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]
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]
Microbiological 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 methods) and coconut sugar	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 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)	[21]
	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.