production conditions, coconut trees’ inflorescence can produce a
mean yield of 2 L of sap per tree every day. So, the yield of four coconut trees per day can
produce 1 kg of sugar. However, as both the sugar content and production of sap depend
on trees’ location and their variety, nutrition, the season, tapping time, and the system,
these conditioning factors also can impact organoleptic and microbiological
characteristics.
Some authors have followed different preservation techniques for bottling palm sap;
although all probes failed, these authors consider it crucial to understand the biochemical
composition, fermentation chemistry, and existing preservation methods [75].
Transforming coconut sap into sugar granules is simple and requires basic
equipment, hence, it is appropriate for and best adapted to farms or medium-sized
enterprises. It is a good source of immediate income for coconut farmers, and demand is
growing on both local and international markets [76].
Engineering the palm sugar production process poses several problems if sap is not
immediately cooked after it is removed from palm trees, which results in a lower pH. A
drop in pH impacts the produced palm sugar’s quality. To obtain a higher product
conversion factor value, engineering the production process by adding plant extracts to
prevent “gait” is feasible [74], and the palm sugar packaging design is more appealing
Int. J. Environ. Res. Public Health 2023, 20, 3671 18 of 25
and varied. Packaging is designed by prioritizing practical, economical, and hygienic
aspects, without burdening producers in production terms and consumers in price terms.
One alternative for PSS with a high quality (soluble solids content 16 degrees brix and pH
4.7) has been presented with the addition of some preservatives such as citric acid (0.09%)
and nisin (10 ppm) [76]. The quality standard in the Philippines includes quality norms to
not only produce PSS, but also to obtain a product of standardized quality and well-
defined organoleptic and microbiological parameters.
Coconut Sap Sugar Production in the Philippines
General considerations: farm-level technology to produce a high-value production
product from coconut inflorescence sap (see Table 5). It is simple, farm-level technology
that involves a natural heat evaporation process that converts liquid sap into a solid form
of sugar granules without having to resort to complicated and costly machinery or
equipment (Figure 2).
Table 5. Reference values for palm sap sugar products. Adapted from Ref. [74].
Physico-Chemical Properties
Reference Values
Color
light yellow to dark brown
Odor
free of burnt odor
Taste
free of burnt taste
Moisture Content (%)
<4.0
Glucose Content
2.8–3
Fructose Content
1.0–4.0
Sucrose
78.0–89.0
Ash
<2.4
Microbiological properties
Salmonella
Negative
E. coli
Negative
Coliform count
<10 ufc/g
Total Plate Count
<10 ufc/g
Molds and Yeasts
<10 ufc/g
Int. J. Environ. Res. Public Health 2023, 20, 3671 19 of 25
Figure 2. Recommendations for coconut sap sugar production in the Philippines. Adapted from
Refs. [17,70,74,77].
Int. J. Environ. Res. Public Health 2023, 20, 3671 20 of 25
5. Nutritional Profile and Health Impacts
Despite its expensive price, coconut sugar is considered by several authors to be one
of the greatest natural sweeteners as it offers a number of health advantages [14]. Tables
6–8 list the biochemical properties, vitamins, and other nutritional components of the
sugar obtained from coconut inflorescence sap.
Vitamins C and E, minerals including zinc, iron, potassium, and phosphorus, and
phytonutrients like antioxidants, flavonoids, anthocyanidins, and polyphenols, are all
present in coconut sugar [21]. Additionally, inulin comes in a substantial quantity (4.7 g,
100 g−1) in coconut sap sugar. It is necessary for the synthesis of short-chain fatty acids
acetate, butyrate, and propionate [31]. Coconut sugar and syrup (the latter contains
dietary fiber and fermentable inulin) are truly promising functional foods and are
converted into short-chain fatty acids [31]. As coconut sugar has a sweetening potential
that is comparable to saccharose, it is utilized as an alternative sweetener for making
confections, drinks, pastries, and other gastronomic delicacies [78]. According to Trinidad
et al. [63], coconut sugar has a low GI that falls within the 35–54 range per serving. Low
GI diets lower the likelihood of developing certain chronic diseases like type II diabetes.
Compared to other sugars, coconut sugar has nutritional superiority. When cane, palm,
and coconut sugars, sorbitol, and other sweeteners are blended with wheat flour, sorbitol
possesses the best starch digestibility—with an almost identical digestibility for palm or
coconut sugars [66]
Compared to the majority of other commercially available sugars, coconut sugar is
certainly a healthy sweetener. It is processed by evaporating sap—which requires
considerable labor and resources when collected from trees—that is then transported,
stored, and processed. Therefore, the manufacture cost is higher than for cane sugar.
People are willing to pay high prices for it given its nutritional value and low GI.
However, one bottleneck is the lack of knowledge about its health advantages. Natural
coconut sugar and other biproducts are produced hygienically as a result of scientific
developments in sap collecting and processing, which have occurred in some major
producing nations, including India, in the last few years [14].
Table 6. Coconut inflorescence sap obtained with a Cocosap chiller (conventional method) and
coconut sugar were studied for their biochemical components and ferric-reducing antioxidant
power [14].
Biochemical
Characteristics
Coconut Inflorescence Sap
Obtained by the Cocosap
Chiller Method (100 mL)
Traditionally Collected
Sap (100 mL)
Coconut Inflorescence Sap
Sugar (100 g)
Total sugars (g)
16.20 ± 0.33
9.20 ± 0.97
91.8 ± 1.01
Reducing sugars (g)
0.68 ± 0.01
1.24 ± 0.87
4.69 ± 4.60
Free amino acids (g)
1.03 ± 0.10
0.413 ± 0.09
3.05 ± 0.07
Total phenolic content (mg
gallic acid equivalent)
21.7 ± 0.48
14.8 ± 1.03
3.05 ± 0.07
Total flavonoids (mg
catechin equivalent)
0.817 ± 0.19
0.177 ± 0.02
4.76 ± 1.21
Ferric-reducing antioxidant
power (mg of ascorbic acid
equivalent)
14.8 ± 0.21
8.34 ± 0.83
22.9 ± 4.12
Table 7. Vitamin composition of coconut inflorescence sap obtained with a Cocosap chiller
(conventional method) and coconut sugar [14].
Biochemical Characteristics
Coconut Inflorescence Sap
Obtained by the Cocosap
Chiller Method (100 mL)
Traditionally
Collected Sap (100
mL)
Coconut Inflorescence Sap
Sugar (100 g)
Water-soluble vitamins
Vitamin C (mg)
19.6 ± 0.95
16.3 ± 0.76
3.98 ± 1.12
Thiamine (µg)
0.07 ± 0.02
0.02 ± 0.00
14.3 ± 1.16
Niacin (µg)
14.9 ± 2.80
11.4 ± 0.7
34.7 ± 2.1
Int. J. Environ. Res. Public Health 2023, 20, 3671 21 of 25
Pyridoxine (µg)
2.35 ± 0.01
1.32 ± 0.12
101 ± 0.3
Pantothenic acid (µg)
3.99 ± 0.08
1.64 ± 0.11
2.53 ± 0.2
Biotin (µg)
0.07 ± 0.01
0.09 ± 0.01
2.51 ± 0.7
Folic acid (µg)
0.036 ± 0.01
0.031 ± 0.00
0.26 ± 0.07
Riboflavin (µg)
-
-
0.25 ± 0.02
Fat-soluble vitamins
Cholecalciferol (µg)
0.056 ± 0.00
0.062 ± 0.00
0.256 ± 0.02
Ergocalciferol (µg)
0.074 ± 0.01
0.028 ± 0.00
0.171 ± 0.02
Tocopherol (µg)
7.20 ± 0.93
2.94 ± 0.46
19.6 ± 3.5
Vitamin K1 (µg)
1.73 ± 0.19
0.601 ± 0.09
7.35 ± 0.95
Vitamin K2 (µg)
0.771 ± 0.12
0.428 ± 0.12
5.57 ± 0.61
Table 8. Nutritional profile of coconut sugar made from inflorescence sap on a double-jacketed
cooker and a modified conventional processing technique. (The results should be interpreted in light
of the biochemical characteristics of coconut sugar, as listed in Tables 6 and 7).
Biochemical Components
Content
Protein (g/100 g)
2.6
Dietary fiber (g/100 g)
3.1
Electrolytes (mg/100 g)
Sodium
568
Potassium
1002
Microminerals (mg/100 g)
Iron
2.2
Zinc
2.1
Essential amino acids (mg/100 g)
Valine
40.68
Threonine
45.81
Leucine
16.01
Lysine
136.5
Methionine
54.55
Histidine
3.48
Phenylalanine
57.66
Tyrosine
5.68
6. Conclusions
The global drive toward better individual and environmental health warrants the
need for better knowledge about what we produce and consume. Sweeteners are
important food ingredients to formulate edible food products, and for health and
sustainability. This review summarizes the micro- and macrocomponents isolated from
coconut sugar, sap, and syrup, the chemical components of these natural sugars, and their
physico-chemical, microbiological, and antioxidant characteristics. A better
understanding of these components reveals the health-giving properties of coconut as a
plant-based sugar, despite the associated costs of taking coconut-based foods to
consumers. Hence, it is important that food industries respond to the demand of health-
conscious consumers by incorporating coconut sugar, sap, and syrup into food products.
Some shortcomings in this review, which can be addressed in the future, are the need to
consider personal dietary preference of coconut sugar in food products, sustainability
issues by more rigorous studies, and to study the role of coconut trees and carbon sinks,
including life cycle assessments (LCAs).
Author Contributions: Conceptualization, A.S., C.C., D.R., F.R., M.L. and A.R.; methodology, A.S.,
C.C., D.R., F.R., M.L. and A.R.; software, A.S., C.C., D.R., F.R., M.L. and A.R.; validation, A.S., C.C.,
D.R., F.R., M.L. and A.R.; formal analysis, A.S., C.C., D.R., F.R., M.L. and A.R.; investigation, A.S.,
Int. J. Environ. Res. Public Health 2023, 20, 3671 22 of 25
C.C., D.R., F.R., M.L. and A.R.; resources, A.S., C.C., D.R., F.R., M.L. and A.R.; data curation, A.S.,
C.C., D.R., F.R., M.L. and A.R.; writing—original draft preparation, A.S., C.C., D.R., F.R., M.L. and
A.R.; writing—review and editing, A.S., C.C., D.R., F.R., M.L. and A.R.; visualization, A.S., C.C.,
D.R., F.R., M.L. and A.R.; supervision, A.S., C.C., D.R., F.R., M.L. and A.R.; project administration,
A.S., C.C., D.R., F.R., M.L. and A.R. All authors have read and agreed to the published version of
the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.
Data Availability Statement: Not applicable.
Acknowledgments: The authors are very grateful to their families and friends for all the support
they provided.
Conflicts of Interest: The authors declare no conflict of interest.
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